Regulació hormonal i redox de processos de senescència d'òrgans

Abstract

Food waste and loss represents 45% of fruits and vegetables production. Global change and the forecasted increase in the frequency of extreme weather events will further strain the production and the logistic chain from the field to the consumer, especially in the developing world where the cold chain cannot always be properly maintained. Post-harvest senescence and associated stresses limit longevity, but also the organoleptic quality and nutritional value of fresh products. Improved understanding of these processes creates options for better management and to inform breeding programs. After harvest, controlled exposure to abiotic stresses and/or exogenous phytohormones can enhance nutraceutical, organoleptic and commercial longevity traits. In this Thesis new methodologies to combine physiological features, hormonal and biochemical profiles, and transcriptomic tools have been developed to better characterise organ senescence processes. Thus, allowing the design of biotechnological strategies to improve the quality and/or longevity of fresh products, describing the underlying effects of this manipulation on post-harvest physiology and fruit maturation. The results suggest the potential to manipulate ABA signalling through ABA and/or pyrabactin applications to improve the post-harvest quality of green leafy vegetables (Brassica oleracea var capitata) stored at room temperature (Chapter 3) and to improve vitamin C and E content of raspberry fruits (Rubus idaeus; Chapters 1 and 2); and the characterization of the post-harvest senescence of ethylene-insensitive flowers (Lilium, Iris) and the potential of melatonin applications to improve Lilium post-harvest longevity (Chapter 1, Appendix 1). It was observed how the processes of leaf and flower senescence, and of fruit ripening, share physiological characteristics and its hormonal and redox regulation, resulting in ABA being an important regulator of these processes.