Avaliação de stress oxidativo em bagos de videira (Vitis vinifera L.) da casta ...

• Author(s): Carvalho, Inês Sequeira de
• Date: 2009
• Persistent ID: http://hdl.handle.net/10400.5/1120
• Origin: Repositório da UTL
• Subject(s): vitis vinifera; antioxidant enzymes; drought stress; grape skin; oxidatiive stress; ripening stage; enzimas antioxidantes; estado de maturação; pelicula do bago; stress hídrico; stress oxidativo
• Document Type: Master Thesis
• Language: Portuguese
• Advisor(s): Martins, Maria Luísa Louro; Francisco, Rita Maria de Brito

Description

Mestrado em Engenharia Agronómica - Hortofruticultura e Viticultura - Instituto Superior de Agronomia The plants respond to oxidative stress with the activation of defensive antioxidants mechanisms, which come up as an integrative part of the drought stress tolerance strategies. With this work it was attempted to evaluate oxidative stress caused by three different irrigation treatments – NI (non irrigated), RDI (Regulated Deficit Irrigation) and FI (Full Irrigation) – in the skin of Vitis vinifera L. cv ‘Trincadeira’ grapes, throughout ripening process. The activity of guaiacol peroxidase (POD), poliphenol oxidase (PPO), ascorbate peroxidase (APX), glutathione reductase (GR) and catalase (CAT) was determined on different stages of ripening. Higher levels of drought stress were found in NI treatment, with the highest average levels of POD activity, and have originated possibly a major incidence of oxidative stress, followed by RDI and FI treatments, where the level of drought stress was respectively minor. Water availability seems to affect the plant’s response to the accumulation of ROS on the different stages of ripening, showing a more efficient response on the final stage in NI treatment and on vérasion on RDI and FI treatments, which may indicate a higher investment of the plant on the final stage of the reproductive cycle under limited water availability.