Plant systems

3 Systems of Plants we will study Root system Stem system Leaf system

Main Functions of the Root system 1. Anchorage and support. The plant root system anchors the plant in the soil and provides physical support. 2. Absorbing nutrients. The plant root system absorbs water, oxygen and nutrients from the soil, mainly through the root hairs. From the root, these are moved upward. 3. Storing nutrients. The root serves as storage organ for water and carbohydrates as in the modified, swollen roots of carrot, sweet potato and yams. Some roots are capable of storing large amounts of water; the taproots of some desert plants store more than 70 kg of water (Moore et al. 2003).

Levels of organization – root system Cell = Plant cell Tissue (vascular) = xylem, phloem Organ = root Organ system = root system Organism = plant

2 main Types of roots Taproot Fibrous A large single root that usually grows straight down Fibrous Numerous roots about the same size

Functions of stem system 1. The stem carries nutrients, and water and the products of photosynthesis (glucose and oxygen) between the plant’s roots and leaves, like plumbing pipes. 2. The stem also provides support for the plant and holds up the leaves so they are exposed to the sun. 3. The stem can help store water in some plants such as cacti.

Types of stems Aerial Subterranean Runner Above ground and usually vertical (tree trunks, dandelion stems) Subterranean Under ground and can resemble roots (ginger, potatoes, onions) Runner Run along the ground with roots coming off of them (strawberries)

Levels of organization – stem system Cell = Plant cell Tissue (vascular) = xylem, phloem Organ = stems Organ system = stem system Organism = plant

Functions of leaf system 1. Making food through photosynthesis. 2. Exchange of oxygen and carbon dioxide through stomata. 3. Evaporation of water on leaf surface and through stomata.

Levels of organization – leaf system Cell = Plant cell Tissue (vascular) = epidermal tissue Organ = leaf Organ system = leaf system Organism = plant

How are Plants Classified? We classify plants into one of two categories: 1) nonvascular plants (without plumbing) 2) vascular plants (with plumbing)

vascular vs nonvascular plants video clip

Non vascular plants Non vascular plants are plants that do not have vascular tissue They don’t have “pipes” to transport water and nutrients They depend on osmosis and diffusion to move materials from one part of the plant to another They are mostly small plants Examples: mosses, liverworts

Brain break 1. Stand up. 2. Take your right hand and grab your left ear. Keep your right arm close to your body. 3. Now take your left hand and touch your nose. 4. Uncross your arms and move your left hand to your right ear and your right hand to your nose. Your left arm should now be closest to your body. 5. Switch back and forth as fast as you can.

Non vascular plants

Vascular plants Have special tissues, vascular tissue, that delivers needed materials throughout the plant. Like pipes carrying water in your house Because they have vascular tissues, these plants have true stems, leaves, and roots Can be almost any size 2 types Non seed producers Ferns, horsetails, club mosses Seed producers (2 types) Flowering plants (angiosperms) Nonflowering plants (gymnosperms) Angiosperms vs Gymnosperms Preview

Vascular plants

Vascular tissue There are two types of vascular tissue: Xylem (water conducting tissue) Phloem (food conducting tissue) The purpose of the vascular tissue is to transport needed materials around the plant. It is similar to our circulatory system.

Xylem = water carrying tissue The xylem of a plant is the system of tubes and transport cells that circulates water and dissolved minerals. A plant has roots to absorb water. If a plant’s leaves need water and they are 100 feet above the ground, it is time to put the xylem into action! Xylem is made of vessels that are connected end to end for the maximum speed to move water around. They also have a secondary function of support. When someone cuts an old tree down, they reveal a set of rings. Those rings are the remains of old xylem tissue, one ring for every year the tree was alive.  Xylem tissue dies after one year and then develops anew (rings in the tree trunk).

Xylem Xylem Video

Phloem = food carrying tissue When the sugars from photosynthesis are made, they need to be given to every cell in the plant for energy. The phloem cells are laid out end-to-end throughout the entire plant, transporting the sugars and other molecules created by the plant. Phloem is always alive. What is the best way to think about phloem? Think about sap coming out of a tree. That dripping sap usually comes from the phloem. 

phloem Phloem Video

How is a plant different from an animal? Plants make their own food Photosynthesis Autotrophs Plants cells have cell walls Provides the shape and support for a plant.

Brain break 1.  Stand Up. 2.  Start by waving your right hand in front of you left to right.  Your palm should be facing away from you while keeping your hand with your fingers pointing up.  3.  Now stop that hand and have your left hand in front of you waving it up and down.   4.  Now practice moving them at the SAME TIME.  Do not move your hands going diagonally.   5.  Now switch to have your right hand up and down and your left hand left and right.  Do this faster and switch often to make it more difficult. 6.  Lastly, to increase the difficulty, have your arms crossed while doing this.