增施硝态氮对Na_2CO_3胁迫下桑树幼苗叶片PSⅡ功能的影响  

Effects of increased NO_3^--N application on PSⅡ function in leaves of Morus alba seedlings under Na_2CO_3 stress

作　　者：许楠[1,2] 张会慧[3] 谷思玉[3] 李鑫[3] 朱玉伟[3] 杨艳[3] 刘昆[3] 张秀丽[1] 

机构地区：[1]东北林业大学生命科学学院,黑龙江哈尔滨150040 [2]黑龙江省科学院自然与生态研究所,黑龙江哈尔滨150040 [3]东北农业大学资源与环境学院,黑龙江哈尔滨150030

出　　处：《草业科学》2017年第1期67-74,共8页Pratacultural Science

基　　金：国家自然科学基金(31500323)

摘　　要：以桑树(Morus alba)为试验材料,在室内以溶液培养的方法研究了增施NO_3^--N(7.5 mmol·L^(-1)增加到17.5mmol·L^(-1))对Na_2CO_3胁迫(50mmol·L^(-1))下桑树幼苗叶片PSⅡ功能的影响。结果表明,50mmol·L^(-1)的Na_2CO_3胁迫下桑树植株表现出明显的盐害症状,叶片的PSⅡ反应中心光化学活性明显降低,PSⅡ电子供体侧和受体侧均受到不同程度的影响。增施NO_3^--N显著提高了Na_2CO_3胁迫下桑树幼苗叶片的光合电子供应和传递能力,表现为PSⅡ电子供体侧放氧复合体OEC的功能增强,PSⅡ电子受体侧受体库接受电子能力增加。另外,增施NO_3^--N还可以相对提高桑树幼苗叶片类囊体膜结构的稳定性,促进Na_2CO_3胁迫下桑树幼苗叶片光能向光化学反应方向的分配,降低以无效热能形式耗散的比例。可见,增施NO_3^--N可显著增强Na_2CO_3胁迫下桑树幼苗叶片PSⅡ的功能,这为其光合作用的正常进行提供了保证。In this study, we analysed the effects of increased nitrate （NOa -N） （from 7.5 mmol · L-1 to 17.5 mmol · L- 1） on the growth and photosynthetic characteristics of mulberry seedlings, which were subjected to alkaline salt （50 mmol · L-1 Na2COa） stress using hydroponic methods. The results showed that plants dis- played obvious symptoms of injury when subjected to 50 mmol · L-1 Na2CO3 stress. Furthermore, compared with the control, the photochemical reaction centre activity of PS Ⅱ in stressed seedlings was significantly decreased, and electron transport was affected to different degrees on both the donor side and receptor side of PS Ⅱ. Under Na2CO3 stress, increasing NO3 -N promoted photosynthetic electron supply and transmission capacity, enhanced the function of the oxygen complex in the electron donor of PSⅡ , and increased the acceptor electron capacity of the receptor library. In addition, increasing NO3--N also improved the stability of leaf thylakoid membrane structure, promoted the distribution of more light energy to the photochemical reaction centre, and decreased the proportion of energy in the form waste heat dissipation. In conclusion, increasing NO3--N enhanced the function of PS Ⅱ under 50 mmol · L-1Na2CO3 stress, which ensured the normal operation of photosynthesis.

关 键 词：桑树 硝态氮 NA2CO3胁迫 PSⅡ反应中心 荧光动力学曲线 电子传递 非光化学猝灭 

分 类 号：S888.2[农业科学—特种经济动物饲养] Q945.78[农业科学—畜牧兽医]