摘要或動機

The special life cycle of the Nymphoides indica: The veins and petioles of the pleustonic leaves can asexually reproduce adventitious buds. Pleustonic adventitious buds will change the density of the plants and sink into water. When the root of submersible plants attaches to the bottom of the pool, they will extend stems to the water surface and resume the life cycle. Reticulate sigmons and astral sclerenchyma appears in the process of transformation. Astral sclerenchyma merely appear in the species of which its leaves float above the water surface, and Nymphoides sp. are the most obvious. The cell wall thickness of astral sclerenchyma is even. The cells are hollow and full of water, and they will utilize water to change turgor between axes and spines. This is also proved in imitating experiments. The reticulate sigmons are frequently seen among aguatic plants, and the horizontal structures prevent air space from collapsing. These two structures make the thin stems of Nymphoides indica sustain the leaves instead of being crushed by the floating water. 印度莕菜 ( Nymphoides indica )獨特的生長週期：浮水型葉的葉脈和葉柄可以無性繁殖不定芽，浮水型的不定芽會改變植株的密度而沉入水中，當沉水型植株的根系在池底固著後，便會以莖延伸出水面，再次展開浮水型葉的成長週期。轉變過程中會出現網狀的橫膈和星狀厚壁細胞。星狀厚壁細胞僅出現於葉片需由水中浮出水面生長的植物種類，而莕菜屬植物更明顯。星狀厚壁細胞其細胞壁厚度均勻，細胞中空且充滿水分，會利用水分在中軸與突起的棘間移動來改變膨壓變化，在模擬的實驗中也得到證實。網狀的橫膈在水生植物中是較常見到的構造，水平方向的支撐可以讓氣室不會塌陷，兩種構造的作用下使得印度莕菜細長的莖能夠支撐葉片，不會被流水沖斷。