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Pericarp Ontogeny and Anatomy in Rhus aromatica Ait. and R. glabra L. (Anacardiaceae)
Abstract
Ontogeny and anatomy of the pericarp were studied in Rhus aromatica Ait. var. aromatica of subgenus Lobadium and in R. glabra L. of subgenus Rhus. The exocarp sensu stricto in both species originated from the outer epidermis of the ovary wall and remained single-layered. However, in a mature, desiccated fruit, the exocarp was united with the outer mesocarp, and this united-layer was physically detached from the rest of the fruit, thus forming a thin, papery peel. The vascular bundles together with the inner mesocarp, which remained parenchymatous in R. aromatica and became sclerified in R. glabra, was attached to the future stone in R. aromatica but detached from it in R. glabra. The endocarp sensu stricto of both species originated from the inner epidermis of the ovary wall. At anthesis, the proto-endocarp was 3-layered; one and two weeks after anthesis in R. glabra and R. aromatica, respectively, it had become distinctively 4-layered, and the innermost layer had elongated 5-10 times. Five weeks after anthesis in R. aromatica but only three weeks after anthesis in R. glabra, all layers except the outermost crystalliferous one were fully elongated and had begun to lignify. In both species, the crystalliferous layer remained parenchymatous, did not elongate, and contained crystals. The similarities in ontogeny and anatomy of the pericarp in these two species support the opinion that Lobadium should be kept as a subgenus within Rhus, rather than being elevated to the generic level. However, more taxa of Rhus need to be studied before the taxonomy of the genus can be clarified.
... Origin and characteristics of mechanical layer(s) Anacardiaceae Endocarp, which develops from inner epidermis of ovary wall; 3 innermost layers of a 4-layered endocarp are palisade-shaped; seed coat undifferentiated (that is, no mechanical layer sensu Corner 1976); with linea lucida (Wannan & Quinn 1990;Li et al. 1999c and references cited therein) Bixaceae ...
... Thus, the water-impermeable layer(s) may be exotestal, exotegmic, endotestal/ endotegmic (Geraniaceae), or, in Convolvulaceae, in which the ovule is unitegmic, exotestal with palisade developed from the subdermal layer of the single integument (Bouman & Schier 1979), and not from the outer hypodermal layer as proposed (Table 2). In Anacardiaceae, the endocarp, which is the waterimpermeable layer, develops from the inner epidermis of the ovary wall (Li et al. 1999c and references cited therein), and in Nelumbonaceae it originates from cells immediately below the epidermis of the pericarp (Shaw 1929). ...
... Its age is about 43 Ma. The three layers of endocarp cells that can be seen (crystalliferous layer not identified) seem to be identical, or nearly so, to the macrosclereid, brachysclereid and osteosclereid layers in extant Rhus species thus far examined (see Li et al. 1999c and references cited therein). Significantly, PY appears to occur throughout the genus Rhus (Li et al. 1999d,e and references cited therein). ...
Abstract Physical dormancy (PY) is caused by a water-impermeable seed or fruit coat. It is known, or highly suspected, to occur in nine orders and 15 families of angiosperms (sensu Angiosperm Phylogeny Group 1998), 13 of which are core eudicots. The Zingiberales is the only monocot order, and Cannaceae (Canna) the only monocot family, in which PY is known to occur. Six of the nine orders, and 12 of the 15 families, in which PY occurs are rosids. Furthermore, six of the families belong to the Malvales. The water-impermeable palisade layer(s) of cells are located in the seed coats of 13 of the families, and in the fruit coats of Anacardiaceae and Nelumbonaceae. In all 15 families, a specialized structure is associated with the water-impermeable layer(s). The breaking of PY involves disruption or dislodgment of these structures, which act as environmental ‘signal detectors’ for germination. Representatives of the nine angiosperm orders in which PY occurs had evolved by the late Cretaceous or early Tertiary (Paleogene). Anatomical evidence for PY in fruits of the extinct species Rhus rooseae (Anacardiaceae, middle Eocene) suggests that PY had evolved by 43Ma, and probably much earlier. We have constructed a conceptual model for the evolution of PY, and of PY+ physiological dormancy (PD), within Anacardiaceae. The model begins in pre-Eocene times with an ancestral species that has large, pachychalazal, non-dormant (ND), recalcitrant seeds. By the middle Eocene, a derived species with relatively small, partial pachychalazal, orthodox seeds and a water-impermeable endocarp (thus PY) had evolved, and by the Oligocene, PD had been added to the seed (true seed + endocarp) dormancy mechanism. It is suggested that climatic drying (Eocene), followed by climatic cooling (Eocene–Oligocene transition), were the primary selective agents in the development of PY. An evolutionary connection between PY and recalcitrance is suggested by the relatively high concentration of these two character states in the rosids. Phylogenetic data and fossil evidence seem to support the PY→(PY+PD) evolutionary sequence in Anacardiaceae, which also may have occured in Leguminosae.
... In Rhus (Toxicodendron) diversiloba (Copeland and Doyel, 1940), the exocarp was papery, but its was unclear how many layers constitute the exocarp. The exocarp of Rhus aromatica and R. glabra was formed by the outer epidermis (Li et al., 1999). Schinus and Lithraea had a friable exocarp that separeted from the mesocarp. ...
... Schinus and Lithraea had a friable exocarp that separeted from the mesocarp. In Rhus glabra and R. aromatica, the single-layerd exocarp and the outer mesocarp (with parenchyma cells) were considered as "papery fruit peel" that separeted from the rest of the fruit (vascular bundles and inner mesocarp) (Li et al., 1999). It was unclear whether other Rhus species had a the presence of friable exocarp and if this separeted from the mesocarp. ...
