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Carbon Dioxide Compensation Points of Flowering Plants
Abstract
Carbon dioxide compensation points of several hundred species of monocotyledons and dicotyledons have been measured during the course of various experiments in our laboratory over a period of several years. These have been classified into two groups: high, compensation points of 40 mul/l or greater; and low, compensation points of 10 mul/l or less. They are listed alphabetically both by families and species for monocotyledons and dicotyledons. Only two species did not unequivocally fit into the above established groups. These were Moricandia arvensis (L.) DC., which had an average compensation point of 26 mul/l and Panicum milioides Nees ex Trin., which was variable, but most often equilibrated between 12 to 20 mul/l CO(2).
... En estas plantas el CO2 se mueve en forma gaseosa por difusión a través de un gradiente de concentración, desde la atmósfera hasta el estroma del cloroplasto, donde también hay O2 procedente tanto del aire como del desprendido por la Fotosíntesis. Por ello, las plantas C3 presentan fotorrespiración aparente y su punto de compensación se encuentra entre 40 y 100 μmol mol -1 (Goldsworthy y Day, 1970;Krenzer et al., 1975;Taiz et al., 2015). Las plantas con metabolismo C4 realizan dos carboxilaciones separadas en el espacio, una en las células más externas del mesofilo a través del enzima fosfoenolpiruvato carboxilasa (PEP) que produce ácidos orgánicos de cuatro átomos de carbono (malato y aspartato, principalmente). ...
... A estas células, además, no llega prácticamente O2 atmosférico al estar más hundidas en la epidermis y porque las paredes de las células de la vaina son impermeables al O2. Por esta razón las plantas C4 no tienen fotorrespiración aparente y, su punto de compensación se sitúa entre 0-10 μmol mol -1 (Goldsworthy y Day, 1970;Krenzer et al., 1975;Taiz et al., 2015). ...
... Por debajo de este límite los procesos respiratorios predominan sobre los fotosintéticos, la fotosíntesis neta tiene valores negativos y el crecimiento se detiene, con consecuencias negativas sobre el rendimiento y la productividad (Dippery et al., 1995;Tissue et al., 1995). Existen variaciones inter-e intraespecíficas para el ΓCO2, especialmente entre plantas C3 y C4 (Goldsworthy y Day, 1970;Krenzer et al., 1975), pero también entre las especies C3 (Bauer y Martha, 1981;Bauer et al., 1983), principalmente causadas por diferencias en la conductividad estomática, en la estructura y permeabilidad al CO2 de las células del mesofilo, en la actividad de los enzimas del Ciclo de Calvin, y especialmente en la intensidad de la fotorrespiración, determinada por la proporción entre la actividad carboxilasa y oxigenasa de la RuBisCO Lambers et al., 2008;Taiz et al., 2015). Actualmente se está investigando sobre la posibilidad de reducir la fotorrespiración en plantas C3 introduciendo de manera estable múltiples copias de los genes para RuBisCO o induciendo cambios conformacionales en el centro catalítico del enzima para disminuir su actividad oxigenasa (Garcia del Moral y Boujenna, 2020). ...
Resumen: El punto de compensación para el CO2 (ΓCO2) es el límite mínimo de CO2 atmosférico necesario para una asimilación fotosintética positiva. Por debajo de este límite los procesos respiratorios predominan sobre los fotosintéticos, la fotosíntesis neta tiene valores negativos y el crecimiento se detiene, con consecuencias negativas sobre el rendimiento y la productividad. Las diferencias en ΓCO2, se han utilizado para seleccionar genotipos con una mayor capacidad de captación de CO2 y con mejor productividad. El objetivo de este trabajo es contribuir al conocimiento práctico, por parte del alumnado de una asignatura de Ecofisiología Vegetal, de cómo se puede calcular el valor del ΓCO2 y su interés para evaluar la eficiencia en la captación de CO2 por plantas con metabolismo fotosintético C3 o C4.
Abstract: The compensation point for CO2 (ΓCO2) is the minimum limit of atmospheric CO2 necessary for positive photosynthetic assimilation. Below this limit, respiratory processes predominate over photosynthetic ones, net photosynthesis has negative values and growth stops, with negative consequences on yield and productivity. Differences in ΓCO2 have been used to select genotypes with a higher CO2 uptake capacity and better productivity. The objective of this work is to contribute to the practical knowledge, by students of a Plant Ecophysiology course, of how the value of ΓCO2 can be calculated and its interest in evaluating the efficiency of CO2 uptake by plants with C3 or C4 photosynthetic metabolism.
... Soon after the discovery of C 4 photosynthesis, it became apparent that transition from C 3 to C 4 photosynthesis could not have been realised in one giant step, but more likely evolved via a series of transitory states (Kennedy and Laetsch, 1974). Potential C 3 -C 4 intermediates were identified by their CO 2 compensation point, which lay between the values of C 3 and C 4 species, as well as some C 4 -like anatomical features in the BS cells (Kennedy and Laetsch, 1974;Krenzer et al., 1975). The Brassicaceae species Moricandia arvensis was among the first species classified as a potential C 3 -C 4 intermediate (Krenzer et al., 1975). ...
... Potential C 3 -C 4 intermediates were identified by their CO 2 compensation point, which lay between the values of C 3 and C 4 species, as well as some C 4 -like anatomical features in the BS cells (Kennedy and Laetsch, 1974;Krenzer et al., 1975). The Brassicaceae species Moricandia arvensis was among the first species classified as a potential C 3 -C 4 intermediate (Krenzer et al., 1975). ...
... This process is also named the glycine shuttle, photorespiratory CO 2 pump, or C 2 photosynthesis (Sage et al., 2014). Species with C 3 -C 4 intermediate characteristics have been identified in diverse groups of plants (Krenzer et al., 1975;Rajendrudu et al., 1986;Moore et al., 1987;Hylton et al., 1988;Apel et al., 1997;Muhaidat et al., 2011;Sage et al., 2011b;Wen and Zhang, 2015;Khoshravesh et al., 2016). Phylogenetic studies have shown that many of these C 3 -C 4 plants are closely related to C 4 siblings, and it is therefore likely that intermediates served as transitory states on the evolutionary path from C 3 to C 4 (McKown et al., 2005;Christin et al., 2011a;Fisher et al., 2015;Lyu et al., 2015). ...
Evolution of C4 photosynthesis is not distributed evenly in the plant kingdom. Particularly interesting is the situation in the Brassicaceae, because the family contains no C4 species, but several C3-C4 intermediates, mainly in the genus Moricandia Investigation of leaf anatomy, gas exchange parameters, the metabolome, and the transcriptome of two C3-C4 intermediate Moricandia species, M. arvensis and M. suffruticosa, and their close C3 relative M. moricandioides enabled us to unravel the specific C3-C4 characteristics in these Moricandia lines. Reduced CO2 compensation points in these lines were accompanied by anatomical adjustments, such as centripetal concentration of organelles in the bundle sheath, and metabolic adjustments, such as the balancing of C and N metabolism between mesophyll and bundle sheath cells by multiple pathways. Evolution from C3 to C3-C4 intermediacy was probably facilitated first by loss of one copy of the glycine decarboxylase P-protein, followed by dominant activity of a bundle sheath-specific element in its promoter. In contrast to recent models, installation of the C3-C4 pathway was not accompanied by enhanced activity of the C4 cycle. Our results indicate that metabolic limitations connected to N metabolism or anatomical limitations connected to vein density could have constrained evolution of C4 in Moricandia.
... Subsequently, this discovery was followed by an extensive screening experiment which 636 measured the CCP of 439 monocot and 335 dicot species (Krenzer et al., 1975). In this 637 experiment, it was found that most species fell within two main groups, of CCPs above 40 ...
... Knowledge about the distribution of species with glycine shuttle metabolism is generally still 777 limited to studies among relatives of C4 species. As such, very few larger surveys have been 778 performed which assess CCP across a broad range of plant species (Krenzer et al., 1975; 779 Apel et al., 1997). This is mainly due to the dependence on gas exchange equipment and 780 time-consuming measurements. ...
Carbon concentrating mechanisms enhance the carboxylase efficiency of the central photosynthetic enzyme rubisco by providing supra-atmospheric concentrations of CO 2 in its surrounding. In the C 4 photosynthesis pathway, this is achieved by combinatory changes to leaf biochemistry and anatomy. Carbon concentration by the photorespiratory glycine shuttle requires fewer and less complex modifications. It could represent an early step during evolution from C 3 to C 4 photosynthesis and an inspiration for engineering approaches. Plants displaying CO 2 compensation points between 10 to 40 ppm are therefore often termed ‘C 3 –C 4 intermediates’. In the present study, we perform a physiological, biochemical and anatomical survey of a large number of Brassicaceae species to better understand the C 3 -C 4 intermediate phenotype. Our phylogenetic analysis suggested that C 3 -C 4 metabolism evolved up to five times independently in the Brassicaceae. The efficiency of the pathways showed considerable variation between the species but also within species. Centripetal accumulation of organelles in the bundle sheath was consistently observed in all C 3 -C 4 classified accessions indicating a crucial role of anatomical features for CO 2 concentrating pathways. Leaf metabolite patterns were strongly influenced by the individual plant accessions, but accumulation of photorespiratory shuttle metabolites glycine and serine was generally observed. Analysis of PEPC activities suggests that C 4 -like shuttles have not evolve in the investigated Brassicaceae.
