陈雯新 李萌 孙悦宸 毛新月 韩秋爽 刘林 张桂芝

摘    要：采用透射电子显微技术对茄子幼叶和衰老叶的质体小球进行了比较，并着重对衰老叶质体小球的降解途径进行了观察。结果表明，茄子幼叶质体小球小，电子染色深，老叶质体小球大，电子染色浅;老叶中质体小球发生降解，降解发生在叶绿体内或液泡内，显示降解遵循叶绿体途径或液泡途径。在叶绿体途径中，降解不是从质体小球整个表面同时开始，而是从质体小球表面某一点开始，降解区域电子透明，结果使质体小球呈现为一侧凸起而另一侧凹陷。在液泡途径中，液泡中的质体小球由基质包围着，显示质体小球并不单独进入液泡，而是连同部分叶绿体基质一起进入液泡。

关键词：茄子;叶衰老;质体小球降解;降解途径

中图分类号：S641.1 文献标志码：A 文章编号：1673-2871（2021）05-109-04

Observation on the degradation pathways of plastoglobules in senescent eggplant leaves

CHEN Wenxin， LI Meng， SUN Yuechen， MAO Xinyue， HAN Qiushuang， LIU Lin， ZHANG Guizhi

（College of Pharmacy， Linyi University， Linyi 276005， Shandong， China）

Abstract： Plastoglobules in young and senescent eggplant leaves were observed comparatively and plastoglobule degradation pathways in senescent leaves were investigated， by means of transmission electron microscopy. Plastoglobules were less in number and size and more strongly stained in young leaves than in senescent leaves. Plastoglobules in senescent leaves underwent degradation inside either chloroplasts or vacuoles. Two pathways were demonstrated， chloroplast associated pathway and vacuolar pathway. During the chloroplast associated pathway， chloroplasts are the site for degradation. The degradation was found to happen from one side of the plastoglobule rather than the whole surface of the plastoglobule. As a result， the plastoglobule became convex on the intact side， but concave on the degrading side. During the vacuolar pathway， where vacuoles are the site for the degradation， plastoglobules were showed to be transported into the vacuole together with a portion of chloroplast stroma that surrounded the plastoglobules.

Key words： Eggplant; Leaf senescence; Plastoglobule degradation; Degradation pathway

電子显微镜刚开始用于细胞研究时就发现，叶绿体、有色体以及白色体等不同类型质体中都存在一种嗜锇小球体[1]，大小不等，直径从30 nm到5 μm，由于小球体的脂含量非常高，因此称为质体小球[1-2]。后来进一步研究表明，质体小球是由半乳糖脂单分子层膜包围甘油三酯所形成的细胞器，膜上结合一层蛋白质[3-5]，甘油三酯中溶解有胡萝卜素、类胡萝卜素和维生素E[4-6]。质体小球不仅发生在维管植物，也发生于藓类植物[7]和藻类植物[3，5，8]。质体小球的大小、数量和嗜锇性因植物种类、质体类型和发育阶段而变化，这些特点显示出质体小球具有多方面生物学作用。……