Stages Of Seed Maturation Research Articles

Effects of time of water stress on flowering, seed yield and seed quality of common onion (Allium cepa L.) under the arid tropical conditions of Sudan

An experiment was conducted for two consecutive seasons to investigate the effect of water stress on seed yield and seed quality of onion (Allium cepa L.). Water stress was imposed on the plants at four stages of reproductive growth, namely, bolting, flowering, seed formation and seed maturation stage, respectively. Watering was withheld for an interval of 2 weeks only once for every treatment “growth stage” during the first season, while during the second season, the interval of watering was extended to 3 weeks. Numbers of leaves per plant, umbel diameter, number of florets per umbel, number of seeds per florets; number of seed stalks per plant, 1000 seed weight per plant and seed yield and seed quality were recorded. Water stress at any stage of reproductive growth significantly reduced seed yield and its effect was variable depending on plant growth stage. Based on 1000 seed weight per seed head, bolting followed by anthesis were the most sensitive growth stages during the first season. Water stress at the time of anthesis significantly decreased the diameter of seed head when compared to control. The average number of seeds per floret was significantly decreased by stressing at bolting compared to all treatments. In the second season, seed formation stage was the most critical only followed by anthesis stage. When seed yield per plant was measured, the most sensitive stage was bolting. Number of florets per umbel and umbel diameter were reduced by water stress. In the first season, 1000 seed weight was not affected, but in the second season, it was significantly reduced with water stress at seed formation stage. Seed germination and field emergence were not affected. However, water stress at bolting in the second season resulted in lower seed quality. Some stress treatments were observed to promote seed germination and seedling emergence.

Evidence for inbreeding depression in the tree Robinia pseudoacacia L. (Fabaceae)

The magnitude of inbreeding depression within populations is important for the evolution and maintenance of mixed mating systems. However, data are sparse on the magnitude of inbreeding depression in Robinia pseudoacacia. In this study, we compared differences in the mature seed set per fruit, seed mass, germination success, and seedling growth between self- and cross-pollination treatments and estimated the inbreeding depression at 3 stages: seed maturation, seedling emergence, and seedling growth at 10 and 20 weeks. We found that progenies resulting from cross-pollination treatments showed significantly higher fitness than progenies resulting from self-pollination, causing high levels of inbreeding depression. Inbreeding depression was not uniformly manifested, however, over the 3 stages. Inbreeding depression was the greatest between fertilization and seed maturation stage (δ = 0.5419), and the seedling emergence (0.3654) stage was second. No significant differences in seedling growth were observed between selfed and crossed progenies. The cumulative inbreeding depression (δ) across all 3 stages averaged 0.7452. Inbreeding depression may promote outcrossing in R. pseudoacacia by acting as a post-pollination barrier to selfing. The large difference in the seed set between self- and cross-pollination that we detected indicated that inbreeding depression would probably be a reasonable explanation for the high abortion and low seed set in R. pseudoacacia.

Effect of different harvest time on yield and forage quality of three varieties of common millet (Panicum miliaceum)

Monitoring forage quality is one of the most important factors of essential and good management of a farm. The most important factor about plants and forage quality is growing stage which can help to identify the optimum time of harvest. As different varieties of plants have different harvest times and quality, in order to search the variety effect on forage yield and quality traits, three varieties of common millet (Panicum miliaceum), namely, KCM2, KCM7, and KCM9 in three phenological growth stages, including booting, milky, and seed maturity stages were studied. Experiments in factorial form were surveyed in Karaj district, Iran with three replications in the form of randomize complete blocks design in 2009. Except ash percentage, there were significant differences among three growth stages in other quality traits and forage yield (P < 0.01). Significant differences among varieties for dry and wet forage yield, dry matter digestibility (DMD), water soluble carbohydrates, and acid detergent fiber percentage were also observed. However, interaction effect of variety and phenological growth stage were not significantly different on acid detergent fiber, crude fiber (CF), and ash percentages. Almost in all varieties, the amount of crude protein (CP) and DMD decreased during developing growth stages, while the amount of CP increased. KCM2 variety had the highest forage quality based on measurement indices and it was chosen as the best variety with regard to the most desirable forage yield. Booting stage (first phenological stage) was the most desirable in quality traits among the three growth stages. However, considering the little difference between the first and second stages in dietary energy, the second stage (milky stage) was recommended as the most suitable time for harvesting, because of high yield and compatibility of farm to plant. Key words: Quality traits, forage yield, dry matter digestibility, crude protein, growth stage, crude fiber.

