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Tissues — Science STD 9 — Question

Gujarat BoardEnglish MediumSTD 9ScienceTissues3 Marks
Question
Aquatic plants have the ability to float rather than being submerged in water. How?
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Answer

Usually it is because their leaves have some spongy cells full of air. Some of them have spongy stems filled with air. Many also have a water repellent surface, so they don't get soaking wet when they go under the surface. Some have minute scales that trap air and help the leaves bounce back to the surface after they get pushed under water.
Examples of the water repellent scales can be seen on Salvinia plants. Water repellent leaves are seen on water lilies. Spongy air filled stems appear on the floating water chestnut. Air filled leaves are seen in Amazon frogbit or duckweeds.

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