| Four-year-old plantation of Machiluspauhoi(B),mixed plantation of M.pauhoi and Cunninghamialanceolata(BS)and mixed forest of M.pauhoi and Phoebe bournei(BM)were used,set four different fertilization treatments: Controlled(CK),nitrogen(+N),phosphorus(+P)and nitrogen(+NP).After 1 year of fertilization,investigate and determine the growth of the wood and the main phenotypes,physiological and nutrient traits of the leaves and the soil traits of the M.pauhoi and its mixed tree species in the experimental site.The effects of fertilization treatment and mixed mode on the growth and main leaf traits of M.pauhoi and its mixed tree species were analyzed.The main results are as follows:(1)The 1 year fertilization treatment and mixed mode have an effect on the plant height,ground diameter and relative growth rate of the wood of M.pauhoi and its mixed species,but the difference is not significant.The relative growth rate were highest in the mixed pattern of M.pauhoi and C.lanceolata,lowest in the mixed forest of M.pauhoi and P.bournei;The relative growth rate of mixed tree species,C.lanceolata,was the highest in CK treatment,and the lowest in P application,P.bournei were highest when applying P,and the lowest in CK.The annual growth rate of M.pauhoi in the mixed mode of M.pauhoi and C.lanceolata was the highest,and the annual growth rate was the lowest in the mixed mode of M.pauhoi and P.bournei;.It shows that the mixed pattern of M.pauhoi and C.lanceolata is more suitable for the growth of M.pauhoi(2)The one-year fertilization treatment and mixed mode had no significant effect on the Specific Leaf Area(SLA),Leaf Dry Matter Content(LDMC),Leaf Relative Water Content(LRWC)and Leaf Tissue Density(LTD)of M.pauhoi and its mixed tree species.But the difference is significant between different seasons.The SLA of M.pauhoi is largest in the mixed mode of BM treated with CK,and the minimum of B treated with CK.The LDMC of M.pauhoiis largest in the mixed mode of BS treated with P,and the minimum of BS treated with CK.The LRWC of M.pauhoiis largest in the mixed mode of BS treated with P,and the minimum of BS treated with NP.The LTD of M.pauhoiis largest in the mixed mode of BS treated with CK,and the minimum of BS treated with N.The SLA of C.lanceolata in mixed tree species is CK > +N > +P > +NP,LDMC is +N > +P > +NP > CK,LRWC is +NP > +N > +P > CK,LTD is CK > +P > +NP > +N.The SLA of P.bournei is +NP > +N > +P > CK,LDMC is CK > +N > +NP > +P,LRWC is +NP > +N > +P > CK,LTD is CK > +N > + NP > +P.The LDMC SLA,LDMC,LRWC,and LTD were significantly different in different seasons.The M.pauhoiand its two mixed tree species showed: SLA was highest in June and September,lowest in December and March;LDMC and LTD were in March > December > June > September.The phenotypic traits of M.pauhoi leaves did not change significantly after nitrogen and phosphorus fertilization.It may be that the fertilization time just 1 year,which is not enough to cause changes.(3)The 1 year fertilization treatment and mixed mode had no significant effect on the soluble sugar,starch and non-structural carbohydrate(NSC)content and net photosynthetic rate(Pn)of M.pauhoi and its mixed tree species,but the difference was significant between different seasons.The soluble sugar of M.pauhoiwas the largest when the application of NP in the BS,and the minimum of B treated with CK.The pure forest model of starch CK treated with CK was the largest,and the mixed mode of BM treated with CK treatment was the smallest.The NSC is the largest when using N at the pure forest mode,and smallest when applying N.The Pn was the largest at BS when applying P,and the CKof B was the smallest.The soluble sugar of C.lanceolata was +P > +N > +NP > CK,starch was +P > CK > +N > +NP,NSC was +P > CK > +N > +NP,Pn was +NP > +P > +N > CK;The soluble sugar of P.bournei is +NP > CK > +N > +P,starch is +N > +NP > +P > CK,NSC is +N > +NP > CK > +P,Pn is +P > +NP > +N > CK.The soluble sugar,starch and NSC content of the three tree species were highest in March and lowest in June,This may be due to the low winter rainfall in Fujian and the high summer rainfall.Drought will affect the secondary metabolic process of plant synthetic structural substances.At the same time,high soluble sugar content can increase the osmotic pressure of plant tissue cells and prevent it from freezing in winter.So safely through the winter.The rhythm of net photosynthetic rate in the season was June(summer)>3 month(spring)> 9 month(autumn)> December(winter),June is the plant growth season,the plant photosynthesis is the strongest,so that more carbohydrates are produced to supply plants to grow rapidly.In December,the plants enter dormancy and stop growing,so the net photosynthetic rate is reduced.(4)The 1 year fertilization treatment and mixed mode had significant effect on the N,P content and C/N,but C content and N/P,of the leaves of M.pauhoiand its mixed tree species.There were significant differences in C,N,P and N/P contents between leaves in different seasons,but the C/N difference was not obvioued.The C content of M.pauhoiwas the largest at BM when the P was applied,and CK treated of B was the smallest.The N content was the largest when using NP at BM,and the BM with P was the smallest.The P content of M.pauhoiwas the largest at BS with CK.C/N is the largest when the P is applied at BM,and the BM with NP is the smallest.The C content of C.lanceolata is +N > +NP > +P > CK,N content is +N > +NP > +P > CK,C/N is CK > +P > +NP > +N;The C content of P.bournei is CK > +N > +P > +NP,N content is +NP > +N > +P > CK,C/N is CK > +P > +N > +NP.The content of leaf C in the three tree species was highest in the month and lowest in March.The N content was the highest in the month and the lowest in September.The C/N was the highest in the month and the lowest in the September.The content of C in the leaves of M.pauhoi did not significantly respond to fertilization,indicating that the C content of the leaves was relatively stable.(5)The relationship between the main soil traits and the leaf traits of M.pauhoiis: There is a significant positive correlation between soil moisture content and starch,NSC,C,N.Soil TC and TN were significantly positively correlated with leaf N content and significantly negatively correlated with leaf C:N.Soil pH was positively correlated with leaf LRWC and negatively correlated with leaf dark respiration rate.The relationship between the soil traits and the leaf traits of the C.lanceolata is: soil moisture content is negatively correlated with ground diameter and positively correlated with leaf net photosynthetic rate.Soil pH is negatively correlated with leaf dark respiration rate.The relationship between the soil traits and the leaf traits of P.bournei is: the soil pH is negatively correlated with the volume. |
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