BIOL 112 Lecture Notes - Lecture 17: Seedling, Coleoptile, Radicle

• School: McGill University
• Department: Biology
• Course: BIOL 112
• Professor: Varied

Document Summary

1- ground tissues = 2 kinds differ by nature of cell walls: parenchyma most common- thin cell walls - functions = storage/photosynthesis/secretion. Thick but flexible cell walls serve mechanical support functions: collenchyma, sclerenchyma thicker walls than collenchyma provide mechanical support. Epidermis cells that cover outside of plant parts guard cells that surround stomata/hair. No cuticle = would prevent them from absorbing water. In aerial portions of plants epidermal cells secrete waxy protective substance = cuticle. Consists of xylem & phloem form vascular bundles: xylem - 2 types of xylem cells. Conduction of water/mineral & functions in mechanical support. Have 2nd cell wall for additional strength dead mature cells - no cellular component. *some places in walls of xylem cells have pits = absence of 2nd cell wall. Long &tapered where water passes from one to another through pits. Shorter & wider w/ have less or no taper at ends. Perforations where h2o pass through from 1 vessel member to next.