Next-Generation Sequencing of Crown and Rhizome Transcriptome from an Upland, Tetraploid Switchgrass

The crown and rhizome transcriptome of an upland tetraploid switchgrass cultivar cv Summer well adapted to the upper Midwest was investigated using the Roche 454-FLX pyrosequencing platform. Overall, approximately one million reads consisting of 216 million bases were assembled into 27,687 contigs and 43,094 singletons. Analyses of these sequences revealed minor contamination with non-plant sequences (< 0.5%), indicating that a majority were for transcripts coded by the switchgrass genome. Blast2Gos comparisons resulted in the annotation of ~65% of the contig sequences and ~40% of the singleton sequences. Contig sequences were mostly homologous to other plant sequences, dominated by matches to Sorghum bicolor genome. Singleton sequences, while displaying significant matches to S. bicolor, also contained sequences matching non-plant species. Comparisons of the 454 dataset to existing EST collections resulted in the identification of 30,177 new sequences. These new sequences coded for a number of different proteins and a selective analysis of two categories, namely, peroxidases and transcription factors, resulted in the identification of specific peroxidases and a number of low-abundance transcription factors expected to be involved in chromatin remodeling. KEGG maps for glycolysis and sugar metabolism showed high levels of transcript coding for enzymes involved in primary metabolism. The assembly provided significant insights into the status of these tissues and broadly indicated that there was active metabolism taking place in the crown and rhizomes at post-anthesis, the seed maturation stage of plant development.

Rice interspecies hybrids show precocious or delayed developmental transitions in the endosperm without change to the rate of syncytial nuclear division

In angiosperms, interspecific crosses often display hybrid incompatibilities that are manifested as under-proliferation or over-proliferation of endosperm. Recent analyses using crosses between Arabidopsis thaliana and its related species with different ploidy levels have shown that interspecific hybridization causes delayed developmental transition and increased mitotic activity in the endosperm. In this study, we investigated endosperm development in interspecific crosses between diploid Oryza species. In a cross between female O.sativa and male O.punctata, we found that the hybrid endosperm was reduced in size and this cross was associated with precocious developmental transition. By contrast, the cross between O.sativa and O.longistaminata generated enlarged hybrid endosperm at the mid-point of seed development and this cross was associated with delayed developmental transition. Subsequently, the hybrid endosperm displayed a shriveled appearance at the seed maturation stage. We found that the accumulation of storage products and the expression patterns of several marker genes were also altered in the hybrid endosperm. By contrast, the rate of syncytial mitotic nuclear divisions was not significantly affected. The gene OsMADS87 showed a maternal origin-specific expression pattern in rice endosperm, in contrast to its Arabidopsis homologue PHERES1, which shows paternal origin-specific expression. OsMADS87 expression was decreased or increased depending on the type of developmental transition change in the hybrid rice endosperm. Our results indicate that one of the interspecies hybridization barriers in Oryza endosperm is mediated by precocious or delayed developmental alterations and de-regulation of OsMADS87, without change to the rate of syncytial mitotic nuclear division in the hybrid endosperm.

Desiccation, postharvest maturity and seed aging of tall oat-grass

The objectives of this work were to determine whether and at which seed physiological maturity stage the diquat desiccant affects the tall oat-grass (Arrhenatherum elatius) seed quality and yield, as well as the proper storage period between harvest and sowing. Diquat desiccation was evaluated in applications during milk or dough seed maturation stages. Seeds conventionally produced and stored under traditional storage conditions were used for the analyses. Seed samples were drawn every 30th day after harvest (DAH). After the 240th DAH, samples were drawn every 90th day up the to 690th DAH. The highest yield were obtained by desiccation applied at the beginning of the seed dough stage, with a satisfactory seed quality. Both final germination and seedling growth parameters achieved their maximum values between 180th and 240th DAH. Oat-grass seeds preserved satisfactory level of final germination (75%) up to 420th DAH. The application of diquat desiccant at the beginning of seed dough maturity stage can be a good solution for seed production of tall oat-grass. Early spring is the best sowing period for freshly harvested seeds of tall oat-grass regarding germination and seedling growth.

