Doupis G.,Nagref Institute For Olive Tree And Subtropical Plants |
Chartzoulakis K.,Nagref Institute For Olive Tree And Subtropical Plants |
Beis A.,University of Ioannina |
Patakas A.,University of Ioannina
Australian Journal of Grape and Wine Research | Year: 2011
Background and Aims: The aim of this study was to evaluate differences in adaptive responses in grapevines (Vitis vinifera L. cv Soultanina) exposed to either drought, enhanced ultraviolet-B (UV-B) radiation or the combination of the two environmental stresses. Methods and Results: Results indicated pronounced effects on allometric parameters in plants exposed to the enhanced UV-B radiation. The combined application of drought and enhanced UV-B radiation considerably affected shoot growth rate and leaf dry weight. Guaiacol peroxidase (GPX, EC 188.8.131.52), ascorbate peroxidase (APX, EC 184.108.40.206), superoxide dismutase (SOD, 220.127.116.11) and catalase (CAT, 18.104.22.168) activities increased significantly in the enhanced UV-B radiation treatment. Drought resulted in a significant increase in proline concentration, while the exposure of plants to enhanced UV-B radiation resulted in the production of UV-B absorbing compounds (UVabs). Conclusions: Under drought conditions proline accumulation seemed to be the main mechanism of adaptation contributing to plant's antioxidant defence. On the other hand, under enhanced UV-B radiation, the accumulation of the UV-B absorbing compounds and the increase in antioxidant enzymes activities constitute the main mechanisms of grapevine adaptation. Significance of the Study: The data obtained indicate the occurrence of two different mechanisms of adaptation in response to the stressor applied. Furthermore, the patterns of proline and UVabs concentration changes under stress conditions suggest that the biosynthesis of these two compounds might follow competing metabolic pathways. © 2010 Australian Society of Viticulture and Oenology Inc.
Varikou K.,Nagref Institute For Olive Tree And Subtropical Plants |
Garantonakis N.,Nagref Institute For Olive Tree And Subtropical Plants |
Birouraki A.,Nagref Institute For Olive Tree And Subtropical Plants
Crop Protection | Year: 2015
Effective insecticidal bait formulations ought to induce high levels of attraction and stimulate flies to ingest a lethal dose of the toxicant upon feeding or contact. The key to the effectiveness of such baits is the amount of time that the bait remains attractive to adult flies after spray application. Solutions of trophical attractants of Bactrocera oleae (two formulations of hydrolysed proteins at 55% and 75% w/w) mixed with various insecticides (alpha-cypermethrin, lambda-cyhalothrin and dimethoate) and a spinosad solution, applied either in McPhail traps or sprayed in olive foliage (except lambda-cyhalothrin), were tested for their attractiveness over time during two periods in successive summers. The results indicated that among all bait spraying solutions tested against B.oleae, the highest catches were recorded with both protein solutions of alpha-cypermethrin; its capture rate ranged from 7.6 to 10.5 olive fruit flies/trap/solution age (seven measurements were made when the trap solution was changed at 3, 7, 10, 14, 17, 20 and 24 days after its preparation). A three-day-old solution of any protein mixed with alpha-cypermethrin was significantly more attractive to olive fruit flies (at least three times) compared with the solutions at other ages, as indicated by the capture of flies in the McPhail traps. No differences were observed among solution ages for dimethoate solutions or spinosad solutions (less than 6 olive fruit flies/trap/week). When olive foliage was sprayed with the solutions under field conditions, they attracted approximately 0.3-1.5 adults per day for a 10-day period. The highest number of flies was recorded on both proteins combined with or without alpha-cypermethrin solution, as indicated by the catches on sticky transparent panels. Finally, changes in the pH values of the aforementioned solutions over time were associated with increased fly catches. © 2014 Elsevier Ltd.