... In all of the species studied in these three genera, the mesocarp was formed largely by parenchyma cells, tannic idioblasts and secretory canals associated with the vascular bundle. However, in Rhus lancea (Von Teichman and Robbertse, 1986;Von Teichman, 1989), R. problematodes (Von Teichman and Van Wyk, 1991), R. glabra and R. verniciflua (Brizicky, 1963;Li et al., 1999), the inner part of the mesocarp was sclerified and could be a part of the endocarp. In Lithraea molleoides, L. brasiliensis (Pienaar and Von Teichman, 1998), Schinus terebinthifolius (Carmello-Guerreiro and Paoli, 2002) and S. molle (Soos and Hausknost, 1951), no sclerification of the inner part of the mesocarp was observed.. ...
The aim of the present work was to record anatomical data for the fruit and seed of Lithraea molleoides (Vell.) Engl, and compare the results with those for L. brasiliensis and the genera Schinus and Rhus. The L. molleoides fruit was a drupe with a friable and lignified exocarp. The mesocarp was parenchymatous with large secretory canals associated with vascular bundles. The endocarp consisted of four layers: an outer layer of polyhedral cells with prismatic crystals of calcium oxalate, and three inner layers of sclereids in a palisade arrangement. The ovule was anatropous, unitegmic, and crassinucelate. In the chalazal region, a cup-like zone of tanniniferous parenchymal cells formed the hypostase. The developing seed had a circinotropouslike shape, that originated through curvature of the long, coarse funicle that surrounded the tegument and embryo sac. The ripe seed was endotestal with bar-like thickenings or pittings in the cell walls.
... Vicia villosa, (Jones, 1928); and Cassia acutifolia, (Bhatia et al., 1977)]; Anacardiaceae [Rhus aromatica and Rhus glabra (Li et al., 1999b)]; and Malvaceae [Sida spinosa (Egley, 1976) and Gossypium hirsutum (Patil and Andrews, 1985)]. However, development of physical dormancy in Convolvulaceae has not been described accurately. ...
... Although the bulge is another distinct anatomical area of the seed coat, its ontogeny hitherto has not been studied. However, the development of the water gap has been studied in several other families known to have PY, including the chalazal plug in several families of Malvales: Malvaceae (Winter, 1960;Egley et al., 1986), Cistaceae (Thanos and Georghiou, 1988), Cochlospermaceae, Dipterocarpaceae and Sarcolaenaceae (Nandi, 1998); the protuberance in Nelumbonaceae (Ohga, 1926); the so-called carpellary micropyle in Anacardiaceae (Li et al., 1999b); the operculum in Cannaceae (Grootjen and Bouman, 1987); and the lens in Fabaceae (Manning and Van Staden, 1987;Martens et al., 1995). The development of the bixoid chalazal plug in Malvales (Chopra and Kaur, 1965;Nandi, 1998) is considerably more complex than that of the water gap in Convolvulaceae. ...
The biology of seed dormancy and germination of 46 species representing 11 of the 12 tribes in Convolvulaceae were compared in laboratory (mostly), field and greenhouse experiments. Seeds were tested for kind of dormancy and storage behavior; artificial or simulated natural treatments were applied to break physical dormancy (PY); the initial route of water entry (“water gap”) into seeds was identified; the morphoanatomy of the water gap was compared in seeds of 17 species; ontogenetical differences between water gap and seed coat away from the hilum were described in Ipomoea lacunosa seeds; cycling of sensitivity to dormancy break was elucidated in seeds of I. lacunosa, I. hederacea, Cuscuta australis and Jaquemontia ovalifolia; and mechanism of opening of the water gap was determined for seeds of I. lacunosa and of I hederacea.
Seeds of only three of the 46 species were nondormant. Two of these were recalcitrant (Maripa panamensis and Erycibe henryi), and the other one was orthodox (Bonamia menziesii). Seeds of the other 43 species were orthodox and had PY except those of Cuscuta europea, which also had physiological dormancy (PD) i.e. combinational dormancy (PY + PD). Two bulges adjacent to the micropyle were identified as the water gap in all seeds with PY except those of Cuscuta, in which the hilar fissure is the water gap. Anatomy of the bulges (water gap) adjacent to the micropyle differs from that of seed coat away from the bulges. A different sequence and phase of anticlinal and periclinal cell divisions during development created weak transitional zones between bulge - hilum and bulge - seed coat away from hilum. Water vapor pressure changes below the bulges caused formation of the opening(s) in water gap. Seeds of I. lacunosa I. hederacea, C. australis and J. ovalifolia cycle between sensitive and insensitive states to dormancy break, but not between PY and nondormancy. Seed dormancy and storage characteristics and anatomy and morphology of dormancy of seeds of Convolvulaceae closely follow the molecular phylogeny of the family. I suggest that PY in seeds of subfamily Convolvuloideae evolved from nondormant recalcitrant seeds of an ancestor closely related to Erycibeae.
... Physical dormancy is usually considered to be a heritable trait, controlled by the testa or endocarp, which are derived from integuments of the ovule and the inner epidermal layer of the ovary wall, respectively (Evenari et al., 1966;Pérez-García and Escudero, 1997;Li et al., 1999a). To date, numerous natural mechanisms of PY breakdown have been described, particularly relating to various combinations of temperature and moisture changes, including high temperatures from summer insolation or fire (e.g. ...
... Evenari et al., 1966;Hill et al., 1986a, b;de Souza and Marcos-Filho, 2001). Furthermore, genetic effects on PY are often assumed to reflect only the maternal genotype, due to the importance of the seed coat (or endocarp) in PY, both of which are derived from parts of the maternal ovule (Roach and Wulff, 1987;Fenner, 1991;Li et al., 1999a;Donohue, 2009;Baskin and Baskin, 2014). However, Ramsay (1997) has shown that hardseededness can also be passed through the paternal line in Vicia faba. ...
