The plant’s inner highway Plant Parts - Stems The plant’s inner highway 2001 AgriTeach.comTM (12901ms)

Why do plants have stems? They have two functions: moving materials (water, minerals, food) supporting the rest of the plant The stem has rings called “nodes” the space in-between is called the “internode” At each of the nodes is a “bud”

Stem Anatomy - External

Stem Anatomy - Internal When a plantlet develops from a seed, it may have one or two seed leaves or “cotyledons” Plants with one are “monocots” Grasses - lawn grasses, corn, wheat, etc. Plants with two are “dicots” Other plants - trees, beans, alfalfa, etc. Both types have different arrangements of their “vascualar bundles” These are the veins and arteries of the plant

Vascular Bundles

Vascular Bundles The arrangement of the bundles: Inside the bundles: Allows dicot stems to grow thicker & taller Trees have active, living tissue around the outside of the trunk; inactive heartwood on the inside. To make syrup, we tap the outside because it is busy moving sap (nutrients). Limits monocots to a certain size Inside the bundles: xylem tissue moves materials up the plant phloem moves materials down the plant

Plant Parts - Roots

Functions of the Roots Anchor the plant Absorb water and nutrients

Different Types of Roots Tap Roots – one main root Ex. Carrots Function – storage of excess food Fibrous Roots – branched roots Spread out in the soil in search of water and nutrients Root Hairs – tiny hair-like roots Absorbs much of the water and nutrients for the plant.

Parts of a seed Embryo - develop into all the different tissues that will ultimately make up the mature plant Seed Coat - protects the internal parts of the seed Endosperm - serves as a food source for the developing embryo

Parts of the Seed endosperm

Germination * When a seed sprouts and begins to grow

Monocot vs. Dicot Dicot Germination Monocot Germination