渭北黄土区核桃根际土壤酶活性动态变化研究

Dynamic Change of Enzyme Activity in Rhizosphere Soil of Juglans regia in Loess Area of Northern Wei River

为了初步探讨渭北黄土区6年生核桃根际土壤酶活性的时间、空间动态变化,本试验以渭北黄土区6年生核桃根际土壤为研究对象,分别在不同时间（2009年4、6、8、10月底）和不同土层深度（0 ～20、20～40、40～60、60 ～80、80 ～ 100 cm）采集样品,测定土壤过氧化氢酶、脲酶、磷酸酶和蔗糖酶的活性.结果表明,核桃根际土壤的过氧化氢酶、脲酶、磷酸酶和蔗糖酶的活性随着土层深度的加深而活性降低,0～20 cm的土层各种土壤酶活性均处于最高值.随着采样时间的不同,各种土壤酶活性变化规律不一致,过氧化氢酶和脲酶的活性呈先升高后降低再升高的趋势;磷酸酶的活性变化为先降低后升高再降低的趋势;蔗糖酶的活性呈先降低后升高的趋势.核桃根际土壤中过氧化氢酶、脲酶、磷酸酶和蔗糖酶的活性可能和核桃根系的分泌物密切有关,土壤剖面越深,根系分布达不到,各种土壤酶活性就越低.核桃根际土壤的过氧化氢酶、脲酶、磷酸酶和蔗糖酶的活性随着时间的变化而变化规律不一致,很有可能是因为核桃根系分泌物对各种土壤酶合成影响不同两表现出的差异性所致.

In order to probe the dynamic changes of enzyme activity in rhizosphere of 6-year-old Juglans regia in the loess area of northern Wei River,taken 6-year-old walnut rhizosphere soil in the loess area of northern Wei River as research objects,the samples were collected respectively at different tine（by the end of April,June,August and October of 2009） and different soil depths （0-20,20-40,40-60,60 -80,80-100 cm）,and the catalase,urease,phosphatase and invertase activities were determined.The results showed that the activities of catalase,urease,phosphatsee and sucrase around J.regia rhizosphere soil decreased with the soil deepening,and in the 0-20 cm soil layer,the activities of four enzymes were the highest.With the different sampling time,the dynamic changes of enzymatic activities showed inconsistent variations.The catalase and urease activities first increased,then decreased,and then increased; Phosphatase activity first decreased,then increased and decreased at last; Sucrase activity first decreased,and then increased.It was concluded that the spatial dynamic change of enzymes activity was related to J.regia root exudates,and the root could not reach the deeper soil layer,so the enzyme activities were decreased with the soil deepening; The dynamic changes of enzyme activities with time were different due to the enzymatic synthesis affected by the type and quantity of J.regia root exudates.