不同水分胁迫下水杨酸对分枝期扁蓿豆生长及光合生理的影响

为明确水杨酸对扁蓿豆分枝期抗旱性的调控作用,采用盆栽试验研究正常供水(80%田间持水量)、轻度水分胁迫(60%田间持水量)、中度水分胁迫(40%田间持水量)以及重度水分胁迫(20%田间持水量)条件下,不同浓度0(对照),0.02,0.10,0.50,2.50 mmol/L]水杨酸处理对扁蓿豆分枝期生长、抗性生理及光合特性的影响。结果表明,轻度、中度水分胁迫下,0.10 mmol/L水杨酸显著提高了叶片相对含水量、叶绿素含量、可溶性蛋白含量,同时使超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性以及叶片光合速率(Pn)、气孔导度(Gs)得到显著提高,而气孔限制值(Ls)显著降低;重度水分胁迫下,0.50 mmol/L水杨酸显著提高了株高、一级分枝数、叶面积、叶片相对含水量、叶绿素含量、游离脯氨酸含量、可溶性蛋白含量,同时SOD、POD、CAT活性以及叶片Pn、Gs、水分利用效率(WUE)显著提高,而使电导率、丙二醛(MDA)含量以及LS显著降低。可见,适宜浓度水杨酸可以改善干旱胁迫下扁蓿豆分枝期的生长,提高其抗旱能力。

Effects of salicylic acid on growth and photosynthetic characteristics of Melilotoides ruthenica in branching stage under different water stress

The pot experiment was conducted to determine the effects of the different concentrations 0(The control), 0.02, 0.10, 0.50, 2.50 mmol/L] of salicylic acid on the growth, the physiology characteristics and photosynthetic characteristics of Melilotoides ruthenica in branching stage under normal irrigation (80% field capacity), mild water stress (60% field capacity), moderate water stress (40% field capacity)and severe water stress (20% field capacity) in order to understand the effects of salicylic acid on drought tolerance of M. ruthenica in branching stage. The results showed that under mild and moderate water stress, treatment with 0.1 mmol/L salicylic acid significantly increased leaf relative water content, chlorophyll content, soluble protein content, the activities of superoxide dismutase (SOD), peroxidase (POD) and catlase (CAT), photosynthetic rate (Pn) and stomatal conductance (Gs) compared with the control, but stomatal limitation value (Ls) were significantly decreased; Under severe water stress, treatment with 0.5 mmol/L salicylic acid significantly increased plant height, primary shoot number, leaf area, leaf relative water content, chlorophyll content, free proline content, soluble protein content, the activities of SOD, POD and CAT, Pn, Gs and water use efficiency (WUE) compared with the control, but electrolyte leakage, malondialdehyde (MDA) content and Ls were significantly decreased. The results suggested that salicylic acid with the appropriate concentrations could increase the drought resistance of M. ruthenica and improve its growth in branching stage under water stress.