优质牧草旋扭山绿豆对低温胁迫的生理响应及其耐寒性快速鉴定

Physiological Response of High Quality Forage Desmodium intortum to Low Temperature Stress and Rapid Identification of Its Cold Tolerance

摘要:

为了解旋扭山绿豆（Desmodium intortum）对低温的耐受性，以在南方各省广泛种植的优质牧草紫花大翼豆（Macroptilium atropurureum）为对照，研究了旋扭山绿豆对低温胁迫的生理响应。结果表明，低温胁迫（4℃）下，旋扭山绿豆的实际光能转化效率（Yield）和光合电子传递效率（ETR）在第2~8天时下降幅度显著低于紫花大翼豆（P<0.05）。低温处理使旋扭山绿豆和紫花大翼豆超氧化物歧化酶（SOD）活性显著增加（P<0.05）；过氧化氢酶（CAT）活性则显著降低；旋扭山绿豆的过氧化物酶（POD）没有显著变化（P>0.05），但紫花大翼豆下降了47.11%。低温处理下旋扭山绿豆游离脯氨酸和可溶性糖含量显著高于紫花大翼豆（P<0.05）。回归分析、抵抗力指数和营养成分分析表明，旋扭山绿豆是一种抗寒性与营养价值均优于紫花大翼豆的优良牧草，其中Yield、ETR、CAT与渗透调节物质（游离脯氨酸和可溶性糖）可以作为旋扭山绿豆耐寒性鉴定的重要生理指标。

Abstract:

In order to rapidly identify the tolerance to low temperature of Desmodium intortum, the physiological response to low temperature stress (4℃) was studied by comparing with Macroptilium atropurureum, a high quality forage widely planted in southern provinces in China. The results showed that under low temperature stress, the effective quantum yield (Yield) and electron transfer rate (ETR) from the 2nd to 8th day decreased significantly in M. atropurureum than those in D. intortum (P<0.05). The superoxide dismutase (SOD) activity increased and catalase (CAT) activity decreased significantly (P<0.05) for both D. intortum and M. atropurureum under low temperature stress. Specifically, the decrease of CAT activity in D. intortum was lower than that in M. atropurureum. The peroxidase (POD) activity of D. intortum did not change (P>0.05) under low temperature, while POD activity in M. atropurureum decreased by 47.11%. The contents of free proline (Pro) and soluble sugar were significantly higher in D. intortum than those in M. atropurureum (P<0.05) under low temperature. According to regression analysis, resistance index and nutrient composition analysis, D. intortum was superior to M. atropurureum in cold resistance and nutritional value. Furthermore, Yield, ETR, CAT, Pro and soluble sugar of D. intortum could be used asimportant physiological indexes for identification of cold tolerance.