Species with physically dormant (PY) seeds make up over 25% of plant species in a number of ecologically important ecosystems around the globe, such as savannah and Mediterranean shrublands. Many of these ecosystems are subject to temporally stochastic events, such as fire and drought; but are in areas projected to experience some of the most extreme climatic changes in the future. Given the importance of PY in controlling germination timing for successful recruitment, we ask how plastic the PY trait is, and if changes to the maternal environment from climate change could alter recruitment. This review focuses on: (1) the evidence for inter- and intraspecific variation in PY; (2) the genetic, maternal and environmental controls involved; and (3) the ecological consequences of (1) and (2) above. Evidence for (within-community) interspecific variation in conditions required to break PY is strong, but for intraspecific variation evidence is contradictory and limited by a paucity of studies. Identifying controllers of variation in PY is complex, there is some suggestion that conditions of the maternal environment may be important, but no consensus on the nature of effects. The implications of PY plasticity for the persistence of seed banks, species and communities under climate change are discussed. We highlight a number of key knowledge gaps, such as a lack of research estimating the components of variation in non-agricultural species, and identify a suite of seed attributes relevant to understanding the potential impacts of climate change on the population dynamics of PY species in the future.
... physical dormancy, PY) is known to occur in 16 angiosperm families, but in no gymnosperms (Baskin et al., , 2006). A palisade layer(s) in the seed (or fruit) coat is (are) responsible for this impermeability to water (Van Staden et al., 1989; Li et al., 1999a, b). Water enters the seed when the 'water gap', a special morpho-anatomical area in the seed coat, opens. ...
... 6 % (Graff and Van Staden, 1987); Trifolium pratense and T. repens, 14 % (Hyde, 1954); and Vicia villosa, 14 % (Jones, 1928); in Malvaceae: Gossypium hirsutum, 12 % (Patil and Andrews, 1985) and Sida spinosa (Egley, 1976); and in Anacardiaceae: Rhus aromatica, 6 . 1 % and Rhus glabra, 9 . 3 % (Li et al., 1999a). Germinability of I. lacunosa seeds was 100 % at 24 DAP, which was 2 d after physiological maturity. ...
Disruption of one or both of the bulges (water gap) in the seed coat adjacent to the micropyle is responsible for breaking physical dormancy (PY) in seeds of Ipomoea lacunosa and other taxa of Convolvulaceae. Hitherto, neither ontogeny of these bulges nor onset of PY together with anatomical development and maturation drying of the seed had been studied in this family. The aims of this study were to monitor physiological and anatomical changes that occur during seed development in I. lacunosa, with particular reference to ontogeny of the water gap.
Developmental anatomy (ontogeny) of seed coat and dry mass, length, moisture content, germinability and onset of seed coat impermeability to water were monitored from pollination to seed maturity. Blocking/drying and dye-tracking experiments were done to identify site of moisture loss during the final stages of seed drying.
Physiological maturity of seeds occurred 22 d after pollination (DAP), and 100 % of seeds germinated 24 DAP. Impermeability of the seed coat developed 27-30 DAP, when seed moisture content was 13 %. The hilar fissure was identified as the site of moisture loss during the final stages of seed drying. The entire seed coat developed from the two outermost layers of the integument. A transition zone, i.e. a weak margin where seed coat ruptures during dormancy break, formed between the bulge and hilar ring and seed coat away from the bulge. Sclereid cells in the transition zone were square, whereas they were elongated under the bulge.
Although the bulge and other areas of the seed coat have the same origin, these two cell layers underwent a different series of periclinal and anticlinal divisions during bulge development (beginning a few hours after pollination) than they did during development of the seed coat away from the bulge. Further, the boundary between the square sclereids in the transition zone and the elongated ones of the bulge delineate the edge of the water gap.
... The chloroplast genome is a valuable resource in molecular phylogenetic analysis [20,21], and contains a pair of inverted repeat (IR) regions separated by a large single copy (LSC) and a small single copy (SSC) region [22,23]. This quadripartite structure is highly conserved in gene content and genome organization relative to the plant nuclear and mitochondrial genomes [23]. ...
Background
The suamc genus Rhus (sensu stricto) includes two subgenera, Lobadium (ca. 25 spp.) and Rhus (ca. 10 spp.). Their members, R. glabra and R. typhina (Rosanae: Sapindales: Anacardiaceae), are two economic important species. Chloroplast genome information is of great significance for the study of plant phylogeny and taxonomy.
Results
The three complete chloroplast genomes from two Rhus glabra and one R. typhina accessions were obtained with a total of each about 159k bp in length including a large single-copy region (LSC, about 88k bp), a small single-copy regions (SSC, about 19k bp) and a pair of inverted repeats regions (IRa/IRb, about 26k bp), to form a canonical quadripartite structure. Each genome contained 88 protein-coding genes, 37 transfer RNA genes, eight ribosomal RNA genes and two pseudogenes. The overall GC content of the three genomes all were same (37.8%), and RSCU values showed that they all had the same codon prefers, i.e., to use codon ended with A/U (93%) except termination codon. Three variable hotspots, i.e., ycf4 - cemA , ndhF - rpl32 - trnL and ccsA - ndhD , and a total of 152–156 simple sequence repeats (SSR) were identified. The nonsynonymous (Ka)/synonymous (Ks) ratio was calculated, and cemA and ycf2 genes are important indicators of gene evolution. The phylogenetic analyses of the family Anacardiaceae showed that the eight genera were grouped into three clusters, and supported the monophyly of the subfamilies and all the genera. The accessions of five Rhus species formed four clusters, while, one individual of R. typhina grouped with the R. glabra accessions instead of clustering into the two other individuals of R. typhina in the subgenus Rhus , which showed a paraphyletic relationship.
Conclusions
Comparing the complete chloroplast genomes of the Rhus species, it was found that most SSRs were A/T rich and located in the intergenic spacer, and the nucleotide divergence exhibited higher levels in the non-coding region than in the coding region. The Ka/Ks ratio of cemA gene was > 1 for species collected in America, while it was < 1 for other species in China, which dedicated that the Rhus species from North America and East Asia have different evolutionary pressure. The phylogenetic analysis of the complete chloroplast genome clarified the Rhus placement and relationship. The results obtained in this study are expected to provide valuable genetic resources to perform species identification, molecular breeding, and intraspecific diversity of the Rhus species.
