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        검색결과 65

        61.
        2008.10 KCI 등재 서비스 종료(열람 제한)
        Korea has experienced a rapid warming of 1.5℃ during the last 100 years and it is projected more faster rise of air temperature in the future. Temperature is an important factor that impacts directly on the growth and development of plants. To figure out the impact of temperature rising on rice growth, grain yield, and quality, an experiment was conducted at the 3 plastic houses that were controlled to ambient, ambient+1.5℃, and ambient+3℃throughout the growing season at the Seoul National University Experimental Farm. A rice variety "Hwaseongbyeo“ was grown using 1/5000a Wagner pot under two nitrogen levels of 12 and 18kg/10a. Heading date in elevated temperature treatments was earlier by two days than in ambient temperature. Compared to the ambient temperature, number of tiller, leaf area index, and dry weight of root, stem, leaf, and panicle was greater in elevated temperature conditions throughout the rice growing season, the difference being smaller in later grain filling period. There was no interaction effect on growth between nitrogen levels and temperature treatments. Grain yield and grain quality are under measurements.
        62.
        2008.10 KCI 등재 서비스 종료(열람 제한)
        Changing climate could be effect on the growth of soybean and seed yield, so we evaluated newly developed soy cultivars in the point of the physiological characteristics by changing temperature and light intensity in the phytotron. Two soy cultivars evaluated in three temperature levels (T1, 20/15; T2, 25/20; T3, 30/25oC at day/night) the pot experiment in phytotron between winter and spring in 2006 and spring and summer in 2007. Increased temperature from T1 to T2 and T2 to T3 enhanced crop growth parameters greatly and shortened growth duration and increased seed yield, however, grown in winter and spring enhanced too much plant height, so plant stems were very slim and weak and it resulted in the lodging problem. In this results we can estimate warming in Korean peninsular which might be increase temperature with low light intensity, so plant breeders and physiologists should be develop improved lodging resistance cultivars under low light intensity and high temperature.
        64.
        1998.06 KCI 등재 서비스 종료(열람 제한)
        Effects of elevated CO2 and temperature on nitrogen (N) uptake , leaf N concentration, N partitioning , N use efficiency (NUE) and grain yield of pot and field grown rice (Oryza sativa. L.cv. Chukwangbyeo) under canopy-like conditions were studied over three years. Rice plants were grown in pots and in the field in temperature gradient chambers containing either ambient(350ppm) or elevated CO2 concentrations (690 or 650ppm) in conbination with either four or seven temperature regimes ranging form ambient temperature(AT) to AT plus 3℃. There were three N supplies 94g or 6g m-2 to 20g or 48g m-2.Elevated CO2 increased N uptake in field-grown rice ; the magnitude of this effect was thelargest (+15%) at the highest N level. However, in pot-grown rice, N uptake was suppressed with the effect was the largest at high N levels. Leaf N concentration declined at elevated CO2 mainly due to a decrease in N partitiioning to the leaf blades. Air temperature had little effect on the N parameters mentioned previously, wherease NUE for spikelet production declined rapidly with increased temperature irrespective of CO2 concentration. The response of the biomass to elevated CO2 varied with N level, with the greatest response at 20g N m-2 (+30%) . At AT, where high temperature-induced sterility was generally not observed, elevated CO2 increased yield. However, the magnitude of this effect varied greatly (2-39%) with N level, and was mainly dependent on the magnitude of the increase in spikelet number.
        65.
        1998.04 서비스 종료(열람 제한)
        The objective of this study was to determine how elevated CO2 and temperature affected early growth and competition between direct seeded rice (Oryza sativa) and a common paddy weed (Echinochloa glabrascens). By using temperature gradient chambers. Rice and E. glabrescens were grown for 5 weeks at ratios of 1:0. 3:1 and 0:1 at three temperatures (16.4℃, 19.8℃, and 22.2℃) and either in ambient (361ppm) or elevated (566ppm) CO2. For both species. elevated CO2 had no effect on mainstem leaf number while air temperature had a slight positive effect which was greater in E. glabrescens than rice. With elevated CO2 rice leaf area index and plant height increased alightly in all species combinations but no increases were observed for E. Glabuescens. For rice in all combinations. elevated CO2 tended to increase the rot and total biomass much more than any other growth parameters: the increases in root and total biomass resulting from elevated CO2 ranged from 16% to 40%. depending on air temperature. At the lowest temperature, the decrease in rice biomass in combination with E. glabrescens was significantly greater at elevated CO2 (18%) than ambient CO2 (3%). At the highest temperature, however, the decrease in rice biomass at elevated CO2 (22%) was less than that at ambient CO2 (36%). The competitive ability of rice as measured by the decrease in biomass when grown in combination with E. glabrescens depended strongly on root growth and/or allocation. These results suggest that at higher temperatures elevated CO2 could enhance the competitive ability of direct seeded rice during early growth. However, at lower temperatures. the competitive ability of E. glabrescens seems to be greater.
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