深淹对狗牙根根际土壤酶活性及肥力的影响

以三峡库区消落带生境和非消落带生境生长的狗牙根(XC、FC)为试验材料, 研究了不同生境狗牙根经不同深度水淹胁迫后, 植株根际土壤酶活性和土壤肥力状况。结果表明: 未淹对照植株根际土壤的蔗糖酶活性明显大于不同深度淹水处理, 说明淹水处理不能给植物提供与未淹对照同样多的营养源; FC 根际土壤的脲酶和酸性磷酸酶活性都较XC 的高; 淹水处理后, FC 根际土壤的全氮含量明显低于XC; 淹水前FC 根际土壤的全磷含量明显高于XC, 表明在未进行淹水处理之前的生长时期, XC 可能较FC 利用更多的土壤营养进行生长, 储备更多的能量, 从而为淹水期间植株提供能量供应, 为增强其耐淹能力奠定较好的能量基础。以上结果说明不同生境狗牙根在不同水淹胁迫下, 植株根际土壤酶活性和土壤肥力的变化与其耐淹能力有关。

Effect of submergence on rhizospheric soil enzyme activity and fertility of bermudagrass (Cynodon dactylon)

Bermudagrass that naturally grows in water fluctuation (XC) and non-water fluctuation (FC) zones in the Three Gorges Reservoir Area was submerged in different depths of water in order to investigate rhizospheric soil enzyme activities and fertility under different submergence stresses. The results showed that sucrase activity in non-flooded rhizospheric soil was higher than those in soils submerged with different depths of water, suggesting the flooded soils were not as rich in plant nutrients as non-flooded soils. The activities of urase and acid phosphatase in FC rhizospheric soil were higher than those in XC rhizospheric soil. FC rhizospheric soil N content was significantly lower than that of XC after flooding. Total phosphorus in FC rhizospheric soil was significantly higher than that in XC before flooding. This suggested that XC used more soil nutrients than FC during growth period and reserved more energy which enhanced its submergence-resistant ability. All these findings indicated that there existed some relationships among rhizospheric soil enzyme activity, fertility and tolerance to submergence in bermudagrass under different habitats (submergence stress).