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作 者 ：李娟1;2;周健民1

期 刊 ：植物营养与肥料学报 2007年 13卷 5期 页码：865-870

关键词：番茄；pH；根系；生长发育；

Keywords:tomato, pH, roots, growth and development,

摘 要 ：为探讨CO₂浓度升高能否减缓高浓度NH₄⁺-N对番茄根系的毒害作用,本试验在营养液栽培条件下,以番茄为材料,在CO₂生长箱中研究2个CO₂浓度与5个不同NH₄⁺/NO₃^-配比的交互作用对生长介质的pH、根系生长及根系活力的影响。结果表明,随着生育期的推进与CO₂浓度的升高,pH变化幅度增大。两个CO₂浓度均表现为全NO₃^--N含量营养液的pH呈上升趋势,其它处理营养液的pH均呈现出不同程度的下降趋势,下降的幅度随NH₄⁺/NO₃^-比例的增加而增加;而且全NH₄⁺-N引起pH值下降的程度大于全NO₃^--N引起pH增加的程度。CO₂浓度升高增加了低NH₄⁺/NO₃^-比例供应处理的蕃茄幼苗冠干重、根干重、根系活力、根系总吸收面积、活跃吸收面积。这些指标对CO₂的响应随NH₄⁺/NO₃^-比例的降低而加强,冠干重、根干重、根系活力、根系总吸收面积、活跃吸收面积增加分别高达65.8%、78.0%、18.9%、12.9%与18.9%。说明在CO₂浓度升高条件下,番茄幼苗根生长潜力在全NO₃^--N处理中最大,但不能减弱全NH₄⁺-N对番茄根系的毒害作用。

Abstract:In order to understand whether the elevated CO₂ does alleviate the toxic effect on tomato root system due to high NH₄⁺-N concentration in nutrient solutions,a growth chamber experiment was conducted to determine the influence of NH₄⁺/NO₃^- ratio and elevated CO₂ concentrations on the pH in nutrient solution,growth and root vigor system of tomato seedling roots.Tomato(Lycopersicon esculentum Mill var.Hezuo 906) was grown in pots with nutrient solutions varying in NH₄⁺∶NO₃^- ratio(0∶1,1∶3,1∶1,3∶1 and 1∶0) in growth chambers with ambient(360 μL/L) or elevated CO₂ concentrations(720 μL/L).It enhanced the changes of pH with promotion of growth time and CO₂ enrichment.At two CO₂ levels,pH increased with whole NO₃^--N in nutrient solution and decreased in other treatments and enhanced the decrease of pH with increasing proportion of NH₄⁺-N in nutrient solutions.The decrease in pH value with only NH₄⁺-N in nutrient solution was higher than the increase in pH with only NO₃^--N in nutrient solution. Elevated CO₂ increased the dry weight of shoots and roots,root vigor system, total absorbing area,active absorbing area of tomato seedlings.All measurement indices above of tomato seedlings were increased in the elevated CO₂ treatment with increasing proportion of NO₃^- in nutrient solutions and the dry weight of shoots,dry weight of roots,root vigor system,total absorbing area and active absorbing area were up to 65.8%,78.0%,18.9%,12.9% and 18.9% higher at elevated than at ambient CO₂ concentration,depending on NH₄⁺/NO₃^- ratio.The results indicated that tomato seedling roots may benefit best from CO₂ enrichment when 100% NO₃^--N in nutrient solutions is supplied,and elevated CO₂ did not inhibit the adverse effects on tomato seedling roots when 100% NH₄⁺-N in nutrient solution is supplied.

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