Leaves, Roots, Stems Plant organs and their functions
Leaves
Leaf Parts Two major parts to the leaf: Blade Petiole
Leaf microanatomy Epidermis and cuticle do what? Mesophyl does what? Veins do what? Guard cells in the lower epidermis do what?
Photosythesis The purpose of photosynthesis is to produce organic (carbon-based) molecules (such as sugars). The plants use these molecules for two purposes: As an energy source As building material
The mesophyl in this leaf is what kind of tissue? 1.Dermal 2.Ground 3.Vascular
On your own paper, list plant leaves or products of plant leaves that you have used in the past few days. What qualities of the leaves made them useful? WORKTOGETHERWORKTOGETHER
Roots
Types of root systems Taproot systems: main root, lateral branches. Fibrous root systems: lose the primary root, replaced by many smaller roots.
Root Anatomy Parts of a root: Root cap Root meristem Zone of elongation Zone of maturation
Roots: Epidermis Root epidermis lacks a cuticle, and is porous. Usually has many root hairs. Water enters through membranes of epidermal cells or through spaces between cells.
Roots: Cortex The cortex layer is made up of parenchyma cells. What is the main function of these cells? Endodermis separates the cortex from the vascular cylinder.
Roots: vascular cylinder Casparian strip around endodermis cells controls water movement. Why? Pericycle: layer of parenchyma cells, inside of endodermis, from which branch roots can arise.
Roots: vascular cylinder Vascular cylinder contains: Phloem: what does phloem do? Xylem: What does xylem do?
The vascular cylinder of a root contains mostly what kind of tissue? 1.Dermal 2.Ground 3.Vascular
If a tap root is thick and contains a lot of starchy parenchyma cells, what is a function of that root? 1.Reproduction 2.Food storage 3.Photosynthesis 4.Support
On your own paper, list any roots that you have used in the past few days. What qualities of the roots made them useful? WORKTOGETHERWORKTOGETHER
Stems
Stems: Epidermis In herbaceous plants and young woody plants, the stem is covered with epidermis. Epidermis secretes cuticle, has stomata, and may be photosynthetic.
Stems: Cortex and Pith Cortex layer contains parenchyma cells and vascular bundles. Pith makes up the center of the stem, and is absent in hollow stems.
Stems: vascular tissue Vascular bundles are in the cortex. Between the xylem and phloem is the vascular cambium, a meristem layer. What is it for?
Stems: Secondary growth Secondary growth is seen in woody plants. This kind of growth produces stronger, thicker stems from the vascular cambium and cork cambium.
Stems: wood and bark What tissue makes up the wood of a tree trunk? (hint: water flows there.) What tissue makes up the “green bark?” (hint: sap flows there.) Dead cork cells make up the bark.
Stems: Annual Rings Trees in temperate zones grow at different rates in different seasons, causing annual rings to form. In some parts of the tropics, if seasons vary little, tree rings are indistinct.
Wood is made up of what tissue? 1.Dermal 2.Ground 3.Vascular
Stems that contain lots of vascular tissue are primarily for: 1.Food storage 2.Absorbing water 3.Transporting materials 4.Protecting the plant
On your own paper, list any stems or products of stems you have used in the last few days. What qualities of these stems made them useful? WORKTOGETHERWORKTOGETHER