Effect of High Temperature during the Seed Development on Quality and Chemical Composition of Chili Pepper Seeds

An analysis was performed on chili pepper (Capsicum annuum (L.) cv. Huay Si Thon and Shishito) seed vigor and quality produced by plants grown under control and high temperature conditions (29} 2/24}2 and 36 + 2/27} 2Ž, mean day and night temperatures, respectively) after anthesis to elucidate the effect of high temperature during seed development on seed quality. High temperature significantly reduced fruit growth in both varieties . More than 20 % of the seeds produced under the high temperature regime were flat with a dark brown color and did not germinate. High temperature inhibited seed fresh and dry weight increase and the seed size was slightly reduced. Standard germination of Huay Si Thon and Shishito seeds occurring under the high temperature conditions was lower than that of the control seeds by 28 and 25 %, respectively. Similarly, seed vigor was reduced, as evidenced by the reduction in the accelerated aging germination rate and the higher value of the germination index. Protein content was maximal during the early stages of seed development and decreased afterwards continuously during the seed maturation stage, while no conspicuous reduction of the protein content by heat was observed. High temperature reduced the carbohydrate content of seeds by 40 % in Huay Si Ton and 50 % in Shishito, respectively. High temperature reduced the lipid content to less than half. These results suggested that high temperature during seed development reduced chili pepper seed germination and vigor, presumably due to the limitation in the accumulation of storage products, especially carbohydrates, and lipids.

Seed α-D-Galactosides of Selected Vicia Species and Enzymes Involved in Their Biosynthesis

We compared the soluble carbohydrate composition of seeds of ten wild and cultivated species of the genus Vicia. In some Vicia species (V. angustifolia, V. grandiflora, V. sativa, V. sepium) they contained only raffinose family oligosaccharides (RFOs) and in others also D-pinitol and its α-D-galactosides. In terms of galactosyl pinitol composition they were divided into three groups: those accumulating small amounts of mono-, di-, tri-galactosyl pinitol A (GPA, ciceritol and TGPA, respectively) and unknown compound (V. sylvatica and V. hirsuta); those accumulating more ciceritol than TGPA (V. tetrasperma and V. villosa); and those accumulating more TGPA than ciceritol (V. cracca and V. tenuifolia). The differences in the activity of galactosyltransferases engaged in RFOs and galactosyl pinitol synthesis confirmed this classification. Seeds of V. angustifolia, naturally accumulating only RFOs, showed an ability to accumulate exogenously applied D-pinitol or D-chiro-inositol and to form the respective α-D-galactosyl cyclitols. Levels of synthesized galactosides depended on the type and concentration of cyclitol in the feeding solution, and seed maturation stage. However, even a high level of D-pinitol or D-chiro-inositol in the feeding solution caused accumulation of only small amounts of mono- and di-galactosyl pinitols, or tri-galactosyl D-chiro-inositol in seeds of V. angustifolia. Enhanced synthesis of galactosyl cyclitols, mainly mono- and di-galactosides of D-chiro-inositol (fagopyritols), clearly reduced production of verbascose. We suggest that exogenously applied free cyclitols inhibit biosynthesis of tri- and di-galactosides and/or cause substrate competition in enzymes of Vicia species.

Avaliação in situ do feno de Brachiaria decumbens Stapf cv. Basilisk submetido ao tratamento com amônia anidra ou uréia

Brachiaria decumbens Stapf cv. Basilisk hay ammoniation effects were evaluated at Unesp, Câmpus de Jaboticabal , state of Sao Paulo, Brazil, after harvesting at seed maturation stage and submitted to the following treatments: untreated and treated with NH 3 (2.0% and 3.0% DM) or with urea (3.6% and 5.4% DM), using in situ technique with incubation bags in the rumen of fistulated animals. The experiment was conducted in split-plot randomized blocks with 3 replications. Ammoniation increased (P 3 increased (P Brachiaria decumbens hay treatment in advanced maturation stages.

Change in activity and electrophoretic spectra of certain enzymes in cultivated and wild soybean plant leaves

The activity of catalase and esterase complex in soybean leaves increased in the pod formation stage and that of peroxidase in the seed maturation stage. The maximum value of specific catalase and peroxidase activity was noted in wild soybean leaves. Heterogeneity of catalase and esterases decreased and that of peroxidase increased during leaf ontogeny.

