Water deficit presents new challenges for fruit production, among which, obtaining and selecting tolerant genotypes has become relevant. The aim of this work was to characterize novel Prunus rootstocks in regard to tolerance to water deficit as a key trait to cope the challenges for agriculture imposed by the climate change expected in the near future. Here, we report the assessment of physiological parameters and growth responses to water deficit of four interspecific Prunus rootstock hybrids. Two commercially available rootstocks, ROOTPAC^®40 and ROOTPAC^®20, and two experimental genotypes, AGAF 0301-07 and ADAGAF 0403 were evaluated. Plants were subjected to two irrigation treatments (well-watered and water deficit) during 33 days. During this period, stomatal conductance (g_s) and photosynthetic CO₂ assimilation (P_n) were measured. At the end of the experiment, biomass accumulation was registered for all the genotypes, while the expression of seven aquaporins belonging to plasma membrane intrinsic proteins subfamily (PIPs) was assessed in ROOTPAC^®40 and ROOTPAC^®20. ROOTPAC^®20 had a decrease in the aquaporin gene expression in roots and this could be associated with its early decline in transpiration. Biomass accumulation was lower in ROOTPAC^®20, AGAF 0301-07 and ADAGAF 0403 due to the water deficit. However, ROOTPAC^®40 showed a larger whole-plant water use efficiency under water deficit because of a later reduction in relative transpiration under low fractions of transpirable soil water. This response resulted in higher biomass accumulation in ROOTPAC^®40 than the other genotypes. We identified ROOTPAC^®40 as a tolerant genotype to water deficit, which is majorly explained by a later reduction in relative transpiration under water deficit.

中文翻译：

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蒸腾作用的后期减少是种间李砧木杂种耐缺水的重要特征

水分亏缺给水果生产带来了新的挑战，其中，获得和选择耐性基因型已经变得很重要。这项工作的目的是在耐缺水方面鉴定出新的李属砧木，这是应对不久的将来预期的气候变化对农业挑战的关键特征。在这里，我们报告的生理参数和四个种间李属砧木杂交种对缺水的生长响应的评估。两种市售砧木，ROOTPAC ^® 40和ROOTPAC ^®20，并评估了两个实验基因型AGAF 0301-07和ADAGAF 0403。在33天内对植物进行了两次灌溉处理（浇水和缺水）。在此期间，测量气孔导度（g _s）和光合作用CO ₂同化（P _n）。在实验结束时，生物量积累被注册为所有的基因型，而七水通道蛋白表达属于质膜固有蛋白亚家族（PIPS）的混合物在ROOTPAC评估^® 40和ROOTPAC ^® 20. ROOTPAC ^®20在根部的水通道蛋白基因表达下降，这可能与蒸腾作用的早期下降有关。生物量的积累在ROOTPAC较低^® 20，AGAF 0301-07和ADAGAF 0403由于水分亏缺。然而，ROOTPAC ^® 40显示由于在相对蒸腾transpirable土壤水分低的级分下稍后减少水分亏缺下一个更大的整体植物的水分利用效率。这种反应导致ROOTPAC较高的生物量积累^® 40比其它基因型。我们确定ROOTPAC ^® 40作为一个宽容的基因型缺水，这是majorly在相对蒸腾水分亏缺以后减少解释。