光周期对光敏胞质不育小麦花药发育过程中Ca^(2+)-ATPase分布的影响

Effect of Photoperiod on Ca^(2+)-ATPase Distribution in Photoperiod-Sensitive Cytoplasmic Male-Sterile Wheat During Anther Development

应用铅沉淀法 ,研究了不同光照条件下光敏胞质不育小麦 (TriticumaestivumL .)可育花药和不育花药发育过程中Ca2 + _ATPase的分布。短日照可育条件下 ,单核早期至成熟花粉 ,Ca2 + _ATPase在花粉表面、外壁内先增加后减少 ,在花粉内壁及质膜上逐渐增加 ,在胞质内分布较少 ;成熟花粉的营养细胞核仁内有大量Ca2 + _ATPase分布 ,精细胞核仁内亦有Ca2 + _ATPase分布。乌氏体上、绒毡层细胞内或其解体残留物上有大量Ca2 + _ATPase的分布 ,药壁其他细胞亦有Ca2 + _ATPase分布。自单核期开始 ,长日照不育条件下花药内Ca2 + _ATPase分布与短日照下相比有以下差异 :花粉质膜上Ca2 + _ATPase虽逐渐增多 ,但与同时期短日照下相比明显减少 ;其内壁发育不完善 ,无或少有Ca2 + _ATPase的分布 ;花粉表面、外壁内、乌氏体表面及药壁细胞内分布较少 ;但绒毡层外膜、表皮与药室内壁细胞间隙内有明显Ca2 + _ATPase分布。对花粉发育过程中Ca2 + _ATPase的来源、在维持Ca2 + 稳态中的作用及其与花粉败育的关系作了讨论。

Lead nitrate was used to locate Ca 2+ _ATPase in fertile and sterile anthers of photoperiod_sensitive cytoplasmic male_sterile wheat (Triticum aestivum L.). The amount and distribution of Ca 2+ _ATPase in pollen changed during pollen development and were different between fertile and sterile anthers under different daylight exposure. The anther was fertile under short daylight exposure. A very small amount of Ca 2+ _ATPase distributed on the plasmalemma, proplastid membrane of the pre_uninucleate pollen and appeared in anther wall cells, but did not appear simultaneously in the exine and intine of pollen. The Ca 2+ _ATPase on the surface of pollen and in exine gradually increased from later uninucleate pollen to binucleate pollen and then gradually decreased from binucleate pollen to trinucleate pollen stages, while Ca 2+ _ATPase gradually accumulated on plasmalemma and in intine during pollen development. The endoplasmic reticulums on which the Ca 2+ _ATPase distributed were observed in the vegetative cell cytoplasm bounding the generative cell that located at the edge of pollen. In the trinucleate pollen stage, abundant Ca 2+ _ATPase distributed in the nucleolus of vegetative cell and a little appeared in the nucleus and nucleolus of the sperm cell. There was a large amount of Ca 2+ _ATPase on the Ubisch bodies, in the degrading tapetal cells and their debris as well as in the other cells of the anther wall. The anthers were sterile under long daylight exposure and were different in Ca 2+ _ATPase distribution as compared with the same kind of cells of fertile anther at similar developmental stages. Less Ca 2+ _ATPase was seen on the surface and plasmalemma of pollen, pollen intine and exine, although the amount of Ca 2+ _ATPase was gradually increased on plasmalemma. A very small amount of Ca 2+ _ATPase was distributed on Ubisch bodies and anther wall cells, but a large amount appeared on the tapetal epine, gap between epidermal cells and endothecium cells. The results also indicated that the Ca 2+ _ATPase accumulated on pollen plasmalemma and intine not only come from gametophyte but also from sporophyte during pollen development. A very small amount of Ca 2+ _ATPase that accumulated on pollen plasmalemma and in intine resulted in abundant Ca 2+ accumulation in pollen cytoplasm, which might be associated with the failure of pollen development induced by long daylight exposure in photoperiod_sensitive male_sterile wheat. The role of Ca 2+ _ATPase in Ca 2+ _homeostasis of pollen, the source of Ca 2+ _ATPase in pollen and the relationship between Ca 2+ _ATPase and anther sterility were also discussed.