干旱胁迫对红豆草根系生长及生理特性的影响

Effects of drought stress on root growth and physiological characteristics of sainfoin

摘要:

采用不同浓度 PEG-6000 模拟干旱胁迫(渗透势分别为 0、-0. 4、-0. 8、-1. 2、-1. 6 和 -2. 0 MPa)，研究干旱胁迫对 5 份红豆草材料根系生长及生理指标的影响，并对其苗期抗旱性进行分析和评价。结果表明：随干旱胁迫的加剧，供试红豆草的根冠比、根表面积、根尖数、根系可溶性蛋白、 根系可溶性糖、根系活力均先增加后下降，根系平均直径、根体积、叶片相对含水量下降，根长和丙二醛含量增加；重度胁迫下，材料 P1 的根体积、根表面积、根直径降幅最小、丙二醛含量最低，材料 P2 的可溶性蛋白含量增幅最大，甘肃红豆草的根冠比降幅最小、可溶性糖含量增幅最大，蒙农红豆草的根系活力、根尖数降幅最低，根长最长。经隶属函数法分析得出供试红豆草的抗旱性顺序为：材料 P1＞P3＞ P2＞甘肃红豆草＞蒙农红豆草，主成分分析显示根直径、脯氨酸、可溶性糖可作为筛选抗旱红豆草的参考指标。

Abstract:

PEG-6000 was used to simulate drought stress， and the effects of PEG - 6000 concentrations (0， -0. 4，-0. 8，-1. 2，-1. 6，and -2. 0 MPa) on seedling root growth and physiological indexes of 5 samples of sain- foin were studied. The drought resistance in seedling stage was also analyzed and evaluated. The five sainfoin samples including 3 sainfoin lines (P1， P2， P3)，Onobrychis viciaefolia‘Gansu’(CK1) and O. viciaefolia‘Meng- nong’(CK2). The results showed that root shoot ratio， total root surface， root tip number，contents of soluble pro- tein and soluble sugar increased first and then decreased， average root diameter and root volume significantly de-creased， root length and MDA content significantly increased with the increasing of PEG-6000 concentration. Un- der severe stress，root volume，total root surface，average root diameter of P1 decreased the least， and MDA content of P1 was the lowest. The Root soluble protein content of P2 increased the most. Root shoot ratio of CK1 decreased the least， whereas soluble sugar content of CK1 increased the most. Root activity and root tip number of CK2 de- creased the least， and root length of CK2 was the longest. According to the membership function analysis， the drought resistance order of the tested sainfoin was as follows：P1＞P3＞P2＞CK1＞CK2. Principal component analysis indicated average root diamater， proline，and soluble sugar were the most suitable indicators for the tolerance to drought.