Effect Of Storage Microenvironment On Cellular Senescence Of Wheat

Two varieties of wheat high gluten“ruixing-1” and medium-gluten “ruixing-8998” werestudied in this paper. Simulate four climate conditions of wheat storage area (Meng Area,Northern Region, Central Region, Southern Region), temperature and humidity were setcorresponding to A:(15℃, RH50%), B:(20℃, RH65%), C:(28℃, RH75%), D:(35℃,RH85%). Using artificial storage with humidity chamber for300days. Using way ofcombination of physiological and biochemical analysis and cell observation, the variation ofphysiological and biochemical indicators and enzymatic and non-enzymatic defense system inwheat cell were measured during storage, and the changes of microstructure of wheatendosperm cell and ultrastructure of embryo cell were observed with SEM and TEM electronmicroscopy. Which was used to discuss the relationship between them and wheat aging, andascertain the influence of storage microenvironment on senescence of wheat cell, providing atheoretical basis for the scientific and safe storage of wheat. The results showed that:Storage microenvironment had significant effect on changes of physiological andbiochemical indicators and enzymatic and non-enzymatic defense system in wheat cell (P<0.05). The longer the storage time and the higher the temperature and humidity, the moreobvious changes which got and the faster aging cell would be. Under high temperature andhumidity(C and D), although the changes in the high and gluten wheat were slightly different,but the basic rules were similar, with the extension of storage time, O2·-rapid accumulated,content of toxic substance MDA continue increased, respiratory enzyme COX activitydecreased, membrane permeability increased, content of storage substances soluble proteinand soluble sugar reduced. At the same time, both of the activity of antioxidant enzyme(SOD、CAT、POD) and content of anti-oxidants (ASC、DSH)in the cell defense systemcontinue decreased, which resulted in significant lower of seed vigor. In particular, changes ofthe condition under D were more obvious, seed vigor of high-gluten wheat was from96%to0,the gluten of wheat from95%to27%.,and the changing amplitude of the indicators under theD were significant higher than that under A and B by analyzing of T test (P <0.05). Thecorrelation between O2·-、indicators、antioxidant enzymes and antioxidants showed significant(Sig <0.05) by correlation analysis, the correlation between O2·-、seed vigor and ASC were themost significant (Sig <<0.01).With the storage temperature and humidity getting high, the damage and deteriorationof cell structure in endosperm and embryo of high, medium gluten wheat became serious,changes in high gluten wheat were more obvious than medium gluten wheat. Structural changes in the endosperm mainly as follow: extent of binding between matrix proteins andstarch grains reduced,matrix proteins decreased, matrix changed from half-gelatinized stategradually to flaky, a small portion of protein occurs aggregation and degeneration; changes inthe structure of embryo cell were more obvious than that in the endosperm, mainly as follows:cell morphology gradually deformed; membrane damaged in different degrees; the number ofmitochondria reduced, the outer membrane dissolved, ridge of internal membrane disorderedand aggravated, vacuoles phenomenon became gradually serious; chromatin agglomerated,nucleolus deformed、splited and even dissolved; protein aggravated, fat decreased. In whichchanges of the mitochondria and chromatin.were more sensitiveLevels of free radicals in wheat cell and changes of physiological and biochemicalindicators、enzymatic and non-enzymatic defense system、damage in cell structure wereinterrelated. which working together to promote the wheat cell aging. In the wheat storageprocess, using low temperature and humidity environment can easy to slow down the aging ofwheat and maintain the quality.