花生荚果发育过程中子叶细胞的超微结构和脂酶活性的研究

在花生(Arachis hypogaea)荚果发育过程中,子叶细胞的超微结构和脂酶活性皆发生了显著变化。子叶生长初期,缅胞中质体较多,并不断形成淀粉粒;脂酶活性低,脂体和蛋白体很少。子叶发育中期,子叶细胞质中出现大量体积较大的脂体,液泡中的蛋白体不断形成和增大,而且细胞质、内质网、蛋白体外膜、细胞质膜和细胞间隙上皆显示较强的脂酶活性。子叶发育后期,脂体数量不再增加,但体积略有增大,间质透明度也有提高;蛋白体增大较小,但数量却进一步增多;细胞质中仍显示较强的脂酶活性。至末期时,蛋白体形态变得不规则,甚至出现部分解体,其基质充挤脂体间隙;细咆中的脂酶活性减弱。研究表明,花生脂体起源于细胞质,蛋白体起源于液泡,子叶油分和蛋白质的积累足体内脂体和蛋白体不断发育的结果,细胞中脂酶活性的变化可能与脂体发育有关。

ULTRASTRUCTURE AND LIPASE ACTIVITY OF COTYLEDON CELL DURING POD DEVELOPMENT IN PEANUT

A series of significant changes of the ultrastructure and lipase activity of cotyledon cell were found in peanut (Arachis hypogaea) during pod development.In the initial stage of co- tyledon development there were many plastids which kept producing starch grain and there were low lipase activity and very few lipid and protein bodies in the cell.In the middle stage of cotyledon development,a great number of larger lipid bodies were seen in the cell and a lot of protein bodies formed in the vacuoles arid continued to increase in size.Lipase activity increased in the cytoplasm,endoplasmic reticulum,protein bodies,plasmalemma and in- tercellular space.In the later stage of cotyledon development,the lipid bodies did not increase in number but became slightly larger.The protein bodies continued to increase both in num- ber and in size.Lipase activity was even hegher in the cytoplasm.In the final stage the protein bodies became irregular in shape and some of them tended to disintegrate with their content entered into the space around the lipid bodies.The lipase activity in the cell declined.The re- sults indicated that the lipid body originated in the cytoplasm and the protein body originated in the vacuole;that the accumulation of oil and protein in peanut cotyledon resulted from the formation and development of lipid and protein bodies in the cell,and that the changes of plastid and lipase activity in the cell played a role in the development of lipid body during the development of cotyledon.