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作 者 ：高青海;王秀峰;史庆华;杨凤娟;魏珉

期 刊 ：应用生态学报 2008年 19卷 05期 页码：976-980

关键词：黄瓜；

摘 要 ：采用水培方法研究了LaCl₃对硝酸盐胁迫下黄瓜幼苗生长及叶片抗氧化酶活性的影响.结果
表明：硝酸盐胁迫显著抑制了黄瓜幼苗的生长，尤其是地上部生长.在处理7 d时，与对照相
比，硝酸盐胁迫下的黄瓜单株地上部鲜质量降低了12.77 g，叶片超氧化物歧化酶（SOD）
、过氧化物酶（POD）、过氧化氢酶（CAT）活性升高，而抗坏血酸过氧化物酶(APX)、脱氢
抗坏血酸还原酶(DHAR)和谷胱甘肽还原酶(GR)活性显著降低.外加低浓度（0.05 mmol·L^-1）LaCl₃可以显著提高硝酸盐胁迫下黄瓜幼苗单株鲜质量，比硝酸盐胁迫下提高了35%左右，还提高了叶片热稳定蛋白含量及SOD、POD、CAT、APX、DHAR、GR活性，降低了电解质渗漏率及丙二醛(MDA)含量，在一定程度上缓解了硝酸盐对黄瓜幼苗生长的抑制作用.但外加高浓度LaCl₃（0.5 mmol·L^-1）长期处理对黄瓜硝酸盐胁迫的缓解效果并不明显.因此外加一定浓度的LaCl₃可通过提高黄瓜抗氧化酶活性及热稳定蛋白含量来缓解硝酸盐胁迫.

Abstract:The study with water culture showed that nitrate stress had significan
t inhibitory effects on the plant growth, especially the shoot growth of cucumbe
r seedlings. On the 7th day under nitrate stress, the shoot fresh mass per plant decreased by 12.77 g, leaf SOD, POD and CAT activities increased, while leaf APX, DHAR and GR activities decreased significantly, compared with the control. The addition of low concentration (0.05 mmol·L^-1) LaCl₃ increased the s
hoot fresh mass per plant by 35%, enhanced the leaf thermally stable protein content and SOD, POD, CAT, APX, DHAR and GR activities, and decreased the leaf MDA content and electrolytic leakage, resulting in a definite alleviation of the inhibitory effects of nitrate. However, an addition of high concentration (0.5 mmol·L^-1) LaCl₃ had no obvious alleviation effect. It was concluded that t
he addition of certain concentration LaCl₃ could alleviate the nitrate stress
on cucumber via increasing anti-oxidative enzymes activities and thermally stable protein content.

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