Introduction to Plant Science & Plant Classification .

Introduction The basic industry of agriculture is dependant on plants. The animal grower needs many kinds of plants to feed livestock. The plant industry needs superior plants that are productive and resistant to insects, disease, and drought. Plants are needed for landscaping the inside and outside of homes & office buildings. Wildlife are dependant upon plants for food and shelter.

Careers involving plants Plant scientists: Plant breeders develop new varieties with improved traits of economically important plants. Agronomists specialize in the production & cultivation practices of plants for food and fiber. They understand soils, irrigation practices, planting & harvesting practices fertilizers, insects & pesticides. Horticulturalists produce ornamental plants in greenhouses & nurseries that used in homes, offices and landscapes. They specialize in flowers, trees, shrubs, and turf grass.

Careers involving plants Foresters grow, manage and harvest trees for lumber, poles, posts, and pulpwood. Range managers, manage water sheds, wetlands and rangeland used for grazing, both livestock and wildlife. There are literally hundreds of careers that are either directly or indirectly associated with plants and require a basic understanding of plants.

Plant Classification. There are many different types of plants and ways of classifying them. In the scientific Taxonomy system of classification. There are two major kingdoms. Plants & Animals. The plant kingdom is divided into four divisions or phylla. 1. Algae & Fungi 2. Green plants without roots or flowers like mosses & Lichens 3. Green plants with vascular tissue, true roots, distinct leaves and stems but no true flowers or seeds & they reproduce by means of spores on the backs of the leaves like ferns. 4. Plants which have true flowers and produce seeds. (The majority of our agriculture crops.)

Plant Classification This 4th Division is refered to as Spermatophyta and are your seed producing plants. There are two classes of plants within this division. Gymnosperms Angiosperms Gymnosperms are most of your cone bearing trees. (Used to harvest lumber) Angiosperms are those species that have flowers and seeds always protected by a fruit.

Plant Classification Most of our food producing crops are Angiosperms. Angiosperms have to main divisions Monocotyledons or (Monocots) 1 Cotlyledon Dicotlyledons or (Dicots) 2 cotlyedons A Cotyledon is the first leaf that emerges from a germinating seedling. Broad leaf plants have two cotyledons and are refered to as Dicots. (Peas, Beans, alfalfa, Tomatoes, most weeds) Monocots make up all of the grasses, and cereal grains (Corn, wheat, barley, oats, ext.) Plants are also sometimes classified by their life cycle.

Plant life cycles. Annual: Plants start from seed, produce seed and die in one year. Biennial: Plants live two years, sprouting from seed the first year and grows leaves, stems & roots. The second year the plants produce seed and die after the seed matures. Many broad leaf weeds are considered biennials. Perennial; Plants live three or more years. Each year new stems grow from the crowns. Perennial plants have deep root systems. Alfalfa and the majority of Montana’s range plants are perennials.

Plant Growth Season Plants are also classified based on their season of growth. Cool Season Plants: Grow best and flower during the spring and early summer when weather conditions are cool. These plants may grow again in the fall if temperatures and moisture conditions are ideal. Warm Season Plants: Warm Season plants grow and flower in the mid to late summer. Evergreens: Perennial plants that have green leaves the entire year. Deciduous: Plants that loose there leaves each fall.

Cool Season Plants Cool and warm season plants have different photosynthetic systems. Cool season plants originate in cooler regions of the earth and have a C3 photosynthetic process. In comparison to warm season plants, cool season plants are less efficient at gathering carbon dioxide and using water. Optimum temperature for cool season plants is a cool 65 to 75 degrees. These plants are most productive in early spring and late fall. Most of the range plants in Montana are cool season plants.

Warm Season Plants Warm Season plants originated in tropical conditions and have a C4 photosynthetic process. Warm season plants are very efficient at gathering and processing carbon dioxide and water. Ideal temperature for warm season plants is 90 to 95 degrees. These plants are most productive in the hot summer months. Many of today’s noxious weeds are warm season plants.

Plant Identification & Anatomy Regardless of class or type, all plants have four basic physiological structures that influence plant growth and are important in plant identification. 1. Roots 2. Leaves 3. Stems 4. Seed head / Flowers

Plant Roots The largest part of the plant is the root system. The roots take up more space in the soil than does the top part of the plant seen in the air above the ground. Some roots may extend, 6,8 even 10 ft into the soil. Roots anchor the plant to the soil. They provide plants with water and minerals that are absorbed from the soil. Healthy plants have healthy roots. There are two main types of root systems. Fibrous Roots. Tap Roots.

Root Systems

Leaves Leaves are the food factories of the plant. Undergo Photosynthesis and use sunlight, water and carbon dioxide to build carbohydrates for growth and release oxygen. Several aspects of the leaf are used to identify the type of plant. Leaf type Leaf Arrangement Leaf Venation Leaf Shape Leaf Margins Leaf Surfaces

Leaf Type There are two basic types of leafs: Simple and Compound. Simple leaves have a single leaf blade generally with a petiole attached to the main plant stem. Compound leaves have secondary, small leaves, called leaflets, attached to each leaf stalk. The leaf stalk is connected to the main stem.

Simple & Compound Leaves

Leaf Arrangement

Leaf Veins Leaf veins also fall into three categories. Parallel: Veins run up and down (vertical) and are spaced equally apart. Pinnate: Veins are attached to the main (central) vein at many different points. Palmate: Veins are attached at the base of the main (Central) vein.

Leaf Veination

Plant Stems The function of the plant stem is to hold the plant upright and through various vascular tissues, (xylem & phloem) transport water and minerals and food through out the plant. Another name for plant stems are plant culms.

Plant Stem Growth Forms

Plant Seed head / Flowers The seed head ultimately produces genetic material for reproduction. Another name for the seed head is an Inflorescence.

Inflorescences

Indentify the parts to a plant Spikelet Inflorescence Culm Collar Leaf Blade Internode Leaf Leaf Sheath Node Crown Fibrous Roots