Influence Of Drought、Salt、UV-B、ABA On The Wheat And Rice Leaves Cuticle

During their life activities, plant often subjected to a series ofenvironment stress, including drought, salt, pathogen and insectattack,UV-B damage.In order to resistance different kinds ofenvironment stress, plant cuticle was formed which covered withthe air ogan epidermal cell wall.This was the first barrier of theplant contanted with the external environment. Plant cuticle wascomposed of cutin and wax, its chemical compositions waslipophilic. The physical and chemical character of plant cuticle playan important role in resistance the biotic and abiotic stress.Atpresent, the effect of stress(ABA, UV-B, salt, drought ) on plantphysiological leaves has been obtained great progess, but all kindsof environment stresses on the plant cuticle was not much known.In this paper, JinMai 2018 wheat and ZhongHua 10 rice (Oryzasativa) were used as the experimental materials. After the wheatand rice seedlings growing 1-2weeks, they would get through five stresses including drought, ABA (40μMABA、100μMABA) sprayed,NaCl (150mM) irrigated and UV-B radiation. Through observation ofthe phenotype of wheat and rice plants, observation the cuticularwax distribution of the leaves surface by scanning electronmicroscopy, determination of changes the permeability of leavesand leaves surface wax content, We can make sure that the drought,salt, UV-B, ABA can effect on the wheat and rice leaves wax andcutin synthesis and cuticle had an important role on resiatancestress.The major results were as following: After five kinds stresses,the wheat and rice seedlings became small, leaves had differentdegrees of yellow. After the ABA sprayed ,the wheat and rice leavessurface had yellow spots.The leaves appeared low-grade wiltingafter drought.After UV-B radiation, the leaves became crispation.Through the scanning electron microscopic,we found the number oftrichome and white wax which located around the epidermalincreasing in wheat leaves surface.The rice leaves surface waxshowed slice, and papillary structures covered wax become big andmore.After the stress treatments,the relatively water content ofwheat and rice leaves significantly increased,the increasing trendof the wheat relatively water content leaves was: UV-B> Drought>Salt>100μM ABA>Control, the increasing trend of the rice relatively water content leaves was: UV-B> Drought> Salt>40μMABA>100μMABA >Control.But the rate of leaves water loss and totalchlorophyll extracted gradually decreased, the trend was contraryto the former results.Plant can enhance the capacity of retainingwater by increasing the cuticle wax content and limiting thenon-stomatal water loss.The wheay and rice leaves cuticle wax wasextracted by organic solvent chloroform.The wheat and rice leaveswax content obviously added by stress treatments. The increasingtrend of wheat leaves wax cantent was: UV-B(87.39 mg/cm~2) >Drought (76.72mg/cm~2)>Salt(72.09mg/cm~2)>100μM ABA (67.59mg/cm~2) >Control(66.14mg/cm~2). The increasing trend of rice leaveswax content was: UV-B(35.86mg/dm~2) >Drought (32.66 mg/dm~2)>Salt(23.26mg/dm~2)> 40μMABA (17.45mg/dm~2) >100μMABA (19.9mg/dm~2) >Control(15.18mg/dm~2). This paper showed that kinds ofstresses had different effectes on cuticle wax, leaves epicuticularwax production and accumulation was an active and regulatedprocess.In addition, 9-cis-epoxycarotenoid dioxyg (NCED) is the keyenzyme in ABA synthesis pathway. In this study, the combination ofUbi :: AtNCED3 gene successful transformed in rice(Oryza sativa) bythe agrobacterium-mediated method.Thirty transgenic lines wereindenified by PCR.This study showed Ubi::AtNCED3 rice had higher relatively water content, lower water-loss rate of cuticlestranspiration and total chlorophyll extracted than WT.