摘要
莲胚子叶细胞中质体的产生从受精后的４ｄ左右一直延续到２１ｄ左右。质体的分裂是质体数目增加的一种方式。子叶细胞在发育阶段Ⅰ，即分生组织细胞中前质体大量出现，体积小，多为变形虫状，大量的位于细胞的外围。在电子密度低的区域能观察到前质体的纤维丝。从发育阶段Ⅱ（液泡化时期）一直到阶段Ⅲ中期（细胞处于功能期，物质合成与积累时期），质体在发育中出现一些片层结构和管状复合体，这时淀粉粒开始沉积，同时在淀粉质体的膜结构和基质中常能观察到像核糖体的颗粒。在受精后的１５ｄ左右，子叶细胞中质体开始大量合成并积累淀粉。与此同时，淀粉体ＤＮＡ开始出现，子叶细胞发育到授精后的１８－２２ｄ时，是淀粉质体ＤＮＡ复制的盛期。２３ｄ后，部分淀粉体显ＤＮＡ拟核区域，有的出现多个ＤＮＡ拟核区，这时淀粉体中有大量的蛋白质和蛋白块积累，一般沉积在质体的内膜周围。在部分质体中同时能观察到ＤＮＡ区域、蛋白质的积累和淀粉部分的存在。约在受精后２０ｄ，淀粉体核糖体的结构已清晰可辨。在发育阶段Ⅲ的后期，质体周围的基膜结构和核糖体颗粒已经观察不到了。淀粉质体是个半自主性的器官，它有自己的ＤＮＡ和ＲＮＡ。
The plastids generation of cotyledon cells of lotus from 4 days after fertilization continue till about 21 days.A pattern of increased plastids are the plastids division. Small volume of plastids develope during phase Ⅰ largely in meristematic cells.Through an ameboid stage,to the larger forms with more abundand storage in the outmost cells.Fine fibrils of proplastid were observed in electronic less dense region.From the phase Ⅱ of cell vacuolation until the middle of the phase Ⅲ (main physiological function in which the materials are largely synthesized and accumulated).The plastids contain some lamella structure and tubular complex,a starch grain,ribosome like particles in cotyledon cell of lotus.The ribosome like particles are accumulated which on membrane and in the stroma of plastid.About 15 days after fertilization,the starch begin largely synthesized and accumulated in palstids of cotyledon cells.On the same time,amyloplasts DNA begin to appear.The main period of making a copy of amyloplast DNA is within 18-22 days after fertilization.After 23 days,some plastid contain nucleoid,also some amyloplasts appear several nucleoids.In the course of investigation it was observed that many of these plastids contain DNA as well as starch,and protein.Whereas the protein and protein lump always are deposited surrounding within membrane of plastids.About 20 days,structure of ribosome have been shown clearly.Some ribosomes distribute in the stroma and combine on the membrane of plastid.The later period of development pahse Ⅲ,the plastid membrane basilaris and ribosomes particles have not been observed. Amyloplasts in the cotyledon of lotus have semiautonomous organells characteristic,containing their own DNA,RNA and ribosomes that involved in protein synthesis machining.
出处
《西北植物学报》
CAS
CSCD
1998年第4期570-576,共7页
Acta Botanica Boreali-Occidentalia Sinica
基金
国家自然科学基金
