Volkamer lemon tetraploid rootstock transmits the salt tolerance when grafted with diploid kinnow mandarin by strong antioxidant defense mechanism and efficient osmotic adjustment

Fasih Khalid Muhammad, Morillon Raphaël, Akbar Anjum Muhammad, Ejaz Shaghef, Junaid Rao Muhammad, Ahmad Shakeel, Hussain Sajjad. 2022. Volkamer lemon tetraploid rootstock transmits the salt tolerance when grafted with diploid kinnow mandarin by strong antioxidant defense mechanism and efficient osmotic adjustment. Journal of Plant Growth Regulation, 41 : 1125-1137.

Résumé : Salinity restricts plant growth and production by specific ions toxicity to particular plants. Cl ion is exceptionally toxic to citrus. Citrus rootstock and scion has a significant effect on each other under unfavourable conditions. Nevertheless, their specific response can be different depending on the way to translocate and compartment the toxic ions, or to induce antioxidant systems. In this paper, we studied the behaviour of diploid (2x) and tetraploid (4x) Volkamer lemon rootstocks grafted with commercial cultivar Kinnow mandarin (KM/VM2x and KM/VM4x, respectively) when exposed to moderate (75 mM) and high salt stress (150 mM). Both genotypes showed a decrease in their photosynthetic variables (Pn, gs, E, Fv/Fm, Fv′/Fm′, NPQ), and the decline was more significant in KM/VM2x plants as compared to KM/VM4x. The highest increase in the concentration of stress indicators (MDA and H2O2) was observed in leaves and roots of KM/VM2x at 75 and 150 mM of salt stress. The KM/VM4× showed the maximum increase in antioxidative enzymes (SOD, CAT, POD, APx, GR) and osmolytes (PRO, GB) in leaves and roots at 75 and 150 mM. Minerals (Cl ion, Na, K, P, N, Ca) accumulation was also significantly affected in leaves and roots of KM/VM2x and KM/VM4x under moderate and high NaCl stress. Overall, our results showed that Cl ion accumulation presents a robust correlation with stress indicators and their scavenging enzymes in leaves and roots. Moreover, 2x scion significantly mitigated by the 4x rootstock and showed more tolerance as compared to grafted on 2x rootstock.

Mots-clés Agrovoc : tétraploïdie, tolérance au sel, Citrus volkameriana

Mots-clés libres : Antioxidant enzymes, Minerals translocation, Rootstock-scion interaction, Salinity, Polyploidy

Classification Agris : F60 - Physiologie et biochimie végétale
H60 - Mauvaises herbes et désherbage

Champ stratégique Cirad : CTS 2 (2019-) - Transitions agroécologiques

Auteurs et affiliations

• Fasih Khalid Muhammad, Bahauddin Zakariya University (PAK)
• Morillon Raphaël, CIRAD-BIOS-UMR AGAP (FRA)
• Akbar Anjum Muhammad, Bahauddin Zakariya University (PAK)
• Ejaz Shaghef, Bahauddin Zakariya University (PAK)
• Junaid Rao 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/602018/)

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