水盐胁迫对超高产小麦幼苗生长及根系导水率的影响

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

【目的】揭示水盐胁迫对超高产小麦幼苗生长及根系导水率的影响机制。【方法】以超高产小麦品种“烟农1212”为研究对象,设置水分胁迫、盐分胁迫和水盐胁迫3种胁迫处理(2%PEG6000、0.1%Na Cl和2%PEG6000+0.1%Na Cl)和对照(Hoagland营养液,CK),测定不同处理下的小麦的生长指标、根系导水率及全氮、K^(+)和Na^(+)量,利用逐步回归分析方法,分析水盐胁迫下导致小麦幼苗根系导水率降低的因素。【结果】(1)与CK相比,水分胁迫、盐分胁迫和水盐双重胁迫分别使冬小麦幼苗的株高和叶面积显著降低。(2)水分及盐分胁迫处理的根冠比与CK相比分别增加了12%和14%,而在水盐双重胁迫条件下则显著降低了6%。(3)与CK相比,盐分胁迫和水盐双重胁迫显著增加了小麦叶片和根系的Na^(+)/K^(+)比,水分胁迫下的Na^(+)/K^(+)比虽然也有增加,但差异不显著。(4)水分胁迫、盐分胁迫及水盐双重胁迫显著降低了叶片的全氮量。(5)与CK相比,水分、盐分及水盐双重胁迫使小麦幼苗根系总导水率显著降低了58%、51%和93%,逐步回归分析表明,小麦幼苗的叶面积与根系导水率显著正相关(R^(2)=0.9619)。【结论】水盐胁迫条件下,叶面积可作为表征根系导水率的关键指标。

【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.