Nitrogen Uptake and Plant Growth I. Effect of Nitrogen Removal on Growth of Polygonum cuspidatum

Publisher Website
Google Scholar
Abstract
Polygonum cuspidatum was grown hydroponically to examine the effect of nitrogen removal from the nutrient solution upon plant growth and the partitioning of dry matter and nitrogen among organs. Nitrogen removal reduced the growth rate mainly due to the reduced growth of leaf area. Accelerated root growth was observed only in plants which earlier had received high levels of nitrogen. Nitrogen removal caused almost exclusive allocation of available nitrogen to root growth. Nitrogen flux from the shoot to the root occurred in plants which had received low nitrogen. Not only was net assimilation rate (NAR) little affected by nitrogen removal, but it also was not correlated with the concentration of leaf nitrogen on an area basis. Light-saturated CO. exchange rate (CER) was highly correlated with the concentration of leaf nitrogen. Nitrogen use efficiency (NUE) in CER (CER divided by leaf nitrogen) remained constant against leaf nitrogen, indicating efficient use of nitrogen under light saturation, while NUE in terms of NAR decreased with higher concentration of leaf nitrogen.