Lipoxygenase activity and proline accumulation in leaves and roots of olive trees in response to drought stress

Abstract

The olive tree (Olea europaea L.) is commonly grown in the Mediterranean basin and is able to resist severe and prolonged drought. Levels of proline (PRO) and malondialdehyde (MDA), and the lipoxygenase (LOX) activity were determined in 2-year-old olive plants (cv. 'Coratina') grown in environmental conditions characterized by high temperatures and high photosynthetic photon flux density levels and gradually subjected to a controlled water deficit for 20 days. Before and during the experimental period, leaf and root samples were collected and analysed for PRO and MDA. The levels of PRO increased in parallel with the severity of drought stress in both leaves and roots. Significant increases of LOX activity and MDA content were also observed during the progressive increment of drought stress in both leaf and root tissues. Measurements of transpiration and photosynthetic rate, stomatal conductance and substomatal CO(2) concentration were carried out during the experiment. The accumulation of PRO indicates a possible role of PRO in drought tolerance. The increases of MDA content and LOX activity show that the water deficit is associated with lipid peroxidation mechanisms.

Identification of leaf volatiles from olive (Olea europaea) and their possible role in the ovipositional preferences of olive fly, Bactrocera oleae (Rossi) (Diptera: Tephritidae)

“…We hypothesize that lipoxygenase activity in olive leaves can be significantly influenced by the climatic conditions. Lipoxygenase is more active in stressed plants and drought conditions (Sofo et al, 2004). Therefore, high levels of GLVs as of the first dates could be due to higher lipoxygenase activity, as the plants were in drought conditions for a long period.…”

“…Therefore, high levels of GLVs as of the first dates could be due to higher lipoxygenase activity, as the plants were in drought conditions for a long period. During collection, mainly during the end of September and beginning of October, with increasing rainfall, GLVs and (Z)-3-hexen-1-ol acetate contents decrease drastically, because lipoxygenase can reduce its activity threefold in plants experiencing water availability (Sofo et al, 2004). Furthermore, LOX substrate (a-linoleic free fatty acids) could also be reduced, as olive leaves from irrigated olive trees reduce their linoleic acid content , thus influencing the LOX mechanisms.…”

Physiological and biochemical traits of drought tolerance inArgania spinosa

“…The enhanced generation of ROS in response to drought stress might activate some specific isoenzymes of LOX in water-stressed plants (Ye et al 2000). Sofo et al (2004) have suggested the existence of a strict relationship between the gradual increase of LOX activity and the progression of drought-stress conditions. Knowing that polyunsaturated fatty acids, the major component of cell membranes phospholipids is considered as the substrate of LOX, the enhancement of LOX activity has been noticed to damage cell membranes and destroy other cell components.…”

Effects of Cycocel and Irrigation Regimes on Some Physiological Parameters of Three Olive Cultivars

“…Fernandez et al (1994) found that rainfed olive roots were more concentrated around stem with longer distances than the irrigated olive roots. Root growth rate directly related to soil water content (Fernandez et al, 1994;Dichio et al, 2002;Sofo et al, 2004). Under stress conditions, the shoots lose more water than roots (Torrecillas et al, 1995).…”