The association between the growth and water-use efficiency in three populations of C. odorata in Veracruz Mexico （La Antigua, Misantla and Catemaco） from two agroforestry system sites was studied, one in associatio...The association between the growth and water-use efficiency in three populations of C. odorata in Veracruz Mexico （La Antigua, Misantla and Catemaco） from two agroforestry system sites was studied, one in association with corn and another with pipiain. TRP （transpiration）, gs （stomatal conductivity）, CO2A （CO2 assimilation）, WUE （water use efficiency）, height, coverage and stem diameter were measured. The populafon of La Antigua associated with pipian presented the highest WUE （7.13 μmol CO2 m2-sl/mmol H20 m2.sl）, while the population of Catemaco reached high values （10 μmol CO2 m2 sl/mmol H20 m2-s1） in the site associated with corn, the populations established with corn presented a great growth in height and stem diameter. Based on the physiological responses and growth of the studied populations, the towns of La Antigua and Catemaco may be recommended for the establishment of commercial plantations.展开更多
Sumithion is widely used to control brittle in paddy fields and tiger bug in fish larval rearing ponds. The objective of this study was to elucidate the toxic effects of sumithion on larval stages of stinging catfish ...Sumithion is widely used to control brittle in paddy fields and tiger bug in fish larval rearing ponds. The objective of this study was to elucidate the toxic effects of sumithion on larval stages of stinging catfish Heteropneustes fossilis. Larvae were exposed to two concentrations(150 and 250 μg/L) of sumithion with one control in three replicates of each. Larvae samples were collected at 20- and 24-h intervals followed by observation under a digital microscope. Exposures of stinging catfish larvae to sumithion produced deformities including irregular head shape, lordosis, yolk sac edema, body arcuation, tissue ulceration, etc. The mortality rates of larvae were significantly increased in response to increase in sumithion concentrations. Furthermore, around 30% of the total adult stinging catfish reared in sumithiontreated aquaculture ponds were found to be deformed permanently. These findings highlight that exposure of stinging catfish to sumithion at the critical and sensitive stages in their life cycle may significantly reduce the number of returning adults. Therefore, the use of sumithion for crop protection needs to be considered carefully and alternatives to sumithion should to be developed for controlling aquatic insects in aqua-ponds during larval rearing.展开更多
文摘The association between the growth and water-use efficiency in three populations of C. odorata in Veracruz Mexico （La Antigua, Misantla and Catemaco） from two agroforestry system sites was studied, one in association with corn and another with pipiain. TRP （transpiration）, gs （stomatal conductivity）, CO2A （CO2 assimilation）, WUE （water use efficiency）, height, coverage and stem diameter were measured. The populafon of La Antigua associated with pipian presented the highest WUE （7.13 μmol CO2 m2-sl/mmol H20 m2.sl）, while the population of Catemaco reached high values （10 μmol CO2 m2 sl/mmol H20 m2-s1） in the site associated with corn, the populations established with corn presented a great growth in height and stem diameter. Based on the physiological responses and growth of the studied populations, the towns of La Antigua and Catemaco may be recommended for the establishment of commercial plantations.
文摘Sumithion is widely used to control brittle in paddy fields and tiger bug in fish larval rearing ponds. The objective of this study was to elucidate the toxic effects of sumithion on larval stages of stinging catfish Heteropneustes fossilis. Larvae were exposed to two concentrations(150 and 250 μg/L) of sumithion with one control in three replicates of each. Larvae samples were collected at 20- and 24-h intervals followed by observation under a digital microscope. Exposures of stinging catfish larvae to sumithion produced deformities including irregular head shape, lordosis, yolk sac edema, body arcuation, tissue ulceration, etc. The mortality rates of larvae were significantly increased in response to increase in sumithion concentrations. Furthermore, around 30% of the total adult stinging catfish reared in sumithiontreated aquaculture ponds were found to be deformed permanently. These findings highlight that exposure of stinging catfish to sumithion at the critical and sensitive stages in their life cycle may significantly reduce the number of returning adults. Therefore, the use of sumithion for crop protection needs to be considered carefully and alternatives to sumithion should to be developed for controlling aquatic insects in aqua-ponds during larval rearing.
