林业科学Issue(7)：84-90,7.DOI:10.11707/j.1001-7488.20150709
干旱环境下接种根际促生细菌对核桃苗光合特性的影响
Effect of Plant Growth-Promoting Rhizobacteria on Photosynthetic Characteristics in Walnut Seedlings under Drought Stress
摘要
Abstract
[Objective]Plant growth-promoting rhizobacteria ( PGPR ) are rhizosphere inhabitants that can promote plant growth and suppress diseases. The study of PGPR effect on photosynthetic characteristics will provide scientific basis for application potential under drought stress and technical support for afforestation and vegetation ecological restoration in arid environments. [Method]A pot experiment was conducted in order to evaluate the effects of PGPR on the photosynthetic characteristics under drought conditions. A dominant species of PGPR with the ability to produce cytokinins,namely Bacillus cereus L90,was selected to use in this study. Walnut ( Juglans regia ) seedlings were inoculated with B. cereus L90 and then subjected to moderate soil drought stress. The net photosynthesis rate ( Pn ) , stomatal conductance (gs),intercellular CO2 concentration (Ci) and chlorophyll (Chl) content of the walnut seedlings were measured with a LI-6400 portable photosynthesis system and a portable chlorophyll meter. [Result]The results indicated that drought stress and B. cereus L90 inoculation had significant effects on the Pn,Gs,Ci and Chl content of walnut leaves. Compared with the control,the Pn and Gs under drought stress ( DS) were significantly decreased by 21. 78% and 29. 47%. However,the decreases with inoculation of B. cereus L90 were only 11. 62% and 23. 84%, respectively. Therefore,B. cereus L90 inoculation was able to relieve negative effects of DS on Gs and Pn. The relieving effect of B. cereus L90 inoculation on DS increased along with the prolonged period of stress after the initial stage of drought. The Ci of walnut leaves in DR treatments decreased significantly at the initial stage,and then continuously elevated,whereas the Gs continuously declined. The result suggested that the reductions in net photosynthetic rate resulted from both stomatal and non-stomatal limitations. In B. cereus L90 treatment,Ci and Gs decreased continuously,indicating that the Pn reductions mainly resulted from stomatal limitations. The Chl contents of leaves decreased with drought stress. In the late period of drought stress,the chlorophyll content of walnut seedlings in DR treatment significantly decreased 9. 22%,compared with the control. However,the chlorophyll content with inoculation of B. cereus L90 was 9. 49% higher than that of the DS. B. cereus L90 inoculation could significantly decrease the decomposition of chlorophyll content under drought stress. In re-watering after DS,the Pn,Gs and Chl content were still lower than the control,by 9. 46%,10. 29%and 5. 86%,and the Ci was higher than the control by 8. 72%. However,re-watering the drought-stressed seedlings inoculated with B. subtilis increased Pn,Gs and Chl contents to the control’s level,and the contents were higher than the DR seedlings by 7. 01%,12. 15%,5. 81%,respectively. The photosynthetic ability of B. cereus L90 inoculated seedlings was more easily recovered to the level of control after re-watering.[Conclusion]The present study demonstrated that Pn,Gs and Chl content of walnut leaves significantly decreased due to water stress. Cytokinin-producing,B. cereus L90 inoculation under drought conditions could alleviate non-stomatal limitations and interfere with the suppression of net photosynthetic rate. Additionally,L90 is conductive to the photosynthetic ability recovery of walnut leaves after re-watering.关键词
干旱胁迫/根际促生细菌/蜡样芽孢杆菌/核桃苗/光合Key words
drought stress/plant growth-promoting rhizobacteria ( PGPR )/Bacillus cereus/walnut seedlings/photosynthesis分类
农业科技引用本文复制引用
刘方春,马海林,马丙尧,杜振宇,井大炜,邢尚军..干旱环境下接种根际促生细菌对核桃苗光合特性的影响[J].林业科学,2015,(7):84-90,7.基金项目
山东省科技发展计划项目“山东省干旱瘠薄山地集雨造林关键技术研究”(2010GSF10621)。 （2010GSF10621）
