如果我们用手指轻轻碰一碰含羞草的叶子,它马上就闭合起来,紧接着整个叶子又垂下去,过了片刻,它又渐渐恢复原状。含羞草为什么有这种奇妙的现象呢?原来在它的叶柄基部,复叶的小叶基部都有一个比较膨大的部分,叫做叶枕,它对刺激的反应最敏感。在叶枕的中心有一个大的维管束,维管束的周围充满着具有许多细胞间隙的薄壁组织。当我们轻轻碰一下叶子,刺激立即传递到小叶柄基部的叶枕,于是这个叶枕的其上半部薄壁细胞里的细胞液被排出到细胞间隙中,使叶枕上半部细胞的膨压降低,而下半部薄壁细胞仍保持原来的膨压,结果就引起小叶片的直立而两个 If we touch the leaf of the mimosa gently with our fingers, it closes right away, and then the whole leaf hangs down again. After a while, it gradually regains its status. Mimosa why such a wonderful phenomenon? In the base of its petioles at the base of the compound leaflets have a more swollen part, called the leaf pillow, the most sensitive to the stimulus response. There is a large vascular bundle in the center of the leaf pillow and the periphery of the vascular bundle is filled with parenchyma with many intercellular spaces. When we gently touch the leaves to stimulate the leaf pillow immediately passed to the base of the petiole, then the upper part of the leaf pillow in the parenchyma cell liquid is discharged into the cell gap, so that the upper part of the leaf pillow inflated Pressure drop, while the lower half of the parenchyma cells still maintain the original turgor, the result will cause the erect small leaf and two