Effect of slight shading on accumulation and partitioning of carbon assimilation in fruit-bearing limb of greenhouse-grown nectarine

Kong Yun1,2,Wang Shaohui2,Ma Chengwei1,Yao Yuncong2※(1.Key Laboratory of Bioenvironmental Engineering of Ministry of Agriculture,College of Hydraulic and Civil Engineering,China Agricultural University,Beijing 100083,China;2.Department of Plant Science & Technology,Beijing Agricultural College,Beijing 102206,China)

slight shading;greenhouse-grown nectarine;photoassimilation accumulation;carbon assimilation partitioning

Carbon assimilation accumulation and partitioning was studied in one-year-old fruiting limbs of greenhouse-grown "Ruiguang 5" nectarine(Prunus persica L.var.nectarina Ait), affected by about 10%~12% shading treatment(simulating the light intensity decrease due to dust accumulation on greenhouse covering by adding old plastic film to it) during the second rapid swell of peach fruit growth.The results showed that net photosynthesis rate and starch content decreased markedly and total soluble sugar content changed little in leaves of terminal shoot under shading conditions.After labeling terminal shoot by 14CO2,more carbon was found to export from fed shoot to the nearby fruit and less carbon to the distant fruits.Moreover,a reduction of carbon assimilation partitioning in mesocarp was also observed within fruit.Fruits harvested in fruiting limbs by shading treatment were observed to have less fresh weight and transverse diameter and poor red coloration.Therefore,to improve the fruit quality it is necessary to increase the sunlight intensity inside greenhouse as far as possible during the second rapid swell of peach fruit growth.