We evaluated the dietary protein requirements of juvenile turbot (Scophthalmus maximus L.) and their effects on aquatic quality. Five experimental diets were formulated containing 450, 480, 500, 520, and 540 g/kg. Eac...We evaluated the dietary protein requirements of juvenile turbot (Scophthalmus maximus L.) and their effects on aquatic quality. Five experimental diets were formulated containing 450, 480, 500, 520, and 540 g/kg. Each diet was randomly assigned to triplicate groups of juvenile turbot (mean initial body weight 34.5 ± 5.5 g) for 88 d. Both the weight gain ratio and feed efficiency increased with increasing dietary protein up to 500 g/kg, but no further improvement was detected when dietary protein levels were >500 g/kg. Protein intake and digestion increased with protein levels, while fecal nitrogen and nitrogen content in seawater increased only when dietary protein exceeded 500 g/kg. Protein digestibility was highest at intermediate dietary protein levels. Chemical oxygen demand, nitrite-nitrogen (NO2--N) and phosphatic-phosphor (PO43--P) levels increased in the rearing water as dietary protein levels increased. The optimum eco-nutrition level of dietary protein for juvenile turbot was 500 g/kg under the current experimental conditions. The diets containing 540 and 500 g/kg protein had similar growth rates and feed conversion ratios, but levels of ammonia (NH4+) and nitrogen were considerably higher in the water and feces, respectively, at the higher level of dietary protein. The difference in the pattern of change between body weight gain and ammonia concentration in water with increasing dietary protein is described by rhomb characteristics.展开更多
Water plays an important role in food production especially rice. Rice productivity depends greatly on sufficient water to meet evaporative demand and soil moisture. It is certain thalL rice, the most important crop o...Water plays an important role in food production especially rice. Rice productivity depends greatly on sufficient water to meet evaporative demand and soil moisture. It is certain thalL rice, the most important crop of Thailand and Vietnam, is vulnerable to climate change. This paper proposes an analysis on the impact of climate on rice water requirement and food security in Thailand and Vietnam. Water demand, yield and production of rice were computed under the changed surface air temperature for three time slices, namely 2020s, 2050s and 2080s. Food security was analyzed from rice supply （calculated milled-rice product, rice stock, and imports） and demand （domestic uses from population growth, exports to world market, domestic seed and other uses）. The result showed that, under the higher surface air temperature scenario, water requirement office in Thailand and Vietnam could increase by 1.8 times in the end of the 21 st century. Production of rice dropped by declined yield. Thailand and Vietnam which is the world largest rice exporter in last decades will face the rice shortage in 2080s and 2030s respectively.展开更多
Secondary metabolites produced by plants can be used in popular medicine, as well they can interact with plants and other organisms, in which case they are called allelochemicals and influence the neighboring ecosyste...Secondary metabolites produced by plants can be used in popular medicine, as well they can interact with plants and other organisms, in which case they are called allelochemicals and influence the neighboring ecosystem. This work aimed to evaluate the allelopathic effects of Schinus molle L. species widely used in reforestation and urban afforestation. Therefore, leaves of S. Molle were collected from different populations located at Alfenas and Nepomuceno in Minas Gerais, Brazil. Cypselae of lettuce （Lactuca sativa L.） were germinated in biochemical oxygen demand （BOD） chamber at 25 ℃ with a photoperiod of 12 h under different extracts concentrations. The experiment was performed in factorial design （2 × 4） with two kinds of extracts （aqueous and ethanol） and four concentrations （2.5, 5, 10 and 20 mg/mL） in randomized blocks. The variables analyzed were germination （%）, germination speed index （GS1）, % of normal seedlings, root length, fresh biomass and dry biomass. Changes in the cell cycle in meristematic cells of the used model were also evaluated. Concentration-dependent effect on all parameters was observed, with the exception of dry biomass exposed to ethanol extract. The root elongation parameter was different between the extracts even in lower concentrations, thus indicating that this is the most sensitive parameter of this species. Toxic effect from S. rnolle extracts was observed in all parameters regardless the kind of pruning management or method of extraction （water or ethanol）.展开更多
