Welcome to Northwest Plants Northwest Indian College ENVS

Welcome to Northwest Plants Northwest Indian College ENVS 201 Spring Quarter 2012

Plant Parts vegetative organs: reproductive components: stems flowers roots fruits leaves seeds

Today: Roots

bean seedling (Phaseolus) showing root system

Root Features & Functions anchor plants to substrate (e. g. , soil) water and nutrient uptake may be variously modified (e. g. , adventitious roots, food storage, etc. ) interactions with soil, microorganisms (in root nodules) and fungi (mycorrhizae)

adventitious roots (in Coleus)

roots modified for food storage Carrot (Daucus) Beet (Beta) sweet potato (Ipomoea)

mycorrhizal root

hogpeanut (Amphicarpaea bracteata) with root nodules

bacterium—> root cells of pea (Pisum) in root nodules (infected with Rhizobium)

Root Features primary root - the main root of the root system secondary root - a branch rootlet - a small root nodule - swelling produced by bacteria (e. g. , in legumes), site of nitrogen-fixing bacteria (Rhizobium)

Root Types taproot system (common in eudicots, e. g. , dandelion, burdock & carrot) fibrous root system (monocots, e. g. , grasses, and some eudicots) adventitious roots (e. g. , Coleus)

taproots of burdock (Arctium) & dandelion (Taraxacum)

Root Regions root tip - tip (apex) of a young root apical meristem - produces cells that lengthen roots root lateral meristem (vascular cambium) produces cells that thicken roots, vascular tissues root cap - mass of cells at root tip, protective & maintains downward growth root hair - outgrowth of outer cell of root, extends absorbing region of root

root tip root l. s. showing root tip <—apical meristem <—root cap

root hairs (in grass seedling)

vascular—> cambium basswood (Tilia) lateral meristem (vascular cambium)

Questions & Comments?

Roots are cool.

Hy’shqe!