干旱胁迫对光叉委陵菜根系特征、结构和生理特性的影响

Effects of drought stress on root characteristics structure and physiological characteristics of Potentilla bifurca var.glabrata

以光叉委陵菜的多年生植株作为试验材料,通过自然控水法,研究不同干旱处理对植株根系的表型特征、超微结构和生理指标的影响,探究光叉委陵菜的耐旱性。结果表明:干旱胁迫下,光叉委陵菜根系总长度、总表面积、总体积和平均直径持续增加,根系干重在0~15 d增加,20~25 d干重显著降低(P<0.05)。随干旱胁迫程度的增加,根系细胞壁变形破损,线粒体解体消失,淀粉粒出现并不断膨大。丙二醛(MDA)含量、脯氨酸含量在25 d内持续升高,可溶性蛋白含量、超氧化物歧化酶(SOD)活性在0~15 d显著升高,在20~25 d均显著下降(P<0.05);复水后,脯氨酸含量下降但不显著(P>0.05),MDA含量、可溶性蛋白含量、SOD活性均出现显著降低(P<0.05)。综合来看,光叉委陵菜能耐20 d的自然干旱,具有较强的抗旱性,这为东北地区选育耐旱植物提供了参考。

In this research a natural water control method was used to study the effects of different drought treatments on the phenotypic characteristics,ultrastructure and physiological indexes of roots of Potentilla bifurca var.glabrata and to explore the drought tolerance of this species.It was found that under drought stress,the total root length,total surface area,total volume and average diameter of P.bifurca var.glabrata increased continuously over days0-25.The root dry weight increased over days 0-15 d,but decreased significantly over days 20-25 d(P<0.05).With increased drought stress,the root cell wall was deformed and damaged,the mitochondria disintegrated and disappeared,and starch grains appeared and continuously expanded.Malondialdehyde(MDA)content and proline content were increased over days 0-25.Soluble protein content and superoxide dismutase(SOD)activity increased significantly over days 0-15,and decreased significantly over days 20-25 d(P<0.05).After rehydration,the contents of proline and soluble protein decreased nonsignificantly(P>0.05),while MDA content and SOD activity decreased significantly(P<0.05).Generally speaking,P.bifurca var.glabrata can endure natural drought for 20 d and has strong drought resistance.These results provide information for the breeding of drought-tolerant plants in Northeast China.