Study On Introduction Of Paeoni Ludlowii Based On Pollination Process And Mechanism Of Double Flower

Paeoni ludlowii is one of the Ⅱ-class National Protection plants,it has high medicinal and aesthetic value combined,which make it to be precious plant resources and breeding materials.The Project Group in Tibet introduced Paeoni ludlowii from Miri village in Nyingchi to Lhasa,from 3000 to 3800 meters above sea level as well.We found it can blossom normally in Lhasa,and there was a double flower.This study focus on the ornamental characteristics of Paeoni ludlowii,it studied pollination biology,mating system and mechanism of double flower of plant population in the native region and the introduced region.This study probides theoretical basis for introducing Paeoni ludlowii at high altitude.The main results were as follows:1.Biological characteristics of pollination of Paeoni ludlowii(1)Biological characteristics of Paeoni ludlowiiPaeoni ludlowii is grow in bunches form base of the plant and glabrous,having smooth grey bark shedding in patches,it has biternate pinnatisect and glabrous leaf,cymose flower.The petals,filament and anther all are yellow,bract and sepal are both green.Paeoni ludlowii is protandrous,the anthers dehiscence from inner to outer during flowering,and the anthers were gradually getting shrivelled,the filaments were getting curly.The anthers and colum are almost at the same height.The Follicles are cylindrical in shape.Paeoni ludlowii has large seeds with dark brown,which are irregular oblate.(2)Flowering phenologyThe Paeoni ludlowii population in the native region was flowring from late April to late May,the single flowering period was from 4 to 9days(average 6 days),the flowering synchrony index is 0.57.The Paeoni ludlowii population in the introduced region was flowring from late May to early June,the single flowering period was from 3 to 5days(average 4 days),the flowering synchrony index is 0.73.The Paeoni ludlowii population in the introduced region flowered one month later than the Paeoni ludlowii population in the native region,and its flowering period was shorter,and also blossomed more concenetrative.(3)Pollen viability and stigma receptivity of Paeoni ludlowiiThe Paeoni ludlowii population in the native region had the highest pollen viability at the first flowering day,then the viability decrease gradually,there are two days the plants have both higher pollen viability and stigma receptivity.The Paeoni ludlowii population in the introduced region had the highest pollen viability at the first flowering day,then the viability decrease gradually,and the plants don’t have higher pollen viability and stigma receptivity at the same time.2、The breeding system of Paeoni ludlowiiThe outcrossing index of the Paeoni ludlowii population in the native region and introduced region are both 4,it means the Paeoni ludlowii are partial self-compatibility,but mainly outcrossing,pollination requires pollinators.The pollen-ovule ratio of the Paeoni ludlowii population in the native region is 49637,and it is 21196 in the introduced region.According to standard,this species is obligate xenogamy.But the results of bagging and artifical pollination indicate the Paeoni ludlowii was self-compatible.3、Discussing on mechanism of double flowerNumerous studies have shown that AGAMOUS(AG)genes are so important to regulate flower organ differentiation and flowering determination.This study explored the mechanism of double flower Paeoni ludlowii through separating and detecting the AG genes of the double flower plants.In this study,homologous cloning of genes was used to clone AG genes from the early bud total RNA of mutant and maintainer lines of paeonia palmata,and then the nucleotide and amino acid sequence structure and composition of this gene were analyzed by bioinformatics method.Results: the DNA of AG gene was 726,encoding 241 amino acids.Bioinformatics analysis indicates that the cloning of AG in the big flower peony gene belongs to the typical by MADS-box type Ⅱ class MIKC gene family,belongs to the class C gene.The results showed that the change of AG gene sequence was not the cause of the mutation of paeonia grandiflora,and it was speculated that the change of gene expression in the mutant line might be closely related to the petaling character of paeonia grandiflora.