摘要:

Theδ‐zein, a minor component of the maize prolamin, shows extensive immunological cross‐reactivity withα‐ andβ‐zeins. The adsorption of an anti‐δ‐zein serum sequentially with cross‐reacting antigens revealed that only about 18% of the reactivity of the antiserum was directed to epitopes unique toδ‐zein. The localization of the various zein classes within the protein bodies of endosperm cells is important to understanding the synthesis, sequestering, and utilization of these storage proteins. Sections of 28 days after pollination (DAP) isolated protein bodies and 18 and 40 DAP whole endosperms were reacted sequentially with whole anti‐δ‐zein serum and gold‐conjugated protein A. The results showed intense gold labeling in the core (inside the peripheral zone) and weak labeling in the periphery of the sections. This localization was not definitive in view of the above‐mentioned cross‐reactivities. To obtain an unequivocal localization, the whole antiserum was adsorbed withα‐, β‐, andγ‐zeins and rendered monospecific forδ‐zein. Immunostaining of protein body sections with monospecific antiserum showed that gold label was exclusively in the core region of the protein body and appeared to be in discrete lines and zones especially in 18 DAP protein bodies. The data from localizations using the monospecific antiserum indicated thatδ‐zein occurs throughout the core region of the protein body, probably interspersed withα‐ andβ‐zeins. The location ofδ‐zein is consistent with that predicted from its order of degradation during seed germination.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1992.tb14544.x

出版商:Wiley    

年代:1992

数据来源: WILEY

摘要:

Dormancy ofKosteletzkya virginica(L.) Presl. seeds is primarily due to the impermeability of the seed coat to water. The impermeable structure is assumed to be, in other Malvaceae, the palisade layer of the seed coat. The percentage of seeds capable of imbibition and germination increased with increasing time of storage at low temperatures, but the release from dormancy was not accompanied by decreased seed coat resistance to pressure. Under natural conditions, mechanical damage to the seed coat due to changes in temperature and/or abrasion may render the seeds water permeable. It is not clear what causes water permeability during storage under laboratory conditions. During seed maturation and drying, the inner epidermis of the tegmen partly separates from the rest of the seed coat and an air space, which makes the seed buoyant, is formed around the region of the chalazal cleft. The optimal temperature for germination ofK. virginicaseeds is between 28 and 30 C in light or darkness.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1992.tb14545.x

出版商:Wiley    

年代:1992

数据来源: WILEY

摘要:

Scanning electron microscopic investigation of seed surfaces in tribe Hydrophylleae (Hydrophyllaceae) and seed development inNemophilaindicates the presence of four closely related genera (Ellisia, Hydrophyllum, Nemophila, Pholistoma) and one aberrant genus (Eucrypta), which should probably be transferred elsewhere. Comparative evidence from embryology, morphology, cytology, and palynology is roughly corroborative.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1992.tb14546.x

出版商:Wiley    

年代:1992

数据来源: WILEY

摘要:

Glycine max, like many species of Fabaceae, has pulvini at the base of the petiole. In this structure, the vascular cylinder is constricted and consists of a ring of phloem surrounding a ring of xylem. A combination of light and transmission electron microscopy and histochemistry showed that, in addition, there are groups of internal phloem strands in the pulvinar pith. This was confirmed by direct observation of sieve plates and crystalline P‐protein inclusions typical of leguminous sievetube members. Serial sections through the stem–pulvinus–petiole revealed that a spatial reorientation of the vascular tissue in the pulvinus resulted in the formation of internal phloem strands, which are continuous with the external phloem bundles above and below the pulvinus. Using 6(5)carboxyfluorescein (6CF) as a fluorescent tracer of phloem transport, we have shown that the internal phloem was active. In most of the experiments, when 6CF was applied to a source leaf, the internal phloem was not stained when the stem was girdled between the source leaf and the roots. Thus, we suggest that the internal phloem of the pulvinus of soybean is specialized for transport toward the root.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1992.tb14547.x