Highlight
Our physiological, biochemical and anatomical survey of Brassicaceae revels multiple evolution of C 3 -C 4 intermediacy connected to variation in photorespiratory carbon recapturing efficiency and a distinct C 3 -C 4 bundle sheath anatomy.
... In den letzten Jahren sind jedoch bei 21% 02 auch Werte yon/' zwischen 10 und 40 vpm C02 beobachtet worden. Derartige ]ntermedilire Werte yon F konnten bisher bei mindestens 5 verschiedenen Arten nachgewiesen werden: Panicum milioides (BRowN und BROWN 1975, KRENZER et al. 1975, Moricandia arvensis (KRENZER et al. 1975), Panicum hians (GoLDSTEIN et al. 1976), Panicum laxum (GOLDSTEIN et al. 1976) und 3r verticillata (SAYRE und KENNEDY 1977). Bei Panicum milioides (KEcK und OGI~EN 1976, QUEBEDEAUX und CHOLLET 1977 und bei Moricandia arvensis (APEL et al. 1978) wurde auBerdem bei niedrigen 02-Gehalten eine Abweichung yon der flit Ca-Pflanzen bekannten Linearit~t der Beziehung zwischen/" und der O~-Konzentration gefunden. ...
... In den letzten Jahren sind jedoch bei 21% 02 auch Werte yon/' zwischen 10 und 40 vpm C02 beobachtet worden. Derartige ]ntermedilire Werte yon F konnten bisher bei mindestens 5 verschiedenen Arten nachgewiesen werden: Panicum milioides (BRowN und BROWN 1975, KRENZER et al. 1975, Moricandia arvensis (KRENZER et al. 1975), Panicum hians (GoLDSTEIN et al. 1976), Panicum laxum (GOLDSTEIN et al. 1976) und 3r verticillata (SAYRE und KENNEDY 1977). Bei Panicum milioides (KEcK und OGI~EN 1976, QUEBEDEAUX und CHOLLET 1977 und bei Moricandia arvensis (APEL et al. 1978) wurde auBerdem bei niedrigen 02-Gehalten eine Abweichung yon der flit Ca-Pflanzen bekannten Linearit~t der Beziehung zwischen/" und der O~-Konzentration gefunden. ...
Zusammenfassung C3- und C4-Pflanzen unterscheiden sich in der O2-Abhängigkeit ihrer CO2-Kompensationskonzentrationen (Γ) beträchtlich voneinander. Die lineare Zunahme vonΓ mit steigender O2-Konzentration bei den C3-Pflanzen kann auf die Oxygenase-Aktivität der Ribulose-1,5-bisphosphat-Karboxylase zurückgeführt werden, wird aber auch durch die Dunkelatmung beeinflußt. Das nahezu vollständige Fehlen einer O2-Abhängigkeit vonΓ bei den C4-Pflanzen wird mit Hilfe eines einfachen Modells erklärt. Das Modell berücksichtigt die Kompartimentierung der primären Karboxylierung des Phosphoenolpyruvats und der sekundären Karboxylierung des Ribulosebisphosphats sowie die Diffusion von CO2 zwischen den beiden Kompartimenten und der äußeren Atmosphäre. Pflanzen mit intermediärem Metabolismus der CO2-Fixierung zeigen eine geringere O2-Abhängigkeit vonΓ als C3-Pflanzen und Abweichungen von der Linearität bei niedrigen O2-Konzentrationen. Zur Erklärung dieser Erscheinungen müssen eine ähnliche Kompartimentierung der beiden Karboxylierungsreaktionen wie bei den C4-Pflanzen und veränderte Eigenschaften der Ribulosebisphosphat-Karboxylase-Oxygenase angenommen werden.
... The CO2 compensation point (r)3 represents the CO2 concentration at which the rate of photosynthetic CO2 uptake is equal to the rate of CO2 release from photorespiration and dark respiration. Under ambient atmospheric conditions and at 25°C, the r of leaves of terrestrial plants which fix C directly via the Calvin (C3) cycle is typically 40 to 50 MI *L' (8,22). The value of r is, however, strongly dependent on temperature and 02 concentration (16,20,23). ...
... The value of r is, however, strongly dependent on temperature and 02 concentration (16,20,23). In contrast, species which have the C4 pathway of C fixation have a temperature-and 02-insensitive r which is near zero (5,22). Consequently, the magnitude of r, at 21% (v/ ' Supported by grants from the Natural Sciences and Engineering Research Council of Canada (NSERC). ...
The effect of pH, O2 concentration, and temperature on the CO2 compensation point (Г[CO2]) of isolated Asparagus sprengeri Regel mesophyll cells has been determined in a closed, aqueous environment by a sensitive gas-chromatographic technique. Measured values range between 10 and 100 microliters per liter CO2 depending upon experimental conditions. The Г(CO2) increases with increasing temperature. The rate of increase is dependent upon the O2 concentration and is more rapid at high (250-300 micromolar), than at low (30-60 micromolar), O2 concentrations. The differential effect of temperature on Г(CO2) is more pronounced at pH 6.2 than at pH 8.0, but this pH-dependence is not attributable to a direct, differential effect of pH on the relative rates of photosynthesis and photorespiration, as the O2-sensitive component of Г(CO2) remains constant over this range. The Г(CO2) of Asparagus cells at 25°C decreases by 50 microliters per liter when the pH is raised from 6.2 to 8.0, regardless of the prevailing O2 concentration. It is suggested that the pH-dependence of Г(CO2) is related to the ability of the cell to take up CO2 from the aqueous environment. The correlation between high HCO3⁻ concentrations and low Г(CO2) at alkaline pH indicates that extracellular HCO3⁻ facilitates the uptake of CO2, possibly by increasing the flux of inorganic carbon from the bulk medium to the cell surface. The strong O2− and temperature-dependence of Г(CO2) indicates that isolated Asparagus mesophyll cells lack an efficient means for concentrating intracellular CO2 to a level sufficient to reduce or suppress photorespiration.
... Our results indicated that there was no obvious photosynthetic 'lunch break' phenomenon in either male or female H. rhamnoides, and the trend in Ls was the same as Pn, for both males and females, indicating that changes in photosynthetic rate were mainly limited by non-stomatal factors (Farquhar and Sharkey 1982). In addition, LSP, LCP and AQE all reflect the acquisition and utilization strategies of light by plants (Chen et al. 2011;Krenzer et al. 1975;Zhang et al. 2021). Males had higher LSP, AQE, Rd and A max , which meant they had higher utilization efficiency or tolerance to strong light. ...
The dioecious plant, Hippophae rhamnoides, is a pioneer species in community succession on the Qinghai-Tibet Plateau (QTP), plays great roles in various ecosystem services. However, the males and females of the species differ both in their morphology and physiology, resulting in a change in the ratio of male to female plants depending on the environment. To further explore the functional traits critical to this sex-based distinctive response in the alpine grassland, we have surveyed the sex ratios, measured their photosynthetic parameters, height, leaf area and biomass allocation. The results showed that (i) The males had higher Pn, light saturation point, apparent quantum efficiency, Amax and lower water-use efficiency (WUE), which exhibited higher utilization efficiency or tolerance to strong light, while the females indicated higher utilization efficiency for low light and water. And it showed sex-specific biomass allocation patterns. (ii) H. rhamnoides populations across the successional stages all showed a male-biased sexual allocation, which was closely related to sex-specific WUE, Pn, root biomass/total biomass and root–crown ratio. (iii) The leaf traits of H. rhamnoides changed from higher Narea, Parea and leaf mass per area in the early and late to lower in the middle, which meant they moved their growth strategy from resource rapid acquisition to conservation as the succession progressed. (iv) The increasing soil total phosphorus mostly contributed to regulating the sex bias of populations and variations of traits during the succession. The results are vital for the management of grassland degradation and restoration due to shrub encroachment on the QTP.
... In fact, elevated CO 2 did not modify the aboveground biomass of M. jalapa, whereas it favoured the growth of N. glauca. Both species have the C3 pathway of CO 2 fixation (Krenzer Jr. et al., 1975) but they show differences in their invasive character: ...