Pepper Seed Yield and Quality in Relation to Fruit Position on the Mother Plant

Variation in seed yield and quality in relation to fruit position were determined in hot pepper cultivar during 2004 and 2005. Fruits were harvested from different layers (first, second and third) of the plant. In each layer, fruits were harvested 65 days after anthesis to obtain similar seed maturation stage. Fruit weight, seed yield, seed moisture content, germination at 15 and 25 degrees C, germination after controlled deterioration and mean germination time were determined. Fruit weight and seed yield gradually decreased throughout fructification, from the first to the third layer. Seed moisture content did not change between layers. Moisture remained at values of about 48-50%. The seeds extracted from fruits of the first layer had higher germination and vigour, lower mean germination time than those from the other layers. Seeds from the third layer caused decline in seed quality especially vigour with 69.3%.

The germination characteristics of Scrophularia marilandica L. (Scrophulariaceae) seeds

Investigations on seeds of Scrophularia marilandica L. were undertaken to determine their germination requirements. Seeds were collected from three naturally occurring sites and one greenhouse-grown population in London, Ontario in September and October of 1997. Some were set to germinate immediately after collection; others were stored in or on soil outside and/or under controlled laboratory conditions before testing. Germination was assessed under two light/temperature regimes (35°C 14 h light, 20°C 10 h dark and 25°C 14 h light, 10°C 10 h dark), in continuous darkness, and in the presence of two germination-promoting chemicals (GA3 and KNO3). Fresh seeds germinated best at 35/20°C, while stored seeds germinated best at 25/10°C. No differences in percent germination were found among three seed-maturity stages. All chemical treatments, except 0.01 M KNO3, increased percent germination. Significant differences were found both among and within sites for most chemical treatments, but exposure to 3 × 10−4 M GA3 caused almost every seed to germinate. When compared to the control, both the gibberellic acid and the soil-storage treatments contributed to faster germination. Exposure of seeds to naturally prevailing conditions on the soil surface followed by testing under the 25/10°C regime produced the highest percent germination. No seeds germinated in the dark. In summary, seeds of S. marilandica exhibit physiological dormancy, which can be alleviated by exposure to light, after-ripening and/or cold stratification. It is probable that the differences in germination response among sites can be attributed to differences in environmental conditions during seed production. These experiments indicate that the seeds of S. marilandica must be buried shortly after dispersal in order to form a persistent seed bank.

Systematic Studies of 12S Seed Storage Protein Accumulation and Degradation Patterns during Arabidopsis Seed Maturation and Early Seedling Germination Stages

Seed storage proteins (SSPs) are important for seed germination and early seedling growth. We studied the accumulation and degradation profiles of four major Arabidopsis 12S SSPs using a 2-DE scheme combined with mass spectrometric methods. On the 2-DE map of 23 dpa (days post anthesis) siliques, 48 protein spots were identified as putative full-length or partial alpha, beta subunits. Only 9 of them were found in 12 dpa siliques with none in younger than 8 dpa siliques, indicating that the accumulation of 12S SSPs started after the completion of cell elongation processes both in siliques and in developing seeds. The length and strength of transcription activity for each gene determined the final contents of respective SSP. At the beginning of imbibition, 68 SSP spots were identified while only 2 spots were found at the end of the 4 d germination period, with alpha subunits degraded more rapidly than the beta subunits. The CRC alpha subunit was found to degrade from its C-terminus with conserved sequence motifs. Our data provide an important basis for understanding the nutritional value of developing plant seeds and may serve as a useful platform for other species.

Effects of arbuscular mycorrhizal fungi and Bradyrhizobium japonicum on drought stress of soybean

AbstractMycorrhizal symbiosis can potentially improve water uptake by plants. In a controlled pot culture experiment, soybean plants were inoculated with two species of arbuscular mycorrhizal fungi, Glomus mosseae (Gm) or Glomus etunicatum (Ge), or left non-inoculated (NM) as control in a sterile soil. Four levels of soil moisture (Field capacity, 0.85 FC, 0.7 FC, 0.6 FC) in the presence or absence of the Bradyrhizobium japonicum, were applied to the pots. Relative water content (RWC) of leaf at both plant growth stages (flowering and seed maturation) decreased with the dryness of soil; RWC was higher in all mycorrhizal than non-mycorrhizal plants irrespective of soil moisture level. At the lowest moisture level (0.6 FC) Ge was more efficient than Gm in maintaining high leaf RWC. Leaf water potential (LWP) had the same trend as RWC in flowering stage but it was not significantly influenced by decrease in soil moisture to 0.7 FC during seed maturation stage. Seed and shoot dry weights were affected negatively by drought stress. Mycorrhizal plants, however had significantly higher seed and shoot dry weights than non-mycorrhizal plants at all moisture levels except for seed weight at 0.6 FC. Root mycorrhizal colonization was positively correlated with RWC, LWP, shoot N and K, and seed weight, implying improvement of plant water and nutritional status as a result of colonization. Regardless of moisture treatments, bacterial inoculation caused a significant enhancement in N content and the highest N occurred in rhizobial inoculated plants at 0.85 FC and 0.7 FC. Shoot K was enhanced considerably by both bacterial and fungal inoculations, particularly in plants with dual inoculations where the highest shoot K levels were found. The relatively higher shoot and seed dry weights in plants inoculated with both G. etunicatum and B. japonicum could be ascribed to their higher RWC and LWP, suggesting that drought avoidance is main mechanism of this plant-microbe association in alleviation of water stress in soybean.

