4 6 Plant Growth Plant Meristems Meristematic cells

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4. 6 – Plant Growth Plant Meristems Meristematic cells are located near the tips

4. 6 – Plant Growth Plant Meristems Meristematic cells are located near the tips of the roots, in the growing parts of the shoots, and just beneath the outside layer of the stem of woody plants. Apical and lateral meristems are responsible for plant growth.

Apical meristems result in the growth in length of roots and shoots and the

Apical meristems result in the growth in length of roots and shoots and the production of leaves and flowers. Lateral meristems, which produce cork and vascular tissues, are found only in woody plants and result in the growth in width of stems.

Apical Meristems The growing tips of roots have three distinct regions: the meristem region

Apical Meristems The growing tips of roots have three distinct regions: the meristem region of cell division, the region of elongation, and the region of maturation. • When meristem cells first divide in the tips of roots, many of them begin to elongate making the root longer. • Apical meristems of shoots are located in buds at the very tips of the growing stem and also occur at points along the stem.

Lateral Meristems Lateral meristems form two cylinders, one inside the other, that run the

Lateral Meristems Lateral meristems form two cylinders, one inside the other, that run the full length of the shoots and roots. As the plant grows in diameter, the outer lateral meristem produces new dermal tissue, called cork, to replace the old epidermal cells. The inner lateral meristem produces new phloem tissue on its outer surface and new xylem tissue toward its interior.

The xylem keeps accumulating causing the trunk in increase in diameter year after year.

The xylem keeps accumulating causing the trunk in increase in diameter year after year. This creates xylem rings which can be used to determine the age of the tree.

Vegetative Reproduction Many plants use vegetative reproduction to produce new young plants with exactly

Vegetative Reproduction Many plants use vegetative reproduction to produce new young plants with exactly the same genetic information as the parent plant. An example of this is strawberry plants. Humans take advantage of vegetative reproduction to produce many identical new plants from one parent plant. Tissue culture propagation is a modern technique used to mass-produce plants.