Comparative Effect of Nitrogen Forms on Nitrogen Uptake and Cotton Growth Under Salinity Stress |
| |
| Authors: | Jianlong Dai Liusheng Duan |
| |
| Institution: | 1. Cotton Research Center, Key Lab for Cotton Culture and Physiology of Shandong Province, Shandong Academy of Agricultural Sciences, Jinan, China;2. State Key Lab of Plant Physiology and Biochemistry, College of Agronomy and Biotechnology, China Agricultural University, Beijing, China;3. State Key Lab of Plant Physiology and Biochemistry, College of Agronomy and Biotechnology, China Agricultural University, Beijing, China |
| |
| Abstract: | The effects of nitrogen (N) forms (ammonium- or nitrate-N) on plant growth under salinity stress 150 mmol sodium chloride (NaCl)] were studied in hydroponically cultured cotton. Net fluxes of sodium (Na+), ammonium (NH4+), and nitrate (NO3?) were also determined using the Non-Invasive Micro-Test Technology. Plant growth was impaired under salinity stress, but nitrate-fed plants were less sensitive to salinity than ammonium-fed plants due mainly to superior root growth by the nitrate-fed plants. The root length, root surface area, root volume, and root viability of seedlings treated with NO3-N were greater than those treated with NH4-N with or without salinity stress. Under salinity stress, the Na+ content of seedlings treated with NO3-N was lower than that in seedlings treated with NH4-N owing to higher root Na+ efflux. A lower net NO3? efflux was observed in roots of nitrate-fed plants relative to the net NH4+ efflux from roots of ammonium-fed plants. This resulted in much more nitrogen accumulation in different tissues, especially in leaves, thereby enhancing photosynthesis in nitrate-fed plants under salinity stress. Nitrate-N is superior to ammonium-N based on nitrogen uptake and cotton growth under salinity stress. |
| |
| Keywords: | cotton nitrogen forms nitrogen uptake salinity |
|
|
