Abstract: Stylosanthes guianensis is one of the most important leguminous pasture crops in the tropicand subtropic areas of South China,but its growth potential in low-P acidic red soil has not been fully explored.Soil pot experiments with thirteen different Stylosanthes guianensis genotypes were conducted to investigate the genetic variability of this crop in P efficiency.It was found that great genetic variability existed within the tested genotypes when they were grown on a low-P acidic red soil.According to the differentgrowth responses,the tested Stylosanthes guianensis varieties were distinguished into wild type, culturaltype and P-efficient type.No significant difference in P content was observed among the tested genotypes atthe same P level.This implies that the adaptability of different genotypes to low-P stress was not reflectedby P concentration in plant.Comparing P uptake and P utilization efficiency by calculating P uptake ratioand P efficiency ratio,we found the former was more important to P-efficient genotypes.

Key words: Red soil, Stylosanthes guianensis, P efficiency, Genotypic variation

摘要： 本试验选用十三个不同基因型柱花草品种,通过盆栽试验,比较其营养生长和磷吸收情况。结果表明,在酸性低磷红壤区,品种间的磷效率差异明显,根据其在低磷酸性红壤不同的生长状况,可划分为野生型、栽培型和磷高效率型三种类型。在相同磷水平下,不同基因型柱花草品种的磷含量并无明显差异,基因型间对低磷或高磷的适应能力并不表现在植株含磷量的差异方面,通过计算植株吸磷量和磷效率比值,对磷的吸收效率和利用效率进行比较,前者对磷高效率基因型更为重要。

关键词: 红壤, 柱花草, 磷效率, 基因型差异