基金Supported by the National High Technology Research and Development Program of China (863 Program) (No. 2006AA100305)National Agricultural Science and Technology Achievements Commercialization Program (No. 2008GB2C100109)the Knowledge Innovation Program of Institute of Oceanology, Chinese Academy of Sciences (No. L49032503)
文摘We evaluated the dietary protein requirements of juvenile turbot (Scophthalmus maximus L.) and their effects on aquatic quality. Five experimental diets were formulated containing 450, 480, 500, 520, and 540 g/kg. Each diet was randomly assigned to triplicate groups of juvenile turbot (mean initial body weight 34.5 ± 5.5 g) for 88 d. Both the weight gain ratio and feed efficiency increased with increasing dietary protein up to 500 g/kg, but no further improvement was detected when dietary protein levels were >500 g/kg. Protein intake and digestion increased with protein levels, while fecal nitrogen and nitrogen content in seawater increased only when dietary protein exceeded 500 g/kg. Protein digestibility was highest at intermediate dietary protein levels. Chemical oxygen demand, nitrite-nitrogen (NO2--N) and phosphatic-phosphor (PO43--P) levels increased in the rearing water as dietary protein levels increased. The optimum eco-nutrition level of dietary protein for juvenile turbot was 500 g/kg under the current experimental conditions. The diets containing 540 and 500 g/kg protein had similar growth rates and feed conversion ratios, but levels of ammonia (NH4+) and nitrogen were considerably higher in the water and feces, respectively, at the higher level of dietary protein. The difference in the pattern of change between body weight gain and ammonia concentration in water with increasing dietary protein is described by rhomb characteristics.
文摘Water plays an important role in food production especially rice. Rice productivity depends greatly on sufficient water to meet evaporative demand and soil moisture. It is certain thalL rice, the most important crop of Thailand and Vietnam, is vulnerable to climate change. This paper proposes an analysis on the impact of climate on rice water requirement and food security in Thailand and Vietnam. Water demand, yield and production of rice were computed under the changed surface air temperature for three time slices, namely 2020s, 2050s and 2080s. Food security was analyzed from rice supply （calculated milled-rice product, rice stock, and imports） and demand （domestic uses from population growth, exports to world market, domestic seed and other uses）. The result showed that, under the higher surface air temperature scenario, water requirement office in Thailand and Vietnam could increase by 1.8 times in the end of the 21 st century. Production of rice dropped by declined yield. Thailand and Vietnam which is the world largest rice exporter in last decades will face the rice shortage in 2080s and 2030s respectively.
文摘Secondary metabolites produced by plants can be used in popular medicine, as well they can interact with plants and other organisms, in which case they are called allelochemicals and influence the neighboring ecosystem. This work aimed to evaluate the allelopathic effects of Schinus molle L. species widely used in reforestation and urban afforestation. Therefore, leaves of S. Molle were collected from different populations located at Alfenas and Nepomuceno in Minas Gerais, Brazil. Cypselae of lettuce （Lactuca sativa L.） were germinated in biochemical oxygen demand （BOD） chamber at 25 ℃ with a photoperiod of 12 h under different extracts concentrations. The experiment was performed in factorial design （2 × 4） with two kinds of extracts （aqueous and ethanol） and four concentrations （2.5, 5, 10 and 20 mg/mL） in randomized blocks. The variables analyzed were germination （%）, germination speed index （GS1）, % of normal seedlings, root length, fresh biomass and dry biomass. Changes in the cell cycle in meristematic cells of the used model were also evaluated. Concentration-dependent effect on all parameters was observed, with the exception of dry biomass exposed to ethanol extract. The root elongation parameter was different between the extracts even in lower concentrations, thus indicating that this is the most sensitive parameter of this species. Toxic effect from S. rnolle extracts was observed in all parameters regardless the kind of pruning management or method of extraction （water or ethanol）.