出版商:Wiley    

年代:1992

数据来源: WILEY

摘要:

Seeds ofCattleya aurantiaca(Orchidaceae) were germinated and grown aseptically on Knudson C medium containing 2.5, 5, 10, 20, and 50 mg l‐1of 2‐chloroethylphosphonic acid (Ethephon), ethylphosphonic acid, or the inorganic acid moiety of both, phosphosphorous (phosphonic) acid. 2‐Chloroethylphosphonic acid, an ethylene precursor, reduced leaf length at 5–50 mg l‐1proportional to increasing concentrations. Seedlings produced fewer leaves within the range of 20–50 mg l‐1Ethephon compared to lower concentrations (2.5–10 mg l‐1). Germination was not affected adversely. Cultures containing the homologous, but not ethylene‐generating ethylphosphonic acid in the same concentrations brought about similar but generally less severe reductions in leaf length and number. Phosphorous acid at the same concentration levels did not reduce the number and length of leaves. Our observation suggests that the intact organic phosphonates contribute to the inhibition of leaf growth caused by ethylene, which is released slowly from Ethephon in the culture medium and/or plant tissue, following uptake.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1992.tb14548.x

出版商:Wiley    

年代:1992

数据来源: WILEY

摘要:

Pollen‐ovule ratio, pollen grains per flower, pollen grain volume, pollen biomass, ovules per ovary, seeds per fruit, seed volume, seed biomass, and corolla size were studied to reveal patterns of variation within a monophyletic group.Solanumsect.Basarthrumincludes 22 neotropical species of two clades, one having small, few‐seeded red fruits, and the other having larger, many‐seeded green fruits. The former includes self‐incompatible species and a dioecious species, while the latter includes self‐incompatible species, self‐compatible (and autogamous) species, and a domesticate (the “pepino”). Although the pollen quantity and ovule quantity of the self‐incompatible species are significantly higher in the green‐fruited subgroup than in the red‐fruited subgroup, the pollen‐ovule ratios of the self‐incompatible species are not significantly different between the two subgroups, suggesting parallel evolution of the pollen‐ovule ratio. Furthermore, the pollen‐ovule ratio tracks the breeding system: self‐incompatible species have significantly higher pollen‐ovule ratios than self‐compatible species, resulting both from fewer pollen grains and more ovules of the latter. The pollen‐ovule ratio of the dioecious species is among the highest of all, resulting only from fewer ovules. The pepino is self‐compatible but has a pollen‐ovule ratio like its wild self‐incompatible progenitors and shows wide variation in seed production and pollen quality, but not in pollen quantity. Among all species, pollen size and quantity are inversely proportional, as are seed size and quantity.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1992.tb14549.x

出版商:Wiley    

年代:1992

数据来源: WILEY

摘要:

While flower predators can limit the sexual expression and seed production of salt marsh grasses, the relationship between these two effects of consumers has not been explored. At our study site, predation onSpartina patens, Spartina alterniflora, andDistichlis spicatawas twice as high in 1985 (~70% ovule destruction) as in 1986 (~35% ovule destruction). In both years consumers destroyed flowers before maturity, reducing sexual expression, and particularly suppressed male sexual expression. Sexual suppression of males was much more pronounced in 1985 when flower predation was severe and the seed production of undamaged ovules was dramatically reduced. A number of lines of evidence suggest that predator limitation of male sexual expression and pollen supply contributed to low seed output in 1985. 1) Undamaged ovules of all three grasses protected from consumers but exposed to ambient windbome pollen set many more seeds in 1986 than in 1985, suggesting that pollen was more abundant in 1986; 2) Artificial pollinations revealed that marsh grasses are generally pollen‐limited and that pollen limitation at our study site was more severe in 1985 than 1986; and 3) Caging stands of marsh grasses generally led to less predator damage, increased male densities and seed sets similar to those for hand‐pollinated flowers. Our results support the hypothesis that flower predators can indirectly limit seed production by decreasing pollen availability.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1992.tb14550.x

