不同居群马蔺抗旱性评价及生理指标变化分析

Evaluation of drought resistance and analysis of physiological index variation for different Chinese Iris populations

对我国北方不同居群的15份野生马蔺种质材料采用温室苗期模拟旱境胁迫-复水方法,于干旱胁迫0,5,10,15,20,25 d和复水后5 d分别取样测定叶片相对电导率(REC)、游离脯氨酸(Pro)、丙二醛(MDA)、叶绿素SPAD值、相对含水量(RWC)、植株相对生长率(RGR)等生理与生长指标,利用欧氏最大距离法聚类分析划分为强抗旱、中度抗旱和弱抗旱3个抗旱级别,研究其生理指标的变化趋势和规律。结果显示,在连续干旱胁迫下,3个抗旱级别马蔺种质材料的REC、Pro和MDA均呈逐渐增加趋势,增幅表现为强抗旱<中度抗旱<弱抗旱,于胁迫前20 d三者间REC差异不显著,但胁迫到25 d时,呈显著差异(P<0.05);于胁迫前15 d三者间Pro、MDA差异不显著,但胁迫到20和25 d时,差异均显著(P<0.05)。3个抗旱级别种质的叶绿素SPAD值和RWC呈逐渐下降趋势,降幅表现为强抗旱<中度抗旱<弱抗旱,分别于胁迫到20和25 d达到显著差异(P<0.05)。复水后,各指标均有不同程度的恢复。

The drought resistance of 15 germplasms of Iris lactea var chinensis from different populations in northern China at the seedling stage was comprehensively identified and evaluated in a green house using the simulated drought stress and rewatering method. The relative electrical conductivity rate （REC）, content of malondialdehyde（MDA）, free proline accumulation （Pro）, relative water content of leaves （RWC）, SPAD value of chlorophyll, and relative growth rates （RGR） were measured at 0, 5, 10, 15, 20 and 25 d of drought stress and at 5 d after rewatering. Three drought resistant classes （high drought resistance （HDR）, medium drought resistance （MDR）, and weak drought resistance （WDR）） were classified using the maximum distance cluster method, and the variation trends and rules of physiological indexes were analyzed. The REC, Pro, and MDA of three different drought resistant classes showed a gradual increasing trend in the order HDR〈MDR〈WDR. The REC showed no significant difference between the three drought resistant classes before stress day 20, but there was a significant （P〈0.05） difference at 25 d. There was no significant difference in Pro or MDA between the three drought resistant classes before stress day 15, but there was a significant （P〈0.05） difference at days 20 and 25. The SPAD value of chlorophyll and RWC showed gradual decreasing trends in the order HDR〈MDR〈WDR. The SPAD value and RWC had significant differences at days 20 and 25 between the three drought resistant classes. The physiological indexes recovered to different degrees after rewatering.