Leaf exogenous application of abscisic acid triggers tolerance mechanisms to water stress in rubber

• Autor(a) principal: Melo, Hyrandir Cabral de
• Data de Publicação: 2019
• Outros Autores: Rodrigues, Fabrício Jesus, Queirós, Silas Ferreira, Portes, Tomás de Aquino
• Tipo de documento: Artigo
• Idioma: por
• Título da fonte: Ciência Florestal (Online)
• Texto Completo: https://periodicos.ufsm.br/cienciaflorestal/article/view/25824
• topic: ABA; Fluorescence; Photosynthesis; Hevea brasiliensis; Water defcit; ABA; Estresse Hídrico; Fluorescência; Fotossíntese; Hevea brasiliensis

The abscisic acid (ABA) is known as the most influential hormone in triggering mechanisms of stress tolerance in plants, including water defcit. However, the effect of ABA exogenous application as a pre-stress inducing tolerance is poorly studied in plants of agronomic interest. The purpose of this research was to evaluate the effect of ABA triggering mechanisms of stress tolerance in rubber tree seedlings, cultivar RRIM 600. The concentrations used were 0, 50, 100 or 200 µM applied weekly on leaves for 12 weeks, followed by the suspension of watering for 13 days. Leaves of the second node, from the basis to the apex, were analysed, using fve plants per treatment (ABA concentration), which had more than six leaves completely expanded and cultivated in vases of 10 L with dark-red latosol. It was evaluated its influence on the potential quantum effciency of photosystem II (Fv / Fm), measured daily during the suspension of irrigation, and on gas exchanges measured on days 0, 3, 7 and 10 after the suspension of irrigation. After 120 days of the end of the frst period of watering suspension and after occurring natural abscission and leaf recovery, the plants were again submitted to a second period of 13 days of water suspension to check the residual effects of the prior application of ABA on untreated leaves1. It was observed that the exogenous application of ABA induced drought tolerance, particularly in plants treated with 100 and 200 µM and caused residual effect of tolerance on untreated new leaves. It was observed that the frst watering suspension itself triggered tolerance mechanisms observed during the second period of water suspension on ABA untreated plants. The foliar application of ABA triggers mechanisms that improve the tolerance of the plants to the water defcit to which the plants can be submitted.