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Developing Seeds (developing + seed)
Selected AbstractsDevelopmental Anatomy and Morphology of the Ovule and Seed of Heliconia (Heliconiaceae, Zingiberales)PLANT BIOLOGY, Issue 1 2006D. G. Simão Abstract: The developmental anatomy and morphology of the ovule and seed in several species of Heliconia were investigated as part of an embryological study of the Heliconiaceae and to provide a better understanding of their relationships with the other families of the Zingiberales. Heliconia species have an ovule primordium with an outer integument of both dermal and subdermal origin. The archesporial cell is divided into a megasporocyte and a single parietal cell, which in turn are divided only anticlinally to form a single parietal layer, disintegrating later during gametogenesis. The embryo sac was fully developed prior to anthesis. In the developing seed, the endosperm was nuclear, with wall formation in the globular stage; a nucellar pad was observed during embryo development, but later became compressed. The ripe fruit contained seeds enveloped by a lignified endocarp that formed the pyrenes, with each pyrene having an operculum at the basal end; the embryo was considered to be differentiated. Most of these characteristics are shared with other Zingiberales, although the derivation of the operculum from the funicle and the formation of the main mechanical layer by the endocarp are unique to the Heliconiaceae. [source] Antioxidative Enzymes and Sucrose Synthase Contribute to Cold Stress Tolerance in ChickpeaJOURNAL OF AGRONOMY AND CROP SCIENCE, Issue 5 2009S. Kaur Abstract Chickpea is sensitive to low temperature (<10°C) during its reproductive stage. Low temperature adversely affects the development of pods and seeds. This study was undertaken to investigate the role of sucrose metabolizing enzymes in seed development and potential of antioxidative enzymes in protecting seeds and podwalls from the deleterious effects of cold stress in advanced cold tolerant chickpea breeding lines. Healthy pod set was observed in these tolerant lines in the end of December where as low temperature susceptible PBG-1 did not flower. Two lines ICCV 96029 and ICCV 96030 showed susceptible characters such as reduced flowering, blackened and shrivelled seeds and yellowish pods in comparison to other cold stress tolerant lines due to sudden dip of temperature (<1 °C) during the first week of January. These two lines were, therefore, treated as susceptible checks in comparison to other tolerant lines. A significantly higher activity and specific activity of sucrose synthase was observed in seeds of most of the cold tolerant lines in comparison with ICCV 96029 and ICCV 96030, thereby providing sugars as well as sugar nucleotides for their growth and starch synthesis during unfavourable low temperature. The developing seeds and podwalls of tolerant genotypes had higher activities of antioxidant enzymes, i.e. catalase, ascorbate peroxidase and glutahione reductase in comparison with ICCV 96029 and ICCV 96030. It appears that the higher activities of antioxidant enzymes in podwall protect the developing seeds from cold stress. [source] Effects of weather variables on grain mould of sorghum in South AfricaPLANT PATHOLOGY, Issue 2 2006G. Tarekegn Effects of weather variables of mould development on sorghum grain were studied over three consecutive seasons in South Africa. Five sorghum hybrids planted at different dates ensured developing seeds were exposed to different weather conditions. Incidence of grain mould fungi was determined at harvest by incubating seeds on 2% malt extract agar. Averages of different weather variables (maximum and minimum temperatures, maximum relative humidity, total precipitation and frequency of precipitation) were determined for all permutations of weekly time intervals for a 2-month postflowering period to identify when these variables and pathogen incidence were significantly correlated. Significant correlations were used to develop models to quantify relationships between variables. Significant positive correlations were observed between the incidence of mould fungi and weather 4,6 weeks after flowering in the shorter season hybrid cv. Buster, and 5,8 weeks after flowering in the remaining hybrids. In most hybrids, correlations between the incidence of grain mould pathogens, including Alternaria alternata, Curvularia spp. (C. lunata and C. clavata), Fusarium spp. (F. proliferatum and F. graminearum), and Drechslera sorghicola, and average minimum temperature, total rainfall and frequency of rainfall were significant (P = 0·05). In four hybrids, models showing a linear relationship between the logarithm of pathogen incidence and minimum temperature, and in one hybrid, between pathogen incidence and rainfall frequency, were developed. Depending on the hybrid, models that used minimum temperature as predictor described 60,82% of variation in the incidence of pathogens. Frequency of rainfall