Ag. Ch. 15 notes

• Xylem – vessels of vascular bundle that carry the water and nutrients from the roots to the leaves.

• Phloem – the food conducting tissue in plants that transport sucrose from the leaves (after photosynthesis) to the rest of the plant.

• Woody – stiff, dark-colored plant growth in plants…these plants are usually winter hardy.

• Herbaceous – a plant that has a stem that does not stiffen and turn dark. It is softer and more succulent than woody stems, and is usually not winter hardy.

• Bulb – short, underground stems surrounded by many overlapping fleshy leaves.

• Corm – short, flattened underground stems surrounded by scaly leaves. A corm does not have visible storage rings when cut in half.

• Tuber – specialized food-storage stem that grows underground.

• Rhizomes – horizontal, underground stems.

• Stolons – a stem that grows above the ground.

• Internode – the area between two nodes of a plant. The node is the portion of the stem where the buds come out.

• Axillary bud – a bud that is located in the axil of the leaf.

A bud is a swelling on a plant that can grow into leaves, flowers, stems or branches. An axillary bud is found between the stem and branch or leaf.

• Terminal bud – bud at the end or tip of the branch.

                                                         

• Vegetative bud – a bud that will develop into a leafy shoot.

Vegetative bud

                                                         

• Flowering bud – a bud on a plant that produces a flower

                                                         

Leaf Margins

Leaf Tips

Leaf Bases

Leaf Shapes

Leaf Shapes 2

Leaf Arrangements

• Petiole – The slender leaf stock that supports the blade, attaching it to the stem of a plant.

• Simple leaf – a single leaf arising from a plant stem.

• Compound leaf – two or more leaves arising from the same part of the stem.

• Chloroplast – membrane-bound body inside a cell containing chlorophyll pigment. It is necessary for photosynthesis.

• Stoma – small openings, usually on the underside of the leaf, that control movement of gases.

• Guard cells – Cells that surround the stoma.

• Stamen – Male part of the flower that contains the pollen, anther, and filament.

• Filament – the structure that supports the anther; part of the male reproductive system of a flower.

• Anther – portion of the male part of a flower that contains pollen.

• Pollen – small male sperm or grains that are necessary for fertilization of the flower.

• Pistil – Female part of the flower consisting of the stigma, style, ovary, and ovules.

• Stigma – the part of the pistil that receives the pollen.

• Style – The portion of the pistil located between the stigma and the ovary. It is the transportation tube that pollen follows to get to the ovary.

• Ovary – female organ that produces eggs or female sex cells; also the portion of the flower that contains the ovules or seeds.

• Perfect flower – a flower that contains all the male and female parts (stamen and pistil) as well as petals and sepals.

• Imperfect flower – Flower that is missing one or more of the following: stamen, pistil, petals, or sepals

• Corolla – collectively, all of the petals of a flower.

• Sepal – small, green, leaf-like structures found at the base of the flower.

• Fruit – mature ovary of a flowering plant, usually containing seeds.

• Vegetable – any herbaceous plant whose fruit, seeds, roots, tubers, bulbs, stems, leaves, or flower parts are used as food.

• Nut – A fruit or seed contained within a removable outer cover.

Root systems

• Root Systems: Roots often make up the majority of the plant. Some roots grow below ground, while others grow above ground.

Adventitious roots

• – appear where roots are not normally expected and help to prop the plant up or climb nearby structures.

• Ex: poison ivy, corn, mistletoe

Normal root systems

taproot

• – main root of the plant that grows straight down from the stem. It is a heavy, thick root that does not have many side, or lateral, branches. Some taproots are edible (carrots, beets). Some plants with taproots are used for ornamental purposes, to improve the appearance of the area. Taproots can be up to 10 feet deep, allowing the plant to survive in severe drought conditions. These plants are difficult to uproot, and do not hold soil in place.

Fibrous roots

• – thin, somewhat hair-like and numerous. Fibrous roots are typically shallow. Grasses and many ornamental flowers have fibrous root systems. Fibrous root systems do not allow the plant to survive in droughts, but are very effective in holding soil in its place.

Root structures

Root cap – outermost part of the root. It protects the tender growing tip as the root penetrates the soil. As it wears away, it is replace with new cells in the area of cell division.

Root structures

The cells multiply in two directions. The small, tougher cells are produced on the front edge of the region to replace those worn off on the root cap. More tender cells are produced in the back of the region to allow the root tip to grow larger.

Area of cell division – provides new cells that allow the root to grow longer.

Root structures

Area of cell elongation – the cells start to become longer and specialized. The begin to look like older cells and will start to do their specific jobs.

Root structuresXylem – responsible for carrying water and nutrients from the soil to the upper part of the plant.

Phloem – function as the pipeline to carry the manufactured food down from the leaves to other plant parts

Root structuresArea of cell maturation – where the cells mature. This is also where root hairs emerge.

Root hairs – small microscopic roots that rise from existing cells located on the surface of the root. The root hairs take in water and nutrients.

stems

Types of stems

• Woody – tough and winter hardy, usually covered with bark

• Herbaceous – succulent, often green and will not survive winter in cold climates.

Modified stems

• Bulbs – shortened stems surrounded by modified leaves (scales). Ex: lilies, onions

• Corms – thickened, compact, fleshy stems. Ex: gladiolas

• Rhizomes – thick stems that run below ground. Ex: Johnsongrass

• Tubers – thickened, underground stems that store carbohydrates. Ex: potato