Spatial And Temporal Differences Of Photosynthetic Characteristics Of Pinus Koraiensis With Different Fruiting Status

The chlorophyll content,specific leaf area,photosynthetic response curves and non-structure carbohydrate of Pinus koraiensis with different fruiting status in different canopy were observed continuously in every month.The temporal and spatial variation of them were analyzed,and then we compared the differenee between the different fruiting status of Pinus koraiensis.The main conclusions are as follows:There were the same seasonal trend between the Pinus koraiensis with different fruiting status in chlorophyll content,specific leaf area and photosynthetic response parameters.The chlorophyll a(Chla),chlorophyll b(Chib)and total chlorophyll(ChlT)were reduced in every month,but specific leaf area(SLA)were increased.The ratio of chlorophyll a to chlorophyll b(Chla/b)was reduced first and then increased.The maximum net photosynthetic rate(Pmax)and light saturation point(LSP)of needles were decreased gradually,while apparent quantum yield(AQY)increased.We compared with Pinus koraiensis with different fruiting status,Chla,Chib and ChlT of fruiting individual were lower than fruitless individual in each month,but the Chla/b of fruiting individual was higher and ti9s SLA is higher except July.The photosynthetic capacity of Pinus koraiensis needles with different fniiting status had similar spatial variations.The Chla,Chib,ChlT,SLA and AQY of needles that in the forest edge or upper canopy with strong light were lower,but they had higher Chla/b,Pmax and LSP.On the other hand the needles in poor light had higher Chla,Chib,ChlT,SLA,AQY and lower Chla/b,Pmax 5LSP.The comparison with Pinus koraiensis with different fruiting status,fruitless individual had higher Chla,Chib,ChlT and AQY then fruiting individual in each canopy.But the fruiting individual had higher Chla,Pmax Rd and LSP.The changes of season,canopy and habitat had a certain impact on soluble sugar,starch and non-structural carbohydrate(NSC)concentration of needles,branches and stems of Pinus koraiensis with different fruiting status.The seasonal variation of soluble sugar,starch and NSC were significant.At the beginning of growing season,NSC concentration in all organs of Pinus koraiensis declined obviously and then remained stable.On the vertical gradient,the middle canopy of fruiting individual had the highest concentration of NSC,the upper canopy had the highest concentration,and the lower canopy had the lowest concentration.Moreover,concentration of NSC in fruiting individual increased with the rise of canopy.Compared with Pinus koraiensis in forest and edge,there was a higher concentration of starch in each canopy of Pinus koraiensis in forest,and a higher concentration of soluble sugar in each canopy of Pinus koraiensis in forest edge.In conclusion,as the time goes on,the photosynthetic capacity of 1-year-old needles of Pinus koraiensis with different fruiting status was gradually receded,and the needles under better light conditions for a long time had stronger photosynthetic capacity than those under poor light conditions.The growth mainly depended on the NSC that accumulated in the previous year at the beginning of growing season.The light condition affected the concentration of NSC in different spaces.It was higher in the parts with better light conditions.And because of the difference of photosynthetic capacity of needles between Pinus koraiensis with different fruiting status,the fiuiting individual can accumulate more NSC for growth and fruit next year.