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Oxidative stress protection and stomatal patterning as components of salinity tolerance mechanism in quinoa (Chenopodium quinoa)

Citation

Shabala, L and Mackay, A and Tian, Yu and Jacobsen, S-E and Zhou, D and Shabala, S, Oxidative stress protection and stomatal patterning as components of salinity tolerance mechanism in quinoa (Chenopodium quinoa), Physiologia Plantarum, 146, (1) pp. 26-38. ISSN 0031-9317 (2012) [Refereed Article]

Copyright Statement

Copyright 2012 Physiologia Plantarum

DOI: doi:10.1111/j.1399-3054.2012.01599.x

Abstract

Two components of salinity stress are a reduction in water availability to plants and the formation of reactive oxygen species. In this work, we have used quinoa (Chenopodium quinoa), a dicotyledonous C3 halophyte species displaying optimal growth at approximately 150 mM NaCl, to study mechanisms by which halophytes cope with the afore-mentioned components of salt stress. The relative contribution of organic and inorganic osmolytes in leaves of different physiological ages (e.g. positions on the stem) was quantified and linked with the osmoprotective function of organic osmolytes. We show that the extent of the oxidative stress (UV-B irradiation) damage to photosynthetic machinery in young leaves is much less when compared with old leaves, and attribute this difference to the difference in the size of the organic osmolyte pool (1.5-fold difference under control conditions; sixfold difference in plants grown at 400 mM NaCl). Consistent with this, salt-grown plants showed higher Fv/Fm values compared with control plants after UV-B exposure. Exogenous application of physiologically relevant concentrations of glycine betaine substantially mitigated oxidative stress damage to PSII, in a dosedependent manner. We also show that salt-grown plants showed a significant (approximately 30%) reduction in stomatal density observed in all leaves. It is concluded that accumulation of organic osmolytes plays a dual role providing, in addition to osmotic adjustment, protection of photosynthetic machinery against oxidative stress in developing leaves. It is also suggested that salinityinduced reduction in stomatal density represents a fundamental mechanism by which plants optimize water use efficiency under saline conditions.

Item Details

Item Type:Refereed Article
Keywords:halophyte, salt, saline, oxidative stress protection, stomatal density, salinity tolerance, Chenopodium quinoa
Research Division:Biological Sciences
Research Group:Plant Biology
Research Field:Plant Biology not elsewhere classified
Objective Division:Plant Production and Plant Primary Products
Objective Group:Summer Grains and Oilseeds
Objective Field:Summer Grains and Oilseeds not elsewhere classified
Author:Shabala, L (Dr Lana Shabala)
Author:Mackay, A (Mr Alexander Mackay)
Author:Shabala, S (Professor Sergey Shabala)
ID Code:77604
Year Published:2012
Web of Science® Times Cited:58
Deposited By:Agricultural Science
Deposited On:2012-05-10
Last Modified:2013-06-12
Downloads:1 View Download Statistics

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