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模拟三峡库区消落带水位变化情况,对2年生水杉盆栽土壤酶活性进行了研究.试验共设置3个不同的处理阶段,阶段1为淹水阶段,包括常规供水(C),半淹(H)和全淹(F)3个处理组;阶段2为干旱阶段,将阶段1的处理组再随机分为两个处理组,一组继续保持阶段1的水分处理,另一组进行轻度干旱胁迫处理,此时,处理组包括常规供水(C),半淹(H),全淹(F),常规供水-轻度干旱(CD),半淹-轻度干旱(HD)和全淹-轻度干旱(FD)6种不同水分处理组;阶段3将所有处理组恢复到正常供水处理,整个处理持续166d.研究结果表明,与C组相比,短期淹水(75d)处理后H和F组土壤的蔗糖酶活性分别下降了44.2%和47.1%;脲酶活性分别下降了9.3%和14.0%;碱性磷酸酶活性分别下降了56.9%和35.4%;长期淹水(145d)后,与对照组C相比,F组蔗糖酶活性降低了26.3%,H,F的土壤磷酸酶活性分别降低了59.6%和32.4%,而脲酶活性分别升高了20%和26.5%.淹水处理并未对土壤过氧化氢酶活性产生显著影响.经过阶段2的干旱处理后,与CD组相比,HD,FD组土壤脲酶活性分别下降了21.5%和24.3%,土壤磷酸酶活性则降低了62.5%和44.6%.经过阶段3的正常供水处理后,除过氧化氢酶外,所有处理组水杉幼苗盆栽土壤的酶活性均恢复至C组水平.在整个处理阶段,水杉的存活率为100%,可以考虑作为三峡库区消落带植被恢复的树种之一,但是在退水期时应及时浇水灌溉,以恢复其土壤酶的活性.
The changes of water level in the fluctuation zone of the Three Gorges Reservoir were simulated to study the soil enzyme activities of two-year-old Metasequoia glyptostroboides .Three different treatment stages were set up in the experiment, Stage 1 was submergence stage, including conventional water supply (C) H) and total flooding (F). Stage 2 was arid stage, and the treatment group of stage 1 was randomly divided into two treatment groups, one of which continued to maintain the water treatment of stage 1 and the other of which was mild Drought stress treatment, in which the treatment group consisted of conventional water supply (C), semi-submergence (H), total flooding (F), conventional water supply-mild drought (CD), semi-submergence-mild drought (HD) - 6 different water treatment groups with mild drought (FD); Stage 3 all the treatment groups returned to the normal water treatment, the entire treatment lasted 166d.The results showed that, compared with the C group, short-term flooding (75d) after treatment H And F group decreased by 44.2% and 47.1% respectively. The urease activity decreased by 9.3% and 14.0%, while the alkaline phosphatase activity decreased by 56.9% and 35.4% respectively. After long-term flooding (145d) Compared with control group C, the invertase activity of F group decreased by 26.3%, and the soil phosphatase activity of H and F decreased by 59.6% and 32.4%, while the urease activity increased by 20% and 26.5% respectively. Compared with CD group, the soil urease activity of HD and FD groups decreased by 21.5% and 24.3% respectively after treatment of stage 2, and the activity of soil phosphatase Then decreased by 62.5% and 44.6%, respectively.After the normal water supply treatment in stage 3, except for catalase, the enzyme activity of potted soil of Metasequoia glyptostroboides seedlings returned to the level of group C. Throughout the treatment stage, the survival of Metasequoia glyptostroboides The rate of 100% can be considered as one of the tree species for vegetation recovery in the fluctuation zone of the Three Gorges Reservoir. However, water irrigation should be carried out in time to restore the soil enzyme activity.