Effects Of Cycling Stripping,Nitrogen And Phosphorus Addition And Their Interaction On Photosynthetic Physiology And Growth Characteristics Of Sapindus Mukorossi

The seeds of Sapindus mukorossi Gaertn.is high economic value.The seed kernel can be used to extract biodiesel and prepare high-grade lubricating oil.The saponins extracted from the peel have various biological activities such as eluting heavy metals,antibacterial and antitumor.However,it is common for the Sapindus to have strong dryness and less fruiting late,and the research on flower and fruit regulation is still in its infancy.Girdling is often used to regulate reproductive growth on fruit trees.Early investigations have found that the phloem of the Sapindus has strong healing ability.After girdling,it can not only change the vigorous growth state of the tree,but also not affect its subsequent growth and development due to poor wound healing.Nitrogen and phosphorus are important elements of plant growth and assimilation.The supply of nitrogen and phosphorus and the distribution pattern of carbohydrates in the plant body both affect the primary productivity of the plant,thereby changing the plant biomass distribution and tree structure,and then adjusting the process of forest reproduction and growth.Based on this,this article takes 2a Sapindus as research object,using a completely randomized block test design,setting nitrogen and phosphorus addition（appropriate amount,F1;excess,F2）,phloem girdling（PG）,girdling+appropriate amount of nitrogen and phosphorus（PGF1）,girdling+excess nitrogen and phosphorus（PGF2）,with no fertilization and no ring stripping as a control（CK）,by measuring the photosynthetic physiology of leaves in early（May）,mid（August）,and late（November）treatments characteristics,distribution of photosynthetic products in the middle（August）,growth status in the late（November）and new quality（quantity,base diameter,length）in April of the following year,to explore the supply of nitrogen and phosphorus,girdling and their interactions on Sapindus.The effects of growth and photosynthetic characteristics provide references for the cultivation of seedless raw material forests and the regulation of tree nutrition.The results of this study are as follows:（1）In the early stage of treatment,compared with CK,the contents of total nitrogen（TN）and total phosphorus（TP）in PG treated leaves were significantly reduced,and the contents of TN and TP in F1 and F2 treated leaves were significantly increased,and the contents of TN and TP in F2 treated leaves were significantly higher than F1.The TN content of PGF1 treated leaves decreased significantly,which was higher than that of PG treatment,and was not significantly different from that of PG treatment.The TN content of PGF2 treated leaves increased significantly（P<0.05）.With the prolongation of treatment time,the TN and TP contents of F1,F2,PGF1 and PGF2 treated leaves were significantly higher than the CK during the same period（P<0.05）;the TN contents of F2,PGF1 and PGF2 treated leaves and the TP content of PGF2 treated leaves in the later period Both were significantly higher than that of CK in the same period（P<0.05）.（2）In the early stage of treatment,compared with CK,PG treatment of chlorophyll a（Chl a）,chlorophyll b（Chl b）,total chlorophyll（Chls）,carotenoids（Cars）,F1,PGF1 treatment Chl b and Cars content were significantly reduced,F1 treatment of Chla,Chls content,Chla/b,Chls/Cars ratio,F2treatment of Chla,Chl b,Chls content,PGF2 treatment of Chl a,Chl b,Chls,Cars content all increased significantly（P<0.05）.With the prolonged treatment time,in the middle of the treatment,the Chl a/b ratio of PG treatment was significantly smaller than that of CK in the same period,and the contents of Chla,Chl b,and Chls in leaves treated with F1,F2,PGF1,and PGF2 were significantly higher than that of CK in the same period（P<0.05）;In the later period,the content of Chla and Chls in leaves treated with F2,PGF1 and PGF2,the content of Cars in PG and PGF1,the ratio of Chls/Cars in PGF2increased significantly,the content of Cars in PGF2 and the ratio of Chls/Cars in PG decreased significantly（P<0.05）.（3）In the early stage of treatment,compared with CK,the maximum photochemical efficiency（F_v/F_m）,actual primary light energy capture efficiency（Y（II））,electron transfer rate（ETR）,and photochemical quenching coefficient（qP）of PSⅡtreated with PG and F2 were significant.Decrease,non-photochemical quenching coefficient（NPQ）,initial fluorescence（F_o）increased significantly,F1treatment qP,Y（II）significantly increased,NPQ significantly decreased,PGF1,PGF2 treatment Fo,qP significantly decreased,NPQ significantly increased,PGF2 treatment Y（II）decreased significantly（P<0.05）;with the treatment time prolonged,mid-treatment,PG treatment qP,F1treatment F_v/F_m,F1,PGF1,PGF2 treatment Y（II）,ETR,qP,PGF2 treatment NPQ,F2 treatment Y（II）,ETR were significantly higher than the same period CK,PGF1 treatment NPQ was significantly less than the same period CK（P<0.05）;later treatment,PGF1 treatment F_v/F_m,F1,PGF1,PGF2treatment NPQ increased significantly,F2,PG,PGF2 treatment qP significantly decreased（P<0.05）.