Change Regularity Of Yield And Quality To Apocynum Venetum L.Cv.Songyuan Leaf And Tea Products

Soil salinization is a worldwide problem,have hazarded seriously constraints the agricultural development and improvement of living standards of farmers in saline areas.The region of western Jilin province is one of the world famous saline-sodic soil type area.In recent years,due to the unreasonable excessive farming,deforestation,overgrazing and a single crop management,resulting in the saline area of this region fast expanded and socio-economic development backward.The previous saline-sodic soil control experience have shown that,for saline-sodic soil control,a integrative facts should be taken into account,including the people’s livelihood,living activity,ecology-efficiency combined with the economic-benefits.Apocynum is a multi-purpose plant integrating edible,medicinal,fiber,revegetation and sightseeing etc..It is strong resistance to abiotic stress,therefore,the comprehensive development and utilization of apcymum will have strong meaningful in improving Songnen Plain saline-sodic soli governance and local farmers financial benefits.Apocynum Venetum Tea is a kind of health tea,which is made of the apocynum plant leaf,and it possess wide pharmacological activities,including antihypertensive,cardiotonic,antioxidant,lipid-lowering,antidepressant and anxiolytic effects.The purpose of this experiment aim to evaluate Songyuan Apocynum Venetum Tea and apocynum leaf composition and quality through difference plant parts and growing stages by comparing water extracts,free amino acids,polyphenols,total flavonoids,quercetin,antioxidant activity,as well as by detecting heavy metals and selenium content,to explore and determine the best time and the best parts of the original Apocynum leaf picking,thus to provide the theoretical basis for Songyuan apocynum planting,harvesting,industrial producing,safety evaluation and the development and utilization of this healthy tea in future.The main conclusions are as follows:(1)There were significant difference(P < 0.05)in agronomic traits,yield and quality changes of Songyuan apocynum leaves in different growth periods.With growth and development of Songyuan apocynum,plant height showed increased trend in beginning and maintain stable pattern after a period growth;stem-leaf ratio presented increased gradually pattern;fresh-dry ratio decreased gradually through the growth period;while the biomass yield,fresh leaf yield and tea yield changed from increasing trend to decreasing.The content of total flavonoids and antioxidant capacity showed an increasing trend,but decreased to the bottom in the late anthesis.By contrast,the content of quercetin increased continuously through the growth.Therefore,in the case of high biomass yields for the harvesting purpose,the harvest time should be arranged during 24 th of June to 14 th of July;while in the case of high-quality leaf for the harvesting purpose,the harvest time should be arranged during July 24 th of July and 3rd of August in the west region of Jilin Province.(2)There was significant difference in Apocynum Venetum Tea quality changes in different growth stages.Best tea quality was found in podding stage and fruit stage due to the high content tea polyphenols,flavonoids,quercetin,and high antioxidant ability,that means the healthy tea during these stages would have the best functions.(3)The comparison of difference plant parts Apocynum Venetum Tea quality during vegetative,anthesis,podding(upper,middle and lower pod)showed that the polyphenols,total flavonoids,quercetin content were higher in anthesis period,indicating Apocynum Venetum Tea obtained the best quality in this stage,therefore,total flavonoids,quercetin content higher,indicating apocynum best quality tea;furthermore,the young upper leaves could be the best raw materials for the healthy tea during anthesis.(4)The testing results indicated that Songyuan Apocynum leaves heavy metal content was compliance with national standards of heathy tea.The content of selenium showed an increasing trend,then followed by declined pattern,and the content value reached the enriched tea standard during the entire sample period,which indicated Songyuan Apocynum Venetum Tea could be developed into a enriched tea product for commercial,and the highest selenium content indicating the most suitable time for processing enriched tea was in the middle anthesis(4th of July).