Sexual selection has traditionally been divided into competition over mates and mate choice. Currently, models of sexual selection predict that sexual traits are expressed in proportion to the condition of their bearer. In horned beetles, male contest competition is well established, but studies on female preferences are scarce. Here I present data on male mating success and condition dependence of courtship rate in three species of horn-dimorphic dung beetles, Onthophagus taurus, Onthophagus binodis, and Onthophagus australis. I found that in the absence of male contest competition, mating success of O. taurus and O. australis was unrelated to their horn length and body size, whereas in O. binodis horn size had a negative effect but body size had a positive effect on male mating success. Overall, in O. binodis major morph males had greater mating success than minor morph males. In all three species male mating success was affected by courtship rate, and the courtship rate was condition dependent such that when males were manipulated to be in poor condition they had lower courtship rates than males that were manipulated to be in good condition. My findings provide new insight into the mating systems of horned dung beetles and support an important assumption in indicator models of sexual selection. Copyright 2002.
Citrullus lanatus germplasm from southern Africa is a rich source of diversity for cultivated watermelon. Wild, feral, and landrace populations of the species are found throughout the arid regions of southern Africa, where they serve as sources of water and food for humans and wildlife alike. Genetic resources from the region proved to be important sources of disease resistance for cultivated watermelon, contributing to the development of both Fusarium wilt- and anthracnose-resistant cultivars. Basic research, such as genomic mapping and the elucidation of drought tolerance, have also benefitted from the abundant genetic diversity. Currently, several ex situ collections in the region and the rest of the world house accessions originating from southern Africa. The USDA germplasm collection has been screened extensively for traits of interest in watermelon breeding, but full advantage has not been taken of some of the other collections. The C. lanatus germplasm from southern Africa is currently a largely underutilized source of diversity for watermelon improvement. Conservation of and access to ex situ collections should be given priority to ensure that this rich source of genetic variation is utilized to its full potential in both basic and applied research.
Trichosanthes cucumerina Linn (Family: Cucurbitaceae) is a climber grown in Asian countries including Sri Lanka, India, the Malay Penisula, and The Philippines. It is known as dummella in Sinhalese, wild snake gourd in English, kattuppeyppudal in Tamil, and janglichichonda in Hindi. A previous study has shown that hot water extract (HWE) of T. cucumerina can exert significant antihyperglycemic activity in rats. The present study was carried out to investigate the effects of the HWE of T. cucumerina aerial parts on lipid profile of streptozotocin (STZ)-induced Type 1 and Type 2 diabetic rats. In addition, an attempt has been made to identify the active antidiabetic fraction/s of T. cucumerina HWE using streptozotocin (STZ)-induced Type 1 diabetic rats. There was a significant (p ≤ 0.05) decrease in total cholesterol, low density lipoprotein, and triglycerides levels, and a significant (p ≤ 0.05) increase in high density lipoprotein level in the HWE-treated Type 1 and Type 2 diabetic rats compared to their respective controls. In addition, maximum antidiabetic effect was observed in the AQF (aqueous fraction) of the HWE. This study reveals the hypolipidemic and antihyperglycemic effects of T. cucumerina aerial parts.
The carotenoid biosynthetic pathway regulatory mechanisms leading to lycopene accumulation are well defined in the model fruit, tomato (Lycopersicon esculentum L.). The regulatory mechanisms leading to accumulation of other carotenoids and flesh colors, however, are poorly understood. The variety of flesh colors available in watermelon (Citrullus lanatus (Thunb.) Matsum. & Nakai) fruit makes it ideal for investigating the regulation of the full pathway. Carotenoid accumulation was measured in seven watermelon varieties, representing four flesh colors and two ploidy levels, throughout fruit maturation. We found that the putative regulatory mechanisms controlling lycopene accumulation in red-fleshed fruit follows the same regulatory patterns as the other flesh color mutants with differing predominant carotenoids. In general, products downstream of the predominant carotenoid for each color mutant accumulate until a "breaker stage" (approx. 20 days post pollination) at which time the major carotenoid and its precursors accumulate and downstream products diminish. Consistent with other reports, triploid varieties generally had higher concentrations of carotenoids than diploids (an average of 1.5 and 4.0 times in red and orange flesh, respectively). Interestingly, triploid watermelon demonstrated different carotenoid developmental patterns, suggesting the increased carotenoid content is controlled early on in fruit development. Analyzing the carotenoid accumulation in developing fruit suggests that canary yellow-fleshed watermelon have a fully functional carotenoid pathway, red fruit have a nonfunctional β-cyclase gene, and orange and salmon yellow fruit have reduced- or non-functional phytoene desaturase and/or carotenoid isomerase genes. This improved understanding of the biosynthetic pathway regulation will help when planning traditional breeding and biotechnological techniques to improve carotenoid content in watermelon and other carotenoid-containing species.
