Navarro Josefa María, Antolinos Vera, Robles Juan Miguel, Botía Pablo
Irrigation and Stress Physiology Group, Department of Bioeconomy, Water and Environment, Murcia Institute of Agri-Food Research and Development (IMIDA), Murcia, Spain.
Front Plant Sci. 2022 May 30;13:909083. doi: 10.3389/fpls.2022.909083. eCollection 2022.
In arid and semiarid regions, the current lack of natural water resources is driving the use of alternative sources for crop irrigation, such as desalinated seawater (DSW). However, the use of DSW could affect the crop productivity due to its chemical composition (predominance of phytotoxic ions: Na, Cl, and B). Citrus species are classified as salt and boron-sensitive; however, the rootstock plays a fundamental role in the tree's tolerance of abiotic stresses. One-year-old 'Verna' lemon trees grafted on two rootstocks (CM, , and SO, sour orange) were used. These rootstocks differ in their salinity and boron tolerance, SO being more tolerant than CM. The experiment was carried out at high temperature (35/27°C), and the plants were irrigated with three types of water supplemented with Hoagland nutrients: DSW, DLB (DSW with low boron), and Control (distilled water). The plants were irrigated three times per week and harvested 7 months after the treatments started. The response to high levels of Cl, Na, and B was rootstock-dependent. Under the high temperature conditions, the growth of plants grafted on SO was not affected by DSW, and these plants did not reach the Cl threshold of phytotoxicity, so the decrease in the shoot growth of plants grafted on CM due to DSW irrigation was related more to Cl rather than the foliar Na accumulation. Plants grafted on SO and irrigated with DSW accumulated more B than those grafted on CM, surpassing the threshold of phytotoxicity and producing greater oxidative stress. As the growth of these plants was not reduced, the effects of DSW on plant growth were not directly related to the concentration of B and there must be some mechanisms that allow these plants to withstand the negative effects of high foliar B, such as the increased levels of quaternary ammonium compounds. Since the response of citrus plants to DSW depended on the rootstock, the results obtained in this experiment, using DSW at high temperature, could be useful for the future management of citrus crops, because climate change will increase temperatures and exacerbate the scarcity of water resources in citrus-growing areas.
在干旱和半干旱地区，当前天然水资源的匮乏促使人们使用替代水源进行作物灌溉，比如淡化海水（DSW）。然而，由于其化学成分（以具有植物毒性的离子：钠、氯和硼为主），使用淡化海水可能会影响作物产量。柑橘类品种被归类为对盐分和硼敏感；然而，砧木在树木对非生物胁迫的耐受性方面起着至关重要的作用。使用了嫁接到两种砧木（CM和酸橙SO）上的一年生“韦尔纳”柠檬树。这些砧木在盐分和硼耐受性方面存在差异，SO比CM更耐盐。实验在高温（35/27°C）条件下进行，给植株浇灌三种添加了霍格兰营养液的水：淡化海水、低硼淡化海水（DLB）和对照（蒸馏水）。植株每周浇灌三次，在处理开始7个月后收获。对高浓度的氯、钠和硼的反应取决于砧木。在高温条件下，嫁接到SO上的植株生长不受淡化海水影响，且这些植株未达到植物毒性的氯阈值，因此，由于用淡化海水灌溉，嫁接到CM上的植株地上部生长下降更多与氯有关，而非叶片钠积累。嫁接到SO上并用淡化海水灌溉的植株比嫁接到CM上的植株积累了更多的硼，超过了植物毒性阈值并产生了更大的氧化应激。由于这些植株的生长未受到抑制，淡化海水对植株生长的影响与硼浓度没有直接关系，必定存在一些机制使这些植株能够抵御高叶片硼含量的负面影响，比如季铵化合物水平的增加。由于柑橘植株对淡化海水的反应取决于砧木，本实验在高温条件下使用淡化海水所获得的结果，可能对柑橘作物未来的管理有用，因为气候变化将导致气温升高并加剧柑橘种植区水资源的短缺。
