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Plant regeneration from nodal segments and protocorm-like bodies (PLBs) derived from Cattleya maxima J. Lindley in response to chitosan and coconut water

Abstract:

Two experiments on the in vitro propagation of Cattleya maxima were conducted to determine the optimum concentration of chitosan and coconut water in culture media of nodal segments and protocorm-like bodies (PLBs). In the first experiment, nodal segments were grown in Murashige and Skoog (MS) medium with 0, 70, 90, 150, 180, 200 or 250 mg l-1 chitosan. The percentage of explants with formed axillary shoots was calculated after 30 days of in vitro culture and morphogenic parameters were recorded after 90 days of in vitro culture. Highest percentage of nodal segments cultured on medium with 250 mg l-1 chitosan formed axillary shoots (85% higher than the control treatment) and all the morphogenic parameters assessed. In the second experiment, PLBs were also grown on MS medium with a mixture of chitosan and coconut water (doses l-1 of each): T1 (50 mg + 50 ml), T2 (80 mg + 100 ml), T3 (100 mg + 150 ml), T4 (125 mg + 200 ml), and T5 (150 mg + 200 ml). Number of shoots and size in PLBs, central width leaf and root length in each PLBs were recorded at different periods of in vitro culture. Two combinations of chitosan and coconut water (T4 and T5) resulted in the lowest values of explant necrosis (9-times lesser than the control) and highest shoot number, size, central width leaf, and root length (depending on the parameter assessed with increases from 2 to 4-times compared to the control). These results confirm that the combination of both chemical compounds at higher concentration resulted in a better growth of PLBs.