Drought Resistance Identification And Evaluation Of Tobacco

This research mainly studies the effect of drought stress on morphology and thephysiology and biochemistry of five different tobacco varieties widely cultivated in Shaanxivarieties in three key growth stages. Five different tobacco varieties include:Yunyan87(YY87), K326, NC89, Qinyan96(QY96), Yunyan97(YY97), three key growthstages include: Strengthly Growing Stage, Flower Budding Stage, Mature Stage. By screeningof drought resistance indexes and comprehensive analysis of the drought resistance of tobaccovarieties in different stages, the study will provide theoretical support for the identification ofdrought resistance of tobacco and breeding drought-resistant tobacco varieties. This studydesigns pot experiment, adopting randomized block experiment design with the artificialwater control to regulate soil moisture. There are three water treatments, soil moistureaccounted for the largest field capacity75%to80%,50%to55%,40%to45%. Respectively,on the third day and the sixth day after the control of the water, the study determinesmorphological and physiological and biochemical indexes, carries on the analysis of variance,screens drought resistance indexes, analysis screened indicators with subordinate functionvalue method, and compares drought resistance of those five tobacco varieties in variousgrowth stages.The main results are as follows:In Strengthly Growing Stage, the indexes of moisture sensitive include: plant height,maximum leaf length, leaf number, chlorophyll content. Expressed as that, after drought stress,plant height reduced, maximum leaf length reduced, leaf number reduced, the content ofchlorophyll reduced. In Flower Budding Stage, the indexes of moisture sensitive include:plant height, maximum leaf width, maximum leaf length, stem girth, chlorophyll content,Photo, Cond, proline content. Expressed as that, after drought stress, plant height reduced,maximum leaf width reduced, maximum leaf length reduced, stem girth reduced, chlorophyllcontent increased, Photo reduced, Cond reduced, proline content increased. In Mature Stage,the indexes of moisture sensitive include: Photo, Trmmol, Ci, POD activity, MDA content,proline content. Expressed as that, after drought stress, Photo increased, Trmmol reduced, Cireduced, POD activity reduced and then increased, MDA content reduced, proline contentincreased. Under drought stress, the change of the same index in different stage may be the opposite.For example, the chlorophyll content, under drought stress, reduced in Strengthly GrowingStage, but increased in Flower Budding Stage. In addition, effect of varieties on chlorophyllreach extremely significant level in Strengthly Growing Stage, but have little impact in theFlower Budding Stage. In the early period of drought stress in Mature Stage, proline contentreduced and then increased, as time went on, it had no significant effect of drought stress onproline content, but the effect would last much longer in Flower Budding Stage.Under drought stress, the change of seemingly associated indicators is not necessarily thesame. As one indicator of leaf area both, compared with the maximum leaf width, themaximum leaf length is more sensitive to drought stress, particularly in Strengthly GrowingStage. Trmmol and Ci are not sensitive to drought in the Flower Budding Stage, but sensitiveto drought in the Mature Stage, while Cond is exactly the opposite.The results show that: in Strengthly Growing Stage, drought resistance of K326isstrongest, while that of YY87and YY97is weaker, and that of NC89and QY96is weakest. InFlower Budding Stage, drought resistance of YY87is strongest, while that of K326and YY97is weaker, and that of NC89and QY96is weakest. In Mature Stage, drought resistance ofQY96and YY97is strongest, while that of YY87, NC89and K326is weakest. The stabilityof drought resistance of YY87, YY97and NC89is quite high, and drought resistance is in theorder from strong to weak. But drought resistance of QY96and K326is volatile, whichchanges in different stages.