Combined Effect of Water and Salt Stress on Growth and Root Hydraulic Conductivity of Ultra-high Yield Wheat Seedling

Abstract

【Background and objective】 Drought and soil salinization are two common abiotic stresses facing agricultural production worldwide. Plants develop various strategies to grow under these stresses, and the purpose of this paper is to investigate how winter wheat at seedling stage adjusts the hydraulic conductance of its roots as a response to change in water and salt stresses. 【Method】 The experiment was conducted in hydroponic culture, using the ultra-high variety Yannong 1212 as the model plant. Water stress was created by polyethylene glycol (PEG) and NaCL was used as a proxy for soil salinization. There were three treatments: 2% of PEG6000, 0.1% of NaCl, and 2% of PEG6000+0.1% NaCl. Wheat grown in Hoagland nutrient solution without abiotic stresses was taken as the control. For each treatment, we measured the root hydraulic conductivity and analyzed its relationship with environmental factors using stepwise regression method. 【Result】 ① Water stress and salt stress, working alone or in combination, reduced plant height and leaf area significantly, though the level of the significance varied with treatment. ② Compared with the control, water stress and salt stress working alone increased root-shoot ratio by 12% and 14% respectively, while their combination reduced this ratio by 6%; ③ Salt stress and water stress, working separately or in combination, increased Na+/K+ ratio in both leaves and roots, despite that the effect of water stress was not significant. ④ Water stress and salt stress and their combination significantly reduced total nitrogen content in the leaves, and reduced the root hydraulic conductivity by 58%, 51% and 93%, respectively, compared with the control. 【Conclusion】 Water and salt stresses reduced root hydraulic conductivity of the wheat at seedling stage, and the leaf area was positively correlated with the root hydraulic conductivity.

Keywords

• water and salt stress
• super high yield wheat
• k+ content
• na+ content
• root hydraulic conductivity