Study On Regulation Of Abscisic Acid And Gibberellin In Peanut After Ripening

Abscisic acid and gibberellin were the main factors affecting crop post-ripening and dormancy.This study was conducted at the Peanut Research Institute of Jilin Academy of Agricultural Sciences.The peanut variety Jihua 25 with high oleic acid was selected as the test material.A randomized block test was conducted using gibberellin(0.2mmol·L^-1GA)and abscisic acid(0.1mmol·L^-1ABA)and their mixed solutions with different concentrations.Five experimental groups were set up:G（GA）,A（ABA）,AGⅠ（ABA:GA=1:1）,AGⅡ（ABA:GA=2:1）,AGⅢ（ABA:GA=1:2）,and blank treatment was used as CK.To explore the regulatory effects of abscisic acid and gibberellin on peanut after-ripening,as well as the effects on peanut plant traits,photosynthesis,physiological and biochemical characteristics,yield and quality,and germination characteristics.On this basis,the most appropriate hormone application scheme was selected,and germination test was set for further verification.During this process,the transcriptome was sampled and preserved to preliminarily explore the molecular mechanism regulating the postripening process of peanut.The aim is to provide theoretical basis and practical reference for the theory and technology of peanut high yield and high efficiency.The main research results are as follows:（1）The growth of plant traits such as main stem height,lateral branch length and leaf area per plant of G was significantly faster than that of CK at seedling stage and subflowering needle stage,while the growth of these traits began to slow down from subflowering needle stage,and the leaf area was significantly lower than that of CK at satiated fruit maturity stage,because GA treatment accelerated the growth and development of G and advanced the growth period.The main stem height and lateral branch length of A at seedling stage were significantly lower than that of CK before podding stage,and the plant height still showed a tendency to extend at full fruit maturity stage.The leaf area per plant of A was significantly higher than that of the control at the beginning of pod setting stage.At this time,peanut reproductive growth stage had been entered,and A still had a considerable level of vegetative growth,which indicated that the growth period of A was delayed.Therefore,ABA treatment of peanut seeds can prolong the growth period of peanut and prevent the early maturation of peanut.The growth of roots,stems and leaves of AGⅠ,AGⅡand AGⅢwas basically lower than that of CK from the pod stage,which indicated that the mixed treatment of GA and ABA inhibited the growth of peanut seeds at the later growth stage,thus prolonging the growth period of peanut.（2）The net photosynthetic rate of A treatment was the lowest and significantly lower than that of other treatments,and the other treatments had little difference in net photosynthetic rate.The stomatal conductance of A treatment was the lowest,which was significantly lower than that of other treatments,while the stomatal conductance of AGⅢtreatment was the highest,which was significantly higher than that of other treatments.The intercellular CO₂ concentration of all treatments remained basically the same.The transpiration rate of A treatment and AGⅢtreatment was not significantly different and significantly lower than that of other treatments,and the other treatments also had little difference.In conclusion,photosynthetic characteristics of A treatment were significantly lower than those of other treatments.Abscisic acid could inhibit peanut photosynthesis,which was not conducive to peanut growth and material accumulation,which was consistent with the performance of plant traits.（3）At seedling stage,MDA content in G plants was the lowest compared with control and all other experimental groups,indicating that GA treatment significantly reduced MDA content in peanut plants and promoted the growth and development of peanuts.In the later stage of growth,the SOD activity was AGⅠ>A>AGⅢ>G>AGⅡ>CK.POD activity G>AGⅢ>AGⅠ>AGⅡ>CK>A;CAT activity G>AGⅢ>A>AGⅡ>AGⅠ>CK.These results indicated that G had a higher senescence degree and reached maturity earliest in the later growth period.（4）Test the yield and seed of each treatment peanut seed.The data showed that the fruit weight and kernel weight of G treatment were significantly higher than those of other treatments except that the fruit weight and kernel weight of G treatment in the third stage were lower than those of other treatments,and that of G treatment in the first two stages,including the yield of harvest in the third stage,were significantly higher than those of other treatments.Only G per mu yield was higher than CK in the three stages of each treatment,and there was no significant difference in the first stage.G per mu yield in the second stage was 3.3%higher than CK,and 4.7%higher than CK in the third stage.（5）The oleic acid accumulation in G treatment was higher than that in AGⅡtreatment.The protein accumulation in G treatment was the highest.The accumulation of CK,A,AGⅠ,AGⅡand AGⅢhad no obvious rule.These results indicated that GA treatment could improve the quality of peanut seeds at harvest stage,while ABA treatment and different proportions of ABA and GA treatment had no effect on the quality of peanut seeds.（6）The germination rate and vigor index of G were the highest among all treatments.The germination rate and vitality index of A were the lowest in all treatments.The germination rate and vigor index of CK,A,AGⅠ,AGⅡand AGⅢall decreased to some extent during the staging process.Only the germination rate of G remained stable in the third stage,all of which were above 98%,and vigor index did not decrease.（7）In transcriptome analysis of gibberellin on peanut germination under low temperature stress,more genes were enriched in plant hormone signal transduction,amino acid biosynthesis,plant-pathogen interaction,starch and sucrose metabolism,carbon metabolism and other metabolic pathways,and the up-regulated genes were significantly more than down-regulated genes.These results indicated that the genes of metabolic pathway were highly expressed in the germination process of peanut seeds treated with gibberellin,and gibberellin played an obvious promoting role in the process of peanut breaking dormancy and germinating.