Phosphorus uptake by grass species from natural South American grasslands can change depending on root and leaf attributes capable of determining higher, or lower, relative growth rate. The aim of the current study is to investigate whether leaf and root attributes capable of determining leaf and root area production in native C4 grass species Axonopus affinis and Andropogon lateralis are related to higher relative growth rate (RGR), P uptake capacity (maximum P influx; Imax) and concentration. Species grown in 2-litre pots with added nutrition solution were subjected to two treatments, namely 5 μM P l−1 and 30 μM P l−1. Solution aliquots (10 ml) were collected for 30 hours at the end of the study to determine P concentrations. RGR was 3.6 and 2.8 times higher in A. affinis than in A. lateralis in treatments with 5 μM P and 30 μM P. Axonopus affinis recorded the highest P concentration in leaf tissue. This outcome was associated with Imax 85% higher in A. affinis. High RGR was associated with larger leaf and root surface area per dry mass unit, as well as with high P influx capacity and with higher affinity transporters. These species often prevail in areas accounting for greater natural fertility and are more responsive to phosphate fertilization.

中文翻译：

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南美天然草原两种草种的叶和根属性是生长和磷吸收的决定因素

来自南美天然草原的草种对磷的吸收可以根据能够决定更高或更低相对生长速率的根和叶属性而改变。当前研究的目的是调查叶和根属性是否能够确定原生 C 中叶和根面积的产生。4草种亲缘轴霉和仙人掌与较高的相对生长率 (RGR)、P 吸收能力（最大 P 流入量；I最大限度) 和浓度。对添加营养液的 2 升盆中生长的物种进行两次处理，即 5 μM P l-1和 30 μM P l-1. 在研究结束时收集溶液等分试样 (10 ml) 30 小时以确定 P 浓度。RGR 分别高出 3.6 和 2.8 倍A. affinis比在A.lateralis在 5 μM P 和 30 μM P 处理中。亲缘轴霉记录了叶组织中的最高磷浓度。这个结果与我有关最大限度高出 85%A. affinis. 高 RGR 与每干质量单位较大的叶和根表面积、高 P 流入能力和更高的亲和力转运蛋白有关。这些物种通常在自然肥力更高的地区盛行，并且对磷酸盐施肥更敏感。