de Oliveira Leandro Bittencourt, Marques Anderson Cesar Ramos, de Quadros Fernando Luiz Ferreira, Farias Júlia Gomes, Piccin Rogério, Brunetto Gustavo, Nicoloso Fernando Teixeira
LEPAN-Laboratory of Ecology of Natural Grassland, Department of Animal Science, Universidade Federal de Santa Maria, Roraima Avenue 1000, Building 16, Room 3132, CEP: 97105-900, Santa Maria, RS, Brazil.
FISIOPLANT-Laboratory of Plant Physiology, Department of Biology, Universidade Federal de Santa Maria, Roraima Avenue 1000, CEP: 97105-900, Santa Maria, RS, Brazil.
Oecologia. 2018 Mar;186(3):633-643. doi: 10.1007/s00442-018-4059-9. Epub 2018 Jan 13.
Different growth rates of grasses from South American natural grasslands are adaptations to soils of low fertility. Grasses with fast growth rate are species with an accumulation of nutrients in soluble forms, with a high metabolic rate. This work aimed to study whether grasses with different growth rates have different phosphorus (P) uptake and efficiency of P use with high and low P availability in soil, as well as whether phosphatase activity is related to the species growth rate and variations in P biochemical forms in the tissues. Three native grasses (Axonopus affinis, Paspalum notatum, and Andropogon lateralis) were grown in pots with soil. Along plant growth, biomass production and its structural components were measured, as well as leaf acid phosphatase activity and leaf P chemical fractions. At 40 days of growth, leaf acid phosphatase activity declined by about 20-30% with an increase of P availability in soil for A. affinis and P. notatum, respectively. Under both soil P levels, P. notatum showed the highest plant total biomass, leaf dry weight and highest P use efficiency. A. affinis presented the higher P uptake efficiency and soluble organic P concentration in the leaf tissues. A. lateralis showed P-Lipid concentration 1.6 and 1.3 times higher than A. affinis and P. notatum, respectively. In conclusion, acid phosphatase activity in grass of higher growth rate is related to higher remobilization of P due to higher demand, as in A. affinis, and higher growth rates are associated with higher P uptake efficiency.
南美洲天然草原不同草种的生长速率差异是对低肥力土壤的一种适应。生长速率快的草种是那些能以可溶形式积累养分、代谢率高的物种。本研究旨在探讨不同生长速率的草种在土壤磷有效性高低不同的情况下，其磷吸收和磷利用效率是否存在差异，以及磷酸酶活性是否与草种生长速率和组织中磷生化形态的变化有关。选用三种本地草种（近缘地毯草、巴哈雀稗和侧生须芒草）种植于装有土壤的花盆中。在植物生长过程中，测定了生物量生产及其结构组成部分，以及叶片酸性磷酸酶活性和叶片磷化学组分。生长40天时，随着土壤磷有效性的增加，近缘地毯草和巴哈雀稗叶片酸性磷酸酶活性分别下降了约20% - 30%。在两种土壤磷水平下，巴哈雀稗的植物总生物量、叶片干重和磷利用效率均最高。近缘地毯草在叶片组织中表现出较高的磷吸收效率和可溶性有机磷浓度。侧生须芒草的磷脂浓度分别比近缘地毯草和巴哈雀稗高1.6倍和1.3倍。总之，生长速率较高的草种中的酸性磷酸酶活性与因需求较高而导致的更高的磷再利用有关，如近缘地毯草，且较高的生长速率与较高的磷吸收效率相关。
