The Dahlia pinnata varieties 'Dajinhong' and 'Longshangxiongying'were treated with different concentrations of PP333 when the plant height was 20 cm in pots to study the effects of PP333 on the growth and development indicators and the contents of endogenous hormones.The results showed that PP333 could make the internode shorter and the stem diameter larger and also affect the leaf area.Compared with the control,the content of GA3 and IAA decreased and the ABA content increased,but the content of ZT showed ...