Chlorophyll fluorescence emission, pigment composition and photosynthetic rate of shade-grown cotton ( Gossypium hirsutum L.) plants were measured immediately after suddenly exposing to full sunlight and at regular in...Chlorophyll fluorescence emission, pigment composition and photosynthetic rate of shade-grown cotton ( Gossypium hirsutum L.) plants were measured immediately after suddenly exposing to full sunlight and at regular intervals there after within 15 d. Photoinhibition occurred in shade-grown cotton leaves immediately after exposed to full sunlight. The chlorophyll fluorescence parameter F-v/F-m and PhiPS II, which reflect the efficiency of PS II,obviously decreased in shade-grown leaves, much lower than that of the full sunlight-grown leaves. On the contrary, F-o value was sharply increased. Neither of these parameters could completely recover till next morning. The photoinhibition was chronic and continued for about 4 d, while the F-v/F-m and the net photosynthetic rate ( P-n) continued to decline, then began to increase gradually 6 d later and turned stable after 10 - 12 d, appearing as an acclimation phenomenon. However, the final value of F-v/F-m and P-n did not reach the level as in those leaves grown in the full sunlight ever before. The final P-n was higher by 60% than that before exposure, but lower for more than 40% than that of the full sunlight-grown leaves. The most notable response of chloroplast pigment composition was a pronounced increase in the pool size of carotenoids in xanthophyll cycle over a period of 3 d. The results indicated that when shade-grown cotton seedlings were suddenly transferred to the full sunlight, the decline of F-v/F-m and P-n might associate with the damage of the PS II reaction center. During the light acclimation, photoprotective mechanisms such as the xanthophyll cycle-dependent energy dissipation were increased, so that photodamage in leaves transferred from low to high light might be reduced.展开更多
The system of obligatory insurance, regulated by the Social Security Law, includes the design of a mixed system, which allows workers to continue contributing to the social security. This mixed system, called voluntar...The system of obligatory insurance, regulated by the Social Security Law, includes the design of a mixed system, which allows workers to continue contributing to the social security. This mixed system, called voluntary continuation in the obligatory system, contemplates the option for workers who have concluded a work relationship and who wish to continue accumulating weekly contributions necessary to obtain the disability and life insurance rights, such as those of dismissal in old age, and are considered in the Social Security Act of 1973.展开更多
This paper discusses the constraining factors to sustainable utilization ofwater resources in China, and the countermeasures to realize sustainable water utilization. Theresult of comprehensive analysis shows that con...This paper discusses the constraining factors to sustainable utilization ofwater resources in China, and the countermeasures to realize sustainable water utilization. Theresult of comprehensive analysis shows that constraining factors to sustainable utilization of waterresources in China are complicated, including physical geographical factors and socio-economicfactors, such as uneven distribution of water resources at temporal and spatial scales,inappropriate institutional arrangement and non-water-saving and non-wter-conservation productionand life mode. The countermeasures against constraining factors to water resources sustainabledevelopment are put forward as follows: 1) using wetlands and forests, and through spatialconversion to realize temporally sustainable supply of water resources; 2) transferring waterbetween basins and areas and developing various water resources in water shortage area; 3)establishing water-saving society; 4) strengthening water pollution control and water resourcesprotection; and 5) establishing unified water resources management mechanism.展开更多
Limited by the condition of information, technology and natural elements, the compulsive institutions in the environment governance can not form a “hard constraint” to the individuals. Because of the individual'...Limited by the condition of information, technology and natural elements, the compulsive institutions in the environment governance can not form a “hard constraint” to the individuals. Because of the individual's speculative behaviors, the government's deviation from its environmental governance, and the non-cooperative game between individuals and the legal organization, the implementation of the compulsive institutions is not as good as being expected. Through analyzing the mechanism of the compulsive institutions, this paper puts forward some suggestions to enhance the efficiency of such institutions' implementation.展开更多
文摘Chlorophyll fluorescence emission, pigment composition and photosynthetic rate of shade-grown cotton ( Gossypium hirsutum L.) plants were measured immediately after suddenly exposing to full sunlight and at regular intervals there after within 15 d. Photoinhibition occurred in shade-grown cotton leaves immediately after exposed to full sunlight. The chlorophyll fluorescence parameter F-v/F-m and PhiPS II, which reflect the efficiency of PS II,obviously decreased in shade-grown leaves, much lower than that of the full sunlight-grown leaves. On the contrary, F-o value was sharply increased. Neither of these parameters could completely recover till next morning. The photoinhibition was chronic and continued for about 4 d, while the F-v/F-m and the net photosynthetic rate ( P-n) continued to decline, then began to increase gradually 6 d later and turned stable after 10 - 12 d, appearing as an acclimation phenomenon. However, the final value of F-v/F-m and P-n did not reach the level as in those leaves grown in the full sunlight ever before. The final P-n was higher by 60% than that before exposure, but lower for more than 40% than that of the full sunlight-grown leaves. The most notable response of chloroplast pigment composition was a pronounced increase in the pool size of carotenoids in xanthophyll cycle over a period of 3 d. The results indicated that when shade-grown cotton seedlings were suddenly transferred to the full sunlight, the decline of F-v/F-m and P-n might associate with the damage of the PS II reaction center. During the light acclimation, photoprotective mechanisms such as the xanthophyll cycle-dependent energy dissipation were increased, so that photodamage in leaves transferred from low to high light might be reduced.
文摘The system of obligatory insurance, regulated by the Social Security Law, includes the design of a mixed system, which allows workers to continue contributing to the social security. This mixed system, called voluntary continuation in the obligatory system, contemplates the option for workers who have concluded a work relationship and who wish to continue accumulating weekly contributions necessary to obtain the disability and life insurance rights, such as those of dismissal in old age, and are considered in the Social Security Act of 1973.
文摘This paper discusses the constraining factors to sustainable utilization ofwater resources in China, and the countermeasures to realize sustainable water utilization. Theresult of comprehensive analysis shows that constraining factors to sustainable utilization of waterresources in China are complicated, including physical geographical factors and socio-economicfactors, such as uneven distribution of water resources at temporal and spatial scales,inappropriate institutional arrangement and non-water-saving and non-wter-conservation productionand life mode. The countermeasures against constraining factors to water resources sustainabledevelopment are put forward as follows: 1) using wetlands and forests, and through spatialconversion to realize temporally sustainable supply of water resources; 2) transferring waterbetween basins and areas and developing various water resources in water shortage area; 3)establishing water-saving society; 4) strengthening water pollution control and water resourcesprotection; and 5) establishing unified water resources management mechanism.
基金Supported by the National Scientific Technology Project(No.2002BA901A43).
文摘Limited by the condition of information, technology and natural elements, the compulsive institutions in the environment governance can not form a “hard constraint” to the individuals. Because of the individual's speculative behaviors, the government's deviation from its environmental governance, and the non-cooperative game between individuals and the legal organization, the implementation of the compulsive institutions is not as good as being expected. Through analyzing the mechanism of the compulsive institutions, this paper puts forward some suggestions to enhance the efficiency of such institutions' implementation.