The rise in atmospheric CO2 levels is foreseen to enhance the growth of exotic invasive plants and potentially alter the rhizosphere microbial community, which in turn could enhance the risk of invasion by such invaders. This response could be determined by the plant type and the features of invaded soil. The goal of this investigation was to compare the effects of elevated CO2 on the rhizosphere bacterial and fungal communities of two invaders with distinct degrees of invasiveness, Nicotiana glauca and Mirabilis jalapa, by growing the plants in five different semiarid soils at ambient (410 ppm) or elevated (760 ppm) CO2. The changes in soil physicochemical, biochemical and biological features mediated by the invaders were also evaluated. The effect of CO2 supply on shoot dry biomass was only significant for N. glauca, the shoot and root biomass of plants grown under elevated CO2 being about 53 and 14 % greater, respectively, than those of the plants grown under ambient CO2. Elevated CO2 only promoted shifts in the rhizosphere bacterial community composition and enhanced the bacterial functional potential related to nucleoside and nucleotide biosynthesis and N‐cycling, in N. glauca. Among the bacterial indicator species, the genera Sphingomonas, Stenotrophobacter and Gaiella were more abundant in the rhizosphere of N. glauca plants grown under elevated CO2. This study demonstrates that the responses of aboveground and belowground biomass of invasive plants to CO2 enrichment, as well as those of the composition and functioning of soil microbial communities, are dependent on their degree of invasiveness. This article is protected by copyright. All rights reserved.
... Grouping of species according to their photosynthesis pathway was done following information published by Tieszen et al. (1979) and Hesla et al. (1982), for grasses and sedges families of East Africa, and additional sources for weed species of other families (i.e. (Barnes et al., 1983;Bruhl and Wilson, 2007;Cabido et al., 1997;Cavagnaro, 1988;Ehleringer et al., 1987;Ellery et al., 1992;Elmore and Paul, 1983;Hnatiuk, 1980;Kalapos, 1991;Kalapos et al., 1997;Keeley and Rundel, 2003;Krenzer et al., 1975;Kuoh and Chiang, 1991;Li et al., 2009;Prendergast and Hattersley, 1987; Sage et al., 2007;Sikolia et al., 2009;Stowe and Teeri, 1978;Vogel et al., 1986;Wang, 2003;Wentworth, 1985). ...
Weeds are major biotic constraints to rice production worldwide. Compared to other sub-regions, weed communities of rice are not well described for East Africa and there is limited information on environmental factors affecting the distribution of species. This study aimed to address these knowledge gaps. Seasonally flooded rice production fields of 31 sites in Rwanda, Tanzania, Kenya and Uganda, across three altitude classes (Low: <200 m; Medium 200-1,000 m; High: >1,000 m), were surveyed for weed species using quadrats. Data analyses involved multivariate approaches, non-parametric Kruskal–Wallis tests and logistic regressions, followed by calculation of ranked species abundance and Shannon Weiner Index diversity analyses. A total of 286 weed species, belonging to 59 families, were recorded with 42 species not previously reported as lowland rice weed in the sub-region. Twenty-four species were identified as abundant across altitudes. Weed species diversity was higher at medium altitudes compared to high and low altitudes. Significant patterns of floristic distinction between altitudinal classes were observed, with 80% of dissimilarity. The high altitude was dominated by Echinochloa colona, Leptochloa squarrosa and Sphaeranthus suaveolens, the medium altitude was dominated by Crassula granvikii, Pycreus lanceolatus and Ageratum conyzoides while the low altitude was dominated by E. colona, Cyperus difformis and Cyperus esculentus. The weed species composition of seasonally flooded rice fields in East Africa is diverse. Identification of a limited group of (24) commonly abundant weed species as well as the articulation of altitude-specific weed species groups will facilitate the development of better tailored weed control programmes.
... In order to obtain sufficient quality for indoor use, plants require not only light intensity at the light compensation point (Eugene et al. 1975) but also extra light to produce photosynthates to maintain continuous flowering. The plants classified in group 3 described above grew and flowered well under the low light intensity, whereas those in group 2 grew very slowly with poor flowering (Fig. 1, data not shown for vegetative growth). ...
The adaptability of nine bedding plants to low light intensity was evaluated for their indoor use. Based on the duration of flowering under indoor low light intensity [1,000 lx, 16.8 µmol·m⁻²·s⁻¹ photosynthetic photon flux density (PPFD)], the plants’ adaptability was classified into three groups. In group 1, the effect of low light intensity was unclear due to short flowering longevity irrespective of light intensity; this group included Helianthus. Group 2 included species not adaptable to indoor low light intensity, under which the duration of flowering indoors was less than three weeks; this group included Petunia Salvia, and Verbena. Group 3 included species adaptable to indoor conditions, under which the duration of flowering was longer than three weeks; this group included Catharanthus, Impatiens, Tagetes, Torenia and Zinnia. The effect of low light intensity on shoot growth did not appear as a reduction in plant width, but did appear in plant height and length of the longest lateral stem. The leaf color of most species was darkened by low light intensity. Even Catharanthus, Torenia and Zinnia, which showed the highest adaptability to low light intensity, could not maintain sufficient ornamental quality under 8.4 µmol·m⁻²·s⁻¹ PPFD. The duration of flowering became longer as light intensity increased, although the response differed among species. In Torenia and Zinnia, the duration of flowering was extended under 2,500 lx (42.0 µmol·m⁻²·s⁻¹ PPFD), indicating that longterm use was possible under bright indoor conditions, including at such locations as windowsills and showcases.
... Downloaded from the CO 2 compensation point (Г) to varying O 2 concentrations using an inlet mass spectrometer. Typically at ~25°C, C 4 species have a low Г between 1-5 µbar CO 2 , while in C 3 plants the Г is 45-50 µbar CO 2 , and C 3 -C 4 species have intermediate values in the range of 9-30 µbar CO 2 (Krenzer et al., 1975;Ku et al., 1991;Vogan et al., 2007;Voznesenskaya et al., 2013). Increasing levels of O 2 causes a linear increase in Γ in C 3 plants (reflecting an increase in photorespiration), has little or no effect on Γ in C 4 plants, but causes an intermediate, biphasic, response of Г in C 3 -C 4 species (Ku et al., 1991). ...
Portulacaceae is a family that has considerable diversity in photosynthetic phenotypes. It is one of 19 families of terrestrial plants where species having C4 photosynthesis have been found. Most species in Portulaca are in the alternate-leaved (AL) lineage, which includes one clade (Cryptopetala) with taxa lacking C4 photosynthesis and three clades having C4 species (Oleracea, Umbraticola and Pilosa). All three species in the Cryptopetala clade lack Kranz anatomy, the leaves have C3-like carbon isotope composition and they have low levels of C4 cycle enzymes. Anatomical, biochemical and physiological analyses show they are all C3-C4 intermediates. They have intermediate CO2 compensation points, enrichment of organelles in the centripetal position in bundle sheath (BS) cells, with selective localization of glycine decarboxylase in BS mitochondria. In the three C4 clades there are differences in Kranz anatomy types and form of malic enzyme (ME) reported to function in C4 (NAD-ME versus NADP-ME): Oleracea (Atriplicoid, NAD-ME), Umbraticola (Atriplicoid, NADP-ME) and Pilosa (Pilosoid, NADP-ME). Structural and biochemical analyses were performed on Pilosa clade representatives having Pilosoid-type leaf anatomy with Kranz tissue enclosing individual peripheral vascular bundles and water storage in the center of the leaf. In this clade, all species except P. elatior are NADP-ME-type C4 species with grana-deficient BS chloroplasts and grana-enriched M chloroplasts. Surprisingly, P. elatior has BS chloroplasts enriched in grana and NAD-ME-type photosynthesis. The results suggest photosynthetic phenotypes were probably derived from an ancestor with NADP-ME-type C4, with two independent switches to NAD-ME type.
... (This figure is available in color at JXB online.) the CO 2 compensation point (Г) to varying O 2 concentrations using an inlet mass spectrometer. Typically at ~25°C, C 4 species have a low Г between 1-5 µbar CO 2 , while in C 3 plants the Г is 45-50 µbar CO 2 , and C 3 -C 4 species have intermediate values in the range of 9-30 µbar CO 2 (Krenzer et al., 1975;Ku et al., 1991;Vogan et al., 2007;Voznesenskaya et al., 2013). Increasing levels of O 2 causes a linear increase in Γ in C 3 plants (reflecting an increase in photorespiration), has little or no effect on Γ in C 4 plants, but causes an intermediate, biphasic, response of Г in C 3 -C 4 species (Ku et al., 1991). ...
