两个柱花草品种根系构型差异及其对间作柑橘砧木实生苗磷营养的竞争

Difference in Root Architecture of Two Stylosanthes Cultivars and Their Competition for Phosphorus with Citrus Rootstock Seedling

根系构型与植物的养分吸收密切相关,可能影响植物不同个体间的养分竞争。比较了‘格拉姆’和‘184号’柱花草(Stylosanthes Sw.)的根系构型差异,并探讨了两者在间作条件下对柑橘砧木红藜檬(Citrus limonia)实生苗的生长和养分吸收的影响。结果表明,‘格拉姆’和‘184号’在单作条件下生物量、总根长、主根长和根尖数相似,但是‘184号’的基根角度、根系表面积、平均根直径均小于‘格拉姆’;在与柑橘实生苗间作条件下,‘184号’有41.4%的根系进入柑橘根区,而‘格拉姆’仅有0.8%的根系进入柑橘根区,因此与‘184号’间作的柑橘砧木实生苗的生物量和对磷养分的吸收均显著低于与‘格拉姆’间作的柑橘砧木实生苗。本研究表明,与根系垂直生长型的‘格拉姆’相比,根系水平生长型的柱花草‘184号’不宜用于果园生草栽培,根系构型应该成为草种筛选的重要指标。

Root architecture is closely associated with plant nutrient uptake, and can influence the nutrient competition among different plants. Root architectures of Stylosanthes ＇Graham＇ and ＇CIAT 184＇ were compared, and their effects on plant growth and nutrient uptake of Citrus limonia in inter-cropping condition were investigated. Results indicated that, the biomass, total root length, tap root length and root tip number were comparable for ＇Graham＇ and ＇CIAT 184＇ in mono-cropping condition, however, the basal root angle, root surface area and average root diameter of ＇CIAT 184＇ were lower than those of ＇ Graham＇. In inter-cropping condition, 41.4% roots of＇ CIAT 184＇ grew into the root zone of citrus while only 0.8% roots of ＇ Graham＇ grew into the root zone of citrus. Therefore, the biomass and phosphorus uptake of citrus seedlings inter-cropped with ＇CIAT 184＇ were significantly lower than those with ＇Graham＇ . This study suggests that Stylosanthes ＇ CIAT 184＇ with horizontal root growth are not suitable for sod culture in orchard when compared with Stylosanthes ＇Graham＇ with vertical root growth, and that root architecture can be regarded as critical indicator for the screening of grass species.