Spraying plants with exogenous substances have gained more attention due to its potential to reduce the negative impacts of heat and water stress in a climate‐changing environment. Therefore, the effects of spraying kaolin and Ascophyllum nodosum with and without irrigation on leaf gas exchange parameters, plant water status, electrolyte leakage, cuticular waxes, plant hormones and antioxidant enzymes, proline, malondialdehyde (MDA) content and lipid peroxidation of membranes of hazelnut trees were studied. Six different treatments with kaolin (K), A. nodosum (An), irrigation (I), kaolin with irrigation (Ki), A. nodosum with irrigation (Ani) and no irrigation (control) during two consecutive years (2016–2017) were applied in a hazelnut orchard of ‘Grada de Viseu’ cultivar located in Moimenta da Beira region, Northern Portugal. Results showed that K and An were effective for reducing hazelnut heat and drought stress by increasing the water relative content (RWC), net CO₂ assimilation (A), water use efficiency (A/g_s) and reducing the leaf mass per area (LMA), electrolyte leakage (EL). Moreover, concentration of ABA, MDA, proline and lipid peroxidation of membranes, as well the average content of antioxidant enzymes, was lower, suggesting that under K and An, plants have a better physiological performance than without these two exogenous substances. Nonetheless, these benefits only appear to be significant in the second year of the experiment showing that the use of both substances to mitigate climate change adverse effects should be considered as a long‐term strategy.

中文翻译：

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高岭土和基于海藻的提取物可用作中长期策略，以减轻气候变化对榛子树生理性能的负面影响

利用外源物质对植物进行喷涂已经引起了更多关注，因为它具有减少气候变化环境中热量和水分胁迫的负面影响的潜力。因此，喷洒和不喷洒高岭土和延胡索叶对叶片气体交换参数，植物水分状况，电解质泄漏，表皮蜡，植物激素和抗氧化酶，脯氨酸，丙二醛（MDA）含量和榛子膜脂质过氧化的影响研究了树木。六种不同的处理方法：高岭土（K），结节曲霉（An），灌溉（I），高岭土灌溉（Ki），结节曲霉连续两年（2016-2017年）对位于葡萄牙北部莫伊曼塔达贝拉地区的“ Grada de Viseu”品种榛子果园进行了灌溉（Ani）和不灌溉（对照）。结果表明，K和An可以通过增加水相对含量（RWC），净CO ₂同化量（A），水分利用效率（A / g _s）来减少榛子的热量和干旱胁迫_。），并减少每单位面积的叶片质量（LMA）和电解质泄漏（EL）。而且，ABA，MDA，脯氨酸和脂质过氧化膜的浓度以及抗氧化酶的平均含量较低，这表明在K和An下，植物的生理性能要比没有这两种外源物质更好。但是，这些好处仅在实验的第二年才显得很明显，表明使用两种物质减轻气候变化的不利影响应被视为一项长期策略。