Physiological Responses of Pinus yunnanensis var.Seedlings to Different Light Intensities

HUANG Zeyue; ZENG Qingjian; ZHAO Yihui; BEN Yuan; YANG Mei

doi:10.15933/j.cnki.1004-3268.2017.06.020

Abstract：To study the effects of light intensity on the physiological feature of Pinus yunnanensis var.seedlings,1-month-old and 1-year-old seedlings were planted under different light conditions(100%,50.3%,15.0%,4.2% natue sunsine).And their physiological indexes were tested such as the contents of chlorophyll,soluble protein,and antioxidant enzyme activities of SOD and so on.The results showed that with the gradual decrease of light intensity,the chlorophyll-a,chlorophyll-b and total chlorophyll contents of 1-month-old seedlings increased initially and then decreased.The content of soluble protein reached the maximum at 50.3% natue sunsine(NS).The SOD activity,CAT activity,APX activity and MDA content increased with the decrease of light intensity,and reached the maximum at 15.0%NS.The chlorophyll-a,chlorophyll-b and total chlorophyll contents of 1-year-old seedlings gradually increased with the decrease of light intensity,while the soluble protein content decreased gradually.The SOD activity increased firstly and then decreased,which was the highest under the treatment of 15.0%NS.The CAT activity,APX activity and MDA content increased with the decrease of light intensity,and the maximum values were presented at 15.0%NS.The POD activity of the both seedlings was the highest at 50.3%NS.In conclusion,50.3%NS was beneficial to the increase of physiological metabolic activity of Pinus yunnanensis var.seedlings.At this time,the contents of chlorophyll and soluble protein were higher in 1-month-old and 1-year-old seedlings,and the content of MDA,antioxidant enzyme activities of SOD,CAT and so on remained low.Therefore,moderate shade is needed for Pinus yunnanensis var.at juvenility period.