Rice Roots Of Drought Stress On The Photosynthetic Fluorescence Characteristic Influence

to reveal the characteristics of rice root stress on photosyntheticfluorescence effect, the experiment using polyethylene glycol （PEG-6000）processing method of simulated water stress, under hydroponic conditions, in indicarice variety combination, and the japonica rice and japonica rice and upland rice6738as test material, the design of different moisture gradient, and choose differentgenotypes rice varieties, the short （30min and0-0-150min） under water stress in riceleaf photosynthetic characteristics and chlorophyll fluorescence induction kineticsparameters of the internal mechanism. The results are as follows:1.150min short-term water stress on the influence of different genotypes ricephotosynthetic characteristics results showed that rice net photosynthetic rate, stomataconductance （Gs）, intercellular CO₂concentration （Ci）, transpiration rate （Tr）,carboxylation efficiency （CE） presents the downward trend, all falling within30minutes at the beginning of processing speed faster, then the downward trend within30-90minutes of moderate,90min after the drop rate is faster. Differences betweendifferent genotypes rice varieties, net photosynthetic rate, dry processing combination,and prepare the japonica after150min6and738varieties, respectively, comparedwith the initial fell by77.71%,74.59%,80.83%; Leaf stomatal conductance （Gs）drought treatment combination, and prepare the japonica after150min6and738varieties, respectively, compared with the initial fell by86.74%,88.82%,87.52%;Intercellular CO₂concentration （Ci） when handling60min combination, and preparethe japonica6three varieties and738, respectively, compared with the initial fell by23.02%,32.00%,21.29%, processing and at the end of, respectively, compared with60min was increased by70.87%,51.18%,13.27%; Transpiration rate （Tr） treatmentcombination, and prepare the japonica after150min6and738varieties oftranspiration rate was53.67%lower than initial respectively,70.89%,83.49%; Wateruse efficiency （WUE） present a more complex trends, basically presents inverted Schange trend, namely in the treatment of the beginning period within30min, wateruse efficiency （WUE） slow down, then,30-90min has a tendency to rise, decline andobvious after90min, differences between different varieties is bigger also, in theprocess of the whole stress combination, and prepare the japonica6and738varieties of three basic water use efficiency rises to the top, around60-90min, respectively,compared with before treatment increased by4.22%,7.75%,43.19%, and reduce tothe lowest in150min, combination, and prepare the japonica number six was51.88%lower than before treatment, and51.88%respectively.2.150min short-term water stress on the influence of different genotypes rice leaffluorescence properties results show that different genotypes rice for a long timeunder the condition of water stress in rice leaf potential photochemical efficiency（Fv/Fm）, Φ PS â…¡ （actual photochemical efficiency）, and Qp （leaf） photochemicalquenching coefficient, ETR （electron transfer rate） are present different degree ofdownward trend, the rice leaf non photochemical quenching （NPQ） to present thechange trend of first increased and then drop and rise more slowly,120min afterdifferent varieties have different degree of decline, showed that738and preparejaponica to more combination, drought-tolerant the number six.3.30min short-term water stress on the influence of different genotypes ricephotosynthetic characteristics results show that different genotypes rice variety netphotosynthetic rate, stomatal conductance, transpiration rate, carboxylation efficiencyare different degree of decline, the drought treatment began to rate of photosyntheticindicators within10min softer, and deal with the15to30min after decline rapidly.Differences between different genotypes rice varieties, combination,> and thejaponica>6,738. Drought treatment combination, and prepare the japonica after30min6and738varieties of three net photosynthetic rate, respectively, compared withthe initial fell by25.94%,24.25%,30.43%, stomatal conductance, respectively,compared with the initial fell by25%,26.58%,34.96%, transpiration rate,respectively, compared with the initial fell by27.59%,28.82%,38.08%,carboxylation efficiency, respectively, compared with has fallen by17.53%,23.84%,25.13%under normal conditions.4.30min short-term water stress on the influence of different genotypes rice leaffluorescence properties results show that the potential photochemical efficiency,actual photochemical efficiency, photochemical quenching coefficient tend to decline,15min after the water stress drops more apparent, as the stress time extended, theoverall is still in the downward trend, has obvious differences between differentgenotypes rice varieties,30min after water stress combination, and prepare thejaponica6and738varieties of photochemical efficiency potential is lower thanbefore treatment respectively6.24%,6.24%,6.22%; Blade Φ PS â…¡ was12.88% lower than before treatment respectively,9.98%,9.92%; Photochemical quenchingcoefficient respectively12.31%,12.16%,12.31%lower than before treatment.5.150min briefly the influence of different water stress on rice leafphotosynthetic characteristics results show that the figure19,150min in the processof the short-term water stress at different leaf net photosynthetic rate, transpirationrate, water use efficiency and carboxylation efficiency showed a trend of fast-slow-fast three-step changes, deal with0to30min present rapid decline,30-90min presentrelatively gentle decline,90-150min falling speed and speed up. Different withnormal change analysis showed that:10%,20%, processing, significant differenceswere compared with the normal30%processing reached extremely significantdifference. Visible under severe drought stress, rice as the extension of stress time,photosynthesis decline faster. CO₂concentration30%stress0-60min afterprocessing the intercellular CO₂concentration in the change trend of decline, fallingto24.71%before processing,60min after the intercellular CO₂concentration and hasa tendency to rise, there is obvious difference between different treatment,10%and20%in150min after initial fell30.43%and34.50%, respectively, compared withstomatal conductance showed a trend of slow-fast-slow change, reached extremelysignificant level30%, reached20%significant level,10%did not reach significantlevel.6.150min briefly the influence of different water stress on rice leaf fluorescenceproperties results show that the potential photochemical efficiency, actualphotochemical efficiency, photochemical quenching coefficient, electron transferefficiency are different degree of decline, a significant difference between differentwater stress,10%decline rate is lower than20%and30%, after analysis, processingdid not reach significant level10%,20%and20%significant level.