Research On The Returning Planting Conditions Of Horsfieldia Hainanensis Merr.

Horsfieldia hainanensis Merr is a national level II key protected wild plant.In order to protect and utilize the natural resources of H.hainanensis Merr,this study takes H.hainanensis Merr as the research object and adopts different shading treatments(through shading nets.Treatment:100.00%,44.41%,16.19%,7.30%light transmittance),different light intensity(below 20%,30%-50%,60%-80%,more than 80%)and seedling age(1 and3-year-old)and regression planting experiments at different altitudes(300m,600m,900m)to observe the growth indicators,leaf indicators,photosynthetic pigments,and soil physical and chemical properties of H.hainanensis Merr,and explore the appropriate light intensity and return planting of H.hainanensis Merr.In order to reveal the optimal growth light intensity and return to the planting environment of the three-year-old H.hainanensis Merr,it has important guiding and practical significance to promote the sustainable development of forestry,and realizes the effective protection and rescue of H.hainanensis Merr.So as to promote the"return to work"mode of rare and endangered plants throughout the country.The results of the study are as follows:(1)Shading helps to increase the leaf area,leaf length,leaf water content,total chlorophyll and chlorophyll a content of the 3-year-old H.hainanensis Merr.,but is not conducive to the increase of specific leaf weight;high shading(three-layer shading)The shade net,7.30%light transmittance)helps to increase the SPAD value of H.hainanensis Merr..Treatment group 2(two-layer shading net,16.19%light transmittance)can significantly increase the Chl-SPAD value of each part;treatment group 1(One layer of shading net,44.41%light transmittance)can significantly increase the plant height,ground diameter,leaf number,fragility index and volume index of the 3-year-old H.hainanensis Merr.;Treatment group 1(one layer of shading net,44.41)%Light intensity)can increase the Pn and Tr-PAR curve values of the 3-year-old H.hainanensis Merr.,but has little effect on the gsw and Ls-PAR curves.Shading can significantly reduce the LCP and Rd of the 3-year-old H.hainanensis Merr..AQY and Pnmax have no effect on LSP and R~2;photosynthetic pigments have a relatively large impact on AQY,LCP and Rd in photosynthetic indicators.At the same time,the internal indicators of light sum index and photosynthetic color number index also affect each other,and photosynthetic pigment and light sum index(Except Pnmax and LSP)all significantly affect the morphology and traits of leaves.(2)Return planting with different light intensities has no significant effect on the 1-year-old H.hainanensis Merr.,low light intensity(below 20%)is not conducive to the growth of 3-year-old H.hainanensis Merr.,significantly reducing leaf length and leaf width.Neither the current 1-year-old and the 3-year-old H.hainanensis Merr.has a significant effect on the number of leaves;lower(below 20%)light intensity return to planting can significantly increase the SPAD value of the 1-year-old and 3-year-old H.hainanensis Merr.leaves,but it has an effect on the photosynthetic pigment.The content change and the SPAD value of different positions of the leaves have no significant effect;AP,TK,and Wg are the main factors that affect the growth of the phoebe phoebe seedlings in the year,and the p H and AP are the main factors that affect the growth of the three-year-old phoebe phoebe.The indicators,leaf morphology,and photosynthetic color number indicators have relatively large internal correlations.(3)The 600 m treatment group can significantly increase the plant height and fragility index of H.hainanensis Merr.;the treatment group 600 m can significantly increase the leaf length,width,water content and specific leaf area of H.hainanensis Merr.,and significantly reduce the specific leaf area.Weight;600 m treatment group can significantly increase the content of chlorophyll b and reduce chlorophyll a/b of H.hainanensis Merr.,and treatment group of 300 m can significantly increase the SPAD value of leaf base and mean value of H.hainanensis Merr.leaves;soil factors and H.hainanensis Merr.The correlation of height to diameter ratio is higher,and the correlation to the plant height of H.hainanensis Merr.is weaker.(4)The plant height,ground diameter,and leaf number of H.hainanensis Merr.were gradually analyzed by environmental factors.The results showed that altitude,available phosphorus,and temperature had a significant negative impact on plant height.Light intensity and available potassium would have a significant negative impact on plant height.It has a significant negative impact on the ground diameter,and the total potassium content has a significant positive impact on the number of leaves.In summary,it can be seen that seedling cultivation and shading can help increase the growth and development and photosynthetic rate of the 3-year-old H.hainanensis Merr..The return of light intensity above 30%has a greater impact on the 3-year-old H.hainanensis Merr.,and the return of the H.hainanensis Merr.at an altitude of 600 m The planted growth,leaves and photosynthetic pigments showed the best values.Through the comprehensive evaluation of stepwise regression,it can be known that light intensity,altitude,temperature,available potassium,available phosphorus,and total potassium will have an impact on the return planting of H.hainanensis Merr..