出版商:Wiley    

年代:1992

数据来源: WILEY

摘要:

Queen of the prairie,Filipendula rubra(Rosaceae), is a clonal plant species inhabiting calcareous fens and wet meadows of the northcentral United States.F. rubrareproduces asexually by underground rhizomes and sexually by seed. While many studies have explored genotype diversity in clonal species with limited sexual reproduction, fewer have been conducted on clonal species with the potential for extensive sexual reproduction. We studied the relationship between the extent of sexual reproduction and genotype diversity. Although genotype diversity inF. rubrawas double that reported by others for 27 nearly obligate clonal plant species, it was still quite low. For 25 populations studied, the mean number of genotypes was 5.5 (range = 1–15; SE = 0.964) and the average proportion of distinguishable genotypes was 0.38 (range = 0.03–1.00; SE = 0.07). The production of viable seed was quite variable among populations (mean proportion of viable seeds = 0.242; range = 0.002–0.565; SE = 0.04). Considering that some inflorescences can produce over 5,000 seeds, the potential for recruitment of sexually produced individuals is very large. No correlation was found between seed production and genotype diversity as was expected in a self‐incompatible species in which one‐third of the populations possessed a single genotype. It was hypothesized that the low genotype diversity found in numerous populations may be due to competition limiting recruitment of new seedlings.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1992.tb14551.x

出版商:Wiley    

年代:1992

数据来源: WILEY

摘要:

By decreasing seed density, ants introduced into flats of uniformly sown seeds ofErodium cicutarium(Geraniaceae) created differences in the neighbor‐free area available to individual plants. The changes in spatial patterns brought about by the ants were greater when a higher proportion of seeds was removed but were independent of initial seed density. These spatial changes and differences in seed density were examined for their effects on plant size and reproduction. Gini values were calculated to determine inequalities. As the inequality in space among individual plants increased, the variation in final biomass increased. The number of individuals reproducing was constant among treatments, and yet seed production per plant was significantly greater for populations in which the spatial pattern was influenced by seed predation. The decrease in density and changed spatial pattern, due to previous seed predation, resulted in a few individuals having much more space than others and consequently producing many more seeds. The increase in reproductive effort per flat was much greater than could be explained by the changing density alone. Our experiment demonstrates that spatial inequality, such as that generated by seed predators, can be more important than density in generating size inequalities in plant populations. This result can profoundly alter the competitive interactions between plants and determine which plants produce seed for the next generation.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1992.tb14552.x

出版商:Wiley    

年代:1992

数据来源: WILEY

摘要:

The pollination ecology of fourDalechampiaspecies was studied in three areas in northern Natal, South Africa. All species were pollinated by resin‐ and/or pollen‐collecting megachilid bees (Hymenoptera: Megachilidae). The most common of these at all study sites wasHeriadessp. (Megachilini), which collected both pollen and resin. This bee was the primary pollinator ofD. galpiniiandD. volubilis, and a secondary pollinator ofD.aff.parvifoliaandD. capensis.The primary pollinators of these latter twoDalechampiawerePachyanthidiumnearcucullatumandP. cordatum(Anthididiini), respectively. These are larger bees that collected mainly resin. Other visitors varied amongDalechampiaspecies and among sites. Pairs ofDalechampiaspecies were often found in sympatry (within 30 m of each other) and shared pollinators to varying extents. “Transfer experiments,” in which we placed inflorescences of twoDalechampiaspecies together, reinforced observations of flower discrimination by bees foraging among naturally occurring sympatric pairs.Heriadessp. showed no obvious discrimination betweenDalechampiaspecies, butPachyanthidiumspp. “preferred” theDalechampiaspecies with the greater resin reward. Occasionally, however,Pachyanthidiumwould visit less rewarding species. Thus, although sympatric AfricanDalechampiaspecies showed some pollinator partitioning, it was much weaker than found among New World species, and cannot alone explain the general absence ofDalechampiahybrids in northern Natal.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1992.tb14553.x

出版商:Wiley    

年代:1992

数据来源: WILEY