Influence of ammonium and nitrate supply on growth, dry matter partitioning, N uptake and photosynthetic capacity of Pinus radiata seedlings

摘要: Growth and physiological responses of Pinus radiata D. Don seedlings to a combination N supply regimes (low N = 1.78 mol m−3, high N = 7.14 mol m−3) ammonium:nitrate ratios (80:20, 50:50 20:80; molar basis) were assessed in hydroponic experiment run over the course 105 days. Highly significant (P < 0.001) increases seedling diameter, height, leaf area dry mass occurred at lower two fourfold greater than non-significant (for diameter) marginally (P < 0.05 for other dimensions) these dimensions that with supply. Increases resulted highly reduction biomass partitioning roots allocation foliage. The ratio was not found significantly change either foliage, stems or roots. Ammonium nitrate uptake influenced by form conformed ammonium concentrations nutrient solution. Uptake rates twice those comparable suggesting P. is end reported conifers (range from 2 20 mol mol−1). Despite this, plants growing smaller, exhibited luxurious consumption use efficiency. Differences productivity among treatments partially explained light-saturated photosynthesis associated nutrition.