BIOL 2242 Lecture Notes - Lecture 16: Metal Toxicity, Arceuthobium, Prunus Pensylvanica

• School: University of Manitoba
• Department: Biological Sciences
• Course: BIOL 2242
• Professor: Isobel Waters

Document Summary

Topic 4: establishing a foundation the primary root (chapter 24) Including toxic heavy metals e. g. hg, cd: detect environmental conditions. Summer 2017: via contraction of parenchyma cells in cortex, xylem vessels act as corkscrew, air roots (fig. Air roots on languncularia (white mangrove) (p. 573: also called pneumatophores, breathing tubes, grow out of water to access oxygen, negatively geotropic, e. g. , mangroves, aerial roots (fig. 24. 21, p. 576) orchid green cattleya (root tip: on shoots of epiphytes (epi- above, phyte- plant) photosynthesizes, one of only species with multiple layers of epidermis) Absorb moisture: aerial roots of orchids have velamen. Primary root retained: produces laterals (branch roots, major lateral assumes dominance if primary dies, b) fibrous. System develops from adventitious (prop) roots: arise from base of stem, branch extensively, lack of dominant axis. 24-1, p550: oat (avena sativa) at 31-80 days. 6m alfalfa: most mineral uptake occurs in top 1m.