中文摘要：

【目的】探索土壤紧实胁迫对黄瓜产生伤害的机理,为土壤的可持续利用提供参考。【方法】用容重为1.20 g.cm-3的疏松土壤和1.55 g.cm-3的紧实土壤进行盆栽试验,研究土壤紧实胁迫对‘津春4号’黄瓜叶片及根系中抗坏血酸-谷胱甘肽循环（AsA-GSH）的影响。【结果】在土壤紧实胁迫条件下,黄瓜叶片及根系中过氧化氢（H2O2）含量和丙二醛（MDA）含量显著提高,且根系中两种物质的增幅高于叶片,表明根系的伤害程度高于叶片。与此同时,叶片及根系中还原型抗坏血酸（AsA）含量、AsA＋DHA量、ASA/DHA显著降低,脱氢抗坏血酸（DHA）含量显著提高;还原型谷胱甘肽（GSH）含量显著下降,氧化型谷胱甘肽（GSSG）含量、GSSG/GSH比值显著提高,GSSG＋GSH变化甚微,表明AsA及GSH被消耗以清除H2O2。叶片及根系中抗坏血酸过氧化物酶（APX）、单脱氢抗坏血酸还原酶（MDHAR）、脱氢抗坏血酸还原酶（DHAR）和谷胱甘肽还原酶（GR）活性显著升高,且APX的活性水平远远高于MDHAR、DHAR及GR,表明APX在清除H2O2的过程中氧化AsA的能力远远高于MDHAR和DHAR再生AsA的能力及GR将GSSG还原成GSH的能力。【结论】在土壤紧实胁迫条件下,黄瓜秧苗（叶片及根系）中的AsA-GSH循环加强,削弱了土壤紧实胁迫造成的伤害。

英文摘要：

[Objective ] The objective of this study is to explore the injury mechanism of soil compaction stress to cucumber plants, and to offer a reference for sustainable utilization of soil. [Method] Ascorbate-gluthione cycle was assayed in leaves and fine-roots of cucumber plant, ＇Jinchun 4＇, growing under 1.2 or 1.55 g.cm^-3 in bulk density. [Results] The results showed that the content of H202 and MDA in both leaf and root increased significantly under soil compaction stress. Furthermore, the increase amplitude in H202 and MDA contents was higher in the root than that in the leaf, indicating that the root was damaged more pronouncedly than the leaf by soil compaction stress. Under soil compaction stress, AsA, AsA＋DHA, and GSH contents and AsA/ DHA ratio decreased significantly whereas DHA and GSSG contents and GSSG/GSH ratio increased significantly in both the leaves and the roots. GSSG＋GSH contents hardly changed. The above results suggest that AsA and GSH were consumed to scavenge H202. In addition, the soil compaction stress enhanced the activities of APX, MDHAR, DHAR, and GR in both leaf and root, and APX activity was larger than those three enzymes, which imply that the capacity of AsA oxidation by APX to scavenge H202 was higher than that of re-production of AsA by MDHAR and DHAR and the reduction of GSSG to GSH by GR. [ Conclusion ] AsA-GSH cycle was enhanced in cucumber plants under soil compaction stress, the injury of soil compaction stress to cucumber plants was lowered.