Eco-physiological characteristics of alfalfa seedlings in response to various mixed salt-alkaline stresses.
Soil salinization and alkalization frequently co-occur in nature, but little is known about the mixed effects of salt-alkaline stresses on plants. An experiment with mixed salts (NaCl, Na(2)SO(4), NaHCO(3) and Na(2)CO(3)) and 30 salt-alkaline combinations (salinity 24-120 mmol/L and pH 7.03-10.32) treating Medicago sativa seedlings was conducted. The results demonstrated that salinity and alkalinity significantly affected total biomass and biomass components of seedlings. There were interactive effects of salt composition and concentration on biomass (P<or= 0.001). The interactions between salinity and alkalinity stresses led to changes in the root activity along the salinity gradient (P<or= 0.001). The effects of alkalinity on seedling survival rate were more significant than those of salinity, and the seedlings demonstrated some physiological responses (leaf electrolyte leakage rate and proline content) in order to adapt to mixed salt-alkaline stresses. It was concluded that the mixed salt-alkaline stresses, which differ from either salt or alkali stress, emphasize the significant interaction between salt concentration (salinity) and salt component (alkalinity). Further, the effects of the interaction between high alkalinity and salinity are more severe than those of either salt or alkali stress, and such a cooperative interaction results in more sensitive responses of ecological and physiological characteristics in plants.
Peng
Yong-Lin
YL
Institute of Grassland Science, Northeast Normal University, Key Laboratory of Vegetation Ecology, Ministry of Education, Changchun 130024, China.
Gao
Zhan-Wu
ZW
Gao
Ying
Y
Liu
Guo-Fang
GF
Sheng
Lian-Xi
LX
Wang
De-Li
DL
D018533:Biomass; D002254:Carbonates / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D000455:Medicago sativa / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D012492:Salts / Q000494:pharmacology*; D036226:Seedlings / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D017693:Sodium Bicarbonate / Q000494:pharmacology; D012965:Sodium Chloride / Q000494:pharmacology; D013431:Sulfates / Q000494:pharmacology
D002254:Carbonates; D012492:Salts; D013431:Sulfates; C012036:sodium sulfate; D012965:Sodium Chloride; C005686:sodium carbonate; D017693:Sodium Bicarbonate