Studies on the Relationship Between the Degree of Juvenility and Cell Ultrastructure in Larix principis-rupprechti II. The annual shoots in the upper and lower crown

摘要

The ultrastructure of corlex and pheloem parenchyma cells of annual shoots from the upper and lower crown in Larix principis-rupprechti were studied by Transmission Electron Microscopy. In the cells of the upper crown, in comparison with the cells ofthe lower crown, the plastids with a very obvious thylakoid lamellae structure and lipid droplets were numerous, but the proplastids were less. The mitochondria were numerous, and in which there were more developed cristae. Some mitocondria showed an initial stage of a proliferitive mode. The vacuoles with rich contents existed in the form of the secondary lysosome. There were more plasmatesmata passed through the cell walls, and some of them showed a fine tube-shaped structure. There was a more complicated ultrastructure showing a lower degree of juvenility in the cells of the upper crown than in those of the lower crown. A close relationship was shown between the cell ultrastucture and the degree of juvenility in the trees. The degree of juvenility had an obvious position effect in identical trees.