不同非生物胁迫对麻疯树幼苗光合速率等生理指标的影响

Effects of Several Abiotic Stresses on Photosynthetic Rate and Other Physiological Indexes in Jatropha curcas L. Seedlings

摘要:

对麻疯树(Jatropha curcas L.)幼苗在不同非生物胁迫下的净光合速率(Pn)和蒸腾速率(Tr)等生理指标的变化进行了研究。结果表明,在缺磷处理中,麻疯树叶片Pn 保持在对照的90% 左右,气孔导度(Gs)和胞间CO₂ 浓度(Ci)在处理2 d 后显著增加,Gs 上升20%~40%, Ci 升高4%~16%,Tr 变化不大;处理17 d 时,麻疯树的P 含量下降55%~85%,而干重只下降3%。缺氮处理9 d 时麻疯树叶片的Pn 下降到最低,之后维持在对照的64% 左右,Gs 在处理2~7 d 显著高出对照15%~57%,处理9~16 d恢复到对照水平, Ci 从第2 天开始上升,高出对照4%~24%,Tr 变化不大;处理17 d 时组织中N 含量显著下降47%~78%,植株干重下降23%。盐胁迫处理5 d 后,麻疯树叶片Pn 降低到对照的54%,之后维持在对照的48% 左右,Gs、Ci 和Tr 与Pn的变化一致,均呈下降趋势;处理17 d,叶柄和茎中P 含量增加37%~54%,组织中K⁺/Na⁺ 下降87%~96%,植株干重下降18%。干旱胁迫处理6 d,叶片Pn 快速下降至29%,Gs、Ci 和Tr 与Pn 整体变化趋势一致;处理第7 天,叶片细胞膜透性增加67%,停止浇水17 d 后植株干重下降55%,同时叶片卷曲下垂,老叶脱落。麻疯树植株Pn 在缺磷胁迫过程中最早达到相对稳定状态,其次为盐胁迫和缺氮胁迫。这说明麻疯树植株对缺磷环境具有良好的适应性,而对缺氮环境适应性相对较差;耐盐类型可能属于逃避盐害中的聚盐植物,适应干旱环境的机制属于御旱性类型。

Abstract:

The dynamic changes in several physiological indexes, such as net photosynthetic rate (Pn), transpiration rate (Tr), etc., in Jatropha curcas L. seedlings under different abiotic stresses were studied. The results showed that under phosphorus deficiency, Pn of J. curcas contained about 90% of control, and stomata conductance (Gs) and intercellular CO₂ concentration (Ci) increased 20%-40% and 4%-16% after 2 days, respectively, and little change in Tr. The P content decreased from 55% to 85% under phosphorus deficiency, whereas dry weight only decreased 3% after 17 days. Under nitrogen deficiency, Pn decreased to the lowest level at the 9th day, and then maintained at about 64% of control. Gs increase significantly about 15%-57% treated after 2 to 7 days, and then decreased to control. Ci rose about 4% to 24% from the 2nd day compared with the control, and there was little change in Tr. N content decreased 22% to 53% under nitrogen deficiency and plant dry weight decreased about 23% after 17 days. Under salt stress, Pn decreased to 54% of control at the 5th day, and then maintained about 48%. The changes in Gs, Ci and Tr were consistent with that in Pn. The content of P in petiole and stem increased 37%-54%, while K⁺/Na⁺ decreased 87%-96% in different tissues, and dry weight decreased 18% of control after 17 days. Under drought stress, Pn decreased rapidly to 29% at the 6th day, and the changes in Gs, Ci and Tr were consistent with that of Pn. The cell membrane permeability increased 67% at the 7th day and dry weight decreased 55% of control at the 17th day. Meanwhile, leaves became curly and pendulous, and old leaves fall off. Among all of stresses, Pn of J. curcas reached relative stable state at first under phosphorus deficiency stress, followed by salt stress and nitrogen deficiency. It suggested that the J. curcas had good adaptability to phosphorus deficiency stress, and relatively poor to nitrogen deficiency stress. The salt tolerance of J. curcas should belong to the gathered salt type, which is a type of avoiding salt damage, while the drought adaptation of J. curcas belongs to drought avoidance type.