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以甜瓜耐镉品种‘哈密绿’和镉敏感品种‘秀绿’为试验材料,在人工气候箱内采用基质栽培法,研究了外源水杨酸(SA)处理对镉(Cd)胁迫下甜瓜幼苗生长、光合作用和活性氧代谢的缓解效应。结果显示:与对照(CK)比较,Cd处理显著抑制了甜瓜幼苗的生长和光合作用,降低了叶绿素含量,抗氧化酶活性、脯氨酸(Pro)含量、丙二醛(MDA)含量和超氧阴离子(O2ˉ·)产生速率增加;在Cd胁迫下,SA处理可以有效促进甜瓜幼苗的生长,增加了叶绿素含量、净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)、气孔限制值(Ls)和水分利用效率(WUE),降低了胞间CO2浓度(Ci);提高了超氧化物歧化酶(SOD)、过氧化酶酶(POD)、过氧化氢酶(CAT)和抗坏血酸过氧化物酶(APX),增强植株抗氧化能力,使Pro和可溶性蛋白含量升高,MDA含量和O2ˉ·产生速率下降,能有效抑制镉胁迫引起的膜脂过氧化伤害;镉敏感品种‘秀绿’变化幅度大于耐镉品种‘哈密绿’。研究结果说明,SA有利于甜瓜幼苗在Cd胁迫下活性氧代谢的提高和对光能的捕获与转换,促进了甜瓜幼苗的生长,降低Cd胁迫对甜瓜幼苗的抑制作用,且对镉敏感品种‘秀绿’效果大于耐镉品种‘哈密绿’。
The effects of exogenous salicylic acid (SA) on the growth of melon (Cucumis sativus L.) under the stress of cadmium (Cd) Mitigative effects of seedling growth, photosynthesis and reactive oxygen metabolism. The results showed that compared with the control (CK), Cd treatment significantly inhibited the growth and photosynthesis of muskmelon seedlings and decreased the contents of chlorophyll, antioxidant enzyme, proline, malondialdehyde (MDA) Under the Cd stress, SA treatment could effectively promote the growth of muskmelon seedlings, increased chlorophyll content, net photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (Tr) Stomatal limitation value (Ls) and water use efficiency (WUE) decreased the intercellular CO2 concentration (Ci), increased SOD, POD, CAT, And ascorbate peroxidase (APX), enhance plant antioxidant capacity, increase Pro and soluble protein content, decrease MDA content and O2ˉ production rate, and effectively inhibit membrane lipid peroxidation damage caused by cadmium stress. Cadmium-sensitive cultivars ’Show Green’ changes greater than the tolerance of cadmium varieties ’Hami Green’. The results showed that SA was beneficial to the increase of active oxygen metabolism and the capture and conversion of light energy in melon seedling under Cd stress, promoted the growth of muskmelon seedlings, decreased the inhibitory effect of Cd stress on melon seedlings, Show green ’effect is greater than the tolerance of cadmium’ Hami green ’.