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Interdependence of plant water status with photosynthetic performance and root defense responses in Vigna radiata (L.) Wilczek under progressive drought stress and recovery

Paper ID Volume ID Publish Year Pages File Format Full-Text
30337 44469 2013 12 PDF Available
Title
Interdependence of plant water status with photosynthetic performance and root defense responses in Vigna radiata (L.) Wilczek under progressive drought stress and recovery
Abstract

•Mungbean (Vigna radiata L.) adapts to progressive drought stress through an integrated and dynamic root-shoot response.•Progressive drought decreased energy connectivity among PSII units in V. radiata as evident from positive L-band.•Drought-induced damage on the stability of PSII complex was insignificant.•Root antioxidative defense complemented photosynthetic performance of V. radiata under progressive drought and recovery.•Enhanced proline biosynthesis under drought was followed by rapid proline catabolism during recovery in V. radiata roots.

The present study investigates the interdependence of plant water status with foliar and root responses in Vigna radiata L.Wilczek under progressive drought. Vegetatively-mature V. radiata plants were subjected to water withdrawal for 3 and 6 days (D3 and D6, respectively) and then re-watered subsequently for 6 days (6R) for stress-recovery. Changes in plant water status were expressed in terms of leaf and root moisture contents (LMC and RMC, respectively) and leaf relative water content (LRWC). Progressive drought caused apparent decrease in LRWC, LMC and RMC depicting significant level of dehydration of leaf and root tissues. Stomatal limitation alone could not account for the observed decrease in net CO2 assimilation rates (Pn) due to comparatively less decrease in sub-stomatal CO2 (Ci) concentrations with respect to other gas exchange parameters indicating possible involvement of non-stomatal limitations. Analysis of polyphasic chl a fluorescence kinetics during progressive drought showed decreased energy connectivity among PSII units as defined by a positive L-band with highest amplitude during D6. Efficiency of electron flux from OEC towards PSII acceptor side was not significantly affected during drought conditions as evidenced by the absence of a positive K-band. Increasing root-level water-limitation enforced a gradual oxidative stress through H2O2 accumulation and membrane lipid peroxidation in V. radiata roots exhibiting drastic enhancement of proline content and a significant but gradual increase in ascorbic acid content as well as guaiacol peroxidase activity under progressive drought. Expression analysis of Δ1 pyrroline-5-carboxylate synthetase (P5CS) through real time PCR and enzyme activity studies showed a strong positive correlation between VrP5CS gene expression, enzyme activity and proline accumulation in the roots of V. radiata under progressive drought and recovery. Drought-induced changes in root moisture content (RMC) showed positive linear correlations with leaf water content, stomatal conductance as well as transpirational water loss dynamics and a significant negative correlation with the corresponding drought-induced expression patterns of ascorbate, guaiacol peroxidase and proline in roots of V. radiata. The study provides new insights into the plant water status-dependent interrelationship between photosynthetic performance and major root defense responses of V. radiata under progressive drought conditions.

Keywords
Drought; Oxidative stress; Photosynthesis; Photosystem-II; Root antioxidants; Vigna radiata
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Interdependence of plant water status with photosynthetic performance and root defense responses in Vigna radiata (L.) Wilczek under progressive drought stress and recovery
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Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Photochemistry and Photobiology B: Biology - Volume 127, 5 October 2013, Pages 170–181
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us