Identification Of Drought Resistance Of Transgenic Wheat Lines With W23Gene

As an important abiotic environmental stress factor, drought restrict increase of wheatyield. It is the most effective approach to solve drought stress by breeding wheat varieties ofdrought-tolerant and water-saving with high yield in agriculture. In the past few years, it hasbecome an important method for cultivating wheat varieties of excellent and drought-tolerantto improve the stress tolerant of wheat by the means of adverse-resistance gene engineering.This study used four transgenic wheat lines with W23transcription factor gene which wascorrelated with drought resistance in T5generation by the way of imitating drought stressartificially during the seedling stage and controlling the water content of soil in potexperiment during the adult-plant stage, investigated morphology, growing development,photosynthesis and other physiology indexes related to the drought resistance of wheat,meanwhile, discussed the mechanism of their drought resistance physiology. The mainresearch results of this thesis were as follows:1.15%PEG-6000was used to imitate the drought-rewatering measures artificially inhydroponic culture during the seeding stage. The experimental results showed that thephotosynthetic rate, transpiration rate, leaf relative water content, practical photochemistryquantum efficiency of PSII and other indicators in transgenic lines were superior than that inthe control variety under drought stress, this made transgenic lines show outstandingcapability against drought stress. During the rehydration treatment stage, there were higherrecovery amplitude of every physiological index in transgenic lines than that in the controlvariety, meanwhile, this made transgenic lines show stronger drought stress resiliencecapacity after rehydration. Throughout drought-rewatering stage, it was always higher in thetotal root length, total root surface area, total root volume, leaf area per plant, the biomass ofabove-ground and root in transgenic lines than the control variety, this made transgenic plantsshow a higher growth advantage.2. During the adult-plant stage, the results of the pot experiment by controlling watercondition showed that, transgenic lines could maintain a higher level of leaf relative watercontent than the control variety under drought stress. With the intensification of drought stress,the water use efficiency in all the wheat varieties tended to increase first and then decrease,meanwhile, it was overall higher in transgenic lines than that in the control variety under drought stress. The water use efficiency in G19-X59was extremely significant higher(35.28%) than the control variety under moderate drought stress, meanwhile, the transgeniclines had higher values of photosynthetic rate, efficiency of primary conversion of lightenergy of PSII and other physiological indicators compared with the control. There were noobvious differences between transgenic wheat lines and the control variety in photosynthesisand other physiological indexes under severe drought stress.3. Survey on the agronomic characters showed that the maximum tiller number, mainspike length,1000-grains weight in transgenic lines were significant or extremely significanthigher than the control variety. The plant height, the distance of spicae and leave in transgeniclines were significant longer than the control variety under the normal water supply andmoderate drought treatments. However, they were equal with the control variety under severedrought treatment. The results of yield by calculating the grain yield per pot showed that thegrain yield in transgenic lines were higher than that in control variety under three watertreatments, especially, the yield increment effect of G19-X59reached significant level. Thevalues of drought-resistance index of four transgenic lines were1.09~1.36, which made fourtransgenic lines the category of strong-very or strong drought-resistant materials, especially,G19-X59had the highest value of drought-resistance index (1.36) and belonged to theextremely strong drought-resistant material.4. It was indicated that G19-X59strain had the extremely strong drought-resistant thanthe control variety by the comprehensive analysis of the drought resistance of four transgeniclines with W23gene during the seeding and adult-plant stages, the other transgenic lines alsohad stronger drought-resistance than the control variety. The results showed that transgeniclines with W23gene all had better drought-resistance than the control variety under bothhydroponic and potted plant growing conditions.