Effect of salin stress on the variation of endogenous organic solutes in callus of five citrus rootstocks

Ramdan Rajae; Handaji Najat; Ramdan Btissam; Benyahya Hamid; Ibriz Mohammed

Effect of salin stress on the variation of endogenous organic solutes in callus of five citrus rootstocks

Authors
Ramdan Rajae, Handaji Najat, Ramdan Btissam, Benyahya Hamid, Ibriz Mohammed

Abstract
Introduction: Citrus fruit is the world's largest fruit production with 73 million tonnes in 2013. However, salinity is one of the constraints hindering its development. This work focuses on the study of the mechanisms of tolerance to salinity in citrus rootstocks.

Methods: Embryos from five citrus rootstocks were used. The “Murashig and tucker” medium was used for callogene induction with additional a phytohormonal combination (2,4-dichloro-phenoxyacetic acid / benzylaminopurine). Induction of callus resistance to NaCl was made by direct or gradual submission to salt stress. The proline and sugar contents were determined after 3 weeks of calli development.

Results: Calli cells studied expressed an ability to synthesize proline and soluble sugars regardless of the NaCl dose, their contents vary according to the genotype and the salinity of the medium. The proline accumulation was more marked in susceptible rootstocks than in tolerant ones. In return, tolerant rootstocks accumulated more soluble sugars. Stopping stress allowed a gradual return to the initial values of proline in each of the rootstocks studied.

Conclusion: The proline accumulation was a marker of sensitivity to salt stress, while the accumulation of soluble sugars can be considered as an indicator of resistance.

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