水淹胁迫下三峡库区野生狗牙根根系酶活性变化

三峡库区消落带治理的重点方向是筛选消落带适生植物，故研究已筛选的适生植物狗牙根在水淹生境下抗胁迫相关酶活性变化对于消落带的生态治理具有重要意义。以三峡库区自然消落带野生狗牙根（XC）和非消落带野生狗牙根（FC）为研究对象，采用野外采样和对比分析等手段研究了三峡库区自然消落带野生狗牙根（XC）在不同水淹深度的抗胁迫酶活性变化。结果显示:①随着水淹深度增加，XC组狗牙根根系MDA含量均呈递增趋势，表明狗牙根在深淹胁迫下胁迫程度逐渐加剧。② XC组狗牙根根系乙醇脱氢酶（ADH）、谷胱甘肽还原酶（GR）、过氧化物酶（POD）、超氧化物歧化酶（SOD）的酶活性和游离脯氨酸含量较对照均有增加；ADH、POD和SOD酶活性最高值出现在水淹深度为8 m，而GR酶活性的最高值出现在水淹深度为4 m。③水淹期间，XC组狗牙根根系淀粉含量基本和对照同水平，可溶性糖含量较对照有所降低，表明水淹期间狗牙根处于低代谢和高储能状态。从水淹胁迫下抗胁迫酶活性变化角度解释了筛选到的野生狗牙根是三峡水库消落带植被恢复的适生物种。

Dynamics of Enzyme Activities of Cynodon Dactylon Roots from Hydro-Fluctuation Belt in the Three Gorges Reservoir Area during Flooding

Screening suitable plants is the key to management of Three Gorges Reservoir Area, so exploring dynamics of anti-flooded enzyme activities of suitable Cynodon dactylon to flooding has the important significance for ecological management of hydro-fluctuation belt. With the water-level-fluctuation zone (XC) and non-water-level-fluctuation zone (FC) of Three Gorges Reservoir Area were chosen as the key research sites. Enzyme activities of anti-flooded of XC group to different water depth was studied by field sampling and comparative analysis. The results showed: ① MDA content of Cynodon dactylon root in the XC group increased with the increase of water depth, which showed deep submergence stress was aggravated; ② activitives of alcohol dehydrogenase (ADH), glutathione reductase (GR), peroxidase (POD), superoxide dismutase (SOD) and content of proline in the XC group increased, compared to the control; the peak activity of ADH, POD and SOD appeared in the 8 m water depth, and the peak activity of GR was in the 4 m water depth; ③ during the flooding period, Cynodon dactylon was in low metabolism and high energy storage since the content of starch was the same as control level and the content of soluble sugar decreased. The results showed that Cynodon dactylon was probably regarded as suitable species of management of hydro-fluctuation in Three Gorges Reservoir Area with respect to the physiological responses to flooding stress.