Plant Physiology Essential Standard 3.00: Summarize Plant Anatomy
Objective 3.01 • Discuss biological terms used to describe plants.
Plant Sciences • Biology-the branch of science that deals with both plant and animal organisms and life processes • Zoology-the part of biology that deals with animals • Botany the part of biology that deals with plants
Plant Sciences • Applied plant sciences are based on the purposes for which the plants are grown • Agronomy • Forestry • Horticulture
Agronomy The science and practice of growing field crops such as cotton, wheat, tobacco, corn and soybeans.
Forestry The science and practice of growing, managing and harvesting trees for building materials and other products.
Horticulture The science and practice of growing, processing and marketing fruits, vegetables, and ornamental plants
Life Cycles of Plants • Annual-a plant that completes its life cycle in one year • Biennial-a plant that completes its life cycle in two years • Perennial-a plant that lives more than two years
Leaf Retention • Deciduous-loses leaves during the dormant season • Evergreen-keeps leaves and remains green year-round
Plant Hormones • Several types of hormones are used to help plants work more efficiently. • Inhibitors • cytokinins • gibberellias • auxins
Inhibitors • Inhibitors hasten fruit ripening, retain seed germination and stem elongation.
Cytokinins • Hormones that work with auxins to stimulate cell division.
Gibberellias • Hormones that stimulate cell elongation, premature flowering, and breaking of dormancy.
Auxins • Hormones that speed plant growth by stimulating cell enlargement
Moisture in Plants • Turgid-plant is swollen or filled with moisture • Wilted-plant is limp because it does not have enough moisture
Plant Growth • Dormant • A plant rest or grows very little • Response to an adverse condition
Season Crop Type • Cool Season • Plants relish cool weather • Pansies grow best in spring or fall • Warm Season • Grow best in summer and early fall • Zinnia • Marigold • Vinca • Poinsettia
Objective 3.02 • Discuss the anatomy and functions of plants.
Leaves-External • Petiole-Leaf stalk or part that connects the leaf to the stem • Blade-The large, flat part of the leaf • Midrib-The large center vein • Veins-The structural framework of the leaf • Margin-The edge of the leaf • Apex – Leaf Tip
Leaves-Internal • Upper and lower epidermis-skin of the leaf that prevents the loss of too much moisture • Stomates-small openings under the leaf for breathing or transpiration • Guard Cells-open and close stomates
Leaves-Internal • Chloroplasts-small green particles that contain chlorophyll • gives leaves their green color • necessary for photosynthesis
Leave-Functions • Photosynthesis • process by which plants capture sunlight and use it to convert carbon dioxide and water into food • Respiration • converts sugars and starches into energy • Transpiration • release of water vapor from the leaves of plants • It also cools the plant
Leave-Additions • Sessile describes leaves without a petiole • Example zinnia • Bracts are modified leaves • Example poinsettia • Needles and scales are modified leaves • Example pine tree
Leave-Additions • Glabrous leaves or stems have a smooth non-hairy feel • Example southern magnolia • Pubescent leaves or stems have a hairy feel • Example African violet
Stems-External • Lenticels-breathing pores • Bud scale scars-show where terminal buds have been located • Leaf Scars-show where leaves were attached • Terminal bud-bud on the end of a stem • Axillary or lateral bud-bud on side of stem
Stems-Internal • Xylem-tissue that transports water and nutrients up from the roots to stems and leaves • Phloem-tissue that transports food down from leaves to roots
Stems-Internal Phloem Phloem Xylem
Stems-Internal • Cambium-thin, green, actively growing tissue located between bark and wood and produces all new stem cells • Bark-old inactive phloem • Heartwood-old inactive xylem • Sapwood-new active xylem
Stems-Internal Bark Cambium Sapwood Heartwood
Stems-Internal • Monocota-plant stems have vascular bundles that contain both xylem and phloem in each bundle • examples: corn, grasses • Dicata-plant stems have the phloem layer and xylem layer separated by cambium • example: trees
Stems-Internal Monocot Dicot
Roots-External • Root cap-indicates growth of new cells • Root hairs-absorb moisture (water) and minerals Root images from a rice plant
Roots-Internal • Much like stems in that they have a phloem, cambium, and xylem layer • Phloem-the outer layer that carries food down the root • Xylem-the inner layer that carries water and minerals up to the stem
Layers of Roots • Fibrous-many branched shallow roots • are easier to transplant • Tap-long root with few branched ones • more difficult to transplant
Flowers • Sepals-Green parts that cover and protect flower bud before it opens • Petals-are really leaves that are modified to attract insects for flower pollination, the pretty part that we call flowers • Stamen-male part of the flower • Pistil-female part of the flower
Parts of the Stamen • Filament-short stalk that holds up the anther • Anther-a sac-like structure that contains pollen, the male sex cells
Parts of the Pistil • Ovules-the eggs or female sex cells that become seeds if fertilized • Ovary-if fertilized becomes a fruit or seed coat • Style-holds up the stigma and connects it to the ovary • Stigma-sticky part on top of style where insects leave pollen
Parts of the Pistil Stigma Style Ovary
Complete-vs-Incomplete • Complete flowers have both male and female parts • Incomplete flowers have only male or female parts
Functions of Leaves • Photosynthesis-manufactures food in green plants which is the beginning of the food chain for all living things • Photosynthesis is the process by which carbon dioxide and water in the presence of light are converted to sugar and oxygen
Functions of Stems • Translocation-moves water