... Physical dormancy (PY) is found in several native Australian Fabaceae species [18]. Physical dormancy is controlled either by the seed testa or the endocarp and is a heritable trait [19]. Dormancy loss in seeds with PY occurs due to an irreversible structural change to the "water gap", a specialized region of the testa [20]. ...
Simple Summary
Seed-based restoration is likely to become less successful with climate change due to reduced seed germination and seedling emergence. Studying how native plant species respond to environmental stress using a whole life cycle approach can help predict climate change impacts on successful plant establishment. Therefore, the aim of this study was to understand how temperature and moisture stress affect seed germination and seedling emergence together with determining how soil moisture stress can impact the reproductive biology of plants. A native Australian legume species, Desmodium brachypodum A. Gray, was selected as a model species. The seed germination and seeding emergence were reduced by more than half when exposed to elevated temperatures and moisture stress. When the plants produced seeds under moisture stress, the duration of seed production and the number of produced seeds decreased. On the other hand, no differences were observed in the seed traits of those produced seeds. In conclusion, the reproductive output of D. brachypodum had low seed variability under moisture stress, which might be useful when sourcing seeds from climates with high variability. Even so, a reduction in the seed quantity under maternal moisture stress can impact the long-term survival of restored plant populations.
Abstract
Understanding how seed functional traits interact with environmental factors to determine seedling recruitment is critical to assess the impact of climate change on ecosystem restoration. This study focused on the effects of environmental factors on the mother plant during early plant life history stages and during seed development. Desmodium brachypodum A. Gray (large tick trefoil, Fabaceae) was used as a model species. Firstly, this study analyzed seed germination traits in response to temperature and moisture stress. Secondly, it investigated how seed burial depth interacts with temperature and soil moisture to influence seedling emergence traits. Finally, it determined if contrasting levels of post-anthesis soil moisture could result in changes in D. brachypodum reproductive biology and seed and seedling functional traits. The results showed that elevated temperature and moisture stress interacted to significantly reduce the seed germination and seedling emergence (each by >50%), while the seed burial improved the seedling emergence. Post-anthesis soil moisture stress negatively impacted the plant traits, reducing the duration of the reproductive phenology stage (by 9 days) and seed production (by almost 50%). Unexpectedly, soil moisture stress did not affect most seed or seedling traits. In conclusion, elevated temperatures combined with low soil moisture caused significant declines in seed germination and seedling emergence. On the other hand, the reproductive output of D. brachypodum had low seed variability under soil moisture stress, which might be useful when sourcing seeds from climates with high variability. Even so, a reduction in seed quantity under maternal moisture stress can impact the long-term survival of restored plant populations.
... Glandular trichomes -The glandular trichomes are reported in all families of Sapindales, except for Biebersteiniaceae, for which detailed anatomical studies are lacking ( Fig. 1) (van der Walt and van der Schijff 1969;Li et al. 1999;Caris et al. 2006;Endress 2008, 2009;Bachelier et al. 2011;Kubitzki 2011;Muntoreanu et al. 2011;Alves et al. 2017;Cunha-Neto et al. 2017;Tölke et al. 2017Tölke et al. , 2021Andrade et al. 2020;Cortez et al. 2021). The trichomes are morphologically diverse and distributed mainly on leaves, as well as on stems, inflorescences, flowers, and fruits. ...
... Glandular trichomes -The glandular trichomes are reported in all families of Sapindales, except for Biebersteiniaceae, for which detailed anatomical studies are lacking ( Fig. 1) (van der Walt and van der Schijff 1969;Li et al. 1999;Caris et al. 2006;Endress 2008, 2009;Bachelier et al. 2011;Kubitzki 2011;Muntoreanu et al. 2011;Alves et al. 2017;Cunha-Neto et al. 2017;Tölke et al. 2017Tölke et al. , 2021Andrade et al. 2020;Cortez et al. 2021). The trichomes are morphologically diverse and distributed mainly on leaves, as well as on stems, inflorescences, flowers, and fruits. ...
Sapindales comprise nine families with a mainly tropical distribution and include numerous species of high economic importance. Members of this order are known for the production of chemical constituents with medicinal properties, such as antioxidant, anti-inflammatory, and antimicrobial activity, as well as species with insecticidal properties. Such diversity of chemical compounds is attributed to a variety of secretory structures, which may occur in both vegetative and reproductive organs. During the past decades, tremendous progress has been made in anatomical and analytical chemistry studies, which has led to the next level of knowledge regarding the secretory structures of Sapindales. This comprehensive review embraces the most important data of the secretory structures of Sapindales: ducts, cavities, laticifers, floral and extrafloral nectaries, osmophores, colleters, idioblasts, and trichomes. Our review comprises structural, functional, and evolutionary aspects of these glands, which are fundamental for further studies of the diversification within Sapindales.
... Taira (1990) also reported that seed size was negatively correlated with seed water absorption and cooked seed hardness in soybean. Physical dormancy or hardseededness is usually considered to be a heritable trait, controlled by the testa or endocarp, which are derived from integuments of the ovule and the inner epidermal layer of the ovary wall, respectively (Evenari et al. 1966;Pe´rez-Garcý´a and Escudero 1997;Li et al. 1999a). To date, numerous natural mechanisms of physical dormancy breakdown have been described in different species of family fabaceae, particularly relating to various combinations of temperature and moisture changes, including high temperatures from summer insulation or fire, temperature fluctuations (Va´zquez-Yanes and Orozco-Segovia 1982) and wet heat (van Klinken and Flack 2005). ...
