LAUSR

Adequate management of nitrogen fertilizer application in agriculture can contribute substantially to expanding Eucommia ulmoides Oliv. cultivation in the saline-alkali region of Tianjin. The aim of this study was to explore the changes of chlorophyll and osmotic adjustment substance content in Eucommia ulmoides Oliv. cultivated with different irrigation water salinity and nitrogen concentration. The experiment was carried out under the condition of pot experiment in the greenhouse of Tianjin Agriculture University. The randomized block design with 4×3 factor was adopted for the experiment, with four doses of N (0.3, 0.5, 5.0, 10.0 mmol·L) and three levels of irrigation water salinity (CK,150,300 mmol·L). In this experiment, each treatment was repeated 3 times, with a total of 36 experimental units and 3 plants in each pot. Growth and contents of chlorophyll, carotenoids, soluble sugar and soluble protein were quantified at 60 days after transplantation. With increasing irrigation water salinity, the content of chlorophyll a, chlorophyll b and carotenoids reduced and the content of soluble sugar and soluble protein increased. With the increase of nitrogen concentration, the content of chloroplast pigments first increased and then decreased. Except for the control, soluble sugar and soluble protein content gradually decreased. In a word, increments in N dose attenuate the deleterious effects of irrigation water salinity, and the optimum nitrogen concentration for the growth of Eucommia ulmoides Oliv. seedlings is 5.0 mmol·L.