Interaction Effects Of Different Light Quality And Nitrogen Levels On Growth And Photosynthetic Physiological Characteristics Of Flue-cured Tobacco Seedlings In The Floating System

Interaction effects of different light quality and nitrogen on growth, photosynthetic physiological characteristics, and the mesophyll cell ultrastructure of tobacco seedlings were studied in the national tobacco cultivation key laboratory of Henan Agricultural University in 2014, with the seeds of Yuyan 12. The results were as follows: 1 Interaction effects of different light quality and nitrogen on growth of tobacco seedlingsRed and blue lights could promote germination and emergence of tobacco seeds. Stem height, stem diameter, leaf length, leaf width, leaf areas, dry weight and fresh weight gradually increased with the improving of the level of nitrogen, the tobacco stems were slender and the leaves were longest in the treatment of blue light, the leaf widths of blue treatments were lower than those of white and red treatments, which made leaves long and narrow, and increased the ratio of length to width. The leaf areas of blue treatments were biggest and the leaf areas of white treatments were smallest in the same level of nitrogen when it was 30 d and 45 d, which was opposite when it was 60 d. Dry and fresh weights of the white and blue treatments were respectively highest and lowest in the same nitrogen level. 2 Interaction effects of different light quality and nitrogen on the soluble sugars and proteins of tobacco seedling leavesThe contents of soluble proteins and sugars respectively increased significantly and increased firstly then decreased as the level of nitrogen increased. The soluble protein contents of red treatments were lowest, and the contents of white and blue treatments had no obvious differences. The soluble sugar contents from high to low were respectively red, white, blue treatments. 3 Interaction effects of different light quality and nitrogen on photosynthetic pigment contents of tobacco seedling leavesNitrogen levels and photosynthetic pigment contents had certain correlation, the contents of chlorophyll a, chlorophyll b and carotenoids of red treatments were all highest, those of blue treatments were all lowest. And red light and high level nitrogen were conductive to the synthesis and accumulation of photosynthetic pigments of leaves. 4 Interaction effects of different light quality and nitrogen on the mesophyll cell ultrastructure of tobacco seedling leavesThe photosynthetic rate of leaves under 3 light treatments all increased with the increased application of N from 0g / plant ~ 0.059 g / plant, which showed that the promotion of nitrogen level made for the photosynthesis of tobacco leaves. Hormone levels in N 0g / plant within the range 0.059 g / plant, the increasing of nitrogen level was conductive to the synthesis and accumulation of starch grains and Osmiophilic matter content increased body mass and volume increases, besides, red and white lights were conductive to the accumulation of starch grains and the synthesis of carbohydrates, and the blue light was not. White light and high level nitrogen made the thylakoid lamella keep best, which was more conductive to photosynthesis, and red and high level nitrogen made for the synthesis and accumulation of osmium substances.