（4）In the early stage of treatment,compared with CK,the net photosynthetic rate（P_n）,transpiration rate（T_r）,stomatal conductance（G_s）,and intercellular carbon dioxide concentration（C_i）decreased significantly,and the stomatal limit value（L_s）Significantly increased,Fn treatment P_n,T_r,G_s significantly increased,F2 treatment Ls significantly increased,PGF2 treatment P_n,T_r significantly decreased（P<0.05）;With the treatment time prolonged,mid-term treatment,compared with the same period of CK,PG treatment significantly increased G_s,F1,PGF1 treatment P_n,T_r,G_s significantly increased,L_s significantly decreased,F2 treatment C_i,P_n significantly decreased,L_ssignificantly increased,PGF2 treatment G_s,P_n significantly decreased（P<0.05）;In the later stage of treatment,L_s,PGF2,P_n and F1 treatments increased significantly,F1,F2,PGF1,and PGF2 treatments T_r,F2,and PGF2 treatments,C_i decreased significantly（P<0.05）.（5）In the early stage of treatment,compared with CK,the maximum net photosynthesis rate(P_nmax),apparent quantum efficiency（AQY）,light compensation point（LCP）,light saturation point（LSP）,and dark respiration rate（R_d）of PG treatment were significant Decreased,Pnmax and AQY were significantly increased in F1 treatment,LSP was significantly decreased in F2 treatment,R_d was significantly increased,R_d was significantly increased in PGF2 treatment,AQY was significantly increased in PGF1 and PGF2 treatment,and LSP and LCP were significantly decreased（P<0.05）;With the extension of the treatment time,in the middle of the treatment,compared with the same period of CK,R_d,PG treatment LSP,LCP,F2,PGF2 treatment Pnmax,LCP significantly decreased,F1,PGF1 treatment Pnmax,LSP significantly increased,LCP significantly decreased（P<0.05）.（6）Compared with CK,the content of leaf soluble protein（TSP）in the early stage of PG treatment was significantly reduced,and that in the early treatment of PGF1 and PGF2 was significantly increased（P<0.05）.Except for PG treatment,the TSP content in the later stages of each treatment was significantly higher than that of CK（P<0.05）.（7）Compared with CK,the content of soluble sugar（SS）and stalk starch（ST）in leaves treated with PG increased significantly,and the content of stalk SS,root SS,ST,and non-structural carbohydrate（NSC）decreased significantly.Leaf SS/TN ratio increased significantly,leaf NSC/TP,ST/TP ratio decreased significantly;F1 treated leaf ST,NSC content,root SS/ST,leaf SS/TN,leaf SS/TP,leaf ST/TN,leaf ST/TP,leaf NSC/TN,leaf NSC/TP ratio decreased significantly,stem SS/ST ratio increased significantly（P<0.05）;F2 treated leaf SS,root ST,NSC content,leaf SS/ST,leaf SS/TN and leaf SS/TP ratios were significantly reduced,and leaf ST,stem ST,stem NSC,root SS content,leaf ST/TN,and leaf ST/TP ratios were significantly increased（P<0.05）;PGF1,PGF2 treated leaf ST,root ST content,leaf SS/TN,leaf SS/TP,leaf ST/TN,leaf ST/TP,leaf NSC/TN,leaf NSC/TP ratio decreased significantly,stem SS,NSC content,leaf SS/ST ratio increased significantly,PGF1 treated leaves NSC content decreased significantly,PGF2 treated stem ST content increased significantly,root SS content decreased significantly in PGF1 treatment,PGF2 treatment significantly increased（P<0.05）.（8）Compared with CK,the root shoot ratio of each treatment was significantly reduced,the root dry weight of PG treatment was significantly reduced,and the crown width was significantly increased（P<0.05）.F1 treatment of leaf,root,stem dry weight,plant height,and ground diameter,crown width,new length and base diameter of the next year were significantly increased（P<0.05）,F2 treated leaves,stem weight,plant height,ground diameter,crown width,the number of new length,length and base diameter of the next year were all Significantly increased,and the plant height was significantly less than F1,the next few years and the crown width were significantly greater than F1（P<0.05）,PGF1,PGF2 treated roots,stems,and leaf dry weight increased significantly（P<0.05）.PGF1 treated roots dry weight,plant height,and new length are the largest in the following year.The stem weight,ground diameter,crown width,new number and base diameter in the PGF2 treatment are the largest.To sum up,the photosynthetic physiological characteristics,photosynthetic product content and growth characteristics of Sapindus mukorossi are all affected by ring stripping,nitrogen and phosphorus addition and their interactions.In the early stage of single ring stripping,the nitrogen and phosphorus elements in the leaves of the diseaseless seeds decreased,the photosynthesis decreased,the nitrogen utilization efficiency of the leaves increased in the middle and late stages,and the starch storage of the stem increased,which was unfavorable for root growth.Excessive nitrogen and phosphorus add a large amount of starch accumulation in the leaves and stems in the middle stage,resulting in weakened photosynthesis,which in turn affects growth and root biomass accumulation.Interaction of cyclic stripping and appropriate amount of nitrogen and phosphorus increase the photosynthetic rate of the leaf through stomatal and non-stomal factors,increase the synthesis of organic matter,promote the growth of the ground and the ground,and the plant height is the highest.Limitation,reduced photosynthetic rate,enhanced photosynthesis in the later period,plant height is significantly less than the appropriate amount of nitrogen and phosphorus added,but the new slightly better quality,that is,many branches,large base diameter,moderate length,crown width and ground diameter are also the largest.Therefore,in the cultivation process of the seedless fruit-picking forest,the trunk state of Sapindus mukorossi can be adjusted through the interaction of trunk ring stripping and nitrogen and phosphorus addition（the amount is slightly more than the appropriate amount）to lay the foundation for early fruit and high yield.