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Journal of Agriculture Food and Development

Journal of Current Plant Science Research - Volume 2

Photoprotection Mechanisms in Phlomistuberosa Plants Growing at Low and High Altitudes

Published on: 01 February 2016

Pages: 1-7

GhaderHabibi

Department of Biology, Payame Noor University (PNU), Iran

Abstract: Considering conditions of natural habitat, high mountain plantPhlomistuberosa is expected to be adapted well to high solar radiation. We studied the photosynthetic apparatus and the antioxidant responses of P. tuberosa plants from low (1700 m) and high (2500 m) elevation sites in the Mishou-Dagh Mountains of Iran. The experiments were carried out during the course of a day in natural habitat. Under natural conditions, particularly during noon and afternoon hours, we observed the rapidly reversibleinhibition of PSII reaction centers, which is defined as dynamic photoinhibition. This dynamic photoinhibitionwas an important mechanism for leaves photoprotection of high-altitude plants that are often exposed to intense sunlight. This increased photoprotection activity in high-altitude plants was achieved by higher levels of chlorophyll b, carotenoids and non-photochemical quenching (NPQ). Additionally, the absolute activities of the antioxidant enzymes were considerably higher in high-altitude plants than low-altitude plants. Surprisingly, the accumulation of hydrogen peroxide (H2O2) in leaves of high-altitude plants exhibited diurnal rhythmduring the course of the day.These results revealed that an increase in photoprotection activity may increase plant survival together with the up-regulation of reactive oxygen species (ROS) scavenger systems which alleviate oxidative damage underhigh-mountain conditions.

Keywords: Antioxidant enzymes, Dynamic photoinhibition, High elevation, Phlomistuberosa.

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