The area used for watermelon cultivation in South Korea peaked at 45,207 hectares in 1995, but it has declined in each of the successive years. In 2011, watermelon ranked sixth highest in seed sales for vegetable crops in South Korea. Diverse F1 hybrid cultivars with superior characteristics are produced mainly by the private sector for both the domestic market and overseas export. Breeding goals have shifted from high-yield and hypertrophic fruits for open-field culture to high-quality fruits resistant to soil-borne diseases and abiotic stresses for greenhouse culture. Consumers' and growers' preferences for watermelon now encompass a wide range of fruit sizes and colors, in addition to high functional contents such as citrullin and lycopene. However, sweetness is still a prerequisite for a high quality cultivar. Since grafting of watermelon to the rootstock of bottle gourd or zucchini is a critical cultivation method, seed sales of these two rootstocks is an important market in South Korea. Although development of new cultivars relies mainly on conventional breeding methods, molecular markers are being used in breeding programs of watermelon in South Korea.
We introduce a new framework for analyzing spectra called Moment
Distance that uses metrics derived from the shape of the spectral curve
described by fine resolution data. We use the methodology to (1) locate
potential spectral ranges useful for estimation of foliar pigments such
as chlorophyll and carotenoids, and (2) explore the spectral
separability of maize (Zea mays L.) and soybean (Glycine max (L.) Merr.)
in specific spectral regions previously identified in the literature as
indicative of the foliar pigments. We find that the Moment Distance
Index (MDI) computed for these regions can perform as well as or better
than optimized band ratio models in terms of bias and RMSE. Moreover,
the MDI yields significantly different linear models for retrieval of
chlorophyll from maize and soybean. Although these results have been
obtained from a dataset of leaf level spectra and associated pigment
concentrations, the strength of the relationships suggest possible
application of MDIs to canopy and landscape scales.
Watermelon vine decline (WVD) is an emerging threat to watermelon production in southwest and west-central Florida. Losses in 2004-2005 due to WVD were estimated to be more than 60 million US dollars. The disease is caused by Squash vein yellowing virus (SqVYV, family: Potyviridae, genus: Ipomovirus) and is transmitted by whiteflies (Bemisia tabaci). SqVYV is a close relative of, but distinct from, another cucurbit-infecting ipomovirus, Cucumber vein yellowing virus (CVYV), that has been reported from most countries in the Mediterranean Basin since it was first described in Israel in the 1960s. Symptoms of WVD typically include a sudden decline and death of vines at or just prior to harvest. Fruit symptoms include internal flesh degradation and necrosis of the fruit rind. So far, only cucurbits have been confirmed as hosts for SqVYV, and striking symptoms of vine decline in agricultural production have been observed only on watermelon. Balsam-apple (Momordica charantia), a cucurbit weed that is widely distributed in Florida, was found to be a common reservoir host for SqVYV. Management of whitefly populations using insecticides was shown to reduce WVD development and incidence of fruit symptoms. Sources of resistance to SqVYV have been identified, and resistant germplasm resources are being developed. Present recommendations for managing WVD include management of whitefly populations, removal of SqVYV reservoir hosts, and crop destruction soon after harvest. This manuscript will review the progress and challenges in dealing with WVD since it first appeared in Florida in 2003, and compare and contrast it with CVYV.
Watermelon in the US traditionally has been viewed as a sweet but non-nutritional fruit. Over the last ten years, we have delved into the world of watermelon to find the horticultural, genetic, and environmental linkages of compounds with demonstrated bioactivity in animal models and clinical trials. Watermelon contains large amounts of lycopene and citrulline in addition to ascorbic acid, potassium, flavonoids, and beta carotene. Germplasm greatly influences lycopene content (<1 to 120 mg/kg fresh weight) while environmental effects can enhance pigment content by 10 to 20%. In contrast, the influences of germplasm and environment on citrulline content are less clear, with amounts reported from 0.9 to 4.3 mg/kg fresh weight. Watermelon is now recognized as a horticultural crop providing important nutritional and bioactive benefits.
The cereal crops wheat, rice, maize, and sorghum show conservation of large syntenic blocks in spite of more than 40-fold variation in genome and 20-fold variation in chromosome size. It has been proposed that independent mutations at orthologous loci in traits such as shattering, tough fruiting cases (glumes, in the case of wheat), and threshing may have led to domestication-driven convergent evolution. A different picture is emerging from comparative mapping and cloning of these genes in different cereal crops. It appears that these spike traits are controlled by multiple genetic pathways, and mutations at different loci have been selected during domestication-driven evolution.