Presence of hard seeds in seed lots reduces the seedling emergence percentage in field leading to non-uniform, lowered plant population and uneven maturity. Seed hardness, characterized by no water imbibition, is controlled by both genetic and environmental conditions. To estimate the broad sense heritability (H 2) of hardseededness, 20 mungbean genotypes with >22% hard seeds were grown in four different environments (Env.) viz., high average temperature and high soil moisture (Env. 1), mild temperature and low soil moisture (Env.2), mild temperature and high soil moisture (Env. 3) and low average temperature and low soil moisture (Env.4). The average per cent hard seed in seed lots was 5.42, 28.7, 19.4 and 33.9 under Env.1, Env.2, Env.3 and Env.4, respectively. The H 2 estimate of hardseededness under Env.1, Env.2, Env.3 and Env.4 was 0.67, 0.97, 0.96 and 0.98, respectively. Decreasing soil moisture, low temperature and delayed harvest increased occurrence of per cent hard seed. The force required in Texture Analysis Machine to break seeds produced under Env.1 ranged from 9.23 to 33.31 Newton while the same ranged from 39.51 to 71.53 Newton in seeds produced under Env.4. The Scanning Electron Microscope images indicated that the seeds produced under low average temperature and soil moisture had a presence of compact outer cell layer with low surface deposition and depression on the seed coat of seeds produced in Env.1 and there is existence of loose cells and cracks in the seed coat with high depression and surface deposition in the seeds produced under Env.4. A lower heritability of 0.67 for hardseededness in high temperature and soil moisture condition suggested that the character is influenced by stress conditions. Growing of genotypes under low temperature and moisture condition is suggested for screening of genotypes for hardseededness in mungbean.
... Other secretory structures in drupes are the cavities and ducts, formed by several specialized cells which release those secondary metabolites to the intercellular space. This characteristic is very conspicuous in the mesocarp of drupes of the Anacardiceae family i.e. [46][47][48][49][50][51][52] , also referred to as lacunar mesocarp 44 . ...
In this work, several attributes of the internal morphology of drupaceous fruits found in the archaeological site Monte Castelo (Rondonia, Brazil) are analyzed by means of two different imaging methods. The aim is to explore similarities and differences in the visualization and analytical properties of the images obtained via High Resolution Light Microscopy and X-ray micro-computed tomography (X-ray MicroCT) methods. Both provide data about the three-layered pericarp (exo-, meso- and endocarp) of the studied exemplars, defined by cell differentiation, vascularisation, cellular contents, presence of sclerenchyma cells and secretory cavities. However, it is possible to identify a series of differences between the information that can be obtained through each of the methods. These variations are related to the definition of contours and fine details of some characteristics, their spatial distribution, size attributes, optical properties and material preservation. The results obtained from both imaging methods are complementary, contributing to a more exhaustive morphological study of the plant remains. X-ray MicroCT in phase-contrast mode represents a suitable non-destructive analytic technique when sample preservation is required.
... Taira (1990) also reported that seed size was negatively correlated with seed water absorption and cooked seed hardness in soybean. Physical dormancy or hardseededness is usually considered to be a heritable trait, controlled by the testa or endocarp, which are derived from integuments of the ovule and the inner epidermal layer of the ovary wall, respectively (Evenari et al. 1966;Pe´rez-Garcý´a and Escudero 1997;Li et al. 1999a). To date, numerous natural mechanisms of physical dormancy breakdown have been described in different species of family fabaceae, particularly relating to various combinations of temperature and moisture changes, including high temperatures from summer insulation or fire, temperature fluctuations (Va´zquez-Yanes and Orozco-Segovia 1982) and wet heat (van Klinken and Flack 2005). ...
Presence of hard seeds in seed lots reduces the seedling emergence percentage in field leading to non-uniform, lowered plant population and uneven maturity. Seed hardness, characterized by no water imbibition, is controlled by both genetic and environmental conditions. To estimate the broad sense heritability (H2) of hardseededness, 20 mungbean genotypes with >22% hard seeds were grown in four different environments (Env.) viz., high average temperature and high soil moisture (Env. 1), mild temperature and low soil moisture (Env.2), mild temperature and high soil moisture (Env. 3) and low average temperature and low soil moisture (Env.4). The average per cent hard seed in seed lots was 5.42, 28.7, 19.4 and 33.9 under Env.1, Env.2, Env.3 and Env.4, respectively. The H2 estimate of hardseededness under Env.1, Env.2, Env.3 and Env.4 was 0.67, 0.97, 0.96 and 0.98, respectively. Decreasing soil moisture, low temperature and delayed harvest increased occurrence of per cent hard seed. The force required in Texture Analysis Machine to break seeds produced under Env.1 ranged from 9.23 to 33.31 Newton while the same ranged from 39.51 to 71.53 Newton in seeds produced under Env.4. The Scanning Electron Microscope images indicated that the seeds produced under low average temperature and soil moisture had a presence of compact outer cell layer with low surface deposition and depression on the seed coat of seeds produced in Env.1 and there is existence of loose cells and cracks in the seed coat with high depression and surface deposition in the seeds produced under Env.4. A lower heritability of 0.67 for hardseededness in high temperature and soil moisture condition suggested that the character is influenced by stress conditions. Growing of genotypes under low temperature and moisture condition is suggested for screening of genotypes for hardseededness in mungbean.
... Lobadium and subgen. Rhus) were distinguished initially based on differences in inflorescence structure, bracts, bracteoles, flowering time, fruit pubescence and flavonoid chemistry (Heimsch 1940;Barkley 1937Barkley , 1942Barkley , 1963Brizicky 1962Brizicky , 1963Young 1975Young , 1979Li et al. 1999). Based on morphological data, Barkley (1937) suggested that subgen. ...
