Standardization of a Low-Cost Micropropagation Protocol for Aloe vera L. and Assessment of Field Establishment of Regenerated Plantlets
Aloe vera L. (Asphodelaceae), a major commercial and therapeutic succulent plant, is widely farmed for its leaf gel and utilized extensively in the pharmaceutical, cosmetic, nutraceutical, and food sectors. The conventional replication of Aloe vera by offsets or suckers is sluggish, provides limited planting material, and is sometimes linked to disease carryover from the parent stock, limiting large-scale production to satisfy growing industrial demand. Tissue culture micropropagation provides a reliable method for rapid multiplication of disease free and true-to-type plants but conventional protocols based on high concentrations of purified plant growth regulators, commercial gelling agents, and sucrose may be economically unviable for large scale production especially for nurseries in the developing world that lack resources. The present study was undertaken to standardize a low cost micropropagation technique of Aloe vera by replacing expensive culture ingredients with locally accessible cheaper alternatives and to analyze the consequent field establishment performance of the regenerated plantlets. Shoot tip and axillary bud explants were surface sterilized and cultured on Murashige and Skoog (MS) medium supplemented with different concentrations and combinations of 6-benzylaminopurine (BAP) and naphthaleneacetic acid (NAA) using both commercial-grade and cost-reduced formulations in which agar was replaced with locally available isabgol (Plantago ovata husk) and sucrose was partially replaced with commercial-grade sugar. Best shoot multiplication was obtained on MS medium with 2.0 mg/L BAP and 0.5 mg/L NAA with an average of 8.6 shoots per explant and the low cost medium formulation was statistically comparable in multiplication rates (7.9 shoots per explant) at approximately 61% lower cost per liter of medium. Half strength MS media supplemented with 1.0 mg/l indole-3-butyric acid (IBA) had the best rooting response with an average of 6.4 roots per shoot and 94% rooting frequency. Hardening was done in a graded acclimatization regime with sand-soil-vermicompost substrate to get 88% survival during ex vitro acclimatization. The field establishing studies revealed 82% survival of the regenerated plantlets over a period of six months with growth characteristics similar to that of traditionally produced offset-derived plants at conclusion of the observation period. Overall, these results suggest that multiplication and field establishment results are statistically similar to those obtained with standard commercial protocols but with a considerably lower cost of the micropropagation protocol. This is a feasible approach to increase Aloe vera planting material production in low resource environments.