Unit 2 Pla

Notes

Unit 2 Plant Structure and Function Dicot root In roots, the vascular tissue forms a central core (like rope) giving a flexible strength as the roots push their way through the soil moving around stones and other obstacles. In (left) typical dicots, the vascular tissue forms an X shape in the center of the root. Root 1. Dicot root ( Ranunculus) Epidermis (one layer of cells) Cortex  Epidermis: single outer layer of cells with a very thin cuticle.  Cortex is thick and made up of rounded parenchyma cells. The parenchyma cells store starch.  Water passes through the cells and in the intercellular spaces heading for the xylem. Vascular bundle or tissue Root 1. Dicot root ( Ranunculus)  Endodermis: a single layer of tightly packed parenchymal cells that possess suberized, waxy, waterproof bands called Casparian strips. The walls between adjacent endodermal cells contain a suberin band (the Casparian strip) that blocks apoplastic flow, forcing water and solutes to cross cell membranes and allowing selective uptake (symplastic route).  Pericycle: single layer of cells beneath the endodermis. These are lateral meristematic cells that divide by mitosis, making the root thicker...