Optimizing Nitrogen Nutrition And Light Environment Of Soilless Cultivation Platycodon Grandiflorum Under Facilities

Wild medicinal plant resources are increasingly scarce and medicinal plant cultivation areaincreased year by year with demand for medicinal herbs. However, the sustainable development ofChinese herbal medicine industry were restricted because the cultivation land area become narrowwith the change of cropping system, and medicinal quality and yield were declined due to pesticide andheavy metal residues of medicinal plants and cropping obstacles. As a new cultivation method, soillesscultivation within the facility has a substantial increase in yield potential with the advantages ofenvironmentally controlled, clean, non-polluting and continuous anniversary production. Therefore,soilless cultivation of medicinal plant was conducive to anniversary and standardization of medicinalplants production and sustainable development. Platycodon grandiflorum is a kind of importantmedicinal plants, and it was used to cure chest tightness and abdominal distension. Soilless cultivationof platycodon grandiflorum was still blank. In this study, platycodon grandiflorum as material undersoilless culture through the study of nitrogen nutrition, light environment parameters, growth media andcultivation devices within the facility to provide technically support for its soilless cultivation. The mainresults and conclusions are as follows:1. The nitrogen nutritional conditions of platycodon grandiflorum in facilities of soiless cultivationwere nitrate form of nitrogen and concentration of5mmol L-1.Under hydroponic conditions,compared with1,2.5and7.5mmol·L-1when nitrate concentration of nutrient solution was5mmol·L-1, dry weight, fresh weight and phosphorus absorption of platycodon grandiflorum rootwere maximum,the difference were significant, and its dry weight of root was5times than1mmol·L-1nitrate concentrations, and root fresh weight of per pot were above5.56g.When nitrogenconcentration were5mmol·L-1, dried and fresh weight of platycodon grandiflorum were maximumunder all nitrogen forms were of nitrate, the difference was significant. However, growth ofplatycodon grandiflorum were inhibited when the nutrient solution contained1mmol·L-1nitrateand4mmol·L-1ammonium, and root werer poisoned by ammonia. Under conditions of vermiculiteas the cultivation substrate, concentration of nitrate in nutrient solution5mmol·L-1, dry and freshweight of platycodon grandiflorum were maximum, the significant were difference; and, the rootand shoot fresh weight of platycodon grandiflorum were maximum with nitrogen form of1mmol·L-1nitrate plus4mmol·L-1ammonium nitrogen.2. Light environment conditions of platycodon grandiflorum in facilities of soiless cultivation were3:1of red and blue LED light quality and16hours of photoperiod.Dry weight of platycodongrandiflorum aboveground were the largest and dry weight of root LED red light were minimum,blue light and red plus blue light were on the contrary, root to shoot ratio of platycodongrandiflorum were maximum under the blue light and was minimum under red light. And nitrogenuptake of platycodon grandiflorum aboveground under red light were smallest, root nitrogenabsorption were the maximum, the difference was significant;shoot and root biomass platycodon grandiflorum were maximum under red and blue3:1of LED and16hours of photoperiod, freshand dry weight of shoot were1.4g and0.4g respectively, while white light and hours of photoperiodcultivation were only0.14g and0.05g, fresh and dry weight of root per plant under were1.09g and2.5g, white light and8hours photoperiod were only0.15g and0.03g.3. The matrix composition of platycodon grandiflorum in facilities of soiless cultivation was1:2:1ofpeat, vermiculite and perlite radio.The matrixes were screened among6kinds of different volumeratio of peat, vermiculite and perlite mixed. The root volume and number of flowering ofplatycodon grandiflorum were maximum at the volume ratio of1:2:1, the difference wassignificant,but there was no significant difference in biomass among the six kinds of growingmedia.4. The semi-hydroponic soilless cultivation device can be used to cultivate platycodon grandiflorum,and the yields of the unit square were than the open field. The semi-hydroponic soilless cultivationdevice were developed to achieve nutrient solution and growing media separation and providedexcellent environment for the growth of platycodon grandiflorum based on the weakness of potexperiment as less root growth space and less dissolved oxygen content. The per square meter yieldof platycodon grandiflorum under natural light in greenhouse glass were1500g,tis higher than opensoil cultivation of300-800g.