【摘要】 本文报道莲(Nelumbo nucifera)胚芽包埋在密闭的三层厚的覆盖物(果皮、种皮和肥厚的子叶)中,其形成期间保持黑暗,但它却能由淡黄色变成蓝绿色,其胚芽的叶绿体内在无可见光下能发育有巨大的基粒。其叶绿体的独特发育途径,比一般高等植物少两个发育步骤。在结构上,除原质体外,其它两个发育阶段均出现异常,表现在前质体内形成的类晶格状前片层体组成的质体中心尚完整存在时,便有许多前类囊体膜从一个质体中心的一个方向或两个方向平行延伸或从两个质体中心向着两两相对应的方向平行排列于前质体内,同时往往伴有大的淀粉粒。待发育成叶绿体后,体内只形成1—2个巨基粒,贯穿于整个叶绿体中,被巨大淀粉粒排挤到被膜的内缘。基粒类囊体膜长度比一般高等植物的长约3—5倍。而其基质类囊体膜却特别稀少且很短。靠近基粒边缘膜的核糖体颗粒较大而致密。更多还原

【Abstract】 The present paper reports that the development ultrastructural observations of chloroplasts from sacred lotus(Nelumbo nucifera)embryo buds under invisible light.Embryo bud of sacred lotus is enclosed by three layers of thick integument(pericap,seed coat and thick fleshy cotyledons).During the period of the formation of embryo bud,it remained in dark condi- tion,but turned from pale yellow to bluish-green.It was noteworthy that chloroplasts of the embryo bud had well developed giant grana under invisible light.Their developmental path- way in sacred lotus,however,was different from those of other higher plants grown under sun- light,intermittent light,or even in dark conditions(Fig.1).The chloroplast development of embryo buds in Sacred lotus seeds in invisible light underwent only in the following three stages:(1)In the first stage the development was similar to that from other higher plants,the inner envelope membranes of the proplastids were invaginating.(2)In the second stage,a proplastid centre composed of prolamellar bodies(PLB)with semicrystalline structure was for- med,and was accompanied by one or two huge starch grains in almost each proplastid.In the meantime,prothylakoid membranes extended parallelly from the plastid centre in three forms:(a)One plastid centre extending parallelly prothylakoid membranes from itself in one direction;(b)The same to(a),but extending in two directions;(c)Two plastid centres ex- tending parallelly prothylakoid membranes between the centres.(3)In the third stage,grana and stroma thylakoid membranes of chloroplasts were formed.It is to be noted that most of chloroplasts had only one or two giant grana which often extended across the entire chloro- plast body,and the length of the grana thylakoid membranes of the chloroplasts from embryo bud in Sacred lotus is 3 to 5 times as many as that in other higher plants.However,their stromatic thylakoid membranes were rather rare and very short.The giant grana were squeezed to the margin of the chloroplast envelope by one or two huge starch grains.更多还原