Roots Stems PLANT ANATOMY Copyright Pearson Prentice Hall

Roots & Stems PLANT ANATOMY

Copyright Pearson Prentice Hall PLANT ANATOMY Roots �absorb water and dissolved nutrients. �anchor �protect plants in the ground. the plant from harmful soil bacteria and fungi.

ROOT STRUCTURE AND GROWTH � The root’s surface is covered with cellular projections called root hairs. � Root hairs provide a large surface area through which water can enter the plant. Root hairs

ROOT STRUCTURE AND GROWTH � Roots grow in length as their apical meristem produces new cells near the root tip. � These new cells are covered by the root cap Apical meristem that protects the root as it forces its way through the soil. Root cap

Copyright Pearson Prentice Hall TYPES OF ROOTS � The 1. two main types of roots are: Taproots - primary root that grows long and thick � 2. Ex: carrot Fibrous roots - branch to such an extent that no single root grows larger than the rest. � Ex: grasses

PLANT ANATOMY Stems � produce leaves, branches and flowers � hold leaves up to the sunlight � transport substances between roots and leaves

Copyright Pearson Prentice Hall PRIMARY GROWTH OF STEMS Primary growth Stem growth Apical meristem � All seed plants undergo primary growth, which is an Primary increase in length. growth � For the entire life of the plant, new cells are produced at the tips of roots and shoots. Leaf scar Year 3 21

Copyright Pearson Prentice Hall SECONDARY GROWTH OF STEMS Secondary Growth of Stems �The method of growth in which stems increase in width is called secondary growth. � In conifers and dicots, secondary growth takes place in the vascular cambium and cork cambium.

Copyright Pearson Prentice Hall SECONDARY GROWTH OF STEMS Secondary Growth of Stems �The method of growth in which stems increase in width is called secondary growth. � In conifers and dicots, secondary growth takes place in the vascular cambium and cork cambium. � Produces wood Wood Bark