Electron transport system (ETS ) / dehydrogenase activity in a paddy field soil was measured under a variety of incubation conditions using the reduction of 2- (p-iodophenyl- 3- (p-nitrophenyl ) -5- phellyl tetrazoliu...Electron transport system (ETS ) / dehydrogenase activity in a paddy field soil was measured under a variety of incubation conditions using the reduction of 2- (p-iodophenyl- 3- (p-nitrophenyl ) -5- phellyl tetrazolium chloride (INT) to iodonitrotetrazolium formazan (INTF). The results exhibited a high positive correlation between the ETS activity and the incubation temperature and soil moisture. Dehydrogenase/ETS activity displayed a negative correlation with insecticide concentrations, and the activity affected adversely as the concentration of the insecticide increased. The higher doses, 5 and 10 field rates (1 field rate ~ 1500 mL ha-1), of insecticide significantly inhibited ETS activity, while lower rates failed to produce any significant reducing effect. Inorganic N (as urea) of concentrations from 0 to 100 ug N g-1 soil showed a positive response to ETS activity. However, at concentrations of 200 and 400 ug N g-1, the activity was reduced significantly.展开更多
Phytoplankton respiratory electron transport system (P-ETS) activities were studied in two cruises in Taiwan Strait (Aug. 1997 and Feb. –Mar.1998) and two cruises in Xiamen Harbour (Oct., 1997 and Apr., 1998). Result...Phytoplankton respiratory electron transport system (P-ETS) activities were studied in two cruises in Taiwan Strait (Aug. 1997 and Feb. –Mar.1998) and two cruises in Xiamen Harbour (Oct., 1997 and Apr., 1998). Results showed that P-ETS activity in the surface water of southern Taiwan Strait in summer was homo- geneous [mean value of 0.106 μlO2/(L?h)], inhomogeneous in northern Taiwan Strait in winter. Variation of P-ETS activity in middle part of the Strait was not obvious between summer and winter. Mean P-ETS activity of Xiamen Harbour in autumn was 0.255 μlO2/(L?h) with a little higher value in Jiulong River estuary areas. In spring, P-ETS activity was more homogeneously distributed and the mean value was 1.076 μlO2/(L?h). P-ETS activity in spring was obviously higher than in autumn in Xiamen Harbour. Vertical distribution of P-ETS in Taiwan Strait was homogeneous at some stations in winter and in summer. An obvious daily variation of P-ETS activity was recorded at Stn 9837, high at midnight and low in the early morning. Significant correlation between P-ETS activity and Chl-a was observed. Results also showed that the ratio of estimated respiratory rate to photosynthetic rate varied seasonally, high in winter (0.41) and low in summer (0.12).展开更多
基金Project supported by the International Rice Research Institute (IRRI) under project of Reversing Trendsof Declining Productiv
文摘Electron transport system (ETS ) / dehydrogenase activity in a paddy field soil was measured under a variety of incubation conditions using the reduction of 2- (p-iodophenyl- 3- (p-nitrophenyl ) -5- phellyl tetrazolium chloride (INT) to iodonitrotetrazolium formazan (INTF). The results exhibited a high positive correlation between the ETS activity and the incubation temperature and soil moisture. Dehydrogenase/ETS activity displayed a negative correlation with insecticide concentrations, and the activity affected adversely as the concentration of the insecticide increased. The higher doses, 5 and 10 field rates (1 field rate ~ 1500 mL ha-1), of insecticide significantly inhibited ETS activity, while lower rates failed to produce any significant reducing effect. Inorganic N (as urea) of concentrations from 0 to 100 ug N g-1 soil showed a positive response to ETS activity. However, at concentrations of 200 and 400 ug N g-1, the activity was reduced significantly.
基金Supported by NSFC (No.40331004, 40376043), partially National
文摘Phytoplankton respiratory electron transport system (P-ETS) activities were studied in two cruises in Taiwan Strait (Aug. 1997 and Feb. –Mar.1998) and two cruises in Xiamen Harbour (Oct., 1997 and Apr., 1998). Results showed that P-ETS activity in the surface water of southern Taiwan Strait in summer was homo- geneous [mean value of 0.106 μlO2/(L?h)], inhomogeneous in northern Taiwan Strait in winter. Variation of P-ETS activity in middle part of the Strait was not obvious between summer and winter. Mean P-ETS activity of Xiamen Harbour in autumn was 0.255 μlO2/(L?h) with a little higher value in Jiulong River estuary areas. In spring, P-ETS activity was more homogeneously distributed and the mean value was 1.076 μlO2/(L?h). P-ETS activity in spring was obviously higher than in autumn in Xiamen Harbour. Vertical distribution of P-ETS in Taiwan Strait was homogeneous at some stations in winter and in summer. An obvious daily variation of P-ETS activity was recorded at Stn 9837, high at midnight and low in the early morning. Significant correlation between P-ETS activity and Chl-a was observed. Results also showed that the ratio of estimated respiratory rate to photosynthetic rate varied seasonally, high in winter (0.41) and low in summer (0.12).
基金Supported by the National Natural Science Foundation of China, Grant No. 30470123, the Natural Science Foundation of Yunnan Province, Grant No. 2001C0008R, the Research Fund for Returned Overseas Chinese Scholars, Grant No. 20010713093959, and the Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry, Grant No. 2001-498.
