Iqbal Noushina, Umar Shahid, Per Tasir S, Khan Nafees A
a Department of Botany , Jamia Hamdard , New Delhi , India.
b Plant Physiology and Biochemistry Laboratory, Department of Botany , Aligarh Muslim University , Aligarh , India.
Plant Signal Behav. 2017 May 4;12(5):e1297000. doi: 10.1080/15592324.2017.1297000. Epub 2017 May 24.
Salinity is a serious threat to plant growth and development worldwide reducing agricultural productivity each year. Ethylene is an important phytohormone that affects plants performance under normal and abiotic stress conditions. In this study, role of ethylene was investigated in mitigating salinity stress (100 mM NaCl) effects on photosynthesis in mustard plants subjected to different nitrogen (N; 5 and 10 mM) levels. Plants under salinity stress exhibited marked increase in proline and reduced glutathione (GSH) content and activity of antioxidant enzymes. Nitrogen supplementation at 10 mM was better than 200 µl l ethephon treatment under no stress. However, under salinity stress, both N and ethephon were equally effective. The combined application of 10 mM N and ethephon to salinity stressed plants produced greatest increase in photosynthesis by increasing proline and antioxidant metabolism. Ethylene evolution was high under salinity stress, but treatment of 10 mM N and 200 µl l ethephon greatly decreased ethylene evolution that was equivalent to the 10 mM N treatment alone. This concentration of ethylene decreased the oxidative stress and increased the photosynthetic nitrogen use efficiency (NUE) maximally to increase photosynthesis. The use of ethylene action inhibitor, norbornadiene (NBD) showed reduction in ethylene mediated effects in alleviating salinity. Norbornadiene decreased the photosynthetic-NUE, proline and GSH content that resulted in decrease in photosynthesis under salinity stress. This study indicated that ethylene regulated the proline and antioxidant metabolism under salinity stress to increase photosynthetic functions of mustard grown with low and optimum N. The modulation of ethylene could be adopted in agricultural practices to increase photosynthesis under salinity stress.
盐度是对全球植物生长和发育的严重威胁，每年都会降低农业生产力。乙烯是一种重要的植物激素，在正常和非生物胁迫条件下都会影响植物的性能。在本研究中，研究了乙烯在缓解盐胁迫（100 mM NaCl）对不同氮（N；5和10 mM）水平芥菜光合作用影响方面的作用。盐胁迫下的植物脯氨酸和还原型谷胱甘肽（GSH）含量显著增加，抗氧化酶活性降低。在无胁迫条件下，10 mM的氮补充比200 μl l乙烯利处理效果更好。然而，在盐胁迫下，氮和乙烯利同样有效。向盐胁迫的植物中联合施用10 mM氮和乙烯利，通过增加脯氨酸和抗氧化代谢，使光合作用增加最多。盐胁迫下乙烯释放量很高，但10 mM氮和200 μl l乙烯利处理大大降低了乙烯释放量，这与单独的10 mM氮处理相当。这种浓度的乙烯降低了氧化胁迫，并最大程度地提高了光合氮利用效率（NUE）以增加光合作用。使用乙烯作用抑制剂降冰片二烯（NBD）表明，乙烯介导的缓解盐胁迫的作用降低。降冰片二烯降低了光合NUE、脯氨酸和GSH含量，导致盐胁迫下光合作用下降。本研究表明，乙烯在盐胁迫下调节脯氨酸和抗氧化代谢，以增加低氮和最佳氮条件下生长的芥菜的光合功能。在农业实践中可以采用调节乙烯的方法来增加盐胁迫下的光合作用。
