低氮对苦荞苗期土壤碳转化酶活性的影响

The effect of nitrogen stress on carbon invertase enzyme activities in tartary buckwheat seedling stage

为探究不同耐氮性苦荞在苗期土壤碳转化相关酶活性对低氮胁迫的响应,采用盆栽试验,选用迪庆苦荞(耐氮能力强,DQ)和黑丰1号(耐氮能力弱,HF)两个不同耐氮性苦荞品种,设不施氮(CK)、低氮处理(N1)和正常供氮(N2)3种不同施氮量处理,对苦荞苗期土壤理化性质和3种碳转化酶活性进行研究。结果显示:(1)低氮胁迫下迪庆苦荞具有一定的品种优势,其株高、茎粗、叶面积、土壤有机碳、速效氮(铵态氮和硝态氮)均明显高于黑丰1号,土壤含水量和pH值低于黑丰1号。(2)氮肥处理和品种均对苦荞土壤碳转化相关酶活性产生显著的影响。低氮处理下迪庆苦荞土壤中的单糖酶(β-葡糖苷酶)活性和二糖酶(蔗糖酶)的活性显著高于黑丰1号,迪庆苦荞的单糖酶比黑丰1号高了58.3%,二糖酶为黑丰1号的3.3倍;而在常氮处理下则为迪庆苦荞低于黑丰1号,分别低了 19.7%和42.8%。在不同氮处理下迪庆苦荞分泌更多的多糖酶(纤维素酶),3种氮处理下酶活性分别比黑丰1号高66%、40%和22%。综上分析,耐低氮能力强的苦荞品种可以通过调节土壤酶活性来适应低氮的生长环境,并可能通过此种方式来改变其对碳源的偏好。

In order to investigate the carbon invertase enzymes activities under different nitrogen (N) tolerant tartary buckwheat to low N stress in seedling stage, using Diqing tartary buckwheat (low N tolerance, DQ) and Heifeng No. 1 (low N sensitive, HF) as materials. The study was carried out in a pot experiment to evaluate the different N treatments of no N (CK), low N (N1) and normal N (N2) as the treatments. The physicochemical properties and three carbon invertase activities of tartary buckwheat seedlings were measured. The results showed that:(1) DQ had species advantages under low N stress. Plant height, stem diameter, leaf area, soil organic carbon and available N were significantly higher than that of HF, while soil moisture content and pH were lower than that of HF.(2) Both N fertilizer treatments and cultivars had significant effects on the activities of carbon related enzymes involved in the transformation in tartary buckwheat growing soil. The activities of the monosaccharide hydrolase (β-glucosidase) and disaccharidease hydrolase (sucrose) in DQ were significantly higher than that of HF under low N treatment, the monosaccharide enzyme of DQ was 58.3% higher than that of HF, and the disaccharide enzyme was 3.3 times higher than that of HF. Under normal N treatment, both enzyme activities with DQ were 19.7% and 42.8% lower than that with HF, respectively. Under different N treatments, DQ secreted more polysaccharide enzymes (cellulase) and were 66%, 40% and 22% higher than HF under 3 N treatments, respectively. In summary, the varieties of tartary buckwheat with strong ability to tolerate low N can adapt to the low N growth environment by regulating the soil enzyme activities, and may change their preference for carbon sources in this way.