Unlocking the Potential of Phloroglucinol and Tocopherol in Improving the Photosynthetic Efficiency, Membrane Stability, and Antioxidant Enzyme Activities of Cryopreserved In Vitro Raised Plantlets of Citrus maxima Merr. And Citrus jambhiri Lush

Abstract

Abstract This study examined the effects of tocopherol (Vitamin E) and phloroglucinol (1,3,5-trihydroxybenzene) on cryopreserved plantlets of Citrus jambhiri Lush and Citrus Maxima Merr., two important Citrusspecies used in citrus breeding and variety development. After undergoing cryopreservation using conventional desiccation methods, the seeds of these two species were propagated in Murashige and Skoog (MS) medium with various concentrations of tocopherol and phloroglucinol. Plantlets raised from both cryopreserved and non-cryopreserved seeds were multiplied using clonal propagation on MS medium supplemented with the specified two chemicals. The clones were subsequently assessed by a range of procedures, including the quantification of chlorophyll levels, measurement of electrolyte leakage, and evaluation of specific antioxidant enzyme activities, including superoxide dismutase, catalase, and peroxidase. Cryopreserved and non-cryopreserved C. jambhiri and C. maxima clones subjected to 2.0 µM and 15.0 µM tocopherol showed improved membrane stability compared to their control counterparts. Increased photosynthetic efficiency was attained by supplementing 0.3 µM and 4.0 µM phloroglucinol to C. jambhiri and C. maxima, respectively. Both cryopreserved and non-cryopreserved C. jambhiri clones had their maximum antioxidant enzyme activity when cultured in a medium with 2.0 µM tocopherol and 0.3 µM phloroglucinol. In C. maxima, cryopreserved and non-cryopreserved clones had higher antioxidant enzyme activity in medium with 15.0 µM tocopherol and 4.0 µM phloroglucinol. In conclusion, the use of vitamin E and phloroglucinol in cryopreservation can greatly improve the important developmental traits of cryopreserved citrus plantlets.