异质生境条件下荒漠草原蒙古冰草生理生态特征的研究

Physiological and ecological characteristics of Agropyron mongolicum in desert steppe under heterogeneous habitats

【目的】研究荒漠草原蒙古冰草对生境变化的生理生态适应策略。【方法】分别在宁夏盐池县大水坑镇、青山乡、花马池镇和高沙窝镇选取4种不同生境以蒙古冰草(Agropyron mongolicum)为优势种的群落,研究蒙古冰草渗透调节物质及抗氧化系统等生理生态特征对异质生境的响应。【结果】荒漠草原不同生境群落蒙古冰草可溶性糖含量、脯氨酸含量、过氧化物酶活性、叶片相对含水量、叶绿素含量及氨基酸含量随生境的改变均有显著变化(P<0.05)。【结论】在土壤水分、养分等资源有限的环境条件下,荒漠草原蒙古冰草种群可通过自身渗透调节物质的积累及抗氧化系统的激活等协同和权衡作用适应变化的生境。在大水坑镇和花马池镇自然生境条件下,蒙古冰草主要通过增强过氧化物酶活性抵御逆境胁迫;在青山乡和高沙窝镇更为严酷的环境条件下,蒙古冰草主要通过脯氨酸或可溶性糖的积累适应逆境胁迫。

【Objective】In order to understand the physiological and ecological adaptation strategies of Agropyron mongolicum to habitat changes.【Method】Four kindsof habitat communities whichdominated by Agropyron mongoli⁃cum in Dashuikeng Town,Qingshan Town,Huamachi Town and Gaoshawo Town in Yanchi County,Ningxia were selected.The response of osmotic regulatory substances and antioxidant enzyme system of Agropyron mongolicum to heterogeneous habitats were studied.【Result】The soluble sugar content,proline content,peroxidase activity,leaf relative water content,chlorophyll content and amino acid content of Agropyron mongolicum in different habitats in desert steppe changed significantly with the change of habitat(P<0.05).【Conclusion】Under the conditions of lim⁃ited soil water and nutrient resources,Agropyron mongolicum population could adapt to the changing habitat through synergistic and tradeoff effects such as accumulation of osmotic regulation substances and activation of antioxidant sys⁃tem.Under the natural habitat conditions of Dashuikeng and Huamachi,the Agropyron mongolicum could resist stress by enhancing the activity of peroxidase.Under the harsher environmental conditions in Gaoshawo town and Qingshan township,the Agropyron mongolicum adapted to stress mainly through accumulation of proline or soluble sugar.