A phylogenetic analysis of Rhus (Anacardiaceae) was conducted using nuclear and chloroplast sequences. The nuclear (Nia-i3) and chloroplast (trnC-trnD) sequence data generated in this study were compared with previously published phylogenies of Rhus based on nuclear ribosomal ITS data and chloroplast trnL-F and ndhF sequences. The Nia-i3 data provided more parsimony-informative characters than ITS; the trnC-trnD data provided the most parsimony-informative characters among three chloroplast markers. All data sets support the monophyly of Rhus. Within Rhus, nuclear data support the monophyly of subgen. Lobadium and the monophyly of subgen. Rhus. Chloroplast data suggest a paraphyletic subgenus Lobadium with R. microphylla and R. rubifolia of subgen. Lobadium placed within subgen. Rhus. Rhus coriaria and R. michauxii of subgen. Rhus also have discordant positions in cpDNA and nuclear trees. Each species with discordant positions (R. coriaria, R. microphylla, R. michauxii and R. rubifolia) has a single allele or different alleles of the same species forming a monophyletic group in the nuclear ITS and Nia-i3 data. Incongruence among nuclear and chloroplast datasets, together with the phylogenetic positions, sympatric distributions, and morphological intermediacy of discordant taxa, suggest possible reticulate evolution among members of Rhus.
Information in the literature and unpublished results of the authors on Dobinea were used to determine the kind [class(es)] of seed (true seed + endocarp) dormancy and of non-dormancy of genera in all five tribes of Anacardiaceae, and the results were examined in relation to the taxonomic position and endocarp anatomy within the family. Reports of both seed germination and endocarp anatomy were found for 15 genera in tribe Spondiadeae, 6 in tribe Anacardieae, 30 in tribe Rhoeae, 3 in tribe Semecarpeae and 1 in tribe Dobineeae. In Spondiadeae ( Spondias -type endocarp), Anacardieae, Semecarpeae and Dobineeae ( Anacardium -type endocarp), seeds are either non-dormant (ND) or have physiological dormancy (PD). In Rhoeae ( Anacardium -type Rhoeae Groups A, B, C and D endocarps), on the other hand, seeds are ND or have physical dormancy (PY), PD or PY + PD. PY/PY + PD in this tribe seems to be restricted (or nearly so) to Rhus s.s . and closely related genera (e.g. Cotinus , Malosma and Toxicodendron ) with an Anacardium -type Rhoeae Group A endocarp. However, seeds of other genera (e.g. Astronium and Schinus ) with this type of endocarp and those with Rhoeae Group B (e.g. Pistacia ), Group C (e.g. Pentaspadon ) and Group D (e.g. Heeri a) endocarps are either ND or have PD. The fossil fruit record strongly suggests that present-day relationships between diaspore dormancy (or non-dormancy), endocarp structure and taxonomic position within Anacardiaceae extend back to at least the Palaeogene.
Astronium and Myracrodruon are small genera of Anacardiaceae characterized by having fruits with calycinal wings, which play an important role in dispersion. Molecular phylogenetic studies have indicated that both genera form a monophyletic clade, but the taxonomic circumscription remains controversial, with several discussions either recognizing Myracrodruon as a genus or an infrageneric category of Astronium. In this study, the fruit anatomy of both genera was reevaluated to further develop the understanding of their circumscription and taxonomic position. To this end, the morphoanatomy of the ripe fruits of Myracrodruon balansae and seven species of Astronium was analyzed using standard techniques of light microscopy. In addition, the fruit ontogeny in both genera was evaluated for distinguishable differences and similarities among them. As a result of the emanating study, it can be concluded that fruits of Astronium and Myracrodruon, previously classified as pseudosamara and drupe, respectively, should both be called pseudosamara. Findings such as uniseriate exocarp, parenchymatic mesocarp with large secretory ducts, endocarp organized in discrete layers, and similar development of the calycinal wings support the inclusion of Myracrodruon as a section of Astronium.
Most species of Anacardiaceae have drupes containing secretory structures.. Th e substances produced by these structures may have importance to industry and folk medicine, and may even cause allergenic eff ects. Th is work describes the ontogeny of pericarp of Tapirira guianensis with an emphasis on the secretory structures present at diff erent stages of development. Ovary and fruits in various stages of development were collected, fi xed and processed for studies using light and scanning electron microscopy according to conventional techniques. Histochemical tests were employed to identify the major metabolites present in the tissues. Th e fruit is a drupe formed by exocarp, mesocarp containing secretory ducts and idioblasts, and endocarp with some lignifi ed layers. Fruit growth occurs through the division and elongation of cells. Th e secretory ducts produce mainly phenols and lipids and are active during all stages of development. Th e secreted substances protect the fruit against pathogens and predators. In ripe fruits the cells of the mesocarp accumulate starch. Th is study is the fi rst report of the presence of a secretory endocarp in young fruits of a species of Anacardiaceae. Th e substances produced by the endocarp in early developmental stages may play an important role in seed dispersal and germination.
Most species of Anacardiaceae have drupes containing secretory structures.. The substances produced by these structures may have importance to industry and folk medicine, and may even cause allergenic effects. This work describes the ontogeny of pericarp of Tapirira guianensis with an emphasis on the secretory structures present at different stages of development. Ovary and fruits in various stages of development were collected, fixed and processed for studies using light and scanning electron microscopy according to conventional techniques. Histochemical tests were employed to identify the major metabolites present in the tissues. The fruit is a drupe formed by exocarp, mesocarp containing secretory ducts and idioblasts, and endocarp with some lignified layers. Fruit growth occurs through the division and elongation of cells. The secretory ducts produce mainly phenols and lipids and are active during all stages of development. The secreted substances protect the fruit against pathogens and predators. In ripe fruits the cells of the mesocarp accumulate starch. This study is the first report of the presence of a secretory endocarp in young fruits of a species of Anacardiaceae. The substances produced by the endocarp in early developmental stages may play an important role in seed dispersal and germination.
The reference list of 874 field botany entries principally from 1985 to 2006 updates two previous reference lists, the last of which appeared in 1989. Seventy-seven relevant entries through 1987 are included that were not indexed in the last reference list. One hundred fifty-two entries are from 1989 or earlier, 391 from the 1990s, and 331 since 2000. The references include 606 peer-reviewed journal articles, 67 scientific botanical books, 62 technical articles, 46 theses, 30 technical reports, 22 dissertations, 18 book chapters, and 23 popular books. The four largest botanical subjects within 11 subdivisions are floristics (247), synecology (205), autecology (134), and systematics (126).
