Effect Of Forest Gap Size On Litter And Soil Phenolic Acid In Broad Leaf-Pinus Koraiensis Mixed Forest

In order to reveal law of of gap size on the release of phenolic compounds during the decomposition of litter and the mechanism of interaction with phenolic compounds in the surface soil,In this study,the samples were collected in large,medium,small gaps and Canopy foerest(as control)in the mixed forest of broad-leaved Korean pine in the Xiaoxing'an moutain Liangshui National Nature Reserve in June 2015 and then refrigerated.The samples were undivided(L),semi-decomposed(F),humic(H)and 0 ~ 10 cm soil.NaOH as a leaching solution,then through shock,centrifugal,adjust the pH,standing and recentrifugation process to be measured liquid.The content of six kinds of phenolic compounds in gallic acid,p-hydroxybenzoic acid,syringic acid,vanillin,p-coumaric acid and cinnamic acid were determined by HPLC.Research indicates:(1)the presence of 6 kinds of phenolic acids had been detected in all of the four sampling layers of large,moderate and small forest gap.The contents of 6 kinds of phenolic acids varied with the time of sampling,and the variation rules of 6 phenolic acids in the four sampling layers of large,moderate and small forest gaps(layer L,F,H and soil layer)were all 0-123 d increase;123-397 d decrease;397-458 d increase and 458-519 d decrease;all of the lowest content appeared in the sampling days with a low temperature(0d,397d),the highest content appeared in the sampling days with a high temperature(123d,458d).(2)Among 4 sampling layers,the large,moderate and small forest gap had different influence on the content of 6 phenolic acids,on the layer L,the content of gallic acid and phydroxybenzoic acid was less regular in different sampling days,but their maximal contents all appeared in the large forest gaps;syringic acid,vanillic aldehyde,p-coumaric acid,cinnamic acid all presented the same law in most of the sampling days,namely,small forest gap>moderate forest gap>large forest gap.On the layer F,gallic acid presented a law which was large forest gap>moderate forest gap>small forest gap in most of the sampling days;phydroxybenzoic acid were less regular in different sampling days,but their maximal content appeared in the small forest gap in most of sampling days;the law of content of syringic acid was that small forest gap>large forest gap>moderate forest gap;the law of content of vanillic aldehyde,p-coumaric acid and cinnamic acid was that,small forest gap>moderate forest gap>large forest gap.On the layer H,the content of gallic acid presented a variation rule that was large forest gap>moderate forest gap>small forest gap;the maximal content of,phydroxybenzoic acid and appeared in small forest gap in most of sampling days;The rule of variation of content of syringic acid was that,small forest gap>large forest gap>moderate forest gap;the rule of variation of content of vanillic aldehyde,p-coumaric acid and cinnamic acid was that,small forest gap >moderate forest gap>large forest gap.On the soil layer,the maximal content of gallic acid appeared in the moderate forest gap in most of sampling days;the maximal content of appeared in the small forest gap in most of sampling days;the rule of variation of content of p-hydroxybenzoic acid and syringic acid was that,moderate forest gap>small forest gap > large forest gap;the rule of variation of content of vanillic aldehyde,pcoumaric acid and cinnamic acid was that,small forest gap >moderate forest gap>large forest gap.(3)The content of 6 phenolic acids on 4 sampling layers differed with different forest gaps.With the large forest gap,the gallic acid and syringic acid in most of the sampling days presented a rule of variation that layer L>F>H>soil layer;the didn't present a specific rule;phydroxybenzoic acid and p-coumaric acid presented a rule of variation that layer L>H>F>soil layer in the month of a relatively high temperature;vanillic aldehyde presented a rule of variation that layer F>H>L>soil layer;the cinnamic acid presented a rule of variation that Layer H>F>L>soil layer.In moderate forest gap,The gallic acid in most of the sampling days presented a rule of variation that layer L>F>H>soil layer;the didn't present a specific same rule;p-hydroxybenzoic acid and syringic acid presented a rule of variation that layer L>H>F>soil layer;vanillic aldehyde presented a rule of variation that layer F>H>L>soil layer;p-coumaric acid presented a rule of variation that layer H>F>soil layer>layer L;the cinnamic acid presented a rule of variation that Layer H>F>L>soil layer.In small forest gap,The gallic acid in most of the sampling days presented a rule of variation that layer L>F>H>soil layer;The and syringic acid had no specific rule of variation,but the maximal content of syringic acid in most of sampling days appeared on the layer L;p-hydroxybenzoic acid presented a rule of variation that layer L>H>F>soil layer;the vanillic aldehyde presented a rule of variation that layer F>H>L>soil layer;p-coumaric acid presented a rule of variation that layer H>soil layer>layerF>layer L;the cinnamic acid presented a rule of variation that Layer H>F>L>soil layer.