Plant cells usually have a large vacuole in a central position. It contains cell sap, which is a solution of chemicals including useful substance, e.g. pigments, sugars and other food substance.Some cell sap also contain waste. When the vacuole is full of water, the cell becomes turgid and hence, provides support to the plant. 書裡沒有嗎 ? ================== 考完試後什麼也不記得了,要直接抄書= = [ 本帖最後由 abc666 於 9/6/2007 20:24 編輯 ] |