Water released at night from roots into upper portions of the soil profile in the process of hydraulic lift may contribute to reducing spatial soil nutrient heterogeneity. A manipulative field experiment was conducted in a semiarid shrub stand to determine if circumvention of hydraulic lift, by nighttime illumination of the shrub canopy, would result in greater soil nutrient heterogeneity than if the hydraulic lift process was allowed to operate. Nutrient-enriched patches were superimposed on the existing soil heterogeneity and after 40 days, the patches and interspaces were sampled for ions of different mobility and for root mass. There was no indication under these conditions that hydraulic lift was contributing to smoothing spatial nutrient heterogeneity.
Treated sewage effluent is a valuable and reliable agricultural irrigation resource in areas of low or unpredictable rainfall. Its importance is likely to grow under the influence of global climate change. The use of this resource is not, however, without health risk which is difficult to estimate using data from standard microbial and physicochemical monitoring alone. A health risk management system enables risk reduction through hazard identification, risk characterisation and analysis, strategy development and implementation, intervention assessment and risk communication. In this process data from both risk assessment and routine technological monitoring are integrated to yield synergies. In addition to meaningful information is a need for intersectoral collaboration in making the right decisions. This can be achieved through the establishment of a multidisciplinary risk management team with members drawn from communities of practice. Examples from the University of Western Sydney (UWS) experience are used to support the suggestions made.
Plant-damaging concentrations of B and Cl in treated effluents used for irrigation could adversely affect performance of plum (Prunus Domestica L.) trees. Use of rootstocks that both tolerate the damaging ingredients of the sewage water and impart appropriate horticultural traits might reduce the damage. Rootstocks' responses to the damaging levels of Cl and B present in the effluents may appear only after long-term exposure, e.g., years of exposure to these low quality irrigation water, and selection projects in the field are consequently long-term endeavors. In the present project we have applied a short-term screening procedure for identification of sensitive rootstocks by exposing the plants to very high levels of B and Cl in concentrations. Commercial plum rootstocks of ‘GF 677’, ‘Hansen 536’, ‘Myran’, ‘S.2729’, ‘Mariana’, ‘Citation’, and ‘Ferciana’ were grafted with the plum scion ‘Sungold’. The trees were grown in perlite medium in pots and were treated with B (at 5 or 2 ppm), Cl (at 500 ppm, as NaCl), and Cl (at 500 ppm) plus B (at 2 ppm) in fresh irrigation water. The damage to leaves was assessed visually, and B and Cl in leaves were evaluated three times during the first year. The rootstocks were ranked according to their tolerance to each treatment, for each response parameter, and for each time of assessment. The rankings of tolerance at the three times of measurement were significantly intercorrelated. Most of the rootstocks were ranked quite similarly in the correlation between the parameters of leaf accumulation of Cl and B; the exception was ‘S.2729’, which was more tolerant to Cl accumulation than to B accumulation. ‘Mariana’ and ‘Myran’ appeared more tolerant according to the leaf B accumulation parameter than according to the leaf damage parameter. ‘Mariana’ was ranked more tolerant and ‘Hansen’ more sensitive by the leaf Cl accumulation parameter than by the leaf damage parameter. When all the parameters and times of measurement were considered, ‘Fersiana’ was significantly the most tolerant and ‘Citation’ was significantly the most sensitive of the rootstocks to B and Cl phytotoxicity.
Shortage of water in Israel necessitates utilization of increasing volumes of marginal water for irrigation. Marginal water is characterized by higher concentrations of heavy metals then the potable water from which they were derived. Over time, irrigation with treated water carrying appreciable amounts of heavy metals can contribute to their build-up in soils. The actinomycete Frankia is a nitrogen-fixing root-nodule endosymbiont that is present free in the soil or in association with dicotyledonous plants roots. Frankia has the ability to bind and sequester several toxic heavy metals and is a potentially bioremediation agent. The sensitivity to heavy metals of seven Frankia strains (1F, 5F, 6F, 7F, Fb, Fc, and d) recently isolated in our lab and one reference strain (DSM-44251) was determined. A differential response of these strains to Cd, Al, and B was observed. Toxic levels of the different strains for Cd and B were determined as well as the deficiency levels of B. For all Frankia strains except 7F, increasing Al concentrations enhanced the growth at low pH. Strain d had the highest tolerance to Cd and toxic levels of B with no inhibitory effect of Al, albeit with low growth enhancement by Al compared to the other strains. Irrigation with treated wastewater may reduce growth of some Frankia strains and reduce their nodulation efficiency. Given the potential of Frankia in bioremediation and phytoremediation applications it is important to elucidate Frankia isolates' sensitivity and tolerance to water pollutants such as heavy metals.
