ROOT-ANATOMY.pptx

1. ROOT ANATOMY

2. EXTERNAL STRUCTURE Organization Of Root Structure Structure Of Individual Roots

3. ORGANIZATION OF ROOT SYSTEM Taproot – develops and forms the embryonic root called the radicle, that was present in the seed; after germination, it grows extensively and usually become the largest root in the system.

4. Fibrous roots - the opposite of a taproot  system. It is usually formed by thin, moderately branching  roots growing from the stem. A fibrous root system is universal in  monocotyledonous plants and  ferns . The fibrous root systems look like a mat made out of roots when the tree has reached full maturity.

5. Adventitious roots - roots are plant roots that form from any non-root tissue and are produced both during normal development.

6. STRUCTURE OF INDIVIDUAL ROOTS

7. INTERNAL STRUCTURE Root Cap Root Apical Meristem Region of Elongation Region of Differentiation or Maturation

8. ROOT CAP

9. ROOT CAP Thimble-shaped mass of parenchyma cells at the tip of each root protects the root from mechanical injury. Dictyosomes or Golgi bodies release a mucilaginous lubricant (mucigel) cells that lasts less than a week, then these die possibly important in the perception of gravity (i.e., geotropism or gravitropism) amyloplasts (also called statoliths) appear to accumulate at the bottom of cells.

10. ROOT APICAL MERISTEM Apical meristem - cells divide once or twice per day. The transitional meristems arise from the tips of roots and shoots. These include: – the protoderm (which forms the epidermis) – the ground meristem (which forms the ground tissue) – the procambium (forms the primary phloem and xylem) - quiescent center (reserve meristem)

11. Region of Elongation It is the region where cells expand greatly; some meristematic activity continues, out mostly cells are enlarging. In this region, tissues are all permeable.

12. Region of Maturation or Differentiation Root hairs develop as protuberances from epidermal cells. Increase the surface area for the absorption of water.

13. ENDODERMIS   Is the central, innermost layer of the cortex in land plants.   It is a cylinder of compact living cells, the radial walls of which are impregnated with hydrophobic substances to restrict the apoplastic flow of water to the inside. The boundary between the cortex and the stele.

14. CASPARIAN STRIP A band of waterproof, corky tissue that is found on the side and walls of the endodermis of roots.   The strip prevents water from entering the pericycle except through the cytoplasm of endodermal cells; this may be important in producing root pressure.

15. The Casparian strip is a waxy-like material or substance that layers around the endodermis. Due to its hydrophobicity, water or dissolved minerals in the water will be prevented from moving from the cortex into the vascular cylinder and vice versa. It will prevent anything from moving between the cells. So if any material wants to move from the cortex to the vascular cylinder, they now have to first move into a cell, then will be transported cell to cell through connections between cells. The purpose of this action or mechanism is to filter out which materials are needed to be transported into the vascular cylinder from those materials that are unnecessary or harmful to the plant.

16. DICOT ROOT

17. MONOCOT