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Study On The Effect Of Growth, Physiogy, Yield And Quality Of Rice Exposed To Enhanced UV-B Radiation

Posted on:2010-08-10Degree:MasterType:Thesis
Country:ChinaCandidate:Z F GuiFull Text:PDF
GTID:2143360302958121Subject:Science of meteorology
Abstract/Summary:PDF Full Text Request
Enhanced ultraviolet-B(UV-B) radiation resulting from ozone depletion is one of the global environmental problems. Up to now, the effects of UV-B Radiation on organisms have been studied extensively. In this experiment, I used the rice"Shan You63"(Sy63), as my experimental material. The rice were treated with UV-B Radiation with the intensities of 0W/m2 (CK), 0.5W/m2 (T1) and 1.0W/m2( T2), the duration of UV-B radiation treatment was ten hours per day (from 7:00 to 17:00), all plants were treated from tillering stage to maturation stage.The responses of rice under enhancment UV-B radiation levels were discussed through the studies on plant height,biomass,length of panicle,dry matter accumulation,leaf shape (the length,width and the ratio of the maize leaf length to width of upper three leaves),the net photosynthetic rate,transpiration,stomatal conductance,water use efficiency(WUE),solar-energy use efficiency(SUE),productivity and yield components,chlorophyll content,protein and amino acid content,and the change of plant growth based on previous researches. The results showed as followed:1.Enhanced UV-B radiation decreased plant height,leaf weight, weight of single stem-sheath,weight of single panicle,aboveground biomass, and the length,width and ratio of the maize leaf length to breadth of upper three leaves .The effects of T2 was higher than T1 . Change of plant height, leaf weight, weight of single stem-sheath, weight of single panicle, aboveground biomass, and the length,width and ratio of the maize leaf length to breadth of upper three leaves was: CK>T1 >T2.2.Enhanced UV-B radiation decreased chlorophyll a, chlorophyll b, the content of carotenoids,the net photosynthetic rate,transpiration,stomatal conductance,water use efficiency(WUE) and solar-energy use efficiency(SUE).The effects of T2 was higher than T1.The change of chlorophyll a,chlorophyll b,the content of carotenoids,the net photosynthetic rate,transpiration,stomatal conductance,water use efficiency and light use efficiency was CK>T1>T2.The diurnal variations of net photosynthesis rate(Pn) during different growth stages showed double-peak curves,and midday depression of photosynthesis was obvious under enhancment UV-B radiation, while transpiration and stomatal conductance showed single-peak curve.3.Enhanced UV-B radiation decreased yield of rice and had important influence on yield components of rice(length of panicle, total grains of per panicle, thousand seeds weight and seed setting rate). When UV-B radiation levels were T1 and T2, compared with the background (CK), the length of panicle were decreased 8.73% and 21.94%, also total grains of per panicle, thousand seeds weight and seed setting rate dropped by 12.82% and 18.15%,8.30% and 19.23%,9.58% and 15.27%,respectively.4.Enhanced UV-B radiation decreased protein content and protein content subjected to T1 and T2 dose UV-B radiation was decreased by 0.49% and 1.94%, respectively. The overall differences in protein content didn't reach a significant level. With the increasing UV-B radiation, the amino acid contents and amino acid components in rice also changed, the content of PRO and GLU dropped mostly, SER and LEU were the smallest rates of decline,another the content of HIS,TRY,GLY and TYR increased, the content of CYS and MET had no significant changed,the content of ILE,LYB and ASP first increased after reduced.With the increasing UV-B radiation levels, total amino acids and essential amino acids showed overall downward trend.When UV-B radiation levels were 0.5W/m2 (T1) and 1.0W/m2( T2), compared with the background (CK), the total content of amino acids were decreased 5.36% and 10.22%, respectively, and the total content of 8-essential amino acids dropped by 6.03% and 9.20%. Increased UV-B radiation levels on rice the content of VAL and TRY appropriate to increase the role-played.
Keywords/Search Tags:rice, UV-B radiation, net photosynthesis rate, yield, quality
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