The Levant's biogeographic setting also makes it a palaeobiologically significant location, as will be demonstrated here for the past 135 million years of plant evolution. Some of the earliest evidence for angiosperm diversification and dominance come from the Levant, and are possibly related to the environmental conditions in the region at the time. Later mammal migrations from Eurasia to Africa through the Levant resulted in the evolution of African savannas and the rise of grasses and humankind. Humankind left Africa through the Levant, in which it also settled. Agriculture and crop evolution began in the Levant and were to a large part an outcome of previous events. Thus, the geographic and climatic position of the Levant played significant direct and indirect roles in shaping plant life as we know it today. A temporally broad view of the Levant's role in plant evolution offers us insights into the relations between abiotic and biotic evolutionary drivers. This review corroborates that biotic evolutionary drivers are stronger and more apparent at small spatial, temporal and taxonomic scales, whereas abiotic evolutionary drivers are stronger and more apparent at larger scales.
Nitrogen assimilation and amino acid production in Spirodela oligorrhiza plants exposed to 30 mM ¹⁵ NH 4 Cl was studied using l5 N NMR spectroscopy. Green and etiolated plants were studied under different light regimes and in the presence of added carbon, either as sucrose or as α-ketoglutarate. Etiolated plants are capable of ammonium assimilation and, as in green plants, this occurs via the glutamine synthetase/glutamine oxoglutarate amine transferase (GS/GOGAT) and the aspartate aminotransferase/asparagine synthetase pathways. The major assimilation products in both etiolated and green plants were glutamine and asparagine. Thus our results confirm that N-amides are key detoxification products when plants are exposed to external ammonium ion, and act as storage reservoirs or sinks for assimilated ammonium. In plants grown under continuous light, ammonium ion was taken up and assimilated to completion. L-methionine DL-sulfoximine, a GS inhibitor, inhibited ammonium ion assimilation but not its uptake. Addition of azaserine, a GOGAT inhibitor, resulted in the disappearance of α-amino signals, and l5 N incorporation into the glutamine amide-N position only. This is evidence for the operation of the GS/GOGAT pathway, as opposed to the glutamate dehydrogenase (GDH) pathway, in both green and etiolated plants. Even in the dark and under various stress conditions, no sign of ammonium ion assimilation via the GDH pathway could be detected.
The amount of amino acid metabolites strongly depended on the light regime and the extent of external carbon supply. Supply of α-ketoglutarate to the etiolated plants increased ammonium ion uptake and assimilation. Ornithine and arginine were also formed, consistent with the operation of the ornithine cycle.
A taxonomic list of macro marine algae (seaweeds) described in the literature for the Red Sea during the years 1756–2020 is presented. The list was prepared using existing published studies, local monitoring reports, as well as “grey” or unpublished lists of seaweeds for the area. Altogether, we examined more than 300 publications and compiled more than 900 taxonomic names, of which 576 correspond to valid species, whilst 355 names were considered synonyms for these species. The phylum Chlorophyta (green seaweeds) was represented by 37 currently accepted genera and 133 species (including 74 species synonyms). The phylum Ochrophyta (Phaeophyceae only; brown seaweeds) was represented by 52 genera, 157 species and 99 synonyms; and the phylum Rhodophyta (red seaweeds) by 130 genera, 286 species and 182 synonyms. The brown seaweed Sargassum appears to be a particularly biodiverse genus in the area represented by 58 species and 26 synonyms. Our study shows the inconsistency and lack of long-term taxonomic studies and recent molecular investigations of seaweeds from nearly the whole Red Sea.
The life and scientific activities and discoveries of Dr Abromas Kisinas (1899�1945, also appearing in the literature as Avraham, Abraham, Kisin or Kissin) are presented here for the first time. He was a botanist, a Lithuanian, a graduate of Vytautas Magnus University in Kaunas, a polyglot and a social figure. In 1936, Kisinas’ major phytosociological work “Plant Associations and Complexes of Associations in Lithuanian Seaside (without Klaip_eda Region)” was published in the Works of Vytautas Magnus University Faculty of Mathematics and Natural Sciences. The publication was written in Lithuanian with a summary in German and summarized Kisinas’ PhD dissertation, which was defended in 1934 under the supervision of Prof. Constantin Regel. In his research, Kisinas applied ideas proposed by the Uppsala School of Phytosociology. For plant communities evaluation he used linear transects with 1 m2, 4 m2 and 16 m2 sampling squares. In a 15 km seashore range Kisinas determined 63 plant community associations and 26 sub-associations. The fate of this gifted scientist was tragic. In 1941 he and his family were deported to the Kaunas Ghetto. In 1945 Kisinas died at the Dachau concentration camp in Germany.