Temporal and spatial patterns of photosynthetic enzyme expression and structural maturation of chlorenchyma cells along longitudinal
developmental gradients were characterized in young leaves of two single cell C4 species, Bienertia sinuspersici and Suaeda aralocaspica. Both species partition photosynthetic functions between distinct intracellular domains. In the C4-C domain, C4 acids are formed in the C4 cycle during capture of atmospheric CO2 by phosphoenolpyruvate carboxylase. In the C4-D domain, CO2 released in the C4 cycle via mitochondrial NAD-malic enzyme is refixed by Rubisco. Despite striking differences in origin and intracellular
positioning of domains, these species show strong convergence in C4 developmental patterns. Both progress through a gradual developmental transition towards full C4 photosynthesis, with an associated increase in levels of photosynthetic enzymes. Analysis of longitudinal sections showed
undeveloped domains at the leaf base, with Rubisco rbcL mRNA and protein contained within all chloroplasts. The two domains were first distinguishable in chlorenchyma cells at
the leaf mid-regions, but still contained structurally similar chloroplasts with equivalent amounts of rbcL mRNA and protein; while mitochondria had become confined to just one domain (proto-C4-D). The C4 state was fully formed towards the leaf tips, Rubisco transcripts and protein were compartmentalized specifically to structurally
distinct chloroplasts in the C4-D domains indicating selective regulation of Rubisco expression may occur by control of transcription or stability of rbcL mRNA. Determination of CO2 compensation points showed young leaves were not functionally C4, consistent with cytological observations of the developmental progression from C3 default to intermediate to C4 photosynthesis.
... In the years following the description of M. verticillata, many more potential C 3 -C 4 intermediates have been identified and studied. A survey of CO 2 compensation points in several hundred eudicot and monocot species identified the Brassicaceae Moricandia arvensis and the grass specie Panicum milioides (= Steinchisma hians) as further C 3 -C 4 intermediates (Krenzer et al. 1975). A comprehensive review of C 3 -C 4 intermediates published in 1987 (Edwards and Ku 1987) already listed 22 potential C 3 -C 4 species, most of them belonging to orders which also included C 4 species. ...
C4 photosynthesis enables high photosynthetic energy conversion efficiency as well as high nitrogen and water use efficiencies.
Given the multitude of biochemical, structural and molecular changes in comparison with C3 photosynthesis, it appears unlikely that such a complex trait would evolve in a single step. C4 photosynthesis is therefore believed to have evolved from the ancestral C3 state via intermediary stages. Consequently, the identification and detailed characterization of plant species representing
transitory states between C3 and C4 is important for the reconstruction of the sequence of evolutionary events, especially since C4 evolution occurred in very different phylogenetic backgrounds. There is also significant interest in engineering of C4 or at least C4-like elements into C3 crop plants. A detailed and mechanistic understanding of C3–C4 intermediates is likely to provide guidance for the experimental design of such approaches. Here we provide an overview on
the most relevant results obtained on C3–C4 intermediates to date. Recent knowledge gains in this field will be described in more detail. We thereby concentrate especially
on biochemical and physiological work. Finally, we will provide a perspective and outlook on the continued importance of research
on C3–C4 intermediates.
... The in situ ARA values indicated high N, fixation on some sites and the higher values are of a magnitude similar to the highel-values I-epol-ted for tropical grasses (Balandreau et al. 1976;Schank et al. 1977). With the exception of Sprrrtinn pectitzrrtn, none of the species we examined is reported to be a C,-type plant (Krezner et al. 1975;Downton 1975). Thus if there are differences in the general levels of nitrogenase activity between tempel-ate-and tropical-zone plants, these differences are probably due to general differences in edaphic factors, such as rainfall and soil N, rather than to differences in plant metabolism or in the specific types of N,-fixing bacteria present (Dobereiner 1975(Dobereiner . ...
... A functional analysis of young versus mature leaves of C. gynandra was made by analysing the effect of O 2 on Г to determine if the response is indicative of C 4 , intermediate, or (Krenzer et al., 1975;Brooks and Farquhar, 1985;von Caemmerer, 1989von Caemmerer, , 2000Ku et al., 1991;Vogan et al., 2007;Voznesenskaya et al., 2007). Mature leaves of C. gynandra show a clear C 4 -type response, with values of Г of ~2.5 μbar with insensitivity to O 2 . ...
In family Cleomaceae there are NAD-malic enzyme-type C4 species having different forms of leaf anatomy. Leaves of Cleome angustifolia have Glossocardioid-type anatomy with a single complex Kranz unit which surrounds all the veins, while C. gynandra has Atriplicoid anatomy with multiple Kranz units, each surrounding an individual vein. Biochemical and ultrastructural differentiation
of mesophyll (M) and bundle sheath (BS) cells were studied along a developmental gradient, from the leaf base (youngest) to
the tip (mature). Initially, there is cell-specific expression of certain photosynthetic enzymes, which subsequently increase
along with structural differentiation. At the base of the leaf, following division of ground tissue to form M and BS cells
which are structurally similar, there is selective localization of Rubisco and glycine decarboxylase to BS cells. Thus, a
biochemical C3 default stage, with Rubisco expression in both cell types, does not occur. Additionally, phosphoenolpyruvate carboxylase
(PEPC) is selectively expressed in M cells near the base. Surprisingly, in both species, an additional layer of spongy M cells
on the abaxial side of the leaf has the same differentiation with PEPC, even though it is not in contact with BS cells. During
development along the longitudinal gradient there is structural differentiation of the cells, chloroplasts, and mitochondria,
resulting in complete formation of Kranz anatomy. In both species, development of the C4 system occurs similarly, irrespective of having very different types of Kranz anatomy, different ontogenetic origins of BS
and M, and independent evolutionary origins of C4 photosynthesis.
... In addition, research with various species of C 4 Amaranthus, as discussed above, clearly illustrated the existence of photorespiration. Thus, it can be concluded that the apparent lack of CO 2 release into a rapid stream of CO 2free air and the very low CO 2 compensation point often observed in C 4 species, as compared to the much higher values in C 3 species (Meidner 1962, Moss 1962, Tregunna and Downton 1967, Krenzer et al. 1975) are manifestations of the ability of these plants to refix/recycle their photorespiratory CO 2 before it can leak out of their leaves, as suggested in earlier investigations , El-Sharkawy et al. 1964, Mansfield 1968, Stoy 1969, Ogren 1984. Furthermore, earlier estimation by modeling of the extent of the CO 2 concentration around Rubisco in bundle sheath cells of C 4 plants, via the so-called 'CO 2concentrating mechanism,' ranged from about 2000 to more than 18 000 µmole mol -1 Hatch 1987, Jenkins et al. 1989). ...
Carbon concentrating mechanisms enhance the carboxylase efficiency of the central photosynthetic enzyme rubisco by providing supra-atmospheric concentrations of CO2 in its surrounding. In the C4 photosynthesis pathway, this feat is realised by combinatory changes to leaf biochemistry and anatomy. In contrast to the C4 pathway, carbon concentration can also be achieved by the photorespiratory glycine shuttle which requires fewer and less complex modifications. Plants displaying CO2 compensation points between 10 to 40 ppm are often considered to utilize such a photorespiratory shuttle and are termed 'C3-C4 intermediates'. In the present study, we perform a physiological, biochemical and anatomical survey of a large number of Brassicaceae species to better understand the C3-C4 intermediate phenotype, including its basic components and its plasticity. Our phylogenetic analysis suggested that C3-C4 metabolism evolved up to five times independently in the Brassicaceae. The efficiency of the pathway showed considerable variation between tested plant species. Centripetal accumulation of organelles in the bundle sheath was consistently observed in all C3-C4 classified taxa indicating a crucial role of anatomical features for CO2 concentrating pathways. Leaf metabolite patterns were strongly influenced by the individual species, but accumulation of photorespiratory shuttle metabolites glycine and serine was generally observed. Analysis of PEPC activities and metabolite composition suggests that C4-like shuttles have not evolved in the investigated Brassicaceae. Convergent evolution of the photorespiratory shuttle indicates that it represents a distinct and fit photosynthesis type.
Moricandia arvensis, a plant species originating from the Mediterranean, has been classified as a rare C3-C4 intermediate species, and it is a possible bridge during the evolutionary process from C3 to C4 plant photosynthesis in the family Brassicaceae. Understanding the genomic structure, gene order, and gene content of chloroplasts (cp) of such species can provide a glimpse into the evolution of photosynthesis. In the present study, we obtained a well-annotated cp genome of M. arvensis using long PacBio and short Illumina reads with a de novo assembly strategy. The M. arvensis cp genome was a quadripartite circular molecule with the length of 153,312 bp, including two inverted repeats (IR) regions of 26,196 bp, divided by a small single copy (SSC) region of 17,786 bp and a large single copy (LSC) region of 83,134 bp. We detected 112 unigenes in this genome, comprising 79 protein-coding genes, 29 tRNAs, and four rRNAs. Forty-nine long repeat sequences and 51 simple sequence repeat (SSR) loci of 15 repeat types were identified. The analysis of Ks (synonymous) and Ka (non-synonymous) substitution rates indicated that the genes associated with “subunits of ATP synthase” (atpB), “subunits of NADH-dehydrogenase” (ndhG and ndhE), and “self-replication” (rps12 and rpl16) showed relatively higher Ka/Ks values than those of the other genes. The gene content, gene order, and LSC/IR/SSC boundaries and adjacent genes of the M. arvensis cp genome were highly conserved compared to those in related C3 species. Our phylogenetic analysis demonstrated that M. arvensis was clustered into a subclade with cultivated Brassica species and Raphanus sativus, indicating that M. arvensis was not involved in an independent evolutionary origin event. These results will open the way for further studies on the evolutionary process from C3 to C4 photosynthesis and hopefully provide guidance for utilizing M. arvensis as a resource for improvinng photosynthesis efficiency in cultivated Brassica species.
