不同品种紫花苜蓿根系形态及生理特征对磷水平的响应

为明确不同品种紫花苜蓿(Medicago sativa)根系形态和生理特征对磷水平的响应,以营养液水培的试验方法,分析了0(P₀)、50(P₁)、100(P₂)、500(P₃)1000(P₄)和1500μmol·L^?1(P₅)磷水平下,6种紫花苜蓿根系形态及生理特征对磷水平的响应。结果发现,各品种总根长、根表面积均在P₁处理时达到最大,新牧一号、耐盐之星、肇东、巨能Ⅱ4个品种在P₂低磷水平时总根长、根表面积高于陇东、龙牧801。设定磷水平下,各品种根体积仅在P₀、P₁处理时存在差异性,陇东根体积在P₁、P₂、P₃、P₅处理下均小于其他品种。P₁处理时新牧一号、龙牧801根系磷吸收效率高于其他4个品种,P₂、P₃、P₄处理下肇东根系磷吸收效率显著(P<0.05)高于其他品种。根系酸性磷酸酶活性均在P₁时达到最大且同浓度磷水平时各品种间存在显著差异。低磷水平下,耐盐之星、巨能Ⅱ根系酸性磷酸酶活性显著高于其他4个品种,综合各耐低磷指标表明新牧一号、耐盐之星的耐低磷性高于其他品种是较好的磷高效品种,其次是肇东、巨能Ⅱ,而陇东、龙牧801则可归纳为磷低效品种。

Responses of root morphological and physiological characteristics of different alfalfa genotypes to phosphorus levels

To clarify the response of the root morphology and physiological characteristics of different varieties of alfalfa(Medicago sativa)to phosphorus levels,the test method of nutrient solution hydroponics was used to analyze a total of six alfalfa plants under the phosphorus levels 0(P₀),50μmol·L?1(P₁),100μmol·L?1(P₂),500μmol·L?1(P₃),1000μmol·L?1(P₄),and 1500μmol·L^?1(P₅).The response characteristics of root length,surface area,volume,phosphorus absorption efficiency,and acid phosphatase activity to phosphorus level was ascertained.It was found that there were differences in total root length,root surface area,root phosphorus absorption efficiency,and root acid phosphatase activity among varieties at the same phosphorus level.The total root length and root surface area reached a maximum at low phosphorus levels.The total root length and root surface area of the four varieties of Xinmu No.1,Magnum Salt,Zhaodong,and JunengⅡwere higher than those of Longdong and Longmu 801 at low P₂ levels.The root volume of each variety was different only in P₀,P₁ treatment,and the root volume of Longdong was smaller than that of other varieties in the P₁,P₂,P₃,and P₅ treatments.The phosphorus absorption efficiency of roots of Xinmu No.1 and Longmu 801 was higher than that of the other four varieties under low phosphorus conditions.The phosphorus absorption efficiency of the roots of Zhaodong was significantly higher(P<0.05)than that of the other varieties under P₂,P₃,and P₄ treatments.The root acid phosphatase activity reached a maximum at P₁,and there was a significant difference(P<0.05)among the varieties at the same phosphorus level.Under low phosphorus levels,Magnum Salt and JunengⅡhad significantly higher root acid phosphatase activity than the other four varieties.The comprehensive low-phosphorus tolerance indicators show that Xinmu No.1 and Magnum Salt have lower phosphorus tolerance than the other varieties are phosphorus efficient varieties,followed by Zhaodong and JunengⅡ,whereas Longdong and Longmu 801 can be classified as phosphorus inefficient varieties.