| As the king of flower, peony is an especially precious flower variety in ourcountry. Now it is hard to meet peoples’ needs because of its short flowering. Studieshave shown that MAPK play an important role in plants’ growth. especially for plantsblossom and aging. MAPK cascade was highly conserved modules in all eukaryote. Inrecent years, numerous MAPKs had been isolated from different plants, and studiedthe function of MAPKs. But the relevant research on peony was infrequent.Peony (Paeonia suffruticosa ‘Yumiantaohua’) cut flowers were taken as objectsof study. They were divided into two groups, one pretreated by0.1mM PD98059(MAPK specific inhibitor) for12h, another one pretreated by ditilled water. Eachgroups were divided into four equal groups and randomly put in distilled water,0.1mM ABA,10mM H2O2and1mM CEPA respectively for analysing the morphologicalof flower braches and physiological and biochemical indexes during vasing. Throughstudying analyse the physiological effect of ABA, H2O2, ethylene and MAPKsignaling passway on the aging process of peony cut flower provide theoretical basisfor fresh-keeping technology and prolonging its vase days. The main results were asfollows:1. ABA、H2O2and CEPA accelerated the time of water balance, shortened theperiod of peony flowering, promoted flower opening and increased the maximumflower diameter. The treatment also shortened the best viewing period, and reduced thepeony ornamental quality of cut flowers. The result showed that ABA、H2O2andCEPA could promote flower opening and senescence. CEPA was the strongest factor topromote flower opening and senescence, the influence of ABA and CEPA wererelatively weak.2. Exogenous ABA、H2O2and CEPA could enhance the respiratory rate offlowers, and accompanied ethylene jump phenomenon. It showed that ‘Yumiantaohua’ was ethylene sensitive flower. The change trend of ethylene release was similar to theACC content and the activity of ACO、ACS. It meant that ACC was the premisematerial in the process of ethylene compound, and the ACO、ACS were the importantenzyme of speed in the process of ethylene compound. MAPK cascade pathwaysinvolved the aging of cut flower, and also participated in the regulatory mechanism ofABA、H2O2and CEPA, in addition MAPK cascade pathways had the positive controlin this process.3. ABA、H2O2and CEPA treatments could accelerate the accumulation of MDA,increase membrane-lipid peroxidation, reduce soluble protein content. The activity ofantioxidant enzyme increased earlier than blank treatment, and its change trend in thesame way as H2O2. After using the PD98059, the MDA content、soluble protein andactivity of antioxidant enzymes were reduced compared with the blank control.Therefore, MAPK maybe play an important role in the pathway of the cut peonyflowers senescence.4. Smi-quantitative RT-PCR analysis showed that the gene expression leves ofUbiquitin gene in different developmental stages and different processing of peonywere almost constant. The ACO and ACS genes at the beginning of the vase to expressquantity slightly larger, vase and mid expression quantity decreased, That may becoated the ACO and ACS activity is higher, feedback regulation inhibit geneexpression.Beginning in the late vase, namely into decayed, gene expression quantityincreased again. AS the contrast, the amount of gene expression of ACS and ACO waslarge at the beginning of the vase. Then it was decreased in the middle of the vase.This was likely to be the activity of ACS and ACO was higher, made the feedbackcontrol. But late in the vase, the amount of gene expression was increase. After usedABA、H2O2、CEPA and PD98059, the gene expression of ACS and ACO wasdifferent from the contrast, this showed that the MAPK cascade pathway involved inthe pathway of ABA、H2O2and CEPA regulated flowers senescence. |
PDF Full Text Request