Application of in vitro enzymatic technique by using both pronase and cellulase was investigated to estimate the digestibility of the herbage of both the native pasture composed of Miscanthus sinensis, Pleioblastus chino var. viridis and Arundinella hirta and the improved pasture composed of temperate grasses. For the native grasses, the in vitro dry matter degradability (IVDMD) was lower (p<0.001) than the in vivo dry matter digestibility (in vivo DMD) measured by total fecal collection (TFC) method. There was a positive significant correlation between the IVDMD and the in vivo DMD. In similar, there was the same relationship as the above between the IVDMD and the in vivo energy digestibility. On the other hand for the temperate grasses, there was no significant difference between the IVDMD and the in vivo DMD measured by the TFC method. Moreover, the relationships between the IVDMD and the in vivo digestibilities measured by acid-insoluble ash (AIA) index methed were considered for the herbage grazed in the improved pasture, since the recovery of AIA was about 100% in the TFC trial. A positive significant correlation was detected betweem the IVDMD and the in vivo energy digestibility measured by the AIA method.
The bromegrasses belong to the genus Bromus of which there are some 100 species (Gould & Shaw, 1983). The genus includes both annual and perennial cool season species adapted to temperate climates. Hitchcock (1971) described 42 bromegrass species found in the USA and Canada of which 22 were native (Gould & Shaw, 1983). Bromus is the Greek word for oat and refers to the panicle inflorescence characteristic of the genus. The bromegrasses are C3 species (Krenzer et aI., 1975; Waller & Lewis, 1979).
The CO2 compensation concentration (Γ) in Moricandia arvensis (L.) DC. (Cruciferae) was determined from leaves at different insertion levels and at different O2 concentrations.
While discussing the breeding of drought-resistant cereals Robert Gauss (1910) concluded: “Let no one look with indifference upon the possibility here outlined of acclimatizing valuable crop species to arid regions, or underestimate the magnitude of the achievement suggested… So vast an achievement would rank with the discovery of a new continent in its enlargement of the sources of human subsistence…” Since then, little progress has been made toward the development of drought-resistant cultivars, and crop productivity in semi-Arid environments is substantially lower than yields obtained with adequate irrigation. Gauss (1910) suggested that identifying drought-resistant plants will require the trained eye of a botanist, and that descriptions of characteristics that confer drought resistance should be developed. An analysis of these characteristics will be attempted in this chapter. Physiological, morphological, anatomical, and phenological attributes that contribute to crop adaptation in semi-Arid environments will be discussed. Cultivar development by selection for yield and indices of adaptation will be analyzed. The reviews of Arnon (1972, 1975), Begg and Turner (1976), Fischer and Turner (1978), and Turner (1979) provide valuable analyses and data on these subjects.
Barleys, or other crop plants, are classified for two different purposes. Firstly by the plant taxonomists who wish to decide on the limits — and range(s) — of variability of species to give an indication of their evolutionary relationships. Secondly by ‘practical’ men (plant breeders, agronomists and technologists), who wish to know whether a particular plant or grain sample is of the desired variety. Thus two types of scheme exist: (a) ‘Botanical classifications’, hopefully revealing relationships between tribes, subtribes, genera and species, and (b) ‘Keys’ based on any characters available, designed to allow the identification of barley forms and varieties from the morphology of the plants, or their threshed grains. Unfortunately in the case of barley these objectives have become muddled.
Attempts to breed crop varieties with higher rates of photosynthesis have met with no success although considerable genetic variation in photosynthesis rates exist in several crop species and a positive correlation between leaf photosynthesis and prodpctivity is reponed in a number of experiments. An efficient partitioning of assimilated carbon seems to be more critical in detennining plant productivity. Selection for low darlt respiration or enhanced light interception have successfully increased net carbon gain by the plant Selection by survival under low CO2 atmosphere in tobacco haploids and on Lolium multiflorum L. Italian ryegrass cultivar RvP population showed a significant increase in plant productivity even when the leaf photosynthesis rate was not high. For Italian ryegrass RvP population, the surviving plants under low CO2 had bad significant increase in initial dry weight but the difference disappeared in the second regrowth. No single character of ryegrass or tabacco genotypes could account for their survival under low CO2, Even though photosynthesis and plant production are closely related, large environmental and ontogenic-induced variations in leaf photosynthesis rate make it difficult to achieve a good estimate of its contribution to the entire plant carbon economy.
The “nightmare” of “photorespiration” that Rabinowitch (1945) mentioned has now become reality, but it is now even more appropriate to say that “the relation between photosynthesis and respiration ... has become even less clear and the data even more controversial” (Rabinowitch, 1956).
This chapter focuses on the biochemistry of C3–C4 intermediates. The reductive pentose phosphate pathway, or PCR cycle, is the means through which higher plants assimilate CO2. There is currently no evidence that any terrestrial plants have undergone a change in the properties of D-ribulose 1,5-bisphosphate carboxylase-oxygenase (Rubisco) that would increase its capacity to react with CO2 over O2. In general, a C3–C4 intermediate species can be defined as a species in which: (1) one or more of the features of the Kranz syndrome is “intermediate,” that is, the character is at some stage or level between that of a C3 and a C4 species, or (2) there is a mixture of fully expressed features of the Kranz syndrome combined with those of species lacking this syndrome. If the biochemical and anatomical features of the Kranz syndrome are developed to varying degrees, then a variety of atypical physiological responses in photosynthesis and photorespiration may occur.
C 4 plants account for a small fraction of the total number of plant species (fewer than 1000 out of 250 000). A larger proportion of the world's weed species possess C 4 physiology. There are 2000 species in 500 genera and 125 families of flowering plants listed in the WSSA composite list of weeds. of that number, 146 species in 53 genera and 10 families exhibit the C 4 syndrome. This, as a percentage, is 17-fold greater than the percentage of C 4 plants in the total world plant population. In this report, we have listed the C 4 -weed species and provide specific information concerning various aspects of their Kranz anatomy and C 4 physiology.
The higher plants are classified into three types: C3, C4, and crassulacean acid metabolism (CAM). The classification is based on mechanism of photosynthetic carbon assimilation. In C4 plants, carbon is primarily fixed into C4 acids and subsequently metabolized through Calvin cycle. The two-step carboxylation in C4 plants is facilitated by the intercellular compartmentation of several key enzymes involved in carbon metabolism. The enzymes necessary for formation/carboxylation of phosphoenolpyruvate (PEP) are in mesophyU while those of C4 acid decarboxylation and CO2 refixation are in bundle sheath. Photosynthesis in C4 plants is optimal at high intensities of light and temperature. C4 plants require less water or nitrogen for every unit of carbon assimilated than the C3 species. Due to these features, C4 plants are well adapted to grow in arid or semiarid environments and are generally distributed in tropical and subtropical regions of the world. However, the productivity of C4 plants is quite poor in a temperate environment and may even fall below those of C3 species. Since the discovery of C4 photosynthesis more than 25 years ago, rapid progress has been made in our understanding of the physiology and biochemistry of C4 plants. More research is needed to elucidate the molecular biology of gene expression and regulation in mesophyll and bundle sheath cells of C4 plants.
This report deals with an exotic graminaceous plant, Vetiveria zizanioides (L.) Stapf., a species of great economical and ecological interest, owing to its root essential oil of value in perfume industry and for its potential as a tool against soil erosion. An in vitro procedure of cell culture and plant regeneration has been developed to produce selected plants with an high C4 photosynthetic efficiency. The experimental results and the phenologic characteristics of V. zizanioides strongly support plant spreading in temperate and Mediterranean countries, where vetiver grass could find several applications in environmental engineering and bioremediation.
