2Why do plants have stems? They have two functions:moving materials (water, minerals, food)supporting the rest of the plantThe stem has rings called “nodes”the space in-between is called the “internode”At each of the nodes is a “bud”
4Stem 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
6Vascular Bundles The arrangement of the bundles: Inside the bundles: Allows dicot stems to grow thicker & tallerTrees 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 sizeInside the bundles:xylem tissue moves materials up the plantphloem moves materials down the plant
8Functions of the RootsAnchor the plantAbsorb water and nutrients
9Different Types of Roots Tap Roots – one main rootEx. CarrotsFunction – storage of excess foodFibrous Roots – branched rootsSpread out in the soil in search of water and nutrientsRoot Hairs – tiny hair-like rootsAbsorbs much of the water and nutrients for the plant.
10Parts of a seedEmbryo - develop into all the different tissues that will ultimately make up the mature plantSeed Coat - protects the internal parts of the seedEndosperm - serves as a food source for the developing embryo