Penella Consuelo, Calatayud Ángeles, Melgar Juan C
Departamento de Horticultura, Instituto Valenciano de Investigaciones AgrariasValencia, Spain.
Department of Plant and Environmental Sciences, Clemson University, ClemsonSC, United States.
Front Plant Sci. 2017 Sep 20;8:1627. doi: 10.3389/fpls.2017.01627. eCollection 2017.
Exogenous application of biochemicals has been found to improve water stress tolerance in herbaceous crops but there are limited studies on deciduous fruit trees. The goal of this research was to study if ascorbic acid applications could improve physiological mechanisms associated with water stress tolerance in young fruit trees. Ascorbic acid was foliarly applied at a concentration of 250 ppm to water-stressed and well-watered peach trees (control) of two cultivars ('Scarletprince' and 'CaroTiger'). Trees received either one or two applications, and 1 week after the second application all trees were rewatered to field capacity. Upon rewatering, CO assimilation and stomatal conductance of water-stressed 'Scarletprince' trees sprayed with ascorbic acid (one or two applications) were similar to those of well-irrigated trees, but water-stressed trees that had not received ascorbic acid did not recover photosynthetical functions. Also, water status in sprayed water-stressed 'Scarletprince' trees was improved to values similar to control trees. On the other hand, water-stressed 'CaroTiger' trees needed two applications of ascorbic acid to reach values of CO assimilation similar to control trees but these applications did not improve their water status. In general terms, different response mechanisms to cope with water stress in presence of ascorbic acid were found in each cultivar, with 'Scarletprince' trees preferentially using proline as compatible solute and 'CaroTiger' trees relying on stomatal regulation. The application of ascorbic acid reduced cell membrane damage and increased catalase activity in water-stressed trees of both cultivars. These results suggest that foliar applications of ascorbic acid could be used as a management practice for improving water stress tolerance of young trees under suboptimal water regimes.
已发现外源施用生物化学物质可提高草本作物的水分胁迫耐受性，但对落叶果树的相关研究有限。本研究的目的是探讨施用抗坏血酸是否能改善幼龄果树中与水分胁迫耐受性相关的生理机制。以250 ppm的浓度对两个品种（‘Scarletprince’和‘CaroTiger’）的水分胁迫桃树（对照为水分充足的桃树）进行叶面喷施抗坏血酸。树木接受一次或两次喷施，第二次喷施后1周，所有树木均重新浇水至田间持水量。重新浇水后，喷施抗坏血酸（一次或两次喷施）的水分胁迫‘Scarletprince’树的CO2同化和气孔导度与充分灌溉的树相似，但未接受抗坏血酸的水分胁迫树未恢复光合功能。此外，喷施抗坏血酸的水分胁迫‘Scarletprince’树的水分状况改善至与对照树相似的值。另一方面，水分胁迫的‘CaroTiger’树需要两次喷施抗坏血酸才能达到与对照树相似的CO2同化值，但这些喷施并未改善其水分状况。总体而言，在每个品种中发现了在抗坏血酸存在下应对水分胁迫的不同反应机制，‘Scarletprince’树优先使用脯氨酸作为相容性溶质，而‘CaroTiger’树依赖气孔调节。抗坏血酸的施用减少了两个品种水分胁迫树的细胞膜损伤并增加了过氧化氢酶活性。这些结果表明，叶面喷施抗坏血酸可作为一种管理措施，用于提高在次优水分条件下幼树的水分胁迫耐受性。
