Growth and Photosynthetic Characteristics of Bletilla striata at Seedling Stage in Field Environment

Taking seedlings of Betilla striata（Thunb.） seedlings as test material,using field demonstration test methods,based on the evaluation on the growth of the seedling stage in seedlings of Betilla striata in different sampling plots.The growth characteristics in seedlings of Betilla striata seedlings in different stages and photosynthetic characteristics in seedlings of Betilla striata in sprout tumble stage were measured,and the principal component analysis was used to select the comprehensive indicators to express the growth state in seedlings of Betilla striata.This study can provide reference for the cultivation of seedlings of Betilla striata in the field.The results showed that in the field environment,for the seedlings of Betilla striata in the growing season,the plant height,leaf area,aboveground biomass,tuber biomass,new root biomass and underground biomass all increased during the sprout tumble stage compared with the initial seedling stage.During the sprout tumble stage,the maximum plant height,leaf area,chlorophyll SPAD value,biomass of aboveground,biomass of old roots,biomass of new roots,biomass of tuber,biomass of underground,respiration rates（Rday）,net transpiration rates（Pnmax）,and the apparent quantum efficiency（AQY） were all in plot B or A₃（both level Ⅰ seedlings）,while the minimum were all in plot D₂ or A₁（both level Ⅲ seedlings）.The principle component analysis showed that the indicators with a higher contribution rate of growth characteristics indicators in the seedlings of Betilla striata include the biomass of new roots,the apparent quantum efficiency（AQY）,and biomass of underground.