The covid -19 pandemic has wreaked havoc on the global healthcare system and the economy. At present, no specific antiviral vaccine is available to combat this contagious virus. Traditional medicine has a long history of playing a significant role in managing several infectious diseases. In this context, scientists around the globe are also exploring various traditional medical interventions to prevent the covid -19 pandemic. In the present work, we summarize available scientific data advocating the use of traditional medicine for preventing covid -19. A robust literature review was conducted using scientific platforms such as Science Direct, National Center for Biotechnology Information ( ncbi ), Pubmed, Google Scholar, and online database like The Plant List (The Plant List 2013) version 1.1. Special emphasis was given to potential natural antiviral, immuno-modulator plants, and traditional medicines to highlight their possible roles in reducing the disease burden. Immuno-modulator such as Withania somnifera and other natural compounds especially glycyrrhizin, kaempferol, ginsenoside, and lycorine can be leading candidates against sars -CoV-2. Besides the need for rigorous scientific validation of potential herbs and related formulations, their use can be beneficial for the preventive as well as symptomatic treatment of covid -19 infected patients. This work provides a run-through of the experimental therapeutics, preventive and treatment options for covid -19.
The effects of ¹O2 and OH on alternative pathway respiration in tobacco (Nicotianarustica L. cv. Gansu Yellow Flower) callus were examined. The addition of <15 m Mexogenous ¹O2 induced a pronounced increase in rValt without affecting Valt. For example, upon treatment with 10 mM ¹O2, rValt increased by 1.5 times compared to control, while Valt changed little. When ¹O2 was increased to 25 mM, this induction effect disappeared and both rValt and Valt were suppressed by 59.5% and 40.2%,respectively. Both rValt and Valt were diminished by the addition of exogenous OH, and this inhibition effect increased with OH concentration. At a concentration of 25 mM, for example, rValt and Valt were reduced by 88.9% and 78.2%, respectively. Ohsc avengers, DMSO or MAN, could repress the OH-dependent inhibitory effect. The possible regulation mechanism of alternative pathway by ¹O2 and OH are discussed.
Long-term application of fertilizer and manure may change soil fertility, crop yield, N uptake efficiency, and nitrate and chloride leaching to underground water. The objectives were to quantify those aspects in a long-term (35-year) permanent plots field experiment in a typical arid zone (∼250 mm rain) soil, and suggest fertilization and manuring regimes leading to reduced aquifer pollution by nitrate and chloride without compromising crop yield and soil sustainability. Results proved that mineral-N application exceeding plant demand leached, subject to recommended irrigation plus rainfall, below 4 m, thus becoming a potential underground water pollution hazard. Leaching was significantly reduced by partially replacing fertilizer-N by manure-N, with negligible adverse effect on crop yield. Under ample manure (M2) and mineral N (N3) supply (treatment M2N3), the estimated cumulative (35-year) NO3⁻ leaching was 557 g N/m² and the corresponding Cl⁻ leaching 4097 g Cl⁻/m². In treatment M2N0 the corresponding leaching was 0 and 4135 g/m². The cumulative solute leaching depth was estimated to be 66 m in treatment M2N3 (that gave maximum fruit and dry matter yield) and 125 m in treatment M0N0 (minimum fruit and dry matter yield). Soil cultivation and cropping for 35 years had negligible effect on the plants’ response to fertilizer level and on the soil mineralogical composition.
High-throughput phenotyping is a rapidly evolving field, with new technologies being developed that need to be tested under different experimental conditions. In this study, the PlantEye, a high-resolution three-dimensional (3D) laser scanner was used to phenotype wheat plants grown under control and salt stress in controlled environment conditions. The PlantEye scans plants from overhead, creating a data cloud from which the system computes traits such as 3D leaf area, plant height and leaf number. Moderately high correlations were observed between automatically calculated trait; 3D leaf area, and the manually measured traits leaf area, fresh biomass and dry biomass, although correlations were lower than those reported in previous studies in different crop species. As expected, salt stress caused significant reduction in plant growth, particularly leaf area and biomass production, which resulted in significantly reduced grain number and yield. The results here suggest that PlantEye was effective in phenotyping wheat, although improvements in the system setup, data processing and customer support would make this phenotyping tool suitable to be widely adopted for a range of plant species under diverse environmental conditions.
Interploidy crosses between Lilium lancifolium (3x) and Asiatic lily cultivar ‘Brunello’ (4x) were attempted for creating genetic variability and to analyse the progenies for different ploidy levels. Experimental results revealed that most of the crosses attempted were developed into fruits, confirming that male-sterile triploid lilies can be used as the female parent for crossing with a suitable male parent. Wide variation in chromosome numbers (28 to 38) was obtained in different plant progenies, indicating that aneuploidy is generated by 3x × 4x crosses. The nuclear DNA content analysis of 13 plant progenies showed that the 2C nuclear DNA content has increased (range = 32.60 pg to 41.32 pg) as compared to Lilium lancifolium, while it was found lower than the cultivar ‘Brunello. Further, morphological characterization of different plant progenies revealed significant differences among themselves, which confirmed the dependence of these traits on cultivars ploidy level. Therefore, present findings will be instrumental for development of new Lilium cultivars with high aesthetic value and utility.
