贝加尔针茅草旬草原土壤水解酶活性对增氮增雨的响应

发布时间：2018-04-23 18:07

本文选题：水解酶活性 + 氮沉降　；参考：《东北师范大学》2015年硕士论文

【摘要】：土壤水解酶可以通过催化作用加速陆地生态系统土壤中有机质的降解过程,释放出可以直接被植物和微生物等有机体吸收和利用的营养元素。全球变化能直接或间接影响草地土壤酶活性并进而影响草地生态系统的能量流动和物质循环。本研究以我国内蒙古东部的贝加尔针茅草甸草原为对象,研究草原土壤水解酶活性对两种全球变化——氮沉降和降水量增加的响应。实验样地建立于2010年,采用施氮(N0:0 g N/m2a、N1:5 g N/m2a和N2:10 g N/m2a)和增雨(W0:自然降水、W1:增加1/7自然降水和W2:增加2/7自然降水)二因素、三水平交互设计。于2014年5月、7月、8月和9月取土样(0-15cm)测定了7种土壤水解酶活性,即α葡糖苷酶(αG)、β葡糖苷酶(βG)、β木糖苷酶(βX)、纤维二糖水解酶(CBH)、乙酰氨基葡萄糖苷酶(NAG)、L-亮氨酸氨基肽酶(LAP)和酸性磷酸酶(a P),以及土壤理化性质、植物群落地上生物量和土壤微生物量碳。拟回答以下科学问题:1)植物生长高峰期,不同梯度的增氮、增雨及二者交互作用会对土壤水解酶活性产生怎样的影响?2)增氮、增雨及二者交互作用会对土壤水解酶活性的季节动态变化产生怎样的影响?3)在增氮增雨处理下,影响土壤水解酶活性变化的主要环境因子是什么?得出以下主要结论:(1)低浓度(5g N/m2a)的增氮处理显著提高了植物生长高峰期土壤水解酶的活性,但是随着增氮梯度的增加,这种促进作用被减弱了。在植物生长高峰期低水平的增雨处理(1/7自然降水)提升了βG、LAP和a P的活性,而在高水平增雨(2/7自然降水)处理下,αG、βG、NAG、LAP和a P的活性受到抑制。(2)在植物生长高峰期,增氮与增雨对αG、βG、NAG、LAP和a P的活性都有显著交互作用。但是增雨处理在一定程度上抵消了增氮处理对土壤水解酶活性的促进作用。(3)增氮处理在一定程度上提高了不同季节土壤水解酶的活性,但并没有改变大多数土壤水解酶的季节动态规律。而增雨处理在不同程度上抑制了不同季节土壤水解酶的活性,并且降低了不同季节水解酶活性的变异幅度。(4)在增氮、增雨及二者交互处理下,导致土壤水解酶活性变化的主要因子是土壤中的氮和磷等非生物因素,而植物和微生物等生物因素的作用并不明显。(5)增氮处理对土壤水解酶活性的作用存在一定的阈值,即适度增氮能促进酶活性,而增氮量超过阈值时则表现为抑制效应。而降雨量变化对土壤水解酶的调控作用很大程度上受土壤原有水分状态和当年总降雨量的影响。本实验通过研究贝加尔针茅草甸草原土壤水解酶活性对不同梯度增氮增雨的响应,以及增氮增雨处理对土壤水解酶活性的季节动态变化的影响,发现适度增氮能够促进水解酶活性,但是增雨在一定程度上会掩盖增氮的正效应,即未来该地区降水量的增加将会中和或抑制大气氮沉降增加对土壤水解酶活性的促进效应。土壤水解酶活性对于全球变化的响应很大程度上依赖于该地区原有的降水格局以及土壤的营养状态。土壤水解酶活性对增氮增雨的不同响应能在一定程度上反映出土壤中相应营养元素的流通状态,对于草地土壤营养元素循环具有良好的指示作用。
[Abstract]:Soil Hydrolase can accelerate the degradation process of organic matter in terrestrial ecosystem by catalysis, release nutrients that can be absorbed and used directly by organisms such as plants and microorganisms. Global change can directly or indirectly influence grassland soil enzyme activity and then influence the energy flow and material circulation of grassland ecosystem. In this study, we studied the response of Soil Hydrolase Activity to two global changes - nitrogen deposition and precipitation in the meadow meadow grassland in eastern Inner Mongolia, China. Experimental plots were established in 2010, using nitrogen (N0:0 g N/m2a, N1:5 g N/m2a and N2: 10 g N/m2a) and precipitation (W0: natural precipitation, W1: increase 1/7 self) Precipitation and W2: increased 2/7 natural precipitation) two factors, three level interaction design. In May 2014, July, August and September, 7 soil hydrolase activities were measured, namely alpha glucosidase (alpha G), beta glucosidase (beta G), beta xyleinase (beta X), fiber two sugar hydrolase (CBH), acetaminophen glucosidase (NAG), L- leucine aminopeptidase. LAP) and acid phosphatase (a P), soil physical and chemical properties, aboveground biomass and soil microbial biomass carbon. The following scientific questions are to be answered: 1) how does plant growth peak, different gradient of nitrogen increase, rain increase and two interaction effects on Soil Hydrolase Activity? 2) nitrogen enhancement, precipitation enhancement and the interaction of two parties will be What are the effects of seasonal dynamic changes in Soil Hydrolase Activity? 