干旱胁迫对桔梗幼苗生长及生理特性的影响

Effect of Drought Stress on Growth and Physiological Characteristics of Platycodon grandiflorus Seedling

为了考察干旱胁迫对桔梗生长和生理特性的影响,采用试验盆栽对其进行研究。结果表明:干旱胁迫显著抑制桔梗生物量的积累,但其在中度干旱胁迫下水分利用率和根冠比最大。游离脯氨酸质量分数、可溶性糖质量分数、可溶性蛋白质量分数、超氧阴离子自由基质量分数、MDA质量分数、SOD活性、POD活性均随干旱胁迫程度的增加和干旱胁迫时间的延长而增大,维生素C质量分数随干旱胁迫时间的延长先上升后下降,且随着干旱胁迫程度的增加而减小。试验结果说明,适度的干旱胁迫可以提高桔梗的水分利用率,在干旱胁迫时,桔梗幼苗的渗透调节物质和保护酶系统能够快速适应干旱胁迫,维持植株正常的生理代谢功能。

The drought resistance of Platycodon grandiflorus seedlings was studied under the condi- tion of artificial drought stress and the physiological and growth indexes related to drought resistance were measured. The results showed that the hiomass of Platycodon grandiflorus seedlings was signif- icantly inhibited while the treatment under moderate drought stress had the highest water use efficien- cy and root shoot ratio. At the meantime, the contents of free proline, soluble protein and soluble sug- ar, the activities of SOD and POD, as well as the MDA and superoxide anion free radical content of Platycodon grandiflorus seedlings were increased among the three treatments. The trend of vitamin C content increased at the beginning then decreased, and it also decreased by the prolong of stress time. As a conclusion, the treatment of moderate drought stress could increase the WUE of Platycodon grandiflorus seedlings, the antioxidant enzyme system and osmo-regulation substances in Platycodon grandiflorus seedlings could also change rapidly to adapt to the environmental stress for maintaining the normal function of physiological metabolism.