Mineral content and antioxidant compounds in strawberry fruit submitted to drough stress

Abstract Due mainly to the taste and appearance, the strawberry stands out in relation to the other fruits. and for the presence of antioxidant compounds. However, little attention has been devoted to the impact of abiotic stresses on the quality of strawberry and its agronomic performance. In the present study, we evaluated the effect of two levels of DS (L1 - 70% and L2 - 50% of crop evapotranspiration) on the quality of strawberry fruit and on some agronomic and physiological variables. There was a dose-dependent reduction in the evaluated agronomic variables in the DS plants, and the content of some minerals in the fruit and leaves was modified. The activities of the oxidative enzymes were higher in the fruit of L2 treatment, and the content of sucrose, reduced sugars, phenolic compounds and the total antioxidant activity were increased in the fruit from L2 treatment; while those of anthocyanins and L-ascorbic acid were reduced in L1 and L2 treatments, respectively. The phenylalanine ammonia lyase gene was upregulated and other genes related to phenylpropanoid and ascorbate pathways were downregulated in the fruit of stressed plants. Thus, our results indicate that DS seems to be a promising strategy to improve the content of antioxidant compounds and sugars.

摘要 草莓在各类水果中表现突出，主要得益于其优异的口感与外观，同时还富含抗氧化化合物。然而，目前针对非生物胁迫（abiotic stresses）对草莓品质及其农艺表现的影响，相关研究仍较为匮乏。本研究评估了两种水分亏缺胁迫（DS）水平（L1：作物蒸发蒸腾量（crop evapotranspiration）的70%；L2：作物蒸发蒸腾量的50%）对草莓果实品质以及部分农艺与生理指标的影响。水分亏缺胁迫处理的草莓植株，其测定的农艺指标呈现出剂量依赖性降低的趋势；同时果实与叶片中的部分矿质元素含量也发生了显著改变。L2处理组草莓果实中的氧化酶活性更高，该组果实的蔗糖、还原糖、酚类物质含量以及总抗氧化活性均有所提升；而花青素与L-抗坏血酸的含量则分别在L1与L2处理组中出现下降。胁迫处理植株的果实中，苯丙氨酸解氨酶（phenylalanine ammonia lyase）基因呈现上调表达，而其他与苯丙烷代谢通路及抗坏血酸代谢通路相关的基因则出现下调表达。综上，本研究结果表明，DS似乎是一种可有效提升草莓果实抗氧化成分与糖类物质含量的可行策略。