不同生育时期鹰嘴紫云英根系数量特征及固土能力研究

Study on quantitative characteristics and soil-fixingcapacity of root system of Astragalus cicer indifferent growth periods

摘要:

为了探究鹰嘴紫云英(Astragalus cicer)根系在贫瘠土壤条件下的发育情况,测定了不同发育时期的根系数量特征,包括根系表面积、体积、分枝数、累计根长、累计根表面积、累计根体积及不同时期的侧根分级和根干重,结果表明:贫瘠土壤条件下,鹰嘴紫云英侧根错综复杂,呈网状分布;苗期Ⅰ级侧根占根系比例最高,成熟期最低,所占比例分别为52.8%、14.93%;而Ⅱ级侧根占根系比例呈先增加后减少,在分枝期到达最大值,为66.43%;成熟期Ⅲ级侧根占根系比例最高,苗期最低,所占比例分别为47.9%、12.1%。同一生育时期各级侧根间均存在显著差异。从整个生育期来看,在分枝期根系生长发育最为活跃。苗期代表根径级为0~1 mm,分枝期、开花期、结荚期和成熟期代表根径级为0~1.5 mm。同时,随着生育时期的推进,根系的固土能力逐步增强。综上表明,鹰嘴紫云英在贫瘠土壤条件下根系的发育能力较强,分枝期整株根干重最高,且在土壤中主要以径级为0~1.5 mm的细根为主,可为防止水土流失的适宜材料。

Abstract:

In order to explore the root development of Astragalus cicer in infertile soil,the root quantitative characteristics at different development stages were measured,including root surface area,volume,branch number,cumulative root length,cumulative root surface area,cumulative root volume,lateral root classification and dry weight at different stages.The results showed that the lateral roots were complex and net-like distribution;the proportion of Class I lateral roots was the highest in seedling stage,and the lowest in the mature stage,accounting for 52.8% and 14.93% respectively;the proportion of Class II lateral roots increased first and then decreased,reaching the maximum of 66.43% in branching stage;the proportion of Class III lateral roots was the highest (47.9%) in mature stage,and the lowest (12.1%) in seedling stage.There were significant differences among all levels of lateral roots in the same growth period.In whole growth period,the root growth and development were the most active in the branching period.The representative root diameter class was 0~1 mm at seedling stage and 0~1.5 mm at branching stage,flowering stage,pod setting stage and mature stage.The ability of root system to consolidate soil gradually enhanced with the growth period.In conclusion,the root development ability of A.cicer was strong in infertile soil,and the dry weight of root system was the highest in branching period,and the fine root with diameter class of 0~1.5 mm was the dominant,which could prevent the soil erosion.