The effect of gibberellin A3 (GA3) treatments on flowering of seed-grown globe artichoke (Cynara scolymus) was investigated under controlled environment and field conditions. GA3 induced flower initiation in lines ‘060’ and ‘Talpiot’ under strictly noninductive, short-day-high-temperature conditions. In ‘Talpiot’, GA3 induced microscopically detectable flower initiation but no stem elongation, suggesting involvement of gibberellins in the flower formation process. Under field conditions, GA3 replaced the cold requirements of line ‘HU 271’, thereby enabling the start of flowering during autumn. The vegetative clone Bianca d'Espana flowered during autumn without GA3 treatment, probably due to its minimum cold requirements. Definition of the response type and the role of gibberellins in the flowering of globe artichoke are discussed.
Firewood is a vital energy source for cooking and heating in traditional societies worldwide. During the past century, increasing human populations have depleted many previously available resources, resulting in severe shortages of firewood in many regions, especially in arid zones. Here, I describe the use as a source of firewood for a local semi-nomadic Bedouin village of several dozen families and the fate of a 0.3 km2 abandoned fiber-crop plantation of Agave sisalana Perr. which is more than 50 years old in the Negev Desert, Israel. The amount of firewood extracted in the last decade equals several thousand local wild shrubs, which, in the current vegetation density, grow in a radius of several square kilometers. Harvesting the plantation for about 20 years almost fully exploited the plantation. Because the Bedouins do not replant plants used only for firewood, this source is not sustainable despite its biological potential to be so. However, because Agave are CAM (Crassulacean acid metabolism) plants, they can grow under very arid conditions, and because they are well defended from grazing by thorns and poisons, they may be planted as a source of firewood in various arid regions where other plants will not sustain.
We studied the effects of NH4+, photosynthetic photon flux (PPF), and temperature on growth rates, together with inorganic carbon (Ci) utilization properties of Gelidiopsis sp. cultivated in tanks. At 25% sunlight, weekly growth rates and dry weight yields increased up to 6-fold with increasing NH4+(0–2 mM); however, at 5% or 100% sunlight the effects were much lower. Contents of photosynthetic pigments (chlorophyll a and phycoerythrin) increased in correlation with increases of NH4+. Maximal chlorophyll a concentrations occurred under high PPF, while phycoerythrin concentrations were higher at low PPF. Ash amounts in Gelidiopsis sp. did not vary significantly with different NH4+ or PPF levels. Optimal temperatures and PPFs for growth were 20–25 °C and 170–320 μmol m−2 s−1, respectively, correlating with short-term photosynthetic O2 evolution measurements. The pH of both thallus surface and bulk medium increased during photosynthesis, reaching average values of 8.75, and resulting in low rates of O2 evolution. Activities of carbonic anhydrase (CA) were detected inside and outside the cells and were apparently involved in the Ci uptake system of Gelidiopsis sp. since both acetazolamide (membrane-impermeable) and ethoxyzolamide (membrane-permeable) inhibited photosynthetic O2 evolution by 89% on average. Half-maximal rates of photosynthetic O2 evolution (K0.5) were reached at 17 μM CO2 at pH 5.0 and 2–3 mM Ci at pH 8.0, indicating high affinity for CO2 and close to saturated photosynthesis at Ci levels of seawater. Thus the Ci uptake system of Gelidiopsis sp. probably uses an extracellular CA catalyzed conversion of HCO3− to yield CO2, which could diffuse into the cells, and an intracellular CA catalyzed HCO3− ↔ CO2 interconversion which may assure CO2 for Rubisco. Direct uptake of HCO3− may also be required based on the K 0.5 (CO2) estimated for Gelidiopsis sp. and the pH generated at the thallus surface at which CO2 concentrations would only be approximately 10 μM. Therefore, in addition to limitations of low NH4+ concentrations and high temperatures during the summer, growth of Gelidiopsis sp. from the Israeli Mediterranean may also be restricted by its limited Ci utilization system and the low CO2 concentrations prevailing in seawater.
