Author(s): CHEN Jinling, YANG Qiliang, LIU Xiaogang, WANG Weihua, LIU Yanwei, Faculty of Modern Agricultural Engineering, Kunming University of Science and Technology
Pages: 631-638
Year: 2016 Issue:  7
Journal: Journal of Drainage and Irrigation Machinery Engineering
Keyword:  Jatropha curcas L; salt stress; nitrogen fertilizer; photosynthesis; water use efficiency;
Abstract: In order to study on effects of nitrogen supply on photosynthetic characteristics of Jatropha curcas L. under salt stress,seedlings of Jatropha curcas L. are exposed to three soil salt contents( S1:0. 2%,S2: 0. 4% and S3: 0. 6%) and two nitrogen supply levels( N1: 30 and N2: 60 gram for each plant) in greenhouse plot experiments. The results show that Jatropha curcas L. has some property to resist salt stress,while its photosynthetic capacity decreases with increasing level of salt stress. Moreover,the photosynthetic rate of Jatropha curcas L. increases with increasing nitrogen level,showing that applying nitrogen fertilizer can effectively relieve the harm on photosynthetic physiology caused by salt stress; however the alleviation effect of nitrogen decreases under S3 salt stress. After a short period of drought,irrigation can effectively improve photosynthesis rate of Jatropha curcas L.. The daily variation of photosynthetic rate of Jatropha curcas L. leaves is a double-peak curve. Compared with levelS1,the average daily photosynthetic rates at level S2 and S3 are decreased by 23. 51% and 37. 97%,respectively,but increased by 39. 89% at level N2 against N1. At three salt levels in the experiments,increasing nitrogen supply is beneficial to improving photosynthetic rate,and instantaneous water use efficiency. The optimal combination favourable to increase of photosynthetic capacity and water use efficiency is N2S1 under the present experimental conditions.