Growth of Liriodendron Tulipifera Seedlings with Different Levels of Nitrogen Supply

Liriodendron tulipifera seedlings were grown for 8 weeks in aerated nutrient solutions with five levels of nitrate nitrogen ranging from 13 to 210 ppm N. Classical growth analysis indicated that nitrogen affected rate of dry matter production per unit of leaf area (ULR), with maximumvalues in the 105 ppm N treatment. Ratio of leaf area to plant weight, and leaf initiation were little affected by nitrogen levels. ULR increased with age, while the ratio of leaf area increment to leaf weight increment, and percentage of growth devoted to leaves decreased. Nitrogen supplyaffected the relative distribution of growth within plants so that shoot:root ratios increased with increasing nitrogen supply. Farest Sci. 17:287-292.