Ca deficiencies induce a range of physiological disorders in plants. The disorders typically appear in young growing tissues that are characterized by high demand for Ca and restricted Ca supply due to low transpiration. In this study, we examined the effect of supplementing Ca by foliar spray and through the irrigation solution to Anemone coronaria plants, in order to evaluate if flower abortions and leaf damages that appear in the production fields are related to Ca deficiencies. With the goal to develop a preventive nutritional regime, four Ca treatments were evaluated. The supplemented Ca was applied with the fertigation solution in the concentrations of 60 or 110 ppm Ca; with the 60 ppm application an additional application of Ca by foliar application was tested in concentrations of 3 g/l Ca or 6 g/l Ca, as Ca(NO3)2. The plants were cultivated in a net-house, in soilless culture (Tuff) beds. Application of 110 ppm Ca compared to 60 ppm with the fertilizing solution increased the concentration of Ca in the leaf tissue, resulting in an increase in the quantity and quality of the flowers. Calcium supply by foliar spray, at both 3 g/l or 6 g/l Ca(NO3)2 caused leaf necrosis and did not improve yield production. Application of 110 ppm Ca reduced the concentrations of Mn, Cl and Na in the leaves. Application of Ca in the irrigation solution, or by foliar spray, did not reduce the percentage of non-marketable flowers. The identified lower concentrations of Ca in damaged compared to non-damaged leaves on the flower stem suggests that the damages to the flowers and the leaves is related to local deficiencies of Ca.
The sparsely distributed Limodorum abortivum is a European-Mediterranean orchid species, which grows on decomposing plant material. Although some chlorophyll-pigmentation is observed in the degenerated scales-shaped leaf and stems regions of the plant, its photosynthetic capacity is assumed to be insufficient to support the full energy requirements of an adult plant. In Israel, L. abortivum shows a patchy distribution patterns in the Galilee, Golan, Carmel and Judean regions. To gain more insights into the physiology and photosynthetic activity of L. abortivum , we analyzed the organellar morphologies, photosynthetic activities the chloroplast-DNA sequence by Illumina-HTS. Microscopic analyses indicated to the presence of mature chloroplasts with well-organized grana-thylakoids in the leaves and stems of L. abortivum . However, the numbers of chloroplasts per cell and the grana ultrastructure density within the organelles were notably lower than those of model plant species and fully photosynthetically-active orchids. The cpDNA of L. abortivum (154,954 bp) encodes 60 proteins, 34 tRNAs and 4 rRNAs. The coding-regions of 24 genes are interrupted by 26 group-II intron-sequences. While many genes related to photosynthesis (RuBisCo, PSI, PSII and cytochrome b 6 /f subunits) have remained intact in the cpDNA, the majority of the NADH-dehydrogenase ( ndh ) subunits were either lost or became nonfunctional (i.e. pseudogenized). In agreement with previous reports, the photosynthetic-rates of adult Limodorum plants were found to be very low, further indicating that carbon-assimilation activity is insufficient to support the energy requirements of an adult plant, and may suggest that L. abortivum have adopted nutritional strategies similar to that of mycoheterotrophic orchid species.
Mango is a commercial fruit crop in different parts of the tropical and subtropical world. Commercially important monoembryonic varieties are propagated through grafting onto rootstock seedlings of polyembryonic genotypes that plays an important role in sustained growth and production. Use of salt tolerant genotypes as rootstock to combat the adverse effect of salinity could be helpful for commercial mango production in salt affected areas. Current study was carried out to elucidate the effect of salinity stress induced by NaCl + CaCl 2 (1:1 w/w) at 0, 25, 50 and 100 mM concentrations in irrigation water on candidate polyembryonic mango genotypes namely EC-95862, Bappakkai, Vellaikolamban, Nekkare, Turpentine, Muvandan, Kurukkan, Kensington, Olour, Manipur, Deorakhio, Vattam, Mylepelian, Sabre and Kitchener. We studied the morpho-physiological changes of these seedlings under salinity induced stress for determining their relative tolerance by assessing growth parameters such as plant height, number of leaves, leaf area, inter-nodal length, fresh weight of shoot, fresh weight of root, dry weight of shoot, dry weight of root, stem diameter and physiological parameters like photosynthetic rate, transpiration rate, stomatal conductance, number of stomata and stomata length and width, in addition to ABA content in leaves. Our results clarifies that the polyembryonic genotypes Turpentine, Deorakhio Olour and Bappakkai showed less reduction in terms of growth and better maintenance of gas exchange status under higher level of salinity.
The levels of endogenous free, bound, and total abscisic acid (ABA) and the changes in dry weight of the mycelium depending on the culture periods were examined in Pleurotus florida (Basidiomycetes) cultured both in shaking and static media. The relationship between ABA production and the growth rate of the fungus was determined. Our findings show that this fungus synthesizes ABA as a secondary metabolite and the maximum total ABA is produced on the 24th day of the growth period in both shaking and static conditions. It was observed that, depending on the culture period, the dry weight of mycelium was enhanced in the primary metabolic phase, while it was constant in the secondary metabolic phase.
These results show that there is a negative relationship between growth rate of the fungus and ABA synthesis.