Sustainable agriculture, which reduces environmental burden, has become increasingly important in recent years. C4 plants are considered to be useful plant resources as both food and energy crops, because they show high dry matter productivity with high water and nitrogen use efficiencies. However, the studies on the effective use of C4 plants is not sufficient. In fact, the basic knowledge is scarce on many C4 plants except for a few crops. The C4 plants occurring in Japan are listed in this study, as a first step to utilize C4 plants including weeds. There are 419 C4 plant species belonging to 91 genera in 11 families, identified in Japan. They are comprised of 62 eudicot species belonging to 19 genera in 8 families, and 357 monocot species belonging to 72 genera in 3 families. Compared to the checklist in 1990, 19 eudicot species and 157 monocot species have been added to the list. C4 eudicots belonging to Aizoaceae, Asteraceae and Cleomaceae have newly been identified. However, C4 eudicots belonging to Acanthaceae, Boraginaceae, Caryophyllaceae, Molluginaceae and Scrophulariaceae have not been found in Japan. Monocot submerged aquatic plant, Hydrilla verticillata in Hydrocharitaceae has been found to induce C4 photosynthetic metabolism under conditions of low CO2 concentration in water. This finding has increased the family number of C4 monocots to 3. The list has 6 C3-C4intermediate species, 5 of which have newly been identified as introduced plants. Lots of C4plants identified newly in Japan, more exactly, 84% of C4 eudicots and 46.8% of C4monocots are the introduced plants including cultivated species. This indicates that C4 plant seeds have contaminated imported raw materials, and invaded Japan in the same way as other introduced weed seeds.
It is expected that identification and lists of plants in specific regions are useful not only for the ecological researches that are related to vegetation phenology and succession but also as an index of climate change. In this review, plants growing in South Korea were listed and their life forms were investigated. In addition, we discussed the influences that climatic change and the plants exerted on plant ecosystem. Photosynthetic pathway types ( and ) for the plant species in South Korea were determined by reviewing the scientific literatures published between 1971 and 2010. Of the total 4476 species in 1123 genera and 197 families, 206 species (4.6%) in 84 genera (7.5%) and 21 families (10.7%) were identified as plants (including - intermediate plants). Among the identified species, 53 species (25.7%) in 26 genera and 15 families were classified as Dicotyledoneae, while 153 species (74.3%) in 58 genera and 6 families were classified as Monocotyledoneae. The majority of the species belong to four families: Chenopodiaceae (15 species), Amaranthaceae (13 species), Gramineae (102 speceis) and Cyperaceae (45 species). With respect to life form composition of 206 species, Th---t was most dominant: 95 species (46.1%) were included in Th, 123 species (59.7%) in , 179 species (86.9%) in , and 122 species (59.2%) in t. The projected increase in temperature due to climate change may provide better conditions for the growth of plants. Such a result will have considerable impacts on the interspecific competition between and plants, the distribution of plants, plant phenology, and plant diversity.
This research was carried out to investigate photosynthetic pathway of Scirpus planiculmis L., the genus Scirpus, the family Cyperaceae. The activity of phosphoenolpyruvate carboxylase (PEPCase) of rice (Oryza sativa L.), a plant, was only 1.9-3.8% of that observed in such plants as maize (Zea mays L.) and barnyardgrass (Echinochloa crusgalli P. Beauv. var. oryzicola Ohwi). The enzyme activity, Vmax, Km value, and Lineweaver-Burk plot of PEP in S. planiculmis were similar to those in the rice. While the PEPCase of plants activity was inhibited over 44 to 91% by 1.5 mM of malate and aspartate, the PEPCase of rice and S. planiculmis was not. In the species, the PEPCase activity was protected from thermal inactivation by 10 mM malate and aspartate. However, the PEPCase of S. planiculmis and rice was not protected from heat inactivation by any of the two acids. From these results, we report that S. planiculmis is a plant
Four populations of Mollugo verticillata L. were compared on the basis of their photosynthetic products, photosynthetic rates, enhancement under low oxygen concentration, and CO2 compensation points. In addition, pulse-chase labeling experiments were conducted using one of the four populations. Depending on the plant population, C4 acids ranged from 40% to 11% of the primary products under short-term exposure to (14)CO2. These compounds were also metabolized during pulse-chase experiments. All four populations had significantly different photosynthetic rates and those rates were correlated with the amounts of labelled C4 acids produced and C4-acid turnover. Three populations of M. verticillata had similar compensation points (40 μl/l) and degrees of photosynthetic enhancement under low [O2] (20%), the fourth population was much lower in both characteristics (CO2 compensation, 25 μl/l; low-O2 enhancement, 12%). The results verify the intermediate nature of photosynthesis in this species, and illustrate populational differences in its photosynthetic and photorespiratory carbon metabolism.
When provided a choice between grass species with C3 or C4 photosynthetic pathways, larvae of range caterpillar,Hemileuca oliviae Cockerell, selected C4 grasses. The basis for host selection was examined by conducting analyses of moisture, crude protein, total available carbohydrate, sucrose, glucose, astringency, condensed tannin, silica, and pubescence of 14 grass species, and correlating host plant chemical characteristics with host preference. Most of the variation in host preference was explained by tannin characteristics (astringency and condensed tannin); C3 grass species had significantly higher tannin levels than C4 species.
Leaf anatomical, ultrastructural, and CO2-exchange analyses of three closely related species of Flaveria indicate that they are C3-C4 intermediate plants. The leaf mesophyll of F. floridana J.R. Johnston, F. linearis Lag., and F. chloraefolia A. Gray is typical of that in dicotyledonous C3 plants, but the bundle sheath cells contain granal, starch-containing chloroplasts. In F. floridana and F. chloraefolia, the chloroplasts and numerous associated mitochondria are arranged largely centripetally, as in the closely related C4 species, F. brownii A.M. Powell. In F. linearis, fewer mitochondria are present and the chloroplasts are more evenly distributed throughout the bundle sheath cytosol. There is no correlation between the bundle sheath ultrastructure and CO2 compensation concentration. (Γ) values of these C3-C4 intermediate Flaveria species. At 21% O2 and 25°C, Γ for F. chloraefolia, F. linearis, and F. floridana is 23-26, 14-19, and 8-10 μl CO2 l(-1), respectively. The O2 dependence of Γ is the greatest for F. chloraefolia and F. linearis (similar to that for C3-C4 intermediate Panicum and Moricandia species) and the least for F. floridana, whose O2 response is identical to that for F. brownii from 1.5 to 21% O2, but greater at higher pO2. The variation in leaf anatomy, bundle sheath ultrastructure, and O2 dependence of Γ among these Flaveria species may indicate an active evolution in the pathway of photosynthetic carbon metabolism within this genus.
Three methods of estimating photorespiratory rate in leaves of the C3-C4 intermediate species Moricandia arvensis and the related C3 species Moricandia moricandioides were compared. The results indicated that the photorespiratory rate in M. arvensis is less than in M. moricandioides, and that this is caused partly by reduced carbon flux through the photorespiratory pathway, and partly by the presence of a mechanism for enhanced photorespiratory CO2 reassimilation in the intermediate species. Measurements of the CO2 compensation point (Γ) in the two species supported this conclusion. A functional C4 pathway is unlikely to be involved in the reduction of photorespiratory rate in M. arvensis since pulse-chase experiments showed that carbon did not move from C4 acids to the reductive pentose-phosphate pathway in attached leaves under steady-state conditions at Γ.
Immunogold labelling has been used to determine the cellular distribution of glycine decarboxylase in leaves of C3, C3-C4 intermediate and C4 species in the genera Moricandia, Panicum, Flaveria and Mollugo. In the C3 species Moricandia foleyi and Panicum laxum, glycine decarboxylase was present in the mitochondria of both mesophyll and bundle-sheath cells. However, in all the C3-C4 intermediate (M. arvensis var. garamatum, M. nitens, M. sinaica, M. spinosa, M. suffruticosa, P. milioides, Flaveria floridana, F. linearis, Mollugo verticillata) and C4 (P. prionitis, F. trinervia) species studied glycine decarboxylase was present in the mitochondria of only the bundle-sheath cells. The bundle-sheath cells of all the C3-C4 intermediate species have on their centripetal faces numerous mitochondria which are larger in profile area than those in mesophyll cells and are in close association with chloroplasts and peroxisomes. Confinement of glycine decarboxylase to the bundle-sheath cells is likely to improve the potential for recapture of photorespired CO2 via the Calvin cycle and could account for the low rate of photorespiration in all C3-C4 intermediate species.
This study investigated the effects of water stress on the photosynthetic products, photosynthetic rates and CO2 compensation points in two C4 plants, Zea mays and Portulaca oleracea. Three methods of experimentally inducing water stress were also compared to determine their relative effect on the photosynthetic characteristics listed. Thus, low leaf water potentials were obtained by growing the plants in solutions of NaCl or polyethyleneglycol, or by withholding water.
In most instances, four carbon acid percentages were the lowest in both plants with increased levels of water deficit. Radioactivity located in C3 cycle products, phosphoglyceric acid, sugar phosphates, and several miscellaneous compounds, increased under these conditions. The only exception to this was when Portulaca was grown in the presence of NaCl. Sodium chloride also resulted in increased labeling of amino acids in the dark in Portulaca and in the light in both Portulaca and Zea mays.
