| The objectives of this study were to investigate the effects of fertilization proration on the growth and physiology of cyclocarya paliurus,try to screen out the optimal proration,and provide guidance for the artificial cultivation of cyclocarya paliurus.In this study,L9(34)orthogonal experiment was used to study the effects of NPK fertilization proration on the growth index,physiological index,photosynthesis and leaf structure of la cyclocarya paliurus.The main findings are listed below.(1)The proration of fertilization had significant effects on seedling height,ground diameter and biomass of cyclocarya paliurus.After treatment with fertilization,the seedling heights ranged from 34.41 to 59.51 cm,which were significantly higher than those of the control group except the T1 group.The ground diameter,which ranged from 4.93 to 7.01 mm,was also significantly higher than that of the control group.The total biomass after treatment with high nitrogen fertilization ranged from 50.94 to 94.64 g and was significantly higher than that of the control group.The order of effect of N,P and K fertilization on seedling height and biomass was N>K>P.But as for the effect on growth of ground diameter,N fertilization showed the greatest impact,followed by P and then K fertilization.T7 group(N3P1K3)(N of 1380mg per plant,P of 30mg per plant and K of 450mg per plant)brought about the best results in terms of seedling heights,ground diameter and total biomass accumulation.Upon further analysis,N3P3K3(N of 1380mg per plant,P of 180mg per plant and K of 450mg per plant)and N3P2K3(N of 1380mg per plant,P of 60mg per plant and K of 450mg per plant)might be the optimal proration for seedling heights and ground growth,while N3P1K3(N of 1380mg per plant,P of 30mg per plant and K of 450mg per plant)might be the optimal proration for superterranean,subterranean and total biomass accumulation.(2)Compared to control group,the fertilization treatment group did not show obvious difference in levels of soluble sugar and chlorophyll,but in soluble protein levels in July.However,after fall,fertilization significantly increased the levels of soluble sugar,soluble protein and chlorophyll.Moreover,most of the fertilization groups showed lower levels of propanedione and higher relative electrical conductivity compared to the control group.These results supported the important role of fertilization in adapting to environmental changes.(3)The net photosynthetic rate of all fertilization group increased over time.In summer,no significant difference was observed.However,since fall,the fertilization groups had showed higher stomatal conductance,transpiration rate,net photosynthetic rate and efficiency of water using.Fertilization treatment could prolong the rapid increase phase of net photosynthetic rate in response to photosynthetic effective radiation,augmenting the maximum net photosynthetic rate(Pnmax),which tended to increase with the amount of fertilization within limits.In this study,the Pnmax value was highest in T7 group and started to decline since then.(4)Compared to control group,fertilization treatment significantly increased leaf thickness,while no difference in thickness of upper and lower epidermis was observed.Furthermore,the fertilization groups showed higher main vein thickness,palisade tissue thickness,sponge tissue thickness and higher ratio of palisade to sponge tissue,which demonstrated that fertilization could change the leaf structure.It could be found that T8(N3P2K1)(N of 1380mg per plant,P of 60mg per plant and K of 150mg per plant)performed best.(5)According to the comprehensive evaluation of the membership of the measured indicators,it could be found that T7(N3P1K3)(N of 1380mg per plant,P of 30mg per plant and K of 450mg per plant)performed best. |
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