Changes of starch grains and plastoglobuli in chloroplasts of mesophyll cells in Chinese chestnut leaf at different stages
LIU Lin1,2,LI Ming-ze3,WANG Huai-zhong1,LIU Tie-mei1,LI Yun1,HAN Shi-ming1,LI Chun-qi1 (1College of life sciences,Henan Agricultural University,Zhengzhou,Henan 450002China; 2Department of Biology,Linyi Normal College,Linyi,Shandong 276005 China; 3Puyang Vocation-Technical College,Puyang,Henan 457000 China)
An observation was made on chloroplasts of the mesophyll cells of the young folded leaves and expanded growing young leaves of Chinese chestnut (Castanea mollissima)in spring,of the mature leaves in summer,and of the aging leaves in autumn by transmission electron microscopy. The results showed that:there were no starch grains and plastoglobuli in chloroplasts of young folded leaves in spring,and there were some starch grains but no plastoglobuli in expanded growing young leaves. There were lots of starch grains but only a few plastoglobuli in chloroplasts of mature leaves in summer. The starch grains reduced and disappeared finally but the plastoglobuli increased significantly in chloroplasts of aging leaves in autumn. Some plastoglobuli were found to be degenerating,and the degeneration happened after they were enveloped by a single-layered membrane. Plastoglobuli could be classified into two groups of dark and grey by their electron density. The deterioration of the chloroplasts should have relationship between the starch grains decreasing and plastoglobuli increasing.