Maturation of Arabidopsis Seeds Is Dependent on Glutathione Biosynthesis within the Embryo

Glutathione (GSH) has been implicated in maintaining the cell cycle within plant meristems and protecting proteins during seed dehydration. To assess the role of GSH during development of Arabidopsis (Arabidopsis thaliana [L.] Heynh.) embryos, we characterized T-DNA insertion mutants of GSH1, encoding the first enzyme of GSH biosynthesis, gamma-glutamyl-cysteine synthetase. These gsh1 mutants confer a recessive embryo-lethal phenotype, in contrast to the previously described GSH1 mutant, root meristemless 1(rml1), which is able to germinate, but is deficient in postembryonic root development. Homozygous mutant embryos show normal morphogenesis until the seed maturation stage. The only visible phenotype in comparison to wild type was progressive bleaching of the mutant embryos from the torpedo stage onward. Confocal imaging of GSH in isolated mutant and wild-type embryos after fluorescent labeling with monochlorobimane detected residual amounts of GSH in rml1 embryos. In contrast, gsh1 T-DNA insertion mutant embryos could not be labeled with monochlorobimane from the torpedo stage onward, indicating the absence of GSH. By using high-performance liquid chromatography, however, GSH was detected in extracts of mutant ovules and imaging of intact ovules revealed a high concentration of GSH in the funiculus, within the phloem unloading zone, and in the outer integument. The observation of high GSH in the funiculus is consistent with a high GSH1-promoterbeta-glucuronidase reporter activity in this tissue. Development of mutant embryos could be partially rescued by exogenous GSH in vitro. These data show that at least a small amount of GSH synthesized autonomously within the developing embryo is essential for embryo development and proper seed maturation.

Cytochemical Localization of Phenolic Compounds in Columella Cells of the Root Cap during Maturation of Seeds of Brassica napus L.

Abstract: Ultrastructural localization of phenolic compounds in the columella of the root cap of a canola embryo in Brassica napus L. during subsequent seed maturation stages was investigated. In bright green seeds the first signs of maturation and appearance of the first phenolic structures in the cell nuclei and cytoplasm in the area of the initial centre were found. Phenolics spread acropetally, gradually covering the whole columella in the dark green seeds. An increase in the number of phenolics occurred, together with an increase in the number of endoplasmic reticulum structures and in storage materials. In brown seeds, together with ultrastructural degradation and the end of production of storage substances, the number of phenolic deposits in the nucleus and cytoplasm decreases until their disappearance in black dormant seeds. Simultaneously, numerous phenolic deposits appear between the plasmalemma and the cell walls in the outer layer of the cap columella.

Genotypic differences in cadmium uptake and distribution in soybeans

In order to investigate the genetic differences in uptake and distribution of cadmium in soybeans, 17 varieties of soybean were grown first in soil and then four or five varieties of soybean were grown in nutrient solution with different levels of cadmium.Significant genotypic differences in seed cadmium levels were found. The seed cadmium concentration was lowest for the En-b0-1-2 soybean variety, and highest for Harosoy, in both field and pot experiments. The seed cadmium levels of Tohoku 128, a cross between Enrei and Suzuyutaka, were intermediate between those of the parents. For four soil types, containing from 0.2 to 6.5 mg kg−1 extractable cadmium, the ranking of soybean genotypes based on seed cadmium level was similar, indicating that there is a genetic factor involved in the varietal differences in cadmium concentration. Among the four soybean varieties tested in one experiment in the present study, the cadmium concentrations in leaves, stems and pods as well as the total cadmium uptake were lowest for En-b0-1-2. These results suggest that cadmium uptake and/or translocation from root to shoot are low in En-b0-1-2. In solution culture containing 100 μg L−1 cadmium, the cadmium concentrations in seeds, stems and pods at the seed maturation stage were also the lowest for En-b0-1-2. In a second experiment, the cadmium concentrations in the leaves, stem and petiole were lower at both 7 and 15 days after the addition of cadmium to the nutrient solution for En-b0-1-2 and Enrei than for Tohoku 128, Suzuyutaka and Harosoy; however, the cadmium concentrations of roots for En-b0-1-2 and Enrei were higher than for the other varieties. We propose that the lower levels of cadmium found in the seeds of certain varieties of soybean result from the combination of lower initial uptake and retention of higher levels of cadmium in the roots, thus limiting its translocation to the shoot.

