Principal component analysis of gene expression in heat, drought, combined heat and drought and control experiments.

<p>Prior to principal component analysis, genes were filtered by calculating the coefficient of determination (CoD), with the threshold of CoD > 0. The biological replicates are grouped with an ellipse, colored by experiment; green: control, dark gray: heat, yellow: drought, dark blue: combined heat and drought. The mean of four biological replicates is denoted by “X”.