EDTA对铬胁迫下黄瓜幼苗生长及生理特性的影响

为探究乙二胺四乙酸(EDTA)对缓解黄瓜幼苗铬胁迫的生理调控机制，以亨优小菜园为供试材料，采用土培方式，用120mg/L铬离子溶液模拟铬胁迫，研究不同浓度EDTA(W₁:1mmol/L、W₂:2mmol/L和W₃:4mmol/L)对铬胁迫下幼苗生长及生理特性的影响。结果表明，W₂和W₃处理促进幼苗株高和地上部干物质量的增加；同时W₂处理增加叶片光系统的光化学猝灭和非光化学猝灭系数；经过3种处理的幼苗叶片和根系过氧化物酶(POD)活性显著增强，而叶片丙二醛(MDA)含量在W₂和W₃处理下显著下降，根系MDA含量在W₃处理下显著降低；3种处理下幼苗叶片中可溶性蛋白含量有所下降，而脯氨酸含量一直增加。综上可知，1～2mmol/L EDTA在铬胁迫下可提高黄瓜幼苗叶片的光合作用，增强POD活性和渗透调节能力，减缓幼苗膜脂过氧化程度，促进幼苗地上部形态发育，从而有效缓解铬胁迫对幼苗的危害。

Effects of EDTA on Growth and Physiological Characteristics of Cucumber Seedlings under Chromium Stress

In order to explore the physiological regulation mechanism of ethylenediamine tetraacetic acid (EDTA) under alleviating chromium stress in cucumber seedlings, “Hengyou Vegetable Garden” was used as test materials in soil culture with 120mg/L chromium ion solution to simulate chromium stress, the effects of different concentrations of EDTA (W₁: 1mmol/L, W₂: 2mmol/L and W₃: 4mmol/L) on seedling growth and physiological characteristics under chromium stress were studied. The results showed that, W₂ and W₃ treatments promoted the increase of plant height and dry matter weight of shoot in seedling. Meanwhile, W₂ treatment increased the photochemical and non-photochemical quenching coefficients of leaf photosystem. Peroxidase (POD) activity in leaves and roots of seedlings was significantly increased after the treatments, while malondialdehyde (MDA) content in leaves was significantly decreased under W₂ and W₃ treatments, and MDA content in roots was significantly decreased under W₃ treatment. The content of soluble protein in seedling leaves decreased, while the content of proline had been increased under the treatments. In conclusion, 1-2mmol/L EDTA under chromium stress could improve photosynthesis of cucumber seedlings, enhance POD activity and osmotic regulation ability, slow down the level of membrane lipid peroxidation of seedlings, and promote shoot morphological development of seedlings, thus effectively alleviating the harm of chromium stress on seedlings.