Morphological and physiological plasticity response to low nitrogen stress in black cottonwood (Populus deltoides Marsh.)

Abstract It is important to evaluate nitrogen use efficiency and tolerance of trees in order improve their productivity. In this study, both were evaluated for 338 Populus deltoides genotypes from six provenances. The plants cultured under normal (750 μM NH 4 NO 3 ) low (5 conditions months. Growth, chlorophyll content glutamine synthetase activity each genotype measured. Under nitrogen, heights, ground diameter, leaf area, root biomass, contents significantly lower than those level. Correlation analysis showed that nutrient distribution changed different treatments. There was a negative correlation between traits biomass level, however, the became positive treatment. Moreover, with decrease morphology levels weakened. growth two treatments by combining principal component fuzzy mathematical membership function; results accounted large proportion variation evaluation model. According comprehensive treatments, P. could be divided into nine categories, wide genotypic diversity tolerance. As result, 26 N-efficient 24 N-inefficient selected. By comparative morphological physiological significant indicators tolerance, which considerable significance breeding poplar varieties high efficiencies.