Effects of LED Light Quality on Growth,Photosynthetic Pigments and Nutritional Quality of Pea Seedlings

In order to elucidate the effect of light quality on growth,contents of photosynthetic pigments and nutritional quality,a substrate-pot cultivation experiment was conducted in a glasshouse to investigate the effects of light quality on plants growth,the content of photosynthetic pigments and nutritional substances in pea seedlings.The treatments of light quality were white light,red light(620nm),blue light(460nm) and red plus blue light(620nm+460nm) by light-emitting diodes(LEDs).The contents of photosynthetic pigments and nutritional substances were measured.The results showed that the treatments of blue light and red plus blue light increased significantly the shoot biomass of pea seedlings compared with the white light treatment(P0.05),while the red light did not show any effect on the pea shoot biomass.The four spectral quality treatments presented similar root and total biomass of pea seedlings.Compared with white light,red plus blue light improved chlorophyll a and b contents in leaves(P0.05).Among the four treatments,red light showed the lowest content of chlorophyll a,while blue light in the same way showed the lowest content of chlorophyll b.There were no difference between red and blue light treatments in carotenoid content for pea seedling shoot,and they were inferior to carotenoid content of white and red plus blue treatments(P0.05).It was also observed that red plus blue light treatment improved the content of vitamin C in pea seedling shoot compared with white light treatment(P0.05),while red light and blue light did not show any effect.The four treatments of light quality did not have any effect on nitrate and flavonoid contents in pea seedling shoot.The concentration of anthocyanin substances of pea seedling shoot treated with white light was the highest among the four treatments,and that decreased in the follow order of red light,red plus blue light and blue light.In conclusion,the blue and red plus blue light promoted shoot biomass and contents of chlorophyll a and b,and red plus blue light increased shoot vitamin C content.Additionally,white and red plus blue light improved carotenoid content,and white light treatment presented the highest anthocyanin content.Therefore,selecting suitable light quality could increase yield and nutritional quality of pea seedlings.To summarize,blue light and red plus blue light could improve yield of pea seedlings,while white light and red plus blue light could promote nutritional quality of pea seedlings.