3) what are the main environmental factors that affect the changes in the activity of Soil Hydrolase under the treatment of nitrogen and precipitation enhancement? (1) the following main conclusions are as follows: (1) the nitrogen treatment at low concentration (5g) significantly improves the activity of Soil Hydrolase at the peak period of plant growth, but with the nitrogen adding ladder In the peak period of plant growth, the low level of precipitation treatment (1/7 natural precipitation) increased the activity of beta G, LAP and a P, and the activity of alpha G, beta G, NAG, LAP and a P were inhibited under the high level precipitation (2/7 natural precipitation) treatment. (2) in the peak period of plant growth, nitrogen and rain enhancement There was a significant interaction between the activity of the soil hydrolase activity to some extent. (3) the effect of nitrogen treatment on Soil Hydrolase Activity in different seasons was improved to some extent, but it did not change the seasonal dynamics of most soil hydrolysate. The activity of Soil Hydrolase in different seasons was inhibited and the variation amplitude of the activity of hydrolase in different seasons was reduced. (4) the main factors that resulted in the change of the activity of Soil Hydrolase were the nitrogen and phosphorus in the soil, and the biological factors such as plants and microbes did not affect the activity of hydrolase in different seasons. Obviously. (5) the effect of nitrogen treatment on the activity of Soil Hydrolase has a certain threshold, that is, the moderate nitrogen increase can promote the enzyme activity, while the amount of nitrogen increasing exceeds the threshold, while the regulation effect of precipitation on Soil Hydrolase is largely influenced by the original water status of the soil and the total rainfall in the year. The response of Soil Hydrolase Activity to different gradients of nitrogen and precipitation in the meadow meadow grassland and the effect of nitrogen and precipitation on the seasonal dynamic changes of soil hydrolase activity were studied. It was found that moderate nitrogen increase could promote the activity of hydrolase, but the positive effect of nitrogen increasing was concealed to some extent, that is, the area decreased in the future. The increase in the amount of water will neutralize or inhibit the effect of the increase of atmospheric nitrogen deposition on the activity of soil hydrolase. The response of Soil Hydrolase to global change depends largely on the original precipitation pattern and the nutritional status of the soil in this region. It reflects the circulation state of the corresponding nutrient elements in the soil, and has a good indication function for the nutrient circulation in the grassland soil.

【学位授予单位】：东北师范大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S812.2

【参考文献】