?新鲜的叶类蔬菜表面常残留水溶性有机农药。现取同一新鲜蔬菜若干浸入一定量的纯水中，每隔一定时间测定细胞液浓度，结果如图所示。以下叙述正确的是( )。
- A.AB段细胞吸水.细胞体积明显增大
- B.B点细胞液浓度与外界溶液浓度相等
- C.BC段细胞质壁分离复原，原生质层恢复到原来位置
- D.此曲线说明有机农药溶于水中容易被植物细胞吸收
正确答案及解析
正确答案
解析
图示AB段细胞液浓度减小，说明细胞吸水，由于植物细胞壁的存在，细胞体积不会明显增大，A错误。B点细胞液浓度大于外界溶液，细胞壁限制了细胞继续吸水，B错误。C点细胞液浓度低于A点，说明BC段开始细胞失水，但没有发生质壁分离，C错误。BC段又失水，是因为外界有机农药等随水分子进入细胞内，说明有机农药溶于水中容易被植物细胞吸收，D正确。
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