Erice Gorka, Sanz-Sáez Alvaro, Urdiain Amadeo, Araus Jose L, Irigoyen Juan José, Aranjuelo Iker
Departamento de Biología Vegetal, Sección Biología Vegetal, Facultades de Ciencias y Farmacia, Universidad de Navarra, c/ Irunlarrea 1, Pamplona, Navarra, Spain.
Departament de Biologia Vegetal, Facultat de Biologia, Universidad de Barcelona, Av. Diagonal, 645 08028 Barcelona, Spain.
Funct Plant Biol. 2014 Oct;41(11):1138-1147. doi: 10.1071/FP14045.
Despite its relevance, few studies to date have analysed the role of harvest index (HI) in the responsiveness of wheat (Triticum spp.) to elevated CO2 concentration ([CO2]) under limited water availability. The goal of the present work was to characterise the role of HI in the physiological responsiveness of durum wheat (Triticum durum Desf.) exposed to elevated [CO2] and terminal (i.e. during grain filling) water stress. For this purpose, the performance of wheat plants with high versus low HI (cvv. Sula and Blanqueta, respectively) was assessed under elevated [CO2] (700μmolmol-1 vs 400μmolmol-1 CO2) and terminal water stress (imposed after ear emergence) in CO2 greenhouses. Leaf carbohydrate build-up combined with limitations in CO2 diffusion (in droughted plants) limited the responsiveness to elevated [CO2] in both cultivars. Elevated [CO2] only increased wheat yield in fully watered Sula plants, where its larger HI prevented an elevated accumulation of total nonstructural carbohydrates. It is likely that the putative shortened grain filling period in plants exposed to water stress also limited the responsiveness of plants to elevated [CO2]. In summary, our study showed that even under optimal water availability conditions, only plants with a high HI responded to elevated [CO2] with increased plant growth, and that terminal drought constrained the responsiveness of wheat plants to elevated [CO2].
尽管收获指数（HI）具有相关性，但迄今为止，很少有研究分析其在水分供应有限的情况下，小麦（Triticum spp.）对二氧化碳浓度升高（[CO2]）响应中的作用。本研究的目的是描述HI在硬粒小麦（Triticum durum Desf.）暴露于高[CO2]浓度和灌浆末期水分胁迫时生理响应中的作用。为此，在二氧化碳温室中，对高HI和低HI的小麦植株（分别为Sula和Blanqueta品种）在高[CO2]（700μmolmol-1与400μmolmol-1 CO2）和灌浆末期水分胁迫（穗抽出后施加）条件下的表现进行了评估。叶片碳水化合物积累以及（干旱植株中）二氧化碳扩散受限，限制了两个品种对高[CO2]浓度的响应。高[CO2]浓度仅提高了充分浇水的Sula植株的产量，其较高的HI阻止了总非结构性碳水化合物的过量积累。水分胁迫下植株假定缩短的灌浆期可能也限制了植株对高[CO2]浓度的响应。总之，我们的研究表明，即使在最佳水分供应条件下，只有高HI的植株对高[CO2]浓度的响应是植株生长增加，而灌浆末期干旱限制了小麦植株对高[CO2]浓度的响应。
