Effects of Different Light Quality on Growth and Photosynthesis of Tobacco(Nicotiana tabacum L.) Leaves

By covering tobacco plants with white,red,yellow,blue and purple films to obtain different light quality,the effects of light quality on growth and photosynthesis of tobacco leaves were investigated.The results showed that,compared with white film treatment,red and blue film treatments increased leaf thickness,lowered specific leaf area(SLA),raised the ratio of chlorophyll a/b(Chl a/b),net photosynthetic rate(Pn),the ratio(Fv/Fm) of variable fluorescence intensity(Fv) and maximal fluorescence intensity(Fm),the photosynthetic quantum yield of photosystem Ⅱ(ΦPSⅡ),and light and CO2 saturation points in tobacco leaves.On the contrary,yellow film treatment led to thinner leaves and lower Pn,Fv/Fm,ΦPSⅡ,and light and CO2 saturation points in the tobacco leaves.In addition,purple film treatment demonstrated less SLA and higher Pn and than white film did.In general,red,blue and purple light promoted the growth of tobacco leaves,which was related to higher photosynthetic efficiency;and yellow light inhibited the growth of tobacco leaves to some extent.