Age-stage, two-sex life tables of the melon fly, Bactrocera cucurbitae （Coquil- let-t） （Diptera： Tephritidae）, reared on cucumber （Cucumis sativus L.）, sponge gourd （Luffa cylindrica Roem） and a carrot medium...Age-stage, two-sex life tables of the melon fly, Bactrocera cucurbitae （Coquil- let-t） （Diptera： Tephritidae）, reared on cucumber （Cucumis sativus L.）, sponge gourd （Luffa cylindrica Roem） and a carrot medium （mashed Daucus carota L. mixed with sucrose and yeast hydrolysate） were constructed under laboratory conditions at 25 4- loc, 65% 4- 0.5% relative humidity, and a photoperiod 12 ： 12h （L ： D）. The intrinsic rates of increase of B. cucurbitae were 0.144 6, 0.141 2 and 0.068 8 days on cucumber, sponge gourd, and carrot medium, respectively. The highest net reproduction rate was 172 offspring per fly reared on sponge gourd. The mean generation times ofB. cucurbitae ranged from 34 days reared on cucumber to 56 days reared on carrot medium. The life history raw data was analyzed using the traditional female age-specific life table and compared to results obtained using the age-stage, two-sex life table. When the age-specific female life table is applied to an age-stage-structured two-sex population, survival and fecundity curves will be improperly manipulated due to an inability to include variation in preadult development time. We discussed different interpretations of the relationship between the net reproductive rate and the intrinsic rate of increase to clarify possible misunderstanding in the literature.展开更多
Effects of root-zone temperatures （RZT） （12℃-RZT and 20℃-RZT） and different N, P, and K nutrient regimes on the growth, reactive oxygen species （ROS）, and antioxidant enzyme in cucumber seedlings were investig...Effects of root-zone temperatures （RZT） （12℃-RZT and 20℃-RZT） and different N, P, and K nutrient regimes on the growth, reactive oxygen species （ROS）, and antioxidant enzyme in cucumber seedlings were investigated in hydroponics. Strong interactions were observed between RZT and nutrient on the dry weight （P=0.001）, root length （P=0.001） and leaf area （P=0.05）. Plant dry weights were suppressed at low RZT of 12℃, while higher biomass and growth of cucumber seedlings were produced at elevated RZT of 20℃ under each nutrient treatment. Growth indexes （plant height, internode length, root length, and leaf area） at 12℃-RZT had less difference among nutrient treatments, but greater response was obtained for different nutrients at high RZT. RZT had larger effects （P=0.001） on cucumber seedling growth than nutrients. In addition, N was more effective nutrients to plant growth than P and K under low root temperature to plant growth. Higher hydrogen peroxide （H202）, malondialdehyde （MDA）, soluble sugar （SS） contents in leaves were observed at 12℃-RZT in all nutrient treatments than those at 20℃-RZT, indicating the chilling adversity damaged to plant growth. In general, antioxidant enzyme had larger response under low root-zone temperature. Superoxide dismutase （SOD） activities were higher in both leaves and roots while peroxidase （POD） and catalase （CAT） showed large different action in leaves and roots at both the two root-zone temperature.展开更多
文摘Age-stage, two-sex life tables of the melon fly, Bactrocera cucurbitae （Coquil- let-t） （Diptera： Tephritidae）, reared on cucumber （Cucumis sativus L.）, sponge gourd （Luffa cylindrica Roem） and a carrot medium （mashed Daucus carota L. mixed with sucrose and yeast hydrolysate） were constructed under laboratory conditions at 25 4- loc, 65% 4- 0.5% relative humidity, and a photoperiod 12 ： 12h （L ： D）. The intrinsic rates of increase of B. cucurbitae were 0.144 6, 0.141 2 and 0.068 8 days on cucumber, sponge gourd, and carrot medium, respectively. The highest net reproduction rate was 172 offspring per fly reared on sponge gourd. The mean generation times ofB. cucurbitae ranged from 34 days reared on cucumber to 56 days reared on carrot medium. The life history raw data was analyzed using the traditional female age-specific life table and compared to results obtained using the age-stage, two-sex life table. When the age-specific female life table is applied to an age-stage-structured two-sex population, survival and fecundity curves will be improperly manipulated due to an inability to include variation in preadult development time. We discussed different interpretations of the relationship between the net reproductive rate and the intrinsic rate of increase to clarify possible misunderstanding in the literature.
基金supported by the National Natural Science Foundation of China(41101272)the Open Fund of the State Key Laboratory of Soil and Sustainable Agriculture,Institute of Soil Science,Chinese Academy of Sciences(0812201217)
文摘Effects of root-zone temperatures （RZT） （12℃-RZT and 20℃-RZT） and different N, P, and K nutrient regimes on the growth, reactive oxygen species （ROS）, and antioxidant enzyme in cucumber seedlings were investigated in hydroponics. Strong interactions were observed between RZT and nutrient on the dry weight （P=0.001）, root length （P=0.001） and leaf area （P=0.05）. Plant dry weights were suppressed at low RZT of 12℃, while higher biomass and growth of cucumber seedlings were produced at elevated RZT of 20℃ under each nutrient treatment. Growth indexes （plant height, internode length, root length, and leaf area） at 12℃-RZT had less difference among nutrient treatments, but greater response was obtained for different nutrients at high RZT. RZT had larger effects （P=0.001） on cucumber seedling growth than nutrients. In addition, N was more effective nutrients to plant growth than P and K under low root temperature to plant growth. Higher hydrogen peroxide （H202）, malondialdehyde （MDA）, soluble sugar （SS） contents in leaves were observed at 12℃-RZT in all nutrient treatments than those at 20℃-RZT, indicating the chilling adversity damaged to plant growth. In general, antioxidant enzyme had larger response under low root-zone temperature. Superoxide dismutase （SOD） activities were higher in both leaves and roots while peroxidase （POD） and catalase （CAT） showed large different action in leaves and roots at both the two root-zone temperature.