explained 93% of the variation in pathogen incidence in one sorghum hybrid genotype. Evaluation of the models using an independent data set yielded average prediction errors near zero, indicating that the models were acceptable. [source] Comparative proteomic and transcriptional profiling of a bread wheat cultivar and its derived transgenic line overexpressing a low molecular weight glutenin subunit gene in the endospermPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 14 2008Federico Scossa Abstract We carried out a parallel transcriptional and proteomic comparison of seeds from a transformed bread wheat line that overexpresses a transgenic low molecular weight glutenin subunit gene relative to the corresponding nontransformed genotype. Proteomic analyses showed that, during seed development, several classes of endosperm proteins were differentially accumulated in the transformed endosperm. As a result of the strong increase in the amount of the transgenic protein, the endogenous glutenin subunit, all subclasses of gliadins, and metabolic as well as chloroform/methanol soluble proteins were diminished in the transgenic genotype. The differential accumulation detected by proteomic analyses, both in mature and developing seeds, was paralleled by the corresponding changes in transcript levels detected by microarray experiments. Our results suggest that the most evident effect of the strong overexpression of the transgenic glutenin gene consists in a global compensatory response involving a significant decrease in the amounts of polypeptides belonging to the prolamin superfamily. It is likely that such compensation is a consequence of the diversion of amino acid reserves and translation machinery to the synthesis of the transgenic glutenin subunit. [source] Differential proteomic analysis of the endoplasmic reticulum from developing and germinating seeds of castor (Ricinus communis) identifies seed protein precursors as significant components of the endoplasmic reticulumPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 9 2007Daniel J. Maltman Abstract The endoplasmic reticulum is a major compartment of storage protein and lipid biosynthesis. Maximal synthesis of these storage compounds occurs during seed development with breakdown occurring during germination. In this study, we have isolated four independent preparations of ER from both developing and germinating seeds of castor bean (Ricinus communis) and used 2-D DIGE, and a combination of PMF and MS/MS sequencing, to quantify and identify differences in protein complement at both stages. Ninety protein spots in the developing seeds are up-regulated and 19 individual proteins were identified, the majority of these are intermediates of seed storage synthesis and protein folding. The detection of these transitory storage proteins in the ER is discussed in terms of protein trafficking and processing. In germinating seed ER 15 spots are elevated, 5 of which were identified, amongst them was malate synthetase which is a component of the glyoxysome which is believed to originate from the ER. Notably no proteins involved in complex lipid biosynthesis were identified in the urea soluble ER fraction indicating that they are probably all integral membrane proteins. [source] Endoreduplication in cucumber (Cucumis sativus) seeds during development, after processing and storage, and during germinationANNALS OF APPLIED BIOLOGY, Issue 3 2009M. Rewers Abstract Flow cytometry was used to study endoreduplication in developing, stored and germinating seeds of cucumber (Cucumis sativus). Fruits growing in a commercial seed production field were collected every 7 days, starting 14 days after pollination (DAP) up to 63 DAP (commercial harvest time). Seeds were isolated and the proportion of nuclei with different DNA contents in the whole seeds and in the embryos was analysed. Germination capacity of fresh and dried seeds at 25°C was established. In addition, the same analyses were performed on the seeds after processing (fermentation, drying and cleaning), following 1 and 2 years of storage, and after imbibition for 3, 6 and 12 h. In the young developing seeds, endoreduplication up to 128C occurred but this decreased to 8C by maturity. The proportion of endosperm nuclei was the highest at 21 DAP (30%) and then decreased to below 14% at harvest and 8% after processing. In the mature processed seeds, the majority of embryo nuclei (about 80%) contained 2C DNA; however, about 2% of endoreduplicated (8C) nuclei were still present. Seeds did not show any germination capacity up to 21 DAP; then it gradually increased to reach 100% as early as 49 DAP, 2 weeks before commercial harvest time. The relationship between seed maturity, germination and cell cycle status is discussed. The mean C-value of the seed cells as well as the (4C + 8C + 16C)/2C ratio are recommended as markers of cucumber seed maturity and the advancement of germination/priming (the stage of germination sensu stricto). [source] | ||||||||||