Vertical fiber cables anchored in horizontal diaphragms traverse the air-filled lacunae of the tall, upright, spiraling leaf blades of Typha domingensis, T. angustifolia, T. latifolia and T. × glauca. The fiber cables may make a mechanical contribution to leaf blade stiffness while allowing flexibility under windy conditions. We examined the very tall, upright, spiraling leaf blades of T. elephantina, which can be over 4 m long, for fiber cables. In the tall species of Typha, there are two alternative architectures for upright leaf blades. T. domingensis utilizes fiber cables to enhance stiffness in the tall, upright concavo-convex leaf blades, whereas T. elephantina may maintain their tall stature in the absence of fiber cables by having a different cross-sectional geometry. These alternative architectures can be used as a diagnostic character along with other morphological characters to assess phylogenetic affinity in Typha. The very tall T. elephantina which lacks fiber cables may be more closely related to the much shorter T. minima, which also has no cables, than to the tall T. domingensis and T. angustifolia, both of which have prominent fiber cables. T. elephantina and T. minima share other morphological characters as well.
Artemisia monosperma is a dominant perennial desert shrub occurring in active sand dunes and stabilized sand fields. A cyanobacterial crust develops on stabilized sand and, as a result, runoff water may occur after rains. The mucilaginous achenes may float on the runoff water and disperse into depressions or cracks.
In these experiments, almost half of the achenes remained afloat on distilled water for 3 days and on different concentrations of salt solutions, more achenes remained afloat for longer. High concentrations of salt inhibit germination. NO,” may influence achene germination on cyanobacterial sand crust. Mucilaginous achenes absorb water within about 60 min, and after 120 min reach their water capacity. The achenes from which the mucilage has been removed can float for a longer period and germinate earlier than intact ones. Seedlings that developed from achenes with mucilage had greater vigor than those without.
The ecological significances of mucilaginous achenes is discussed.
Mungbean ( Vigna radiata L. Wilczek) an important legume crop with valuable nutritional and health benefits is severely affected by drought conditions. Desiccation tolerance is a capacity of seeds to survive and maintain physiological activities during storage and stress conditions. LEA proteins are group of stress associated proteins that help the plants survive water deficit stress. Here we have performed genome-wide analysis of mungbean LEA ( VrLEA ) genes, and also insilico physical/functional characterization. Gene-positioning showed that 307 VrLEAs are present in all the eleven chromosomes, but are unevenly distributed.Upstream promoter sequence analysis of LEA genes revealed the occurrence of MYB transcription factor (TF)in higher number compared to other TFs i.e ., bZIP, AP2, WRKY, NAC and bHLH.Further, we downstreamed our analysis to fewer VrLEAs , based on drought responsive data. The VrLEAs obtained from the earlier experimental data were examined for its organelle localization and found that they are intracellular functional proteins.
Coastal sand dunes are susceptible to invasive plants that significantly alter these endangered ecosystems. Acacia saligna is a small Australian tree that has become a significant invasive plant in Israel and in many other Mediterranean countries. The aim of this research was to study the impact of A. saligna on the indigenous vegetation of three coastal habitats (sand dunes, inter-dune depressions, and aeolianite [sandstone] ridges) in the Nizzanim Long Term Ecosystem Research Nature Reserve, Israel. Plant observations were conducted in the spring, in the following site types: (1) sites planted with A. saligna and sites invaded by A. saligna; and (2) reference sites not invaded by A. saligna. A simple index, the aggregate ecological value, was developed in order to evaluate the impact and the ecological value of each habitat and site for conservation purposes. The results indicate that planting A. saligna and invasion by A. saligna changed plant community composition, reduced psammophyte species richness, caused the disappearance of most endemic, rare, and protected species, and overall reduced the ecological value of the Nizzanim Nature Reserve.
The spider mite Eutetranychus palmatus Attiah feeds on various palms. The objectives of this study were: (1) to study the phenology of this little-known species and (2) to determine its status as a pest of date fruit. During a three year study (2001-2003), infestations of E. palmatus on fruit strands began earlier than those of the pestiferous old world date mite, Oligonychus afrasiaticus (McGregor), but peak numbers of the latter were invariably much higher than those of E. palmatus. On fronds E. palmatus was observed from mid-winter throughout summer, its highest numbers being recorded from May to early June. Later, in July and August, E. palmatus populations declined. Oligonychus afrasiaticus was seldom found during winter and spring, but maintained small populations on the fronds in summer, concurrent with very large numbers on the fruit strands. Adult cumulative mite day levels of O. afrasiaticus (on fruit strands) were always considerably higher than those of E. palmatus, but on fronds the opposite was observed. Despite the relatively minor pest status of E. palmatus in comparison to O. afrasiaticus, growers who have experienced spider mite damage caused by high populations of E. palmatus very early in the season (April-May) are applying acaricides to treat this pest. The damage potential of E. palmatus is discussed and compared to that of O. afrasiaticus.