Western analysis of pMsrA, MsrB1, and MsrB2 abundances in the different organs of Arabidopsis plants. Soluble proteins (25 μg per lane) were separated by SDS-PAGE. R, Root; YL, young leaf; ML, mature leaf; OL, old leaf; ST, stem; FB, flower bud; F, flower; Si, silique; S, seed. The sera raised against poplar pMsrA and Arabidopsis MsrB were used diluted 1:1,000. The bands corresponding to pMsrA, MsrB1, and MsrB2 were revealed at 25, 17, and 15 kD, respectively.