热带海草海菖蒲不同组织中硝酸还原酶活力的研究

Studies on Nitrate Reductase Activity in Different Tissue of Enhalus acoroides

利用活体法研究了海南陵水新村湾热带海草海菖蒲不同组织中硝酸还原酶活力以及酶促反应条件因子pH、温度和KNO3浓度对酶活力的影响;pH设3个水平(7,8,9),温度(20～40℃)和KNO3(50～250mmol·L-1)浓度各5个水平。研究表明:酶促反应温度和KNO3浓度对酶活力有显著影响,而pH对酶活力没有影响;海菖蒲的最佳酶促反应条件为:100mmol·L-1KNO3,0.5mmol·L-1Na-EDTA、磷酸缓冲液(pH=8.0)、10mmol·L-1葡萄糖和w=0.5%的正丙醇;温度为30℃。在最佳酶促反应条件下,海菖蒲叶、根和茎的鲜质量组织中硝酸还原酶活力大小分别为:1.01,0.08,0.001μmol.g-1.h-1。

An in vivo method was used to determine the Nitrate reductase （NR） activity in the different tissue from Enhalus acoroides in the Xincun Bay of Hainan Island. The effects of pH of the assay media（7,8 and 9）,temperature （5 ℃ steps,from 20 to 40 ℃） and KNO3 concentrations（50 mmol·L-1 steps,from 50 to 250 mmol·L-1）on leaf NR activity were tested. The results indicated that both assay temperature and KNO3 concentration had a significant effect on NR activity,but pH not; the optimal assay medium contained 100 mmol·L-1 KNO3,0.5 mmol·L-1 Na-EDTA,phosphate buffer （pH=8.0）,10 mmol·L-1 glucose,0.5%（v：v） 1-propanol,and at 30 ℃. NR activity in leaves was 1.01 μmol·g-1·h-1,0.08 μmol·g-1·h-1 in roots and 0.001 μmol·g-1·h-1 in shoots under the optimal assay medium conditions.