野牛草雌、雄株对干旱胁迫的生理响应差异

Differences in the physiological responses of female and male Buchloe dactyloides plants to drought stress

野牛草(Buchloe dactyloides)是草坪草种中少有的雌雄异株植物,分析野牛草雌雄株抗旱差异性,为雌雄异株植物生理差异研究提供理论基础。本研究采用‘Texoka’品种野牛草作为试验材料,使用雌、雄株的克隆分株扦插繁殖,成坪后进行3种干旱胁迫处理:对照处理(田间持水量在90%,CK)、半干旱处理(田间持水量50%,H)、干旱处理(田间持水量30%,D)。结果表明,随着干旱程度的增加,野牛草雌株和雄株的株高、生物量、根冠比、叶片相对含水量以及叶绿素荧光参数的变化不显著(P>0.05);丙二醛含量和脯氨酸含量与干旱程度均呈正相关关系,且雌株含量显著大于雄株(P<0.05)。野牛草雌株超氧化物歧化酶、过氧化物酶、抗坏血酸过氧化物酶活性在干旱处理时显著大于雄株。此外,雌、雄株之间的抗氧化酶活性变化并不一致,在同一水分条件下雌株的抗氧化酶活性显著大于雄株,表明野牛草雌株相对于雄株具有更强的清除活性氧能力。双因素分析结果和主成分分析结果也表明野牛草响应干旱胁迫存在明显的性别差异,隶属函数分析发现,野牛草雌株的抗旱性综合评价高于雄株。综上,野牛草雌、雄株对干旱胁迫的响应存在性别差异,且野牛草雌株的抗旱性强于雄株。

Buffalo grass is a rare dioecious turfgrass.Analyzing differences in drought resistance between male and female buffalo grass provides a theoretical basis for the study of physiological differences in dioecious plants.In this study,buffalo grass of the'Texoka'variety(Buchloe dactyloides)was used as the experimental material,and cloned branches of female and male plants were used for cutting propagation.Three drought stress treatments were applied after flat formation:normal watering/control(field water capacity,90%,CK);semi-drought(field water capacity,50%,H);and drought(field water capacity,30%,D).The results showed that the plant height,biomass,root-shoot ratio,leaf relative water content,and chlorophyll fluorescence parameters of female and male B.dactyloides did not change significantly with increasing drought severity.Malondialdehyde(MDA)and proline(PRO)contents in female plants were significantly higher than those in male plants,and were positively correlated with the degree of drought.Superoxide dismutase(SOD),peroxidase(POD),and ascorbate peroxidase(APX)activities differed significantly between female and male buffalo grass plants.In addition,the antioxidant enzyme activity of B.dactyloides was significantly higher in female plants than that in male plants under the same drought conditions;therefore,the ability to remove reactive oxygen species(ROS)is stronger in female plants than that in male plants.Consistent with these findings,two-factor and principal component analyses showed significant differences in the responses of male and female B.dactyloides plants to drought stress.Membership function analysis showed that the drought resistance of female buffalo grass was higher than that of male buffalo grass.In conclusion,our findings confirm that phenotypic gender differences impact the physiological responses of B.dactyloides to drought stress,with females displaying stronger drought resistance than that of their male counterparts under the same conditions.