| It chose test varieties in middle mature group of rice region in Liaoning province in2011-2012, a hundred high-generation materials from the Rice Institute of Shengyang University in2011-2012and six different temperature types chosen by the test as the materials of the rice varieties in this test. According to a two-year canopy temperature testing, it toke a screening on warm temperature and cold temperature of rice varieties and also gave the studies on physiological properties and production structures of the two types. Meanwhile, it started the pot and box planted test on Kaijing1and Jing294from2011, and at different growth stages, it toke a24-hour outdoor, seven hours daytime interior measurements on leaf temperature and meteorological parameters. From the results, it showed the relationships about the rice leaf temperature with the leave temperature differences, meteorological factors, physiological indexes and production structures at different soil water potential.In2012, it set different water treatments in the field, and gave measurements on the canopy temperature and physiological indicators of Kaijing1, and then it got the relationship of canopy temperature with meteorological factors and physiological properties at different soil water potential. Simultaneously, a study on the water stress index model bases on rice canopy temperature in the field was also carried in the test. The results represented:1. There were some differentiation on different genotypes of rice at each growth stages. By comparing and analyzing the average temperature of each period, in this test, it selected the more prominent4cold-type materials and4warm-type materials. The average canopy temperature difference of all the varieties were at0.5-1.5℃, the canopy temperature at daytime of each variety went up with the air temperature went up, but it never exceeded the air temperature. The canopy temperature difference at13:00-15:00was most obvious, and it was insignificant at night, at same time, it existed a phenomenon that the canopy temperature of cold temperature material exceeded the warm one.2. The net photosynthetic rate, intercellular CO2concentration, stomatal conductance and transpiration rate of the cold temperature variety were significantly higher than the warm temperature variety at tillering and jointing stage. The photosynthetic rate at full filling stage decreased more obviously than at booting stage of the warm temperature variety, but the net photosynthetic rate of the cold temperature variety can still keep at a high level. It got a significant negative correlation of canopy temperature with photosynthetic rate and stomatal conductance via analyzing different temperature-type varieties, and the photosynthetic rate and stomatal conductance showed a significant positive correlation. Also it showed the density and width of rice flag stomatal on warm temperature was higher than the cold temperature one. And the stomatal length of the ventral and back of the flag leaf existed high and low types and was not obvious on all varieties.3. The dry matter accumulation of the cold temperature variety in different growth stage was all higher than the warm temperature variety, and the leaf and sheath output of the warm temperature variety was higher than the cold one, but its contribution rate was lower than the cold one. The output rate and contribution rate of the two types varieties were both negative. The total output rate of the stems, leaves and sheath of the warm temperature type were all much higher, and the total contribution rate of the cold temperature type were much higher. At production structure, the effective panicle, panicle weight, grain weight, seed setting rate and yield of the cold temperature variety were significantly higher than warm temperature variety.4. The relationship between all organ temperature and soil moisture of the rice were much close, when the soil with sufficient water, the ear temperature, stem temperature and leaf temperature differences of rice plant under the same water treatment were not obvious; but when the soil with water deficient, the ear temperature, stem temperature and leaf temperature differences of rice plant under the same water treatment reached a significant level, that is, the ear temperature>stem temperature>leaf temperature, and the less the soil water was, the bigger the difference was.5. The environment affected rice leaf temperature much greater, during the water control at different growth stages, the relation of rice leaf temperature with air temperature and solar radiation showed mostly significant or extremely significant positive, but it had negative correlation to the air humidity, and it had positive correlation to the leaf-air temperature difference. The leaf water potential and leaf relative water content of Liaojing294and Kaijing1decreased with the soil potential, and the leaf water potential and leaf relative water content difference of each water treatment reached a significant level. These two varieties at different water treatments, their photosynthetic rate, stomatal conductance intercellular CO2concentration and transpiration rate showed a significant or extremely significant negative correlation.6. The canopy temperature under different soil water treatments in the field were changed regularly, and its temperature reached the highest value at13:00-15:00of the rice, the lowest temperature appeared at2:00-4:00morning. Canopy temperature amplitude increased with the extension of water stress time. The best time on measuring water stress via canopy temperature difference was at13:00-15:00, and the recovery capability of rice suffered from water stress in the different period was different. Such as, at tiller-jointing stage, the plant recovered quickly after re-water, but the plant recovered slowly after re-water at heading-full heading and filling-full filling.7. According to the analysis of the relativity of the canopy temperature with meteorological factors and canopy temperature differences after water control at tiller-jointing, earing-full earing and filling-full filling stages, it discovered that it showed significant or extremely significant positive correlation on rice canopy temperature with the solar radiation, air temperature and canopy temperature difference, and it had negative correlation to air humidity. With the extension of the water control time, the correlation of the canopy temperature under each water stress treatment with the meteorological factors improved obviously.8. Mostly, the relation of the rice canopy temperature with the photosynthetic rate, stomatal conductance, intercellular CO2and transpiration rate represented positive. After water control at filling-full filling, the canopy temperature with photosynthetic rate and transpiration rate reached significant negative correlation and extremely significant negative correlation. The variable fluorescence (Fv), maximum fluorescence (Fm), the potential activity of PSII (Fv/Fo) and photochemical efficiency of PSII (Fv/Fm) at each stress treatment all represented significant decline. At earing stage, under different water treatments, Kaijing1flag leaf had no obvious difference on stomatal length. The stomatal width at ventral and back decreased with the water stress increased. And the ventral stomatal density of the flag leaf decreased with the water stress increased, but its back stomatal density increased with the stress increased.9. As water stress intensified, Kaijing1on its protein, fatty acids and amylose content showed all went up, and its taste value fell. The fatty acids, protein and amylose were negatively correlated. After water control at tiller-jointing stage, the grain weight and yield of S1treatment all exceeded treatment CK1and CK2which explained that Kaijing1can bring about the effect of saving water and increasing yield by mild stress at tiller-jointing stage. At earing-full earing stage water stress directly influence the rice ears differentiation which led to the significant decline of yield. And then at filling-full filling stage, the water stress caused large number of empty blighted grain which make the seed rate and seed number decreased.10. It simultaneously applied the empirical model and theoretical model of the CWSI in the rice water stress. According to the observation in this experiment, the research got the calculating on the relationship between the differences of the canopy temperature and the differences of the air saturation vapor pressure in the CWSI empirical model, and also the calculating on the relationship between the canopy resistance and other meteorological indicators in the theoretical model. Then after comparing the differences of these two kinds of models, it founded that the empirical model can normally used at an ideal weather condition, once the external environment changed, the CWSI values would overflowed the range of0-1. And the theoretical model was much more stable than the empirical model, thus the theoretical model was much more suitable for reflecting the crop water deficit situation. In this paper, it analyzed the relationship of the theoretical model with the stomatal resistance, transpiration rate, net photosynthetic rate and soil moisture content. The results showed that the theoretical model can much better reflect the situation of the rice water stress. |
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