Brassica campestris ssp. chinensis, also known as non-heading Chinese cabbage, is an important vegetable widely distributed in southern China. High temperature is the most common adversity factor in vegetable producti...Brassica campestris ssp. chinensis, also known as non-heading Chinese cabbage, is an important vegetable widely distributed in southern China. High temperature is the most common adversity factor in vegetable production, because Brassica campestris ssp. chinensis is a thermophilic vegetable, which can＇t well grow at high temperature. In summer and autumn, high temperature stress would prevent Brassica campestris ssp. chinensis from growing and result in poor quality of its seedlings, seriously influencing yield and quality of the vegetable in later period. In this paper, present situation and latest advances in heat resistance research of Brassica campestris ssp. chinensis in recent years were reviewed at home and abroad. The research tendency in Bassica campestris ssp. chinensis was also described, providing reference for breeding of heat-resistant Brassica campestris ssp. chinensis.展开更多
A conduction heat transfer process is enhanced by filling prescribed quantity and optimized-shaped high thermal conductivity materials to the substrate. Numerical simulations and analyses are performed on a volume to ...A conduction heat transfer process is enhanced by filling prescribed quantity and optimized-shaped high thermal conductivity materials to the substrate. Numerical simulations and analyses are performed on a volume to point conduction problem based on the principle of minimum entropy generation. In the optimization, the arrangement of high thermal conductivity materials is variable, the quantity of high thermal-conductivity material is constrained, and the objective is to obtain the maximum heat conduction rate as the entropy is the minimum.A novel algorithm of thermal conductivity discretization is proposed based on large quantity of calculations.Compared with other algorithms in literature, the average temperature in the substrate by the new algorithm is lower, while the highest temperature in the substrate is in a reasonable range. Thus the new algorithm is feasible. The optimization of volume to point heat conduction is carried out in a rectangular model with radiation boundary condition and constant surface temperature boundary condition. The results demonstrate that the algorithm of thermal conductivity discretization is applicable for volume to point heat conduction problems.展开更多
Species may exhibit similar traits via different mechanisms： environmental filtering and local adaptation （geography） and shared evolutionary history （phylogeny） can each contribute to the resemblance of traits a...Species may exhibit similar traits via different mechanisms： environmental filtering and local adaptation （geography） and shared evolutionary history （phylogeny） can each contribute to the resemblance of traits among species. Parsing trait variation into geographic and phylogenetic sources is important, as each suggests different constraints on trait evolution. Here, we explore how phylogenetic distance, geographic distance, and geographic variation in climate shape physiological tolerance of high and low temperatures using a global dataset of ant thermal tolerances. We found generally strong roles for evolutionary history and geographic variation in temperature, but essen- tially no detectable effects of spatial proximity per se on either upper or lower thermal tolerance. When we compared the relative importance of the factors shaping upper and lower tolerances, we found a much stronger role for evolutionary history in shaping upper versus lower tolerance, and a moderately weaker role for geographic variation in temperature in shaping upper tolerance when compared with lower tolerance. Our results demonstrate how geographic variation in climate and evolutionary history may have differential effects on the upper and lower endpoints of physiological tolerance. This Janus effect, where the relative contributions of geographic variation in climate and evolutionary history are reversed for lower versus upper physiological tolerances, has gained some support in the literature, and our results for ant physiological tolerances provide further evidence of this pa^ern. As the climate continues to change, the high phylogenetic conservatism of upper tolerance may suggest potential constraints on the evolution of tolerance of high temperatures.展开更多
基金Supported by Modern Agricultural Industry Technology System Special Funds(CARS-25)Innovation Funds of Jiangxi Academy of Agricultural Sciences(2010CBS004)~~
文摘Brassica campestris ssp. chinensis, also known as non-heading Chinese cabbage, is an important vegetable widely distributed in southern China. High temperature is the most common adversity factor in vegetable production, because Brassica campestris ssp. chinensis is a thermophilic vegetable, which can＇t well grow at high temperature. In summer and autumn, high temperature stress would prevent Brassica campestris ssp. chinensis from growing and result in poor quality of its seedlings, seriously influencing yield and quality of the vegetable in later period. In this paper, present situation and latest advances in heat resistance research of Brassica campestris ssp. chinensis in recent years were reviewed at home and abroad. The research tendency in Bassica campestris ssp. chinensis was also described, providing reference for breeding of heat-resistant Brassica campestris ssp. chinensis.
基金Supported by the National Key Basic Research Program of China(2013CB228305)
文摘A conduction heat transfer process is enhanced by filling prescribed quantity and optimized-shaped high thermal conductivity materials to the substrate. Numerical simulations and analyses are performed on a volume to point conduction problem based on the principle of minimum entropy generation. In the optimization, the arrangement of high thermal conductivity materials is variable, the quantity of high thermal-conductivity material is constrained, and the objective is to obtain the maximum heat conduction rate as the entropy is the minimum.A novel algorithm of thermal conductivity discretization is proposed based on large quantity of calculations.Compared with other algorithms in literature, the average temperature in the substrate by the new algorithm is lower, while the highest temperature in the substrate is in a reasonable range. Thus the new algorithm is feasible. The optimization of volume to point heat conduction is carried out in a rectangular model with radiation boundary condition and constant surface temperature boundary condition. The results demonstrate that the algorithm of thermal conductivity discretization is applicable for volume to point heat conduction problems.
文摘Species may exhibit similar traits via different mechanisms： environmental filtering and local adaptation （geography） and shared evolutionary history （phylogeny） can each contribute to the resemblance of traits among species. Parsing trait variation into geographic and phylogenetic sources is important, as each suggests different constraints on trait evolution. Here, we explore how phylogenetic distance, geographic distance, and geographic variation in climate shape physiological tolerance of high and low temperatures using a global dataset of ant thermal tolerances. We found generally strong roles for evolutionary history and geographic variation in temperature, but essen- tially no detectable effects of spatial proximity per se on either upper or lower thermal tolerance. When we compared the relative importance of the factors shaping upper and lower tolerances, we found a much stronger role for evolutionary history in shaping upper versus lower tolerance, and a moderately weaker role for geographic variation in temperature in shaping upper tolerance when compared with lower tolerance. Our results demonstrate how geographic variation in climate and evolutionary history may have differential effects on the upper and lower endpoints of physiological tolerance. This Janus effect, where the relative contributions of geographic variation in climate and evolutionary history are reversed for lower versus upper physiological tolerances, has gained some support in the literature, and our results for ant physiological tolerances provide further evidence of this pa^ern. As the climate continues to change, the high phylogenetic conservatism of upper tolerance may suggest potential constraints on the evolution of tolerance of high temperatures.