Serial Adjustments in Allocation to Reproduction: Effects of Photosynthetic Genotype

Life history theory predicts that trade‐offs between size and reproductive traits should increase when resources are more limited. This prediction is commonly tested by using plant size as a surrogate for resource status or by comparing trade‐offs across treatments that experimentally manipulate size or environmental resources. In this study, we take a novel and potentially effective approach and compare two well‐characterized genotypes of Amaranthus hybridus that differ in photosynthate availability. We consider these genotypes a valuable proxy for inherent genetic variation in resource status because photosynthate is a resource base that will most likely underlie many allocation‐based trade‐offs. We examine a series of hierarchical stages in which adjustments in allocation are predicted to affect seed production, and we test whether these adjustments are more dramatic in the genotype with less available photosynthate. We find that the response to resource limitation was not to decrease allocation to reproduction, alter floral sex ratio, or abort more seed. Rather, the resource limitation increased the trade‐off between seed number and size. By delaying resource‐based adjustments in allocation until the seed maturation stage, this species has a strategy that places priority on maximizing the quantity rather than the quality of offspring. Genetically based differences in photosynthate availability can affect the relationships between size and reproduction and therefore affect fitness.

Evaluation of salt tolerance in rice genotypes by multiple agronomic parameters

Summary The lack of an effective evaluation method for salt tolerance in the screening process is one of the reasons for limited success in conventional salt tolerance breeding. This study was designed to identify useful agronomic parameters for evaluation of salt tolerance and to evaluate genotypes by multiple agronomic parameters for salt tolerance at different growth stages. Twelve genotypes were grown in a greenhouse in sand and irrigated with nutrient solutions of control and treatments amended with NaCl and CaCl2 (5:1 molar concentration) at 4.4 and 8.2 dS m −1 electrical conductivity. Wide genotypic differences in relative salt tolerance based on seedling growth were identified. The duration of reproductive growth between panicle initiation and anthesis was either reduced or increased by salinity, but the response was not strictly correlated with relative salt tolerance in seed yield among genotypes. Wide genotypic differences in relative salt tolerance based on spikelet and tiller numbers were identified. Few genotypic differences were identified for fertility and kernel weight. Spikelet and tiller numbers contributed most of the variation to seed yield among parameters investigated. When genotypes were ranked for salt tolerance based on the means of multiple parameters, dramatic changes of salt tolerance at early and seed maturity stages were observed in two genotypes, GZ5291-7-1-2 and GZ178. IR63731-1-1-4-3-2 was identified with a favourable combination of salt tolerance at early seedling and seed maturity stages. Cluster group ranking of genotypes based on multiple agronomic characters can be applied in salt tolerance breeding to evaluate salt tolerance and may have great advantage over conventional methods.

Effects of phenological constraints on sex allocation in cosexual monocarpic plants

The effects of two phenological constraints in resource investment to reproduction – resource limitation at the flowering stage and unpredictability of resources gained after flowering – on the resource allocation between male and female functions in monocarpic plants are considered using the ESS (evolutionarily stable strategy) approach. The model predicts that the sex allocation including the seed maturation stage has a female bias, when the quantity of reproductive resources available at flowering is small compared with that which is obtained after flowering, or when the cost of seed maturation relative to ovule production is low. The fluctuation of the quantity of resources available for seed maturation favors overproduction of ovules. As a result, more resources are allocated to female function and less to male function at flowering. The ESS allocation depends on the variability of resources and the cost of seed maturation relative to ovule production. The probability that total resource allocation has a female bias becomes higher than 0.5, and it depends on the cost of seed maturation relative to ovule production rather than resource variability. On the other hand, the probability that resource allocation has a female bias decreases with resource variability if we assume that the floral sex ratio is fixed. Future studies of plant sex allocation would profit by taking account of the phenological process of reproduction such as ovule production or seed maturation.