The epidermal, ground and vascular tissue systems. Then the inner structure of a dicot and a monocot root, stem and leaf, and what tells them apart under the microscope.
3 lessons, about 1 h 30 min3 simulations10 problems3 practice questionsPython in every lesson
Created by StemPy LabThe plant body has three tissue systems. The epidermal system is the outer skin, with the cuticle, stomata, root hairs and trichomes. The ground system fills the body, as cortex, pith, medullary rays and mesophyll. The vascular system carries water and food, in open or closed, conjoint or radial, endarch or exarch bundles.
A root has epidermis with root hairs, cortex, endodermis with Casparian strips, pericycle and radial bundles. A dicot root has a few xylem strands, often four (tetrarch), and a small pith. A monocot root has more than six (polyarch) and a large pith. A dicot stem has open bundles in a ring round a pith. A monocot stem has scattered closed bundles and no distinct pith.
A dicot leaf is dorsiventral: upper and lower epidermis, with more stomata below, and a mesophyll of palisade parenchyma on top and spongy parenchyma below. Veins have xylem facing up and phloem facing down, in a bundle sheath. A monocot leaf is isobilateral: the mesophyll is not divided, the stomata are on both faces, and bulliform cells help the leaf to roll.
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