Monday, January 25, 2010

Chapter 35

Plant Structure and Growth





Vascular system and plants

The three basic plant organs are roots, stems and leaves
They are organized into a root system and a shoot system

Roots rely on sugar produced by photosynthesis in the shoot system. Shoots rely on water.
Roots are multicellular organs with important functions
  • anchor the plant, absorb minerals and water, and store organing nutrients.

A taproot system consists of one main vertical root that gives rise to lateral roots, or branched roots.

A stem is an alternating system of nodes. Each node contains internodes, which are stem segments between the nodes.

An axillary bud is a structure that has the potential to form a lateral shoot or branch.

An apical bud, or terminal bud, is located near the shoot tip and causes elongation of a young shoot.

  • apical dominance helpts to maintain dormancy in most nonapical buds.

The leaf is the maing photosynthetic organ of most vascular plants.

  • a leaf generally consists of a flattened blade and a stalk called the petiole, which joins the leaf to a node of the stem
passage way - vessels, vascular tissue
- xylem and phloem


Alteration of Generations






















Xylem Phloem
trachied (pit) steive tube
vessel element companion cell

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