Journal of Taiwan Agricultural Research

Author:Ming-Hwi Yao*,  Shou-Hung Chen and Kung-Shy Chi

Abstract:

    Anthropogenic emissions of carbon dioxide (CO₂) have serious impact on the global climate system. According to the report of IPCC, the change in global mean temperature of 1.4-5.8℃, accompanying with increased frequency of extreme weather events is likely to occur until 2100. From the view of agrometeorology, the use efficiency of meteorological resources for crop is one of important indices to evaluate the effects of climate change on agricultural production. In this study, radiation- and water-use efficiency for rice were measured using photosynthesis devices under high temperature, drought and enhanced carbon dioxide environment in order to assess the interactions among climate factors, different cultivars and physiological response of leaves. Experimental results showed that both the radiation-and water-use efficiency decreased under high temperature treatment. However, while elevated CO₂ concentration significantly increased the rate of leaf photosynthesis, the radiation use efficiency of tested rice raised by 10-70% depending on different cultivars. Because of the wilt of leaves, drought caused the drop of radiation use efficiency due to closed stomata. Nevertheless the fall in transpiration induced the increment of water use efficiency. In addition, for the combined treatment of three meteorological factors, the radiation use efficiency was lower by 30-40% than that of the normal environment while the water use efficiency was higher up to 29%.

Key words:Climate change, Radiation use efficiency, Water use efficiency, Rice

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