A cladistic analysis is performed using 94 morphological and biochemical characters for 42 genera to compare a phylogeny based on morphological data with those obtained using different genes (rbcL, atpB, 18S RNA, matK) or their combination with morphological data, and to understand the floral evolution within the expanded Brassicales (Capparales) relative to Sapindales and Malvales. The tree produced with morphological data is congruent with those obtained from macromolecular studies in obtaining a well-supported glucosinolate-producing clade and an expanded Sapindales. The combined analysis of the morphological and molecular characters is generally well resolved with support for many of the relationships. The inclusion of the fossil taxon Dressiantha demonstrates the value of inserting fossil evidence in phylogenetic analyses. However, the fossil appears to be related to the Anacardiaceae and not to the Brassicales. The core Brassicales are well supported by a number of synapomorphies, although the internal position of Tovariaceae and Pentadiplandraceae is not well resolved. Emblingiaceae appears to be related to Bataceae and Salvadoraceae. Several significant morphological characters are mapped on the combined trees and their evolutionary significance is discussed. Within Brassicales and Sapindales several well supported clades can be recognized which merit ordinal or subordinal status, putting the present orders at a higher level; these include: Tropaeolales, Setchellanthales, Batidales, Brassicales (Brassiciflorae), Burserales, Sapindales and Rutales (Sapindiflorae). The present scheme of affinities within the Brassicales corresponds well with a gradual morphological evolution in the order. © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society, 2006, 151, 453–494.
Six varieties are recognized in Acacia caven (Leguminosae, Mimosoideae; Acacia subg. Acacia, subsection Polyseriae), based on herbarium studies of vegetative characters, population-level studies of fruit and seed characters, and a map of the species' distribution and morphological variation patterns in southern South America. Two new varieties are described. Ecological and evolutionary aspects of carpological variations are discussed, and a framework is established for further studies in this and related species.
This is the first report on the structure of the pericarp and seed coat of Rhus problematodes Merxm. & Roessl., a curious microphyllous shrublet of very limited distribution in the southern desert region of Namibia. Mainly on the basis of macromorphology, it was hitherto considered to stand somewhat apart from other African members of Rhus L. (sect. Gerontogeae Engl.). R. problematodes clearly agrees with other species of Rhus in its basic pericarp and seed-coat characteristics, including a single-seeded unilocular drupaceous fruit, parenchymatous mesocarp with secretory ducts, ridged outer endocarp, inner endocarp composed of three discrete layers, and an endotegmic, partially pachychalazal seed coat. The scarcity of stomata and heavy deposition of cutin in the exocarp possibly reflect adaptations to its arid habitat. Evidence from fruit and seed structure, combined with that from other sources, reconfirms the view that it is a highly specialized species of Rhus showing several xeromorphic, mainly macromorphological, reductions. The shared presence of glandular stellate hairs and reduced foliage leaves suggests that it might be closely allied to R. horrida Eckl. & Zeyh., a species from Namaqualand.
Rhus longispina Eckl. & Zeyh. and R. pterota Presl are two woody shrubs which are common in the eastern and southern Cape Province. Because of shared habitats and a superficial morphological similarity, these species have been regarded as conspecific and known as R. longispina for over one hundred and fifty years. A table showing the diagnostic characters separating the two species and a detailed description of each is given, followed by a list of selected specimens indicating their distribution.
An exocarp sensu stricto develops from the outer epidermis of the ovary wall. At maturity it comprises extensively radially elongated palisade-like parenchyma cells. Besides having an outer cuticle, the outer tangential and outer parts of the radial cell walls of these cells are strongly cutinized. Large, permanently open stomata and saucer-shaped depressions also characterize the exocarp. The mature mesocarp sensu stricto consists of secondarily thickened parenchyma and brachysclereids. An abundance of tanniniferous deposits and crystals, as well as secretory ducts associated with the vascular bundles also form part of the mature mesocarp. Derivatives of the inner epidermis of the ovary wall differentiate into the stratified endocarp sensu stricto . At maturity this comprises consecutive layers of macrosclercids, osteosclereids (typified by a capirate part and cell wall flutes), brachysclereids, and crystalliferous sclereids. Pericarp structure is related to its taxonomic significance and the possible role of micromorphological characters in the survival strategy of Ozoroa paniculosa. It is shown that ontogenetic studies contribute to the precise interpretation of previously described cell layers, ensuring that homologous tissues are compared in different taxa.
InLithraea brasiliensisMarchand the exocarp is characterized by brachysclereids and the parenchymatous mesocarp by large secretory ducts; inner sclerenchymatous ridges are absent in the mesocarp. The stratified endocarps.s.comprises a crystal layer, palisade-like brachysclereids, osteosclereids and macrosclereids. The osteosclereids are characterized by a distinct light line orlinea lucida, which has hitherto also been recorded in a species ofRhus. In the partially pachychalazal seed, a typical Anacardiaceae-like hypostase typifies the chalazal part of the seed coat, while the integumentary seed coat reveals a well preserved outer epidermis, a compressed endotegmen and well developed inner cuticular layer. Our comparison of the characters of the ovule, fruit and seed ofL. brasiliensiswith those of various species ofRhusand other genera of the tribe Rhoeae (some closely related) presents evidence thatL. brasiliensiscould be most closely associated with the genusRhus.
