Effects Of Shade And Fertilization On Cold Resistance Of Seedlings Of Phoebe Zhennan

Phoebe zhennan is an evergreen large tree with a height of 30-40 meters.It is a unique precious timber species in China.The trunk is straight and has high economic,ecological and ornamental value.Jianghuai region in the north and south transition zone,low temperature stress is a major limiting factor in the introduction of species Phoebe zhennan,through years of observation,Phoebe zhennan has weak cold resistance during sapling,due to the growth characteristics of Phoebe zhennan,low lignification autumn shoots of winter,The top shoots are seriously damaged in winter,and the extremely low temperature will cause the above-ground parts of the young trees to freeze to death,and it is impossible to smoothly winter in the Jianghuai area.Two kinds of fertilizer treatments in this experiment were designed:1)selection of maturity of the cake of organic fertilizer(N:0.915%,P:0.215%,K:1.923%);2)selec-tion of fertilizer(N:27%,P:15%,K:9%).Each processing set three levels(CK;me-dium;high),Set 20 per plant for medium volume,with a double application rate of 40 grams per plant for high volume and set a set of shading,shading nets shade 45%,5 strains were treated for each,and repeated 3 times.From September 2018 to February 2019,Determination of the physiological and biochemical indexes such as relative conductivity,MDA content,soluble sugar content,soluble protein content,free proline content,SOD activity and CAT activity in leaves were determined by fuzzy subordinate method.comprehensive assessment of cold resistance of each treatment.The results are as follows:(1)In this study,organic fertilizer and compound fertilizer were used.In the process of natural cooling,the two fertilizers had higher cold resistance than CK.Among them,the SOD activity,CAT activity,free proline content and soluble protein content of F1 leaves were the highest.The F2 has the strongest cold resistance,and the average membership degree is 0.489;The growth potential of F1 leaves is moderate,es-pecially in the period from October to November,and the degree of lignification in au-tumn is high.The ability of Y1 and Y2 to resist cold is also strong.The difference in cold resistance between the two is not obvious,and the growth potential is moderate.(2)Under low temperature stress,different fertilizer application had significant effects on the cold resistance of Phoebe zhennan.The high concentration of compound fertilizer is better than the low concentration treatment,and the effect of the two was different.High concentration is better than low concentration.In the process,it is necessary to accu-rately grasp the amount of fertilization,in order to significantly improve the cold re-sistance,otherwise the cold resistance effect is not obvious;The overall cold resistance of organic fertilizer treatment was better than that of the control treatment,and the low effect was better than the high amount.Therefore,a small amount of organic fertilizer should be used to significantly improve the cold resistance of Phoebe zhennan seedlings.(3)Effect of Shading on Cold Resistance on leaves of Phoebe zhennan Seedlings:The light had a great influence on the growth and cold resistance of Phoebe bournei seed-lings.Phoebe zhennan is a shade-tolerant,hi-wet tree species.Under shading treatment,the growth of Phoebe zhennan was significantly increased compared with the control group,and the growth rate of plant height was 64.97%,according to the index measure-ment and comprehensive analysis of cold resistance,shading treatment ranks second in cold resistance.In summary,the results of comprehensive analysis using the comprehensive analy-sis to evaluate the cold resistance of each treatment are as follows:under the low tem-perature stress,the physiological indexes of cold resistance are all changed,all of which show a trend of increasing first and then decreasing,The results of comprehensive utili-zation of physiological and biochemical indicators on the cold resistance of Phoebe zhennan are:CK<F1<Y2<Y1<Z1<F2,where F2 has the highest degree of membership and the strongest cold resistance.