Purification of Chloroplasts

Chloroplasts were purified by the procedure previously described by Rhodes et al.（1981）.Freshly harvested leaves were homogenized in a metal Waring blender with liquid nitrogen（Rhodes and Kung，1981）.When the liquid nitrogen had evaporated and the temperature had warmed to—5℃at room temperature，three weight volumes of isolation buffer（Walbot，1977）were added to the powder with rapid mixing.The suspension was filtered through miracloth and centrifuged at 1，500×g for 15 min.The crude chloroplast pellets were gently resuspended in the same buffer and purified through a discontinuous silica sol gradient（Walbot，1977）containing 0.24 mol/L sucrose throughout.(https://www.daowen.com)