Different strategies lead to a common outcome: different water-deficit scenarios highlight physiological and biochemical strategies of water-deficit tolerance in diploid versus tetraploid Volkamer lemon

Fasih Khalid Muhammad, Vincent Christopher, Morillon Raphaël, Akbar Anjum Muhammad, Ahmad Shakeel, Hussain Sajjad. 2021. Different strategies lead to a common outcome: different water-deficit scenarios highlight physiological and biochemical strategies of water-deficit tolerance in diploid versus tetraploid Volkamer lemon. Tree Physiology, 41 (12) : 2359-2374.

Quartile : Q1, Sujet : FORESTRY

Résumé : Water scarcity restricts citrus growth and productivity worldwide. In pot conditions, tetraploid plants tolerate water deficit more than their corresponding diploids. However, their tolerance mechanisms remain elusive. In this study, we focused on which mechanisms (i.e., hydraulic, osmotic or antioxidative) confer water-deficit tolerance to tetraploids. We exposed diploid and tetraploid Volkamer lemon rootstock (Citrus volkameriana Tan. and Pasq.) to quickly (fast) and slowly (slow) developing water-deficit conditions. We evaluated their physiological, antioxidative defense and osmotic adjustment responses, and mineral distribution to leaves and roots. Water-deficit conditions decreased the photosynthetic variables of both diploid and tetraploid plants. Moreover, the corresponding decrease was greater in diploids than tetraploids. Higher concentrations of antioxidant enzymes, osmoprotectants and antioxidant capacity were found in the leaves and roots of tetraploids than diploids under water deficit. Diploid plants showed fast response in slow water-deficit condition, but that response did not persist as the deficit intensified. Meanwhile, tetraploids had lower water loss, which slowed the onset of slow water deficit relative to diploids. This response allowed stronger photosynthesis, while antioxidant and osmoprotectant production allowed for further tolerance once desiccation began. Overall, our results concluded that Volkamer lemon tetraploid plants tolerate rapid and slow water deficit by maintaining their photosynthesis due to low conductance (stem or roots), which helps to avoid desiccation, and stronger biochemical defense machinery than their corresponding diploids.

Mots-clés Agrovoc : Citrus volkameriana

Mots-clés libres : Antioxidant defense, Citrus rootstock, Osmotic adjustment, Transpiration, Water deficits

Classification Agris : H50 - Troubles divers des plantes
F60 - Physiologie et biochimie végétale

Champ stratégique Cirad : CTS 4 (2019-) - Santé des plantes, des animaux et des écosystèmes

Auteurs et affiliations

• Fasih Khalid Muhammad, Bahauddin Zakariya University (PAK)
• Vincent Christopher, University of Florida (USA)
• Morillon Raphaël, CIRAD-BIOS-UMR AGAP (FRA)
• Akbar Anjum Muhammad, Bahauddin Zakariya University (PAK)
• Ahmad Shakeel, Bahauddin Zakariya University (PAK)
• Hussain Sajjad, Bahauddin Zakariya University (PAK) - auteur correspondant

Source : Cirad-Agritrop (https://agritrop.cirad.fr/602017/)

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