Premium
Nitrogen metabolism is related to improved water‐use efficiency of nodulated alfalfa grown with sewage sludge under drought
Author(s) -
Laura Fiasconaro M.,
SánchezDíaz Manuel,
Carmen Antolín M.
Publication year - 2013
Publication title -
journal of plant nutrition and soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.644
H-Index - 87
eISSN - 1522-2624
pISSN - 1436-8730
DOI - 10.1002/jpln.201100393
Subject(s) - rhizobia , agronomy , nitrate reductase , nitrogen fixation , sewage sludge , nitrate , photosynthesis , phosphoenolpyruvate carboxylase , nitrogen cycle , ammonium , sewage , biology , chemistry , nitrogen , environmental science , botany , environmental engineering , ecology , organic chemistry
Leguminous plants grown in sewage sludge–amended soils can acquire nitrogen by assimilation of nitrate and ammonium from the soil solution or from atmospheric‐dinitrogen (N 2 ) fixation through association with N 2 ‐fixing bacteria. We proposed that operation of both metabolic processes could contribute to alleviate the impact of drought in sludge‐treated plants. A greenhouse experiment was conducted to evaluate the involvement of nodule metabolism in the use efficiency of water and N in sludge‐treated plants. Treatments comprised (1) plants inoculated with rhizobia and amended with sewage sludge; (2) plants inoculated with rhizobia without any amendment; and (3) noninoculated plants supplied with ammonium nitrate, each under well‐watered and drought conditions. Under drought, sludge‐treated plants had increased plant growth and higher photosynthetic and water‐use efficiencies than untreated plants. Drought stimulated nitrate reductase and GS/GOGAT activities but did not affect the activities of phosphoenolpyruvate carboxylase and malate dehydrogenase or the leghemoglobin concentration. The results suggest that under drought conditions, both N 2 fixation and nitrate assimilation in nodules of sludge‐treated plants contributed to improve plant N supply and to increase the drought tolerance of alfalfa.