Abstract: 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.

Key words: tomato, leaf, senescence, cytosolic lipid droplet