Pollination of flowers initiates postpollination development in orchid (Doritaenopsis hybrida Hort.) flowers, including perianth senescence, stigma closure, and ovary development. Because ethylene is thought to play ...Pollination of flowers initiates postpollination development in orchid (Doritaenopsis hybrida Hort.) flowers, including perianth senescence, stigma closure, and ovary development. Because ethylene is thought to play a key role in coordinating these developmental changes, the authors studied the temporal and spatial patterns of expression of genes encoding 1 aminocyclopropane 1 carboxylic acid (ACC) synthase and ACC oxidase following pollination associated factor treatments in orchid flowers. Both ACC synthase and ACC oxidase mRNA accumulation in the various parts of the flowers is induced by auxin, and ethylene, but not by emasculation. The patterns of both ACC synthase and ACC oxidase mRNA accumulation are similar in all floral organs following auxin and ethylene treatments. Further, in situ hybridization analysis indicates that the ACC oxidase mRNA is localized in epidermal and parenchyma cells of the stigma after auxin and ethylene treatments. The putative roles of auxin, ethylene and emasculation are discussed in terms of the regulation of ACC synthase and ACC oxidase gene expression in flowers.展开更多
Changes of calmodulin (CaM) distribution in the embryo sac of rice (Oryza sativa subsp. Japonica) at various stages before and after fertilization have been investigated by using immunogold electron microscopy. Before...Changes of calmodulin (CaM) distribution in the embryo sac of rice (Oryza sativa subsp. Japonica) at various stages before and after fertilization have been investigated by using immunogold electron microscopy. Before pollination, both cytoplasm and vacuoles of the egg cell, synergids and central cell were labeled by gold particles. A small amount of gold particles were localized in the nucleus, endoplasmic reticulum, mitochondria and dictyosomes. From pollination to fertilization, CaM amount increased in these cells, especially rich in the starch of amyloplasts. Increase of gold particles in the central cell began about 2 h earlier than that in the egg cell. There was no distinct difference of CaM amount between the degenerated and the persistent synergids. It is interesting to observe an obvious change of CaM distribution form during pollination and fertilization from scattered single particles to clustered particles, and back again to single particles after the fertilization finished. CaM was also localized extracellularly in the embryo sac wall as well as in the wall and intercellular space of nucellus cells. The extracellular CaM also changes in its amount and form after pollination. These results suggest that CaM, either intra- or extra-cellular, may play important roles in fertilization and zygote formation.展开更多
Faba bean is self- and cross-fertilized species. The consequences of self-fertilization are important factors determining the germplasm management in such species with levels of heterogeneity and heterozygsity. Effect...Faba bean is self- and cross-fertilized species. The consequences of self-fertilization are important factors determining the germplasm management in such species with levels of heterogeneity and heterozygsity. Effects of self-fertilization on floral, yield and yield components characters were evaluated by comparing two levels of selfing, produced in bee-proof cages, in open-pollination at two locations in Sudan. Selfing process results in no significant differences in yield and yield components within each cultivar. Autofertile lines with reduced partial dependence on insects for seed set could be produced. Spatial isolation should be used to maintain the genetic purity of such lines. An alternate strategy for entries multiplication should focus on increasing heterozygosity and the maintenance of cross-fertilization inside the entries to prevent contamination with foreign pollens. Our results follow the previous knowledge on faba bean genetic resources conservation and management.展开更多
文摘Pollination of flowers initiates postpollination development in orchid (Doritaenopsis hybrida Hort.) flowers, including perianth senescence, stigma closure, and ovary development. Because ethylene is thought to play a key role in coordinating these developmental changes, the authors studied the temporal and spatial patterns of expression of genes encoding 1 aminocyclopropane 1 carboxylic acid (ACC) synthase and ACC oxidase following pollination associated factor treatments in orchid flowers. Both ACC synthase and ACC oxidase mRNA accumulation in the various parts of the flowers is induced by auxin, and ethylene, but not by emasculation. The patterns of both ACC synthase and ACC oxidase mRNA accumulation are similar in all floral organs following auxin and ethylene treatments. Further, in situ hybridization analysis indicates that the ACC oxidase mRNA is localized in epidermal and parenchyma cells of the stigma after auxin and ethylene treatments. The putative roles of auxin, ethylene and emasculation are discussed in terms of the regulation of ACC synthase and ACC oxidase gene expression in flowers.
文摘Changes of calmodulin (CaM) distribution in the embryo sac of rice (Oryza sativa subsp. Japonica) at various stages before and after fertilization have been investigated by using immunogold electron microscopy. Before pollination, both cytoplasm and vacuoles of the egg cell, synergids and central cell were labeled by gold particles. A small amount of gold particles were localized in the nucleus, endoplasmic reticulum, mitochondria and dictyosomes. From pollination to fertilization, CaM amount increased in these cells, especially rich in the starch of amyloplasts. Increase of gold particles in the central cell began about 2 h earlier than that in the egg cell. There was no distinct difference of CaM amount between the degenerated and the persistent synergids. It is interesting to observe an obvious change of CaM distribution form during pollination and fertilization from scattered single particles to clustered particles, and back again to single particles after the fertilization finished. CaM was also localized extracellularly in the embryo sac wall as well as in the wall and intercellular space of nucellus cells. The extracellular CaM also changes in its amount and form after pollination. These results suggest that CaM, either intra- or extra-cellular, may play important roles in fertilization and zygote formation.
文摘Faba bean is self- and cross-fertilized species. The consequences of self-fertilization are important factors determining the germplasm management in such species with levels of heterogeneity and heterozygsity. Effects of self-fertilization on floral, yield and yield components characters were evaluated by comparing two levels of selfing, produced in bee-proof cages, in open-pollination at two locations in Sudan. Selfing process results in no significant differences in yield and yield components within each cultivar. Autofertile lines with reduced partial dependence on insects for seed set could be produced. Spatial isolation should be used to maintain the genetic purity of such lines. An alternate strategy for entries multiplication should focus on increasing heterozygosity and the maintenance of cross-fertilization inside the entries to prevent contamination with foreign pollens. Our results follow the previous knowledge on faba bean genetic resources conservation and management.
