Grafting Enhances Copper Tolerance of Cucumber Through Regulating Nutrient Uptake and Antioxidative System

• Published in: Agricultural sciences in China 2010-12, Vol.9 (12), p.1758-1770
• Main Authors: ZHANG, Zi-kun, LI, Hua, ZHAG, Yu, HUANG, Zhi-jun, CHEN, Kun, LIU, Shi-qi
• Format: Article
• Language: English
• Subjects: antioxidant; antioxidative enzymes; copper stress; grafted cucumber seedling; mineral content; 养分吸收; 嫁接黄瓜; 抗坏血酸过氧化物酶; 抗氧化系统; 活性氧清除系统; 超氧化物歧化酶; 铜胁迫; 黄瓜幼苗
• ISSN: 1671-2927
• DOI: 10.1016/S1671-2927(09)60274-1

An experiment was carried out to determine plant growth, mineral uptake, lipid peroxidation, antioxidative enzymes, and antioxidant of cucumber plants （Cucumis sativus L. cv. Xintaimici） under copper stress, either ungrafted or grafted onto the rootstock （Cucurbitaficifolia）. Excess Cu inhibited growth, photosynthesis, and pigment synthesis of grafted and ungrafted cucumber seedlings and significantly increased accumulation of Cu in roots besides reducing mineral uptake. Cu concentration in roots of grafted cucumber plants was significantly higher than that of ungrafted plants and obviously lower in leaves. The accumulation of reactive oxygen species （ROS） significantly increased in cucumber leaves under Cu stress and resulted in lipid peroxidation, and the levels of ROS and lipid peroxidation were greatly decreased by grafting. Activities of protective enzymes （superoxide dismutase, SOD; peroxidase, POD; catalase, CAT; ascorbate peroxidase, APX; dehydroascorbate reductase, DHAR; glutathione reductase, GR） and the contents of ascorbate and glutathione in leaves of grafted plants were significantly higher than those of ungrafted plants under Cu stress. Better performance of grafted cucumber plants were attributed to the higher ability of Cu accumulation in their roots, better nutrient status, and the effective scavenging system of ROS.