3种草本植物种子萌发及幼苗生长生理对干旱胁迫的响应  

Changes in seed germination, seedling growth and physiology of 3 herbaceous species in response to drought stress

作　　者：文竹梅 冯玉超 刘青青[1] 陈艳芳 陈云龙 刘博[1,2] 王正宁 WEN Zhumei;FENG Yuchao;LIU Qingqing;CHEN Yanfang;CHEN Yunlong;LIU Bo;WANG Zhengning(College of Forestry,Fujian Agriculture and Forestry University;Cross-Strait Collaborative Innovation Center of Soil and Water Conservation,Fuzhou,Fujian 350002,China)

机构地区：[1]福建农林大学林学院 [2]海峡两岸红壤区水土保持协同创新中心,福建福州350002

出　　处：《福建农林大学学报（自然科学版）》2022年第4期562-569,共8页Journal of Fujian Agriculture and Forestry University:Natural Science Edition

基　　金：国家自然科学基金资助项目(31670714)。

摘　　要：以3种水保草本植物宽叶雀稗(Paspalum wettsteinii)、香根草(Vetiveria zizanioides)和狗牙根(Cynodon dactylon)种子和幼苗为材料,采用聚乙二醇(PEG-6000)溶液模拟水分胁迫方法,研究了不同干旱胁迫环境下(0、5%、10%、15%、20%、25%PEG)3种草本植物的种子萌发、幼苗生长以及抗氧化酶活性对干旱胁迫的响应.结果表明:PEG胁迫显著影响宽叶雀稗、香根草和狗牙根的种子萌发、幼苗生长以及保护酶活性.3种植物种子发芽率随PEG胁迫强度的增加而下降,低浓度PEG胁迫对3种植物种子发芽率的影响不显著,15%、20%PEG胁迫下发芽率虽然显著下降,但仍较高.随着胁迫浓度的提高,植物幼苗的根长、苗高和鲜重均显著下降,干旱胁迫显著影响植物幼苗的生长;25%PEG胁迫下,植物均表现出萌发失败或无根苗现象.随着胁迫时间的增加,各浓度处理3种植物幼苗的SOD活性均下降,胁迫处理后期POD活性增强,均在72 h后达到峰值,并显著高于其他处理(P<0.05).随着渗透势的增加,3种植物CAT活性峰值时间趋于提前.干旱胁迫下草本植物种子发芽率高、幼苗长势弱及保护酶活性调节力不足,势必增加种子库消耗和幼苗死亡数量,导致草本层生物多样性降低.To fully understand the drought-induced responses of germination status and physiological performance of soil and water conservation herbs, the seeds and seedlings of Paspalum wettsteinii, Vetiveria zizanioides and Cynodon dactylon were subject to drought stress, which were simulated by different concentrations of polyethylene glycol(PEG-6000) solutions(0%, 5%, 10%, 15%, 20% and 25%) by controlled experiment. Changes in seed germination, seedling growth and antioxidant enzyme activity of the herbaceous plants were monitored and measured. The results showed that drought stress as a result of the PEG solution adversely impacted the germination process, seedling development and protective enzyme activities of the herbs. The germination rates kept a downward trend in response to increasing PEG concentrations, although they were not significantly inhibited. Under 15% and 20% PEG solutions, the germination rates were still maintained on a relatively high level although they were inhibited significantly;when the concentrations of PEG solutions kept increasing, the root length, height and fresh weight of the seedlings were significantly reduced, indicating that drought stress significantly impeded the development of the seedlings. When the concentration was lifted to 25%, most seeds failed to germinate or became rootless. With the increase of stress duration, superoxide dismutase(SOD) activities of the seedlings were all decreased regardless of PEG concentration;peroxidase(POD) activity tended to increase at the latter stage of the trial, and peaked after 72 h, which was significantly higher than that of other treatments(P <0.05);the peaking time of catalase(CAT) activity tended to advance with the increase of osmotic potential. In conclusion, drought stress resulted in high seed germination rate, weak seedling growth and insufficient enzyme activities, which depleted seed bank and accelerated seedling death, giving rise to decreased biodiversity of herbaceous layer.

关 键 词：红壤 退化 干旱胁迫 种子 植被更新 

分 类 号：S688.4[农业科学—观赏园艺]