Root systems:A root system is the network off all the roots of a plant; the system of roots and related organs that a plant develops.
What are the types of root systems? -Taproot: one main root, has no nodes • (carrot, evergreen, kochia) -Fibrous root: many nodes, branching root system (grasses)
Differences • Taproot • Survive Drought Better • Tend to grow straight down • Very thick center main root • Fibrous • Are thin and hair like • Usually shallow • Will typically dry out easily • Multiple root systems
Root Systems • Root cap- outermost part of a root • Tough cells that penetrate the soil • Pushes through soil partials • Xylem – carry water and mineral travel up the stem • Phloem – manufactured food travels down • Root hairs are small microscopic roots • Area of cell division • Allows roots to grow longer • New cell replace worn away cells • Area of cell elongation • Between the root cap and the plan base • Cells become longer • Cells become specialized
To help prevent soil erosion, which root system would be best? • Fibrous
What are the functions of stems? 1) transport water, nutrients, sugars 2) support leaves, flowers and fruit 3) store food
Stem Types • Woody: • Tough and winter hardy; often covered with bark • Herbaceous: • Succulent; often green; will not over winter in many climates
What are the types of stems? • Woody Stem: trees, shrubs, woody perennials 2) Grass Stem: hollow or filled 3) Herbaceous Stem: like woody but softer (clover, alfalfa) 4) Modified Stem: are plants like corms, rhizomes, and tubers (potatoes, ginger, and bulb plants)
Types of Modified Stems • Bulbs: (onion) • Tubers: (potato) • Stolons/Runners: above ground runner (strawberry) • Rhizomes: below ground runners (field bindweed or creeping jenny) • Tendrils: different types of vines have these to latch onto things (grapes) • Cladophylls: (prickly) most cacti fall under this category
What are the parts of a plant? Xylem and Phloem made up of parenchyma cells Node: swollen part of stem where buds form (leaves or stems grow here) Internode: stem tissue between nodes
What are the parts of a plant? Epicotyl: all of plant formed above cotyledonary node Cotyledons: leaves formed at first node (cotyledonary node) New shoots or budnormally grow out of the axil Axil is the upper angle above a leaf or flower stem, and the stalk Lenticels are pores that allow for gas exchange to pass
What are buds? • special tissue on stems that can grow into new plant parts
What are leaves? • undergo photosynthesis, exchange gases • Manufactures food for the plant by using light energy • Converts sunlight into food
What are leaf margins? • is the boundary area extending along the edge of the leaf. There are lots of different types of leaf margins that are important for plant identification
Common Types • The basic types of margins are:Entire: having a smooth edge with neither teeth nor lobes.Toothed : having a saw like margin with small tooth that can vary in size (from very small to medium), in sharpness (from needle-like to soft) and in shape (from rounded to points). Lobed: having some type of indentation toward the midrib that can vary in profundity and shape (rounded or pointed) and the incisions (sinus) go less than halfway to the midrib.Parted (or cleft): having some type of indentation toward the midrib that can vary in profundity and shape (rounded or pointed) and the incisions (sinus) go more than halfway to the midrib.
What is the difference between a simple leaf and a compound leaf? • simple leaf = 2 parts (leaf blade and petiole) • Petiole is the stem of the leaf, may or may not have one
What is the difference between a simple leaf and a compound leaf? • Compound leaf: leaf blade divided into leaflets
What are the different types of compound leaves? • Palmately compound
What are the different types of compound leaves? • Pinately compound
Buds are described according to: • 1) structures into which they grow • -Vegetative: leaves or stems • -Floral: flowers • -Mixed: both • 2) where buds appear on stem • -Apical: tips of stems • -if floral = bush • -if vegetative = vine • -Axillary: where leaf joins stem • -Adventitious: near wounds
Bud Arrangements • 3) How are Buds arranged? • Alternate (alfalfa) • Opposite (beans) • Whorled (not common)
Leaf Shapes……. • In botany there are many terms, usually derived from Latin, used to describe the shape of a plant leaf. The following are some of the basic ones dealing with leaf blade shapes • General overwiew: • Acicular: Having the shape of a needle Cuneate: Broad and truncate at the summit, narrowly triangular, and tapering toward the base; Deltoid: Triangular in outline, suggesting a capital delta. Lanceolate: Lance-shaped, tapering from a broad base to an apex; much longer than wide Ovate: Egg-shaped with the broadest part toward the base (note that obovate is the reverse relative) Obovate: Stem attaches to tapering point petiole attachment to the blade) Cordate: Heart shaped with a basal sinus. Peltate: Shield shaped with the petiole not attached at the blade margin (peltata): Rounded, stem underneath Scale leaf: Small sharp-pointed leaf with a broad base. They usually overlap on the stem.
Leaf Bases, Venation, and Apices • The leaf base is the lowest part of a leaflamina that is near the petiole. • Leavesbases vary greatly from plant to plant and are useful in classification and identification. Bilateral symmetry is typical. However, when the leaf shows asymmetry at the base this is known as an oblique leaf base. • The outer end or apex (Apices) of a leaflamina that is opposite the petiole. • Leaves apexes vary greatly from plant to plant and are useful in classification and identification. • The venation is the characteristic arrangement of veins in a leaf. • There are lots of different types of leaf venation that are important for plant identification. • The term venation refers to how veins are distributed in the leaf blade
Leaf Functions • Stomata: pores in the stems that allow gas exchange • Guard cells open and close the stoma in a leaf • Chloroplasts give the leaf its strength and are the site for food production • Plant cell gives the leaf its strength and site for food production • What process manufactures food in the leaves? • Photosynthesis • The cuticle is the topmost layer • Epidermis is the surface layer on the upper and lower side of the leaf • Mesophyll contains layers of palisades and spongy tissue
Lets Review A little….. • What are internodes? • Name one type of Modified stem? • Give an example of a tuber? • What are the 2 leaf types? • Name one leaf shape? • What is venation? • Give an example of a Taproot plant?