Phenotypic Diversity And The Effect Of Low Temperature On Germination Characteristics Of Fruit And Seed In Tetracentron Sinense Oliv

In order to explore phenotypic genetic diversity in Tetracentron sinense Oliv with conservation perspective, the 11 phenotypic traits of fruit and seed were investigated based on 11 provenances in 6 provinces from mainly distribution centers in China. In addition, the effects of low temperature, soil moisture and freezing time on the germination of T. sinense seeds were studied by simulating wild environment conditions, and the factors influencing the natural regeneration of T. sinense population were discussed ultimately. The results are as follows:1.Genetic diversity in Phenotypic traits of fruit and seed in T. SinensePhenotypic differentiation of T. sinense reached significant level among populations or within populations(F value: 1.06-27.45; P < 0.01), but the phenotypic differentiation coefficient within populations(Vst=89.87%) was significantly larger than that among populations(Vst=10.13%). The range of CV in fruit and seed phenotypic variation was 0.0961-0.4440, the mean value was 0.2384. Among, the variation of SN(CV=0.4440) and WS(CV=0.4159) were higher in the mean coefficient variation, which was more than 4 times as much as the FW1(CV=0.10)with the smallest degree of variation. Variation of phenotypic traits in T. sinense was mainly associated with latitude, longitude, altitude, annual rainfall and annual sunshine hours, and fruit phenotypic traits were more susceptible to the influence by geographical meteorological factors than that of seed. The dendrogram based on the Principal component analysis(PCA) showed that the characteristic of regional plate features was presented in some areas and random variation in other areas for phenotypic traits in T. Sinense.The results suggested that variation within population was the main source of phenotypic variation in T. sinense, and annual sunshine hours was a dominant environmental factor influencing the variation. For phenotypic variation pattern in T.sinense, regional plate features was presented in some areas and random variation in another areas. Overall, some practical protection strategies were proposed: the WFHH population should be used for in situ conservation of key protection area; the individuals from adjacent populations should be introduced as far as possible in order to enhance the gene exchange among populations in ALM; BDGM population can beserved as the reintroduction of the origin of the germplasm.2. The effect of low temperature during imbibition on Germination characteristics of T. sinense seedsThe imbibition process of T. sinense seed can be divided into four stages,including rapid water absorption, slow water absorption, rapid water absorption and water absorption stagnation period. The water absorbing capacity of T. sinense seed after imbibition would increase with the increase of soil moisture, and the seeds would be fully imbibed under the condition of 30% soil moisture. The germination rate, germination force and water content of T. sinense seed increased with the increase of storage time, and the vigor index gradually decreased after increasing before. At different low temperature, the germination rate of T. sinense seed reached the highest when the soil moisture is 20% or 30%. When treated at 20% soil moisture for 2-4days or 21-28 days, 0℃ is best for the germination rate of T. sinense seed;when treated at 30% soil moisture for 14-28 days,-7℃ is best fort he germination rate of T. sinense seed. When treated at the same condition of freezing time, the germination rate of seeds in fallen leaves had no significant difference with the decrease of low temperature; under the same condition of low temperature(0 ℃ low temperature except), the germination rate increased after frozen 28 days. The results showed that: There is no significant influence of low temperature during imbibition on germination characteristics of T. sinense seeds, indicating that low temperature during imbibition is not the main factor influencing the natural regeneration of T.sinense population.The result showed that: there is no significant influence of low temperature during imbibition on germination characteristics of T. sinense seeds, so low temperature is not the main factor influencing the natural regeneration of T. sinense population.