Fig. 2

Recovery for different sample preparation protocols. A total of 100 μg of protein for each protocol were prepared for protein digestion. The protein and peptide amounts were determined using the amino acid analysis method after the protein was extracted from the leaf and the peptide was desalted on R2 reversed phase microcolumns, respectively. Subsequently, the recovery rate of sample preparation was calculated on basis of these amounts. Data are mean ± SD (n = 3). Different letters indicate significant difference (P < 0.05) between different protocols