Transport Of Substances In Plants

Key Notes :

Need for Transport in Plants

  • Plants require the transport of water, minerals, and nutrients to maintain life processes.
  • Transport is necessary to distribute water from roots to leaves, nutrients from leaves to other parts, and minerals from soil to the plant body.

Types of Substances Transported

  • Water and Minerals: Absorbed by the roots from the soil.
  • Nutrients: Such as glucose, produced during photosynthesis, are distributed from the leaves to other parts of the plant.

Transport of Water and Minerals (Xylem)

  • Xylem: The tissue responsible for transporting water and dissolved minerals from roots to the entire plant, especially to the leaves.
  • Root Pressure and Capillary Action: Help in pushing water upward through the plant.
  • Transpiration Pull: The loss of water vapor from leaves creates a pull that helps draw water up from the roots.

Transport of Food and Nutrients (Phloem)

  • Phloem: The tissue responsible for transporting food (mainly sugars) produced during photosynthesis from leaves to other parts of the plant (stems, roots, flowers).
  • This process is called Translocation, which occurs in all directions (from source to sink).

Role of Stomata

  • Tiny pores present on the surface of leaves called stomata allow water vapor to escape during transpiration, which helps in the upward movement of water through the plant.

Transpiration

  • The process by which water evaporates from the leaves, creating a negative pressure that pulls water and minerals up from the roots via the xylem.

Importance of Transpiration

  • Helps in cooling the plant.
  • Aids in the transport of essential minerals from the soil.
  • Maintains the water balance within the plant.

Root Hairs

  • Tiny hair-like structures on roots that increase the surface area for water and mineral absorption from the soil.

Active and Passive Transport

  • Passive Transport: Movement of substances like water through osmosis without the use of energy.
  • Active Transport: Movement of minerals against the concentration gradient using energy (ATP).

Role of Vascular Bundles

  • Xylem and phloem are organized into vascular bundles, which act like transport highways throughout the plant.

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