Bosen Weng, Xiangyu Xie, Jinjin Yang, Jingchun Liu, Haoliang Lu, Chongling Yan.Marine Pollution Bulletin.76 (2013) 227-240

The present study investigated nitrogen process in rhizosphere of Kandelia obovata under nitrogen input.Results showed that nitrogen additions significantly increased 4 kinds of enzyme activities (Urease, Nitrate reductase, Nitrite reductase and hydroxylamine reductase). The pH value increased to 7.1 underammonium addition, but decreased to 6.9 under nitrate addition. Potential Nitrification Intensity (PNI) increased 200–1500% compared with control under ammonium addition, and Potential Denitrification Intensity (PDI) increased more than 200% under nitrate addition. Ten types of organic acids were detectedfrom root exudates, which mainly included oxalic acid, tartaric acid, formic acid, acetic acid, and citricacid. The abundance of 5 kinds of microbial functional groups (nifH, AOA, AOB, nirS, nirK) responded differently. Total nitrogen in organs of K. obovata increased more than 200%. This indicated that nitrogenadditions accelerated the transformation of nitrogen directly and stimulated the exudation of root exudates and 5 kinds of genes indirectly.