Figure 7. Performance of PfHSP17.2-overexpressing transgenic plants under cold stress. (a) Cold tolerance of the PfHSP17.2 transformants; (b) proline content; (c) chlorophyll content; (d) POD changes. Error bars indicate SD (n=3). *p<0.05, ** p<0.01. WT, wild type; L223, L253, two transgenic Arabidopsis lines.