Phosphatase activity in forage grasses as influenced by soil phosphorus availability and plant cutting height
Phosphatase activity in forage grasses as influenced by soil phosphorus availability and plant cutting height
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饲料草中磷酸酶活性受土壤磷有效性和植物切割高度的影响
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发表时间：
2008
期刊：
影响因子：
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通讯作者：
B. N. Ribeiro
中科院分区：
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作者：
F. N. Nunes;R. B. Cantarutti;R. F. Novais;I. Silva;M. Tótola;B. N. Ribeiro
养分利用效率是植物的一个重要的适应性特征，特别是在低肥力土壤中种植的植物。高磷利用效率（PUE）由高磷再活化速率赋予，即，磷运输到植物中代谢需求较大的区域。高磷再活化率与高酸性磷酸酶（AP酶）和核糖核酸酶（RNase）酶活性有关。在我们的研究中，我们评估了这些酶的活性，在臂形草斜卧，低，和Panicum最大的品种Tanzânia，具有较高的磷需求，在土壤中种植处理不同的磷率和削减在不同的高度。实验在温室中进行，使用粘性黄红色砖红壤的B层样品。处理包括两种草，三个P率（100，200和500毫克dm-3）和三个切割高度的因子组合：不切割，15和30厘米以上的土壤表面臂形草，和不切割，20和40厘米的黍。实验单元由具有10 dm 3土壤的盆组成，每个盆具有10株植物。结果表明，两种牧草的生物量差异不显著，但施磷处理的生物量和地上部含磷量较高。在较低的高度切割的植物的生物量生产较小，地上部的P浓度较高。P水平对两种牧草的APase和RNase活性均有显著影响。在最低磷水平下生长的植物酶活性和PUE最高。两种磷酸酶的活性均随着植物衰老而下降。在最低切割高度的处理中，臂形草和黍属植物的PUE都较低，与磷水平无关。同时，还观察到较高的APase和RNase活性，表明植物对低磷的适应可能涉及其他机制。
The nutrient use efficiency, expressed by the ratio between the produced biomass and nutrient content, is an important adaptive characteristic of plants, particularly of those cultivated in low-fertility soils. A high P-use efficiency (PUE) is conferred by high P remobilization rates, i.e., P transport to regions of greater metabolic demand in the plant. High P remobilization rates have been associated with high acid phosphatase (APase) and ribonuclease (RNase) enzyme activities. In our study, we evaluated the activity of these enzymes in Brachiaria decumbens, with a low, and Panicum maximum cv Tanzânia, with a high P demand, cultivated in soil treated with different P rates and cut at different heights. The experiment was carried out in a greenhouse, using B-horizon samples of a clayey Yellow-Red Latosol. The treatments consisted of a factorial combination of two grasses, three P rates (100, 200 and 500 mg dm-3) and three cutting heights: no cutting, 15 and 30 cm above the soil surface for Brachiaria, and no cutting, 20 and 40 cm for Panicum. The experimental units consisted of pots with 10 dm3 soil, with 10 plants each. Results indicated that there was no significant difference between biomass production of the two grasses, but the P application resulted in a higher biomass yield and P shoot concentration. The biomass production of plants cut at a lower height was smaller and P concentrations in shoots were higher. A significant effect of P rates on the APase and the RNase activities was observed in both forages. In plants grown at the lowest P rate enzyme activities and PUE were the highest. The activity of both phosphatases decreased with plant aging. In the treatment with the lowest cutting height, the PUE in both Brachiaria and Panicum plants was lower, independent of the P rate. At the same time, a higher APase and RNase activity was observed, indicating that other mechanisms may be involved in the plant adaptation to low P availability.