Photosynthetic rates were adversely affected by water stress, the amount of the reduction being dependent on the water potential of the leaves, the osmoticum used, and the basis of calculation. Low leaf water potentials also resulted in increased CO2 compensation points in both C4 plants, and possible explanations for these increases — photorespiration, mitochondrial respiration, or other factors — are discussed.
Early photosynthetic products were determined for three stages of leaf development in Zea mays. After a 10 second exposure to 14CO2, the major percentage of label resides in the four-carbon acids, malate and aspartate, in each leaf age examined. There is a decrease in the amount of C4 acids labeled during leaf ontogeny but this decrease does not lead to an increase in C3 cycle intermediates. Several minor photosynthetic products increase slightly in labeling. Photorespiratory activities for the ontogenetic series were also determined using a 14CO2 assay. Young and mature tissue had light to dark 14CO2 evolution ratios of less that 1.0, as expected of C4 plants. Senescent leaf tissue had a light to dark ratio of 3.3, a value typical for C3 plants, and the amount of 14CO2 evolved in the light was directly influenced by oxygen concentrations. The data indicates that there are physiological changes which occur during development of Zea mays leaves, particularly with respect to photorespiration.
Distribution of the accumulation of calcium oxalate crystals and soluble oxalate is shown in the system of higher plants and compared with the occurrence of the C4 pathway of photosynthesis. In view of the data reported in the literature on oxalate biosynthesis and types of photosynthesis, a correlation between these metabolic pathways seems likely, but closer comparison shows oxalate accumulation to be independent of photosynthetic pathway. The metabolism of oxalic acid may play a role for plant productivity.
The hybrid nature of a cross between Brassica alboglabra and Moricandia arvensis was established by chromosome numbers and by isoelectric focusing pattern of the small subunits of ribulose-1,5-bisphosphate carboxylase. Photosynthetic properties of the hybrid as determined by gas exchange measurements are intermediate between those of the parental species.
A literature survey was made for the occurrence of C3 and C4 photosynthetic pathways in the United States Gramineae. Distinctive characteristics of the two photosynthetic pathways are discussed. Leaf anatomy, CO2 compensation point, net enhancement of photosynthesis in oxygen-deficient atmosphere, 13 C discrimination, and initial product labeling were criteria selected to evaluate data for 6 subfamilies including 25 tribes, 138 genera, and 632 species. The Arundinoideae, Bambusoideae, Oryzoideae, and Pooideae (Festucoideae) are composed of species with C3 pathways. All tribes within the Eragrostoideae have C4 pathways with the exception of Unioleae. Within the Panicoideae, the Andropogoneae and all of the Paniceae, excepting the genera Sacciolepus, Isachne, Oplismenus, Amphicarpum, and Panicum, have C4 pathways. The subgenus Dichanthelium within Panicum is C3 while the Eupanicum subgenus contains plants with both C3 and C4 photosynthetic pathways.
This review summarizes the history of the discoveries of the many anatomical, agronomical and physiological aspects of C4 photosynthesis (where the first chemical products of CO2 fixation in illuminated leaves are four-carbon dicarboxylic acids) and documents the scientists at the University of Arizona and the University of California, Davis, who made these early discoveries. These findings were milestones in plant science that occurred shortly after the biochemical pathway of C3 photosynthesis in green algae (where the first chemical product is a three-carbon compound) elucidated at the University of California, Berkeley, and earned a Nobel Prize in chemistry. These remarkable achievements were the result of ground-breaking pioneering research efforts carried out by many agronomists, plant physiologists and biochemists in several laboratories, particularly in the USA. Numerous reviews and books written in the past four decades on the history of C4 photosynthesis have focused on the biochemical aspects and give an unbalanced history of the multidisciplinary/multinstitutional nature of the achievements made by agronomists, who published much of their work in field study journals such as Crop Science. Most notable among the characteristics of the C4 species that differentiated them from the C3 ones are: (I) high optimum temperature and high irradiance saturation for maximum leaf photosynthetic rates; (II) apparent lack of CO2 release in a rapid stream of CO2-free air in illuminated leaves in varying temperatures and high irradiances; (III) a very low CO2 compensation point; (IV) lower mesophyll resistances to CO2 diffusion coupled with higher stomatal resistances, and, hence, higher instantaneous leaf water use efficiency; (V) the existence of the so-called "Kranz leaf anatomy" and the higher internal exposed mesophyll surface area per cell volume; and (VI) the ability to recycle respiratory CO2 by illuminated leaves. Recent research conducted at CIAT with the tropical root crop, cassava, revealed that it is endowed with a high photosynthetic capacity that is intermediate between C3 and C4 species. Yield under stressfull environment was correlated with leaf photosynthetic rate, as measured in the field, PEPC activity and with leaf photosynthetic nitrogen use efficiency.
Several methods are described for measuring some aspect of the photosynthetic apparatus. The results indicate the division of the members of several genera into two groups. Leaf anatomy, gas exchange, 14CO2 labeling, and carbon isotope ratio showed exact correlations in the species tested. The strengths and weaknesses of some of the techniques are indicated.
1. The pathway of photosynthesis in sugar-cane, which gives most of the radio-activity fixed during short periods in (14)CO(2) in C-4 of oxaloacetate, malate and aspartate, was examined under varied conditions. 2. The pattern of labelling was essentially the same with leaves of different ages and with leaves equilibrated at carbon dioxide concentrations in the range 0-3.8% (v/v) and light-intensities in the range 1400-9000ft.-candles before adding (14)CO(2). 3. Radioactive products were examined after exposing leaves of 33 different plant species to (14)CO(2) for 4sec. under standard conditions. 4. A labelling pattern typical of sugar-cane was found in several species of Gramineae but not in others. Of 16 species from other Families only a species of Cyperaceae contained a large proportion of the fixed radioactivity in oxaloacetate, malate and aspartate.
Leaves of a number of plant species were surveyed for their CO 2 compensation concentration which is one of the distinguishing characteristics used to classify plants on the basis of their photosynthetic capacity. Monocot genera with low CO 2 compensation values are mainly limited to tribes of Chlorideae, Paniceae, Andropogoneae, Tripsaceae, and a part of Festuceae in Gramineae. Major grain crops, except corn ( Zea mays L.) and sorghum ( Sorghum vulgare Pers.), are primarily in the tribes of Hordeae, Aveneae, and Oryzeae, and have high CO 2 compensation concentrations. Seven genera of dicots with low CO 2 compensation occur in the four families of Amaranthaceae, Chenopodiaceae, Portulacaceae, and Euphorbiaceae. Major dicot crops are in the families Leguminosae and Malvaceae and have high CO 2 compensation points. Low CO 2 compensation concentration also is correlated with low carbonic anhydrase activity. Conversely, high CO 2 compensation concentration plants have a high carbonic anhydrase activity. Data on the influence of light intensity and temperature on the rate of photosynthetic CO 2 fixation in leaves from plants with high and low CO 2 compensation concentration indicate differential responses of photosynthesis to these environmental factors. The data are interpreted as supporting a hypothesis for competition by specific plants.
Carbon dioxide compensation concentrations were measured for 325 species of Gramineae . Compensation points of most species of the sub‐family Festucoiaeae were 40 ppm CO 2 or greater at 25 C. Exceptions to this were found in the eight genera examined of the Chlorideae tribe of the Festucoideae as well as in the genera Anthephora, Eragrostis, Vaseyochloa and Pappophorum of other tribes, all of which had low compensation concentrations. Compensation concentrations of most species of the sub‐family Panicoideae were 10 ppm CO 2 or less. Exceptions to this were found in the genus Panlcum , where species of the subgenus Dichanthelium had high compensation concentrations, while members of the subgenera Eupanicum and Paurochaetium had low compensation concentrations. Interspecific crosses between high and low compensating Panicum species may be possible and, if so, would permit study of the interdependence of photorespiration, photosynthetic carbon pathway, leaf anatomy and capacity for high rates of photosynthesis.
The carbon dioxide compensation concentration of members of the Gramineae and a few other plants was determined with an infrared CO, analyzer. These results were then considered in relation to the new photosynthetic carboxylation pathway proposed by Hatch et al., rates of photosynthesis, grass systematics, leaf anatomy, and distribution of starch in the leaf. Plants possessing the new carboxylation pathway had low compensation values whereas those having the Calvin carboxylation reaction had high values. Low compensation plants also had a well-developed parenchyma bundle sheath containing a high concentration of chIoroplasts which accumulated large amounts of starch. Little or no starch was present in the mesophyll cells. Cyperus was exceptional in that it also formed appreciable starch in the mesophyll. Those low compensation members of the Gramineae tested belonged either to the chloridoideragrostoid or the panicoid lines of evolution. A literature survey indicated that low compensation grasses have photosynthetic rates that are about double those of plants with photorespiration correlated with a temperature optimum for photosynthesis of about 35 "C. Those plants with photorespiration have optima within the range 10-25 "C. Some simple assay procedures proposed on the basis of the above correlations allow rapid determination of the physiological and biochemical status of plants with respect to photosynthesis.
