Acclimatization of In Vitro-raised asiatic hybrid lily plants in subtropical climate and associated changes in stress proteins and antioxidant enzymes

A protocol for direct differentiation of shoots from leaf segments of Lilium cv ‘Orange Pixie’ was developed through in vitro methods. After hardening, tissue-raised plants were transferred in the open field conditions from the very beginning. The acclimatized plants not only grew well but flowered also at 43°C under subtropical climatic conditions and regenerated a new bulb at their base after flowering. The activity of different antioxidant enzymes like superoxide dismutase, peroxidase, catalase and ascorbate peroxidase and their isoenzymes patterns showed differential up and down regulation in control and in different parts of in vitro-raised plants. Characterization of both high and low molecular mass heat-shock proteins (HSPs) was done using HSP70 and HSP 18.1 antibodies against pea (Pisum sativum L), respectively. The level of high molecular mass proteins did not change much and was found to be of constitutive nature, whereas a new small protein of 21 kD was induced only in tissue culture-raised flowering (TF) plants indicating the possible role of this stress protein in acclimatization and flowering of Asiatic hybrid lily plants at 43°C under tropical conditions. The amount of this protein was much higher in petals as compared to stem and leaf.