少花蒺藜草与不同牧草混播根际与非根际土壤酶活性变化

Changes of enzyme activities in rhizosphere and non-rhizosphere soil of Cenchrus pauciflorus at differentgrowth stages under substitution competition

摘要:

为了探究牧草对少花蒺藜草(Cenchrus pauciflorus)的竞争影响,采用3种优质牧草紫花苜蓿(Medicago sativa)、羊草(Leymus chinensis)、草木樨(Melilotus officinalis)与少花蒺藜草混播,测定混播模式下少花蒺藜草不同生长时期根际和非根际土土壤pH、脲酶、磷酸酶、蔗糖酶和过氧化氢酶的活性变化。结果表明:与3种牧草混播均显著提高少花蒺藜草根际土壤的酶活性;在紫花苜蓿与羊草混播,少花蒺藜草根际土土壤的脲酶和蔗糖酶活性在开花期最高,磷酸酶活性在苗期最高,而与草木樨混播,少花蒺藜草根际土的磷酸酶和蔗糖酶活性在全生长期内均有大幅提高,脲酶活性在开花期时显著提高,草木樨更能激发少花蒺藜草根际土壤酶活性,与少花蒺藜草的竞争最为激烈。混播模式激发少花蒺藜草的自我保护机制,明显提高少花蒺藜草根际土壤酶活性,增强其自身的竞争能力,避免竞争胁迫带来的危害。

Abstract:

In order to explore the competitive influence of alternative pastures on Cenchrus pauciflorus Benth.,Benth was replaced by three high-quality pastures,Medicago sativa,Leymus chinensis and Melilotus officinalis.Under each replacement,the changes of soil pH,urease,phosphatase,sucrase and catalase activities in rhizosphere and non-rhizosphere soil were analyzed at different growth stages.The results showed that the enzyme activities in rhizosphere soil of C.pauciflorus were significantly increased by all three alternative pastures.Under the substitution of M.sativa and L.chinensis,urease and sucrase activities in rhizosphere soil of C.pauciflorus were the highest at flowering stage,and phosphatase activities were the highest at seedling stage.With M.officinals,the activities of phosphatase and sucrase in rhizosphere of C.pauciflorus increased greatly throughout the entire growth period,and the activity of urease increased significantly during the flowering period.M.officinals could stimulate the enzyme activity of rhizosphere soil of C.pauciflorus,and the competition with C.pauciflorus could be most intensive.This study suggests that substitution could provide self-protection mechanism for C.pauciflorus The increase in the enzyme activity of the rhizosphere soil of C.pauciflorus could enhance its competitiveness and avoid damages caused by competitive stresses.