Heeria argentea(tribe Rhoeae), a monotypic, dioecious tree, is endemic to the core area of the Cape Floristic Region. The mature exocarp consists of a uniseriate layer of palisade-like epidermal cells, interspersed with modified stomata. The mature endocarpsensu strictodevelops solely from the inner epidermis. It is essentially two-layered and resembles the state inProtorhus longifolia. This endocarp is here proposed as a distinct fourth endocarpal subtype under the so-calledAnacardium-type. The large, pachychalazal, recalcitrant seed develops from the single, anatropous, bitegmic, crassinucellate ovule. This ovule is characterized by an extensive chalaza, vascularization and Anacardiaceae-type hypostase. The pachychalazal seed coat contains abundant vascular bundles and a tanniniferous hypostase. The inner epidermis of the inner integument differentiates into an endotegmen. The contribution of the integuments towards seed coat development is negligible. Concerning characters of the disc in the female flower, the meso- and endocarp, as well as seed size, degree of pachychalazy, nutrient reserves (starch) in the chlorophyllous cotyledons and hypogeal germination,Heeriashows a very close phylogenetic relationship toProtorhus longifolia. However, fruit and seed structure clearly supports the taxonomic separation ofHeeriafromOzoroa. Data also support the view thatHeeriais a tropical relict, and the hypothesis that pachychalazy, greater seed size, as well as recalcitrant seed viability behaviour constitute ancestral seed character states. Pachychalazy is regarded as a functional adaptation for more efficient transfer of nutrients.
In Protorhus namaquensis the outer epidermis of the ovary forms the exocarp. At maturity it is uniseriate and consists of palisade-like parenchyma
cells and modified stomata (MS). A cuticle, extensive cutinization of the outer cell walls and starch also characterize the
exocarp. The mesocarp develops from the ground tissue of the ovary wall and includes an outer zone of large-celled tanniniferous
parenchyma, secretory ducts associated with some of the vascular bundles, prismatic crystals of calcium oxalate and brachysclereids.
The inner epidermis of the ovary undergoes successive periclinal divisions whose derivatives form the mature endocarp. It
is stratified and tetraseriate, comprising successive layers (from mesocarp inwards) of crystalliferous cells, brachysclereids,
osteosclereids and macrosclereids. The morphology of the female flower, and the fruit structure of P. namaquensis are compared with that of P. longifolia (lectotype of the genus and only other African species) and species of Ozoroa. We present abundant evidence that P. namaquensis should be associated with some members of the genus Ozoroa , rather than with P. longifolia. The new combination, Ozoroa namaquensis (Sprague) Von Teichman & Van Wyk, is proposed. Characters of the perianth and pericarp, inter alia the occlusion of the pores of most MS, are considered adaptations of the species to its harsh semi-desert habitat.Copyright 1994, 1999 Academic Press
1. Periodic measurements were made of the development of the fruit, seed, and embryo of the Paheri mango, Mangifera indica L. All parts exhibited a sigmoid type of curve when growth data, such as length, diameter, fresh weight, and volume, were plotted against time. 2. A delay in embryo growth for about 4 weeks following fertilization was found to occur, but by 2 weeks later the embryo completely filled the seed coats; growth of the two parts thereafter was rapid until about 12-13 weeks after fertilization and ceased when the husk hardened. 3. Growth of the ovary, at first, was more rapid than that of the seed, but by approximately 10 weeks following fertilization the seed completely filled the loculus, a condition which persisted through fruit maturation. 4. Endocarp lignification occurred during a period of 3 weeks, beginning about 10 weeks after fertilization. The husk, seed, and embryo remained constant in size after husk hardening occurred, but the fleshy part of the fruit continued to enlarge slowly...
Heartwood flavonoids of 23 taxa of Rhus L. were surveyed in order to assess infrageneric relationships and classification. Fourteen flavonoids and two coumarins were detected in the heartwood extracts. All taxa were characterized by a flavonoid complement consisting of eight 5-deoxyflavonoids involving several aglycone classes (e.g., flavonols, flavones, aurones, chalcones and dihydroflavonols) and the aurone rengasin. None of the 5-hydroxyl analogs of the 5-deoxyflavonoids were detected in the heartwood extracts. Infraspecific flavonoid patterns were uniform in different populations, although the presence of 3',4'-dihydroxyflavone 4'-O-,8-glucoside varied in some taxa. Taxa of Rhus subgenus Rhus consistently differed from all taxa of Rhus subgenus Lobadium in lacking glycosides of fisetin, butein and 3',4'-dihydroxyflavone. The major evolutionary trend in the heartwood flavo
Pericarp structure is surveyed in 29 genera. Homologous regions termed exocarp, mesocarp and endocarp are established. While exocarp and mesocarp structure show some uniformity, there are two very distinct types of endocarp, designated the Anacardium-type and the Spondias-type. The distribution of these indicates that the current division of the family into five tribes is artificial. The occurrence of the Spondias-type in Canarium, a member of the sister group Burseraceae, suggests that this type is plesiomorphic in the Anacardiaceae. In addition, the presence of the Anacardium-type in Blepharocarya (Blepharocaryaceae) and Orthopterygium Qulianiaceae) further supports the inclusion of these taxa in the Anacardiaceae.
The first overall study of pericarp anatomy ofCoriaria is presented to discuss its evolution and relationships within a genus. All 14 species investigated (including 11 narrowly
defined species) have somewhat bilaterally flattened mature fruits with five to seven (or more) longitudinal costae. They
share a usually nine-(or more-)cell-layered (at intercostal region), stratified mature pericarp, which is basically constructed
by an exocarp, an outer, a middle and an inner zone of mesocarp, and an endocarp. While a multi-layered endocarp is composed
of circumferentially elongate fibres, a multi-layered inner zone of the mesocarp comprises longitudinally elongate fibres.
Despite its uncertain systematic value, the presence of those fibres arranged crisscross is a characteristic feature of the
genus. Comparisons among species indicate thatCoriaria terminalis, a species of the Eastern Hemisphere, retains a basic or archaic, well-stratified pericarp structure similar to the one found
in all the species investigated of the Southern and Western Hemisphere, and that four species of Asia,Coriaria napalensis, C. sinica, C. intermedia andC. japonica, share a specialized structure (lacking the outer zone of the mesocarp) indicative of their mutual close affinity. Comparisons
further suggest distinctness ofCoriaria intermedia, as well as variously derived position ofC. myrtifolia andC. japonica.