柠檬酸对铝胁迫下苗期黑麦草生长生理的影响

Effects of Citric Acid on Growth Physiology of Ryegrass Seedlings under Aluminum Stress

该研究以多花黑麦草'普通四倍体'为供体材料,采用砂培盆栽法,探究不同浓度柠檬酸(0,0.8,1.5 mmol/L)对铝胁迫下多花黑麦草的若干生长和生理指标的影响,以期了解柠檬酸对铝毒害下多花黑麦草的缓解作用。研究结果显示,适宜浓度的柠檬酸(0.8 mmol/L)能促进多花黑麦草的株高和根长的伸长生长,提高地上部和地下部的自由水含量、多花黑麦草叶片中叶绿素a、叶绿素b和叶绿素a+b含量、根系和茎叶中可溶性蛋白和可溶性糖含量,以及增强了根系和茎叶中SOD、CAT和POD活力,并降低根系和叶片中MDA含量以及叶片中相对电导率,从而有效缓解铝胁迫对多花黑麦草的毒害作用。而柠檬酸浓度过高(1.5 mmol/L)则会在一定程度上对多花黑麦草若干生长和生理指标造成抑制作用。

In order to understand the effect of citric acid on alleviating the toxic effects of aluminum stress on plants,with Italian ryegrass'normal tetraploid'as test materials,the effects of different concentrations of citric acid(0,0.8,1.5 mmol/L)on some growth and physiological indexes of Italian ryegrass under aluminum stress by using sand potting method were studied.The results showed that the optimum concentration of citric acid(0.8 mmol/L)could increase the plant height,root length,free water content of the aboveground and underground parts,content of chlorophyll a,chlorophyll b and chlorophyll a+b in leaves,soluble protein,soluble sugar content as well as the activity of SOD,CAT and POD in roots,stems and leaves,while decrease the content of MDA in roots and leaves and the relative conductivity in leaves.Thereby it effectively alleviated the toxic effect of aluminum stress on Italian ryegrass.However,too high citric acid concentration(1.5 mmol/L)would inhibit the growth of ryegrass and aggravate aluminum toxicity to some extent.