A rapid method of determining CO2 compensation concentrations was developed and applied to woody plants. Whole leaves, needle fascicles, and twigs were excised, the cut ends inserted in a vial of deionized water, and the assembly placed in a Mylar bag. The bag was filled with air containing ca. 400 p.p.m. CO2. After 1 h in a growth chamber (24 °C, 3800 ft-c (40 660 lux)), the air was expelled from the bag through an infrared gas analyzer. Compensation concentrations determined by this method agreed with values obtained by using conventional closed-circuit gas analysis. The method was successfully applied to 14 gymnosperm and 55 angiosperm woody species and clones, including field-grown plants and rooted cuttings grown under controlled environment. Variation among species was small, compensation concentrations usually falling between 55 and 65 p.p.m. CO2, the range associated with C3 plants. The influence of temperature, moisture stress, and leaf ontogeny on leaf CO2 compensation also was studied.
Thesis (Ph.D.)--University of Minnesota, 1972. Bibliography: leaves 85-90.
Unlike other leaves investigated, maize leaves were found to be able to exhaust atmospheric CO2-content to zero concentration. This occurred at 20° C. with a light intensity of 100 f.c. and at 30° C. with a light intensity
of 500 f.c.
The influences of temperature, light intensity, and waterstrain on this property of maize leaves were investigated systematically
and a permanent aftereffect of waterstrain on the leaves was found.
Stomatal conductance measurements showed that maize stomata are sensitive to CO2-concentrations between zero and 100 p.p.m., a circumstance not yet reported for other leaves.
Both high and low C0(2) compensation concentrations were found in the plant genera-Panicum, Cyperus, and Euphorbia. Within each genus, however, high and low compensations were found in different subgenera. Thus, they may not be genetically closely related. No significant differences in CO(2) compensation were found among 100 genetic lines of Triticum aestivum L. or among 20 lines of Hordeum vulgare L.
MANY reports1-5 indicate that plants in a closed system will reduce the concentration of carbon dioxide in the air to a minimum value between 50 and 100 p.p.m. Gabrielsen2 postulates "there exists a threshold value for carbon dioxide in photosynthesis, which for elder leaves is about 0.0090 volume per cent. Below the threshold no assimilation takes place. Thus it seems that only about two-thirds of the atmospheric carbon dioxide is available for photosynthesis".
The effect of O(2) on the CO(2) exchange of detached leaves of corn (Zea mays), wheat (Triticum vulgare), oats (Avena sativa), barley (Hordeum vulgare), timothy (Phleum pratense) and cat-tail (Typha angustifolia) was measured with a Clark oxygen electrode and infrared carbon dioxide analysers in both open and closed systems.Corn leaves did not produce CO(2) in the light at any O(2) concentration, as was shown by the zero CO(2) compensation point and the absence of a CO(2) burst in the first minute of darkness. The rate of photosynthesis was inhibited by O(2) and the inhibition was not completely reversible. On the other hand, the steady rate of respiration after a few minutes in the dark was not affected by O(2).These results were interpreted as indicating the absence of any measurable respiration during photosynthesis. Twelve different varieties of corn studied all responded to O(2) in the same way.The other 5 monocotyledons studied did produce CO(2) in the light. Moreover, the CO(2) compensation point increased linearly with O(2) indicating a stimulation of photorespiration.The implications of the lack of photorespiration in studies of primary productivity are discussed.
The effect of O(2) on the CO(2) exchange of detached soybean leaves was measured with a Clark oxygen electrode and infrared carbon dioxide analysers in both open and closed systems.The rate of apparent photosynthesis was inhibited by O(2) while the steady rate of respiration after a few minutes in the dark was not affected. Part of the inhibition of apparent photosynthesis was shown to be a result of increased photorespiration. This stimulation of photorespiration by O(2) was manifested by an increase in the CO(2) compensation point.The differential effects of O(2) on dark respiration (no effect) and photorespiration (stimulation) indicated that these were 2 different processes.Moreover the extrapolation of the CO(2) compensation point to zero at zero O(2) indicated that dark respiration was suppressed in the light at least at zero O(2) concentration.
Significant differences in CO(2) compensation concentration measured in the field among varieties of the species Zea mays L. are reported for the first time. CO(2) compensation concentrations were significantly (P</= 0.01) and negatively correlated with apparent photosynthesis at 300 mul CO(2)/liter air. The Michaelis constant (as defined) for a leaf was significantly (P</= 0.01) and positively correlated with apparent photosynthesis among varieties. While the first correlation is similar to behavior of CO(2) compensation among species of different photosynthetic efficiency, the latter correlation is the converse of the behavior of Km among species.
Low CO(2) compensation points have been found to be associated with several unusual characteristics related to photosynthesis. One such characteristic is a prominent, chlorenchymatous vascular bundle sheath in the leaves. It has been suggested that the presence of this sheath in dicotyledons can serve as a means of detecting low CO(2)-compensating species. We collected 88 dicotyledon species from 22 families reported to have chlorenchymatous sheaths. Of the 88, only three, Tribulus terrestris, L., Boerhaavia paniculata, L. C. Rich, and Trianthema portulacastrum L., had low CO(2) compensation points. Cross sections of the leaves of the other species revealed that they did have chlorenchymatous vascular bundle sheaths. However, these sheath cells contained chloroplasts which were not specialized for starch formation as were the bundle sheath chloroplasts of the low CO(2)-compensating species.
Leaves of two subgenera of Panicum differ in photosynthetic physiology and bundle sheath characteristics. Species of the subgenus Eupanicum, like other tropical grasses, had high phosphoenolpyruvate carboxylase (E.C.4.1.1.31) activity, had specialized chloroplasts within the parenchyma bundle sheath cells, and lacked phatorespiration. The pattern for the temperate subgenus Dichanthelium was opposite.
Effect on photosynthesis, photorespiration and respiration Soybean
- G Krotxov
FORRESTER, M. L., G. KROTxOV, AND C. D. NELSON. 1966. Effect on photosynthesis, photorespiration and respiration Soybean.Plant Physiol.41: 422-427
Some methods for studying sperms
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TREGUNNA, E. B., B. N. SImTH,J. A. BERRY, AND W. Some methods for studying sperms.Can. J. Bot. 48: 1209-1214
currence of plantswith a lowCO2 compensation point in the tropics
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HOFSTRA, J. J., S. AXSORNKOAE, TOSA, R. A. SASTROHOETOMO,AND L. T. N.THU. currence of plantswith a lowCO2 compensation point in the tropics.Ann.Bogor.5: 143-157
0.BURR. tion insugarcaneleaves
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KORTSCHAK,H. P., C. E. HARTr,AND G. 0.BURR. tion insugarcaneleaves. Plant Physiol.40: 209-213
Genetic and environmental control of photorespiration
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TREGUN-NA, E. B., J. DOWNTON, AND P. JOLLIFFE. 1969. Genetic and environmental control of photorespiration. In: H. Metzner, ed., Progress
Photosynthesis Research. International Union of Biological Sciences, Tubingen.
List of Families and Number of Species for Which CO2 Compensation Points Have Been Reported in Additiont to Those Listed in Tables I and II Famrily Total species High r
- Iii Table
Table III. List of Families and Number of Species for Which CO2
Compensation Points Have Been Reported in Additiont to
Those Listed in Tables I and II
Famrily
Total species High r LowJ
References
Monocotyl edons
Plant Physiol. Vol. 56, 1975
TABLE I.-Continued Speci es H
- C Hack
C. uliginosa Hack.
TABLE I.-Continued
Speci es
H. hystrix Roth
H. jubatum L.
Nees) Stapf Iseilema membranacea Domin I. vaginiflora Domin I. wightii Anderss
- H Rufa
H. rufa (Nees) Stapf
Iseilema membranacea Domin
I. vaginiflora Domin
I. wightii Anderss.
Some methods for studying the photosynthetic taxonomy of angiosperms
- E B Tregunna
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TREGUNNA, E. B., B. N. SImTH, J. A. BERRY, AND W. J. S. DOWU TON. 1970.
Some methods for studying the photosynthetic taxonomy of
angiosperms. Can. J. Bot. 48: 1209-1214.
Carbon dioxide compensation in members of the Amaranthaceae and some related families
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TREGJN NA, E. B. AND J. DOWNTON. 1967. Carbon dioxide compensation in
members of the Amaranthaceae and some related families. Can.
45:
2385-2387.