Two pot experiments were conducted to study the effects of root pruning at the stem elongation stage on non-hydraulic root-sourced signals (nHRS), drought tolerance and water use efficiency of winter wheat (Triticu...Two pot experiments were conducted to study the effects of root pruning at the stem elongation stage on non-hydraulic root-sourced signals (nHRS), drought tolerance and water use efficiency of winter wheat (Triticum aestivum). The root pruning significantly reduced the root weight of wheat, but had no effect on root/shoot ratio at the two tested stages. At booting stage, specific root respiration of root pruned plants was significantly higher than those with intact roots (1.06 and 0.94 mmol g-1 s-1, respectively). The soil water content (SWC) at which nHRS for root pruned plants appeared was higher and terminated lower than for intact root plants, the threshold range of nHRS was markedly greater for root pruned plants (61.1-44.6% field water capacity) than for intact root plants (57.9-46.1% field water capacity). At flowering stage, while there was no significant difference in specific root respiration. The SWCs at which nHRS appeared and terminated were both higher for root pruned plants than for intact root plants. The values of chlorophyll fluorescence parameters, i.e., the effective photosystem II quantum yield (F PS II ), the maximum photochemical efficiency of PS II (F v /F m ), coefficient of photochemical quenching (qP), and coefficient of non-photochemical quenching (NPQ), in root pruned plants were significantly higher than in intact root plants, 7 d after withholding of water. Root pruned plants had significantly higher water use efficiency (WUE) than intact root plants in well-watered and medium drought soil, but not in severe drought condition. In addition, root pruning had no significant effect on grain yield in well-watered and medium drought soil, but significantly decreased grain yield in severe drought condition. In conclusion, the current study showed that root pruning significantly altered nHRS sensitivity and improved WUE of winter wheat in well-watered and medium drought soil, but lowered drought tolerance of winter wheat in severe drought soil. This suggests a possible direction of drought- resistance breeding and potential agricultural measure to improve WUE of winter wheat under semiarid conditions.展开更多
通过盆栽试验研究了返青期根修剪对冬小麦(Triticum aestivum)后期耐旱性及水分利用效率的影响。在返青期设置了两个根修剪处理:1)小剪根,在植株一侧切去部分侧生根;2)大剪根,在主茎四周切去部分侧生根。不剪根者设为对照(CK)。研究结...通过盆栽试验研究了返青期根修剪对冬小麦(Triticum aestivum)后期耐旱性及水分利用效率的影响。在返青期设置了两个根修剪处理:1)小剪根,在植株一侧切去部分侧生根;2)大剪根,在主茎四周切去部分侧生根。不剪根者设为对照(CK)。研究结果显示,两个根修剪处理均显著减少了小麦的根系,但对根冠比没有显著影响。在花期,两个根修剪处理的小麦旗叶的叶绿素荧光参数最大光化学效率(The maximum photochemical efficiency of PSⅡ,Fv/Fm)、PSⅡ潜在活性(PSⅡpotential activity,Fv/Fo)、实际光化学量子产量(Effective PSⅡquantum yield,ΦPSⅡ)、表观光合电子传递速率(Apparent rate of photosynthetic electron transport,ETR)、光化学淬灭系数(Coefficient of photochemical quenching,qP)和非光化学淬灭系数(Coefficient of non-photochemical quenching,NPQ)值,在停止供水7d后,均显著高于对照,这表明根修剪小麦的耐旱性强于对照,因此在干旱胁迫下有较高的光化学活性。小剪根处理在高水条件下对小麦产量无显著影响,而在中度干旱条件下显著提高了小麦的产量,因此,小剪根处理显著提高了小麦的抗旱系数;小剪根处理在高水分处理(土壤水分含量为田间持水量的85%)和中度干旱胁迫处理(土壤水分含量为田间持水量的55%)条件下,均显著提高了小麦的水分利用效率。但大剪根处理由于严重影响了群体数量和产量,水分利用效率和抗旱系数均没有提高。可见,适当地减少根系有助于小麦的耐旱性和水分利用效率的提高。展开更多
