Which plant features reduce their dependence on water but still require moist conditions? Class 9

Which plant features reduce their dependence on water but still require moist conditions? Class 9

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Question 1.

Which plant features reduce their dependence on water but still require moist conditions? Class 9

Answer:

Pteridophytes like ferns have features that reduce dependence on water compared to thallophytes and bryophytes: They possess true roots, stems, and leaves, which are well-developed structures adapted for life on land. They have vascular tissues (xylem and phloem) that transport water and food throughout the plant, reducing the need for all parts to be in direct contact with water. However, pteridophytes still require moist conditions because they depend on water for reproduction - the male reproductive cells must swim through water to reach the female cells for fertilisation. Thus, they are better adapted to land than bryophytes but are not completely independent of water.

Question 2.

Why do taller plants need specialised transport tissues? Class 9

Answer:

Taller plants need specialised transport tissues because water, minerals, and food need to travel over large distances within the plant. In simple, small plants like thallophytes and bryophytes, the plant body is in close contact with the environment, and water and nutrients can be absorbed and distributed directly through diffusion. However, in taller plants, the distance between roots (which absorb water and minerals from soil) and leaves (where photosynthesis occurs) is very large. Diffusion alone cannot efficiently transport substances over such distances. Therefore, specialised vascular tissues - xylem (for transporting water and minerals upward from roots to leaves) and phloem (for transporting food prepared in leaves to other parts of the plant) - are necessary to ensure efficient transport throughout the plant.