外源谷氨酸对铝胁迫下多花黑麦草幼苗生长的缓解作用

本研究以多花黑麦草（Lolium multiflorum Lamk.）为材料，采用盆栽法探究外源添加谷氨酸（2 mmol·L^-1和4 mmol·L^-1）对铝胁迫（500 mg·L^-1）下多花黑麦草生长和生理方面的影响。试验结果表明，单独添加外源谷氨酸显著降低了多花黑麦草叶片和根系中的铝离子含量（P<0.05）；铝胁迫下添加谷氨酸能提高多花黑麦草的株高和根长、地上和地下生物量的积累、叶绿素含量、根系可溶性糖含量、叶片可溶性蛋白含量以及叶片、根系中抗氧化酶SOD和CAT活性，并降低了叶片和根系中相对电导率、根系中MDA含量及叶片中POD活性，且添加4 mmol·L^-1谷氨酸的效果优于2 mmol·L^-1谷氨酸；铝胁迫下4 mmol·L^-1谷氨酸处理显著降低了叶片中谷氨酸、天冬氨酸、丝氨酸、丙氨酸、脯氨酸、缬氨酸含量，但根系中丙氨酸和亮氨酸含量却均有所上升（P<0.05）。综上所述，外源添加谷氨酸能有效缓解铝胁迫对多花黑麦草叶片和根系的毒害作用，且4 mmol·L^-1效果较好。

Alleviation of Exogenous Glutamic Acid on Seedling Growth of Italian Ryegrass under Aluminum Stress

The purpose of this study is to investigate the effects of exogenous glutamic acid (2 mmol·L^-1 and 4 mmol·L^-1) on the seedling growth of Italian ryegrass under aluminum stress (500 mg·L^-1) by potting method. Results showed that the addition of exogenous glutamic acid significantly reduced the aluminum ion content in leaves and roots under aluminum stress (P<0.05). And the addition of glutamic acid under aluminum stress promoted the plant height,root length,the accumulation of above-ground and underground biomass,chlorophyll content,soluble sugar in roots,soluble protein content in leaves and improved antioxidant enzymes SOD or CAT activities both in roots and leaves,whereas decreased the relative conductivity both in roots and leaves,MDA content in roots as well as POD activities in leaves under aluminum stress. And the effect of adding 4 mmol·L^-1 glutamate is better than 2 mmol·L^-1 glutamate. When glutamic acid was added under aluminum stress,the contents of glutamic acid,aspartic acid,serine,threonine,alanine and valine in leaves decreased significantly,however,the content of proline and leucine in the root system were increased (P<0.05). To summary,the addition of a certain concentration of glutamic acid could effectively alleviate the toxic effect of aluminum stress on leaves and roots of Italian ryegrass,and 4 mmol·L^-1 glutamic acid was better.