The Growth And Development Of Platycodon Grandiflorum And Effect On Dynamic Accumulation Of Yield And The Content Of Tatal Saponins By Topping Off And Top Dressing

This paper studied the growth and development of platycodon grandiflorum and effect on dynamic accumulation of yield and the content of tatal saponins by topping off and top dressing in the henan agriculture university laboratory and scientific park during 2004～2005, The results showed that:(1) Germination percentage was highest when seeds were soaked for 24h in 40～50°C warm water and cultivated by the solution of silk liquid;(2) Platycodon grandiflorum ontogeny period included seed germinating stage(seed awaken stage, seed realing stage, sprouting stage, cotyloden stage , main leaf showing stage), seedling stage, stem elongation stage, bud bursting stage, flowering stage, fruit-setting stage, fruit ripening stage and withering stage;(3) Its annual vegetation period lasted 180～200 days;(4) Its leaf function period lasted 25～63 days and life period lasted 35～70 days;(5) Its root grew slowly in vegetative phase (from early-April to mid-July) and fast in progenitive phase(from mid-July to late-October), its root length and diameter reached the maximum in early-October, and root weight reached the maximum in late-October;(6) Topping off, K-top dressing and spraying nutrient solution improved the crop yield respectively, it was best to do Topping off and K-top dressing in bud bursting stage;(7) The content of total saponins from the roots were higher in August than that during September to early-October, and the content of total saponins from the roots rise a little in late-October (withering stage);(8) Topping off, K-top dressing and spraying nutrient solution could increase the content of total saponins from the roots, so do with the aboveground part. They had the same trends.(9) The harvest time of the Platycodon grandiflorum A.DC. should be considered the yield and quality, it was good time for digging in late-October if only Topping off or Additional manuring, and in late-November if Topping off and Additional manuring;(10) The contents of total saponins from the annual roots of Platycodon grandiflorum A.DC. were mostly lower than the standard of the Chinese pharmacopoeia, so it can not be used in medicine.