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3. Ultraviolet-B radiation or heat cause changes in photosynthesis, antioxidant enzyme activities and pollen performance in olive tree

Creator:
Koubouris, G. C., Kavroulakis, N., Metzidakis, I. T., Vasilakakis, M. D., and Sofo, A.
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
fotosyntéza, klimatické změny, ozon, olivovník evropský, photosynthesis, climate changes, ozone, Olea europaea, Kréta (Řecko : ostrov), Crete (Greece), abiotic stress, lipid peroxidation, pollen germination, 2, and 581
Language:
Multiple languages
Description:
The present study attempts to determine how some physiological and reproductive functions of olive tree (Olea europaea L., cv. Koroneiki) respond to enhanced UV-B radiation or heat. Enhanced UV-B radiation was applied to (1) three-year-old potted plants in an open nursery (corresponded to ca. 16% ozone depletion), and (2) in vitro cultured pollen samples (220 μmol m-2 s-1, PAR = 400-700 nm + UV-B at 7.5, 15.0, or 22.5 kJ m-2 d-1). Potted olive plants were also subjected to high temperature (38 +- 4°C) for 28 h to mimic heat levels regularly measured in olive growing areas. A significant effect of UV-B on photosynthetic rate was observed. However, enhanced UV-B radiation did affect neither chlorophyll nor carotenoid content, supporting previous reports on hardiness of the photosynthetic apparatus in olive. Increased superoxide dismutase activity was observed in UV-B-treated olive plants (+ 225%), whereas no effect was found in the plants under heat stress. Neither UV-B and nor heat did affect H2O2 accumulation in the plant tissues. However, the same treatments resulted in enhanced lipid peroxidation (+ 18% for UV-B and + 15% for heat), which is likely linked to other reactive oxygen species. The increased guaiacol peroxidase activity observed in both treatments (+ 32% for UV-B and + 49% for heat) is related to the defense against oxidative membrane damage. The observed reduction in pollen germination (20-39%) and tube length (11-44%) could have serious implications on olive yields, especially for low fruit-setting cultivars or in years and environments with additional unfavorable conditions. UV-B and heat effects described here support the hypothesis that plant response to a given stressor is affected by the overall context and that a holistic approach is necessary to determine plant strategies for climate change adaptation., G. C. Koubouris, N. Kavroulakis, I. T. Metzidakis, M. D. Vasilakakis, A. Sofo., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public