Effect of Complex Saline-alkali Stress on Nitrogen and Phosphorus Absorption and Physiological Traits of Alfalfa Seedlings
Received date: 2014-11-04
Revised date: 2014-12-28
Online published: 2015-09-20
The effect of complex saline-alkali stress on nitrogen and phosphorus absorption and physiological characteristics of alfalfa seedlings were studied with Alfalfa (Medicago sativa, Gannong No.3). Seedlings were stressed with different concentrations of neural salts (NaCl and Na2SO4) and alkaline salts (NaHCO3 and Na2CO3), altogether 5 combinations: A(NaCl:Na2SO4=1:1), B(NaCl:NaHCO3=1:1), C(NaCl:Na2SO4:NaHCO3:Na2CO3=1:1:1:1), D(Na2SO4:Na2CO3=1:1)、E(NaHCO3:Na2CO3=1:1), and 4 concentrations (25, 50, 100 and 150 mmol·L-1) in a sand culture experiment. Results show that with the increase of salt concentration, nodule nitrogenase activity and the content of total nitrogen has dropped, and the content of total phosphorus has no obvious change, while proline (Pro), malondialdehyde (MDA), soluble sugar and superoxide dismutase (SOD) content increased. At the same level of the salt concentration, the content between the groups of higher order: E>D>C>B>A.The change ranges of tested indices have reached significant level under the high salt concentration(150 mmol·-1), in addition to the total phosphorus content.The results suggested that the structure components of alfalfa was damaged under the hybrid salinity-alkalinity stress,reduced nitrogen fixation ability and decreased nitrogen content. Along with the rising of salt concentrations, plant can improve the content of proline and soluble sugar in the body to maintain cell water potential, reduce the injury to the plant cell osmotic stress.
Hao Feng , Liu Xiaojing , Zhang Xiaolei , Qi Minxing . Effect of Complex Saline-alkali Stress on Nitrogen and Phosphorus Absorption and Physiological Traits of Alfalfa Seedlings[J]. Journal of Desert Research, 2015 , 35(5) : 1268 -1274 . DOI: 10.7522/j.issn.1000-694X.2014.00179
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