Question

Internal Structure of Roots A Photograpvic Atlas for the Botanry Laboratory, 7e; p. 133) b. How does this compare with the cortex of the sunflower (Helianthus) stem? Herbaceous Dicot Root c. Give a possible reason for this difference. (7 Examine a prepared slide of a cross section of a buttercup Ramunculus) root. All of the tissues seen will be primary tissues. What does this mean? (3) S. Figure S$.6 shows the main regions of the Ramunculas aria root. Label the epidermis, cortex, and stele. Ar enstem 6. The numerous small structures in the cortex cells are starch grains. What does this tell you about the function of the root cortex? 1. Using low power, note the three main regions of the root: the central vascular cylinder, or stele, the epidermis and the region between the epidermis and the stele, the 7. The endodermis is the innermost layer of the cortex cortex 2. Next, examine the following tissues in more detail The radial and transverse walls of the endodermal with high power: are impregnated with suberin, a waxy material. 3. The epidermis is a single layer of cells surrounding the This band, the Casparian strip, restricts the movement of material into the stele. entire root In the buttercup, some of the endodermal cells 4. The root cortex of Ramunculas consists of several layers may have developed uniformly thickened cell walls. If of cells, but these are not in an orderly pattern. Is this a simple or complex tissue? so, try to find some that are not so thickened but stil show the Casparian strip. These are referred to as transfer cells. a. What type of tissue is found here? (5) 8. The stele includes all of the tissues enclosed by the endodermis.

Answer 1

Answer

4) Root cortex of dicot plant is made of simple parenchyma tissue which differrntiate into outer exodermis which is simgle layered, middle cortical layer which is multilayered and endodermis which is single layered.

a) All of these are nothing but simple parenchyma tissue.

b) and C) sunflower is a dicot. Its cortex is composed of three regions

- hypodermis : which is collenchymal origin

- general cortex : parenchymal origin with large intercellular spaces

-endodermis: rich in starch grains

6) starch granules are responsible for creating osmotic gradient across the cell which helps in absorption of water by osmosis. Also starch grains provides energy for active absorption of minerals from the soil by the root