| Houpo(?)a officinalis,is a deciduous tree which belongs to Magnoliaceae family and has been categorised as CITES category 2,a species at risk in China.The bark of trunk,branch and root of this plant grown more than a decade can be used as medicine.H.officinalis has a long growth and utilization cycle,so that it is difficult to meet the market requirments in practice.Due to the new progress in H.officinalis pharmacology research and the increasement of market requirments,it is extremely necessary to explore new ways to solve the contradiction between the slow growth and increased requirments.In this study,diverse growth parameters and medicinal component of sprouts of different growth time of cultivated H.officinalis was investigated in Chenshan forest farm in Anhua County,Hunan Province.Meanwhile,growth and physiological characteristics of sprouts which stumped in different seasons,stubble height and shading treatments after stumping were compared in Yuantang forest farm in Panan County,Zhejiang Province.Aiming to provide scientific basis and practical guidance for the fast growing and high yield and rejuvenation of H.officinalis.The results were showed as below:1.By investigating on the growth parameters and the content of magnolol and honokiol of stumping sprouts in different growth time,we discovered that: the height,crown breadth,bark thickness and biomass of trunk and root were increased with age.The annual branch length,branch diameter and the numbers of annual branch of three-year sprouts were largest,while the leaf area,dry weight and specific leaf weight of four-year sprouts were largest.The total content of magnolol and honokiol both in trunk and root bark were also increased with growing age,and met the requirements for medicinal use at the fifth year after stumping according to Chinese Pharmacopoeia(2015).2.After stumping in different seasons,diverse indexes of sprouts showed some difference.Results showed that: the height,diameter,crown width,total chlorophyll,carotenoid,soluble protein content of leaves and net photosynthetic rate of sprouts stumped in winter were largest.Meanwhile,the root activity,stomatal conductance and transpiration rate of sprouts stumped in spring were largest.Based on growth and physiological characteristics,sprouts stumped in winter and spring were better than those stumped in summer,suggesting that the optimal time of H.officinalis stumping was in its dormancy period(December to March).3.Based on the dynamic analysis of the growth,photosynthetic parameters and physiological indexes of sprouts in different stubble height were investiaged.The results showed that: the growth and photosynthetic pigment parameters reached to maximum when the stubble height was 25 cm,.and total nitrogen and phosphorus content reached to maximum when the stubble height was 15 cm.However,the total nitrogen,phosphorus and photosynthetic pigment content were lower when the stubble height were 0cm and 35 cm.In summary,in order to make sprouts grow better and to avoid the waste of resources,we suggested that stubble height of 15 to 25 cm as the best height of stumping H.officinalis.4.Based on the dynamic analysis of sprouts treated with shading in different degrees after spring,results showed that: when those sprouts were shaded by slight(20.0%)and moderate(52.5%),growth and leaf parameters(such as the plant height,crown breadth,diameter,sprout numbers and specific leaf weight),physiological indexes(such as the photosynthetic pigment,leaf soluble sugar and protein content,as well as total nitrogen content),root activity and soluble sugar content were higher than those treated with severe shading(78.6%).Therefore,we suggested to choose 20.0% to 52.5% shading when treated stumping sprouts of H.officinalis. |
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