comparison of ion balance and nitrogen metabolism in old and young leaves of alkali-stressed rice plants比较离子平衡和氮代谢的老老少少alkali-stressed水稻的叶子.pdfVIP

Comparison of Ion Balance and Nitrogen Metabolism in Old and Young Leaves of Alkali-Stressed Rice Plants 1 2 1 3 1 Huan Wang , Zhihai Wu , Jiayu Han , Wei Zheng , Chunwu Yang * 1 Key laboratory of Molecular Epigenetics of MOE, Northeast Normal University, Changchun, Jilin Province, China, 2 Department of Agronomy, Jilin Agricultural University, Changchun, Jilin Province, China, 3 Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, China Abstract Background: Alkali stress is an important agricultural contaminant and has complex effects on plant metabolism. The aim of this study was to investigate whether the alkali stress has different effects on the growth, ion balance, and nitrogen metabolism in old and young leaves of rice plants, and to compare functions of both organs in alkali tolerance. Methodology/Principal Findings: The results showed that alkali stress only produced a small effect on the growth of young leaves, whereas strongly damaged old leaves. Rice protected young leaves from ion harm via the large accumulation of Na+ and Cl2 in old leaves. The up-regulation of OsHKT1;1, OsAKT1, OsHAK1, OsHAK7, OsHAK10 and OsHAK16 may contribute to the larger accumulation of Na+ in old leaves under alkali stress. Alkali stress mightily reduced the NO32 contents in both organs. As old leaf cells have larger vacuole, under alkali stress these scarce NO32 was principally stored in old leaves. Accordingly, the expression of OsNRT1;1 and OsNRT1;2 in old leaves was up-regulated by alkali stress, revealing that the two genes might contribute to the accumulation of NO32 in old leaves. NO32 deficiency in young leaves under alkali stress might induce the reduction in OsNR1 expression and the subsequent