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Universidade de Tras os Montes E Alto Douro (2017)

Influência da aplicação de ácido salicílico no comportamento fisiológico de oliveiras submetidas a défice hídrico

Afonso, Ana da Lomba

Titre : Influência da aplicação de ácido salicílico no comportamento fisiológico de oliveiras submetidas a défice hídrico

Auteur : Afonso, Ana da Lomba

Université de soutenance : Universidade de Tras os Montes E Alto Douro

Grade : Mestrado em Engenharia Agronómica 2017

Résumé
Olive tree has a high economic, social, cultural and ecological relevance in Portugal, especially in the inland regions, such as Trás-os-Montes, where it is one of the dominant crops. Olive rainfed orchards predominate in these territories, so there is a high dependence on the climatic conditions, which are usually quite adverse in the spring and summer seasons. In the context of global climate change, a decrease in the availability of water and an increase in temperature during periods of greater vegetative and reproductive development of the olive tree are expected, with significant negative consequences on physiology, growth, production and quality, which could economically cripple this crop and contribute to the exodus of the populations living in these regions. This raises the need to implement adaptation measures that can minimize these effects. One of the possible management practices would be the use of irrigation, but it is not very sustainable and it is expensive in many areas of Trás-os-Montes due to the rugged landscape of the region, its natural limitations on water resources and the need for a water distribution in large scale. Therefore, it is crucial to adopt alternative practices that allow the adaptation of olive trees to a changing environment, in order to preserve the sustainability of the crop. In this context, we proposed to evaluate the effect of the foliar application of salicylic acid (SA ; 100 μM), a hormone with a great diversity of functions in plant metabolism, as a way of minimizing damage in 3-year-old plants of Cobrançosa cultivar subjected to 3 cycles of drought and rehydration. In the study, methodologies focused on the evaluation of olive tree physiology, including water status, gas exchange, chlorophyll a fluorescence and biomass accumulation were used. The results showed that the application of SA led to an improvement in several physiological indicators in the most critical period of stress, including increases in relative water content and leaf succulence, transpiration rate, stomatal conductance, electron transport rate, effective quantum efficiency of PSII and photosynthetic rate and decreases of leaf density, initial fluorescence and non-photochemical quenching. It was also seen that some of these positive effects remained active 7 days after the initiation of rehydration. As a corollary, SA contributed to the increase of biomass and of water use efficiency at the whole-plant level, so the application of salicylic acid could be an effective practice in reducing the negative effects of water stress on rainfed olive groves in the context of climate change.

Mots clés  : Olea europaea Alterações climáticas Ácido salicílico Défice hídrico

Présentation

Page publiée le 5 avril 2018