番茄幼叶、成熟叶和衰老叶胞质脂滴的观察

Observation on Cytosolic Lipid Droplets in Young,Mature and Senescent Tomato Leaves

为揭示番茄叶片有无产生胞质脂滴的能力,胞质脂滴发生是否与叶片发育有关,哪些类型细胞产生胞质脂滴以及胞质脂滴在细胞内什么场所降解等问题,利用透射电子显微技术对不同发育阶段的番茄叶片进行了比较观察。结果表明,番茄幼叶和成熟叶均不含胞质脂滴,而衰老叶含胞质脂滴,显示胞质脂滴是衰老叶的细胞生物学特征。衰老叶表皮细胞、维管薄壁细胞和叶肉细胞等3种主要类型细胞均有产生胞质脂滴的能力,而其他细胞如筛管分子不含胞质脂滴。胞质脂滴在液泡内降解,或在液泡外通过与小泡密切接触从而在接触面上降解。

Tomato leaves at different developmental stages were observed comparatively by means of transmission electron microscope,to understand whether the tomato produces lipid droplets(LDs)in leaves,whether the ability is related to leaf developmental stages and cell types,and where these LDs undergo degradation.The observation demonstrated that there were no cytosolic LDs in young and mature leaves,while LDs were prominent in senescent leaves.Obviously,LDs were a typical characteristic of senescent leaves.LDs were present in the three main cell types,including epidermal cells,vascular parenchyma cells,and mesophyll cells,but were absent in other cell types such as sieve elements.LDs showed a close physical contact with vacuoles and underwent vacuolar degradation.LDs also came in contact with small vesicles and underwent degradation from the contact surface.