基金supported by the Fund of State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau,China(10501-1201)the Key Technologies R&D Program of China during the 11th Five-Year Plan period(2012BAD14B08)the Innovation Team Program,Ministry of Education of China
文摘Two pot experiments were conducted to study the effects of root pruning at the stem elongation stage on non-hydraulic root-sourced signals (nHRS), drought tolerance and water use efficiency of winter wheat (Triticum aestivum). The root pruning significantly reduced the root weight of wheat, but had no effect on root/shoot ratio at the two tested stages. At booting stage, specific root respiration of root pruned plants was significantly higher than those with intact roots (1.06 and 0.94 mmol g-1 s-1, respectively). The soil water content (SWC) at which nHRS for root pruned plants appeared was higher and terminated lower than for intact root plants, the threshold range of nHRS was markedly greater for root pruned plants (61.1-44.6% field water capacity) than for intact root plants (57.9-46.1% field water capacity). At flowering stage, while there was no significant difference in specific root respiration. The SWCs at which nHRS appeared and terminated were both higher for root pruned plants than for intact root plants. The values of chlorophyll fluorescence parameters, i.e., the effective photosystem II quantum yield (F PS II ), the maximum photochemical efficiency of PS II (F v /F m ), coefficient of photochemical quenching (qP), and coefficient of non-photochemical quenching (NPQ), in root pruned plants were significantly higher than in intact root plants, 7 d after withholding of water. Root pruned plants had significantly higher water use efficiency (WUE) than intact root plants in well-watered and medium drought soil, but not in severe drought condition. In addition, root pruning had no significant effect on grain yield in well-watered and medium drought soil, but significantly decreased grain yield in severe drought condition. In conclusion, the current study showed that root pruning significantly altered nHRS sensitivity and improved WUE of winter wheat in well-watered and medium drought soil, but lowered drought tolerance of winter wheat in severe drought soil. This suggests a possible direction of drought- resistance breeding and potential agricultural measure to improve WUE of winter wheat under semiarid conditions.
文摘通过盆栽试验研究了返青期根修剪对冬小麦(Triticum aestivum)后期耐旱性及水分利用效率的影响。在返青期设置了两个根修剪处理:1)小剪根,在植株一侧切去部分侧生根;2)大剪根,在主茎四周切去部分侧生根。不剪根者设为对照(CK)。研究结果显示,两个根修剪处理均显著减少了小麦的根系,但对根冠比没有显著影响。在花期,两个根修剪处理的小麦旗叶的叶绿素荧光参数最大光化学效率(The maximum photochemical efficiency of PSⅡ,Fv/Fm)、PSⅡ潜在活性(PSⅡpotential activity,Fv/Fo)、实际光化学量子产量(Effective PSⅡquantum yield,ΦPSⅡ)、表观光合电子传递速率(Apparent rate of photosynthetic electron transport,ETR)、光化学淬灭系数(Coefficient of photochemical quenching,qP)和非光化学淬灭系数(Coefficient of non-photochemical quenching,NPQ)值,在停止供水7d后,均显著高于对照,这表明根修剪小麦的耐旱性强于对照,因此在干旱胁迫下有较高的光化学活性。小剪根处理在高水条件下对小麦产量无显著影响,而在中度干旱条件下显著提高了小麦的产量,因此,小剪根处理显著提高了小麦的抗旱系数;小剪根处理在高水分处理(土壤水分含量为田间持水量的85%)和中度干旱胁迫处理(土壤水分含量为田间持水量的55%)条件下,均显著提高了小麦的水分利用效率。但大剪根处理由于严重影响了群体数量和产量,水分利用效率和抗旱系数均没有提高。可见,适当地减少根系有助于小麦的耐旱性和水分利用效率的提高。