Effects Of Shading And Fertilization On Growth And Physiology On Seedlings Of Phoebe Zhennan

Phoebe zhennan is a precious timber speeies of PhoebeNees,Lauraceae.Their seedling stage growth rate is slow and site conditions are strict,especially prefer shade and wet environment.In order to achieve fast-growing and high-yielding of it,this research lets 1-year seedlings of Phoebe zhennan as test materials in ShuCheng County of Ta-pieh mountain area,Anhui,and using two-factor split plot design to research effects of shading and fertilization on growth,Photosynthesis,physiological and nutrient demand.Making comprehensive analysis of indicators and revealed the mutual coordination mechanism of growth regularity,photosynthetic,physiological characteristics and supply and demand on nutrient during seedling stage,Screening out the shading-fertilization combination that effectively promoted seedling growth of Phoebe zhennan to provide theoretical basis on well-growing and fast-growing cultivation management of Phoebe zhennan seedlings.The main research results are as follows:1)The seedlings of Phoebe zhennan grew rapidly from July to September,and the lowest growth is from October to November;Compared with full illumination(100%NS),height,ground diameter,dry weight of each part and total biomass were significantly increased under 45.5%NS shading,and were lower than that under 14.7%NS.Under the same shading,each growth index rose first and then fall with the increasing of the amount of fertilization,while the root shoot ratio ruducing.20 g/plant fertilization in 45.5%NS was the most favorable for the growth of seedlings of Phoebe zhennan and 40 g/plant fertilization in 14.7%NS inhibited the gro,th of seedlings.2)The chlorophyll content in the leaves of Phoebe zhennan was significantly increased after shading,Chi a/b was fall.Photosynthetic was the highest at 45.5%NS and the lowest at 14.7%NS.Under the same shading,chlorophyll,Pn,Gs and Tr increased first and then decreased with the increasing of fertilization amount.In early October,under full illumination condition,Pn showed a "double-peak,pattern one day,shading alleviated or even eliminated this phenomenon.The changes of Gs,Tr and were similar to Pn while the changes of Ci were contrary to them.Under the interaction of shading and fertilization,the photosynthetic and physiological indexes of A2B1(45.5%NS,20 g/plant compound fertilizer)were the best,the chlorophyll of CK was the lowest,and the photosynthetic ability of A3B2(14.7%NS,40 g/plant compound fertilizer)was the worst.3)From July to November,C in the leaves of Phoebe zhennan showed an increasing-decreasing-increasing change,N in the leaves fluctuated around 2%,P and K falled,N>K>P.Soluble sugar and soluble protein increased in the final stage compared with the middle stage.With the increasing of shading,the content of soluble sugar and total C in leaves kept decreasing,soluble protein,N,P and K in leaves first rose and then fell.At the same shading level,with the increasing of fertilization application,soluble sugar and soluble protein both rose first and then decreased,while total N increased while total C decreased.P and K increased after fertilization,but the difference was not significant.4)Shading,fertilization and their interaction have significant effects on most indexes,shading is usually the dominant factor.There were significant correlations among growth,photosynthesis,physiology and nutrient index.In the evaluation of seedling quality index and membership function evaluation,A2B1(45.5%NS,20 g/plant compound fertilizer)had the highest score,indicating that this combination was most conducive to the growth and development of seedlings,A3B2(14.7%NS,40 g/plant compound fertilizer)had the lowest score,indicating that excessive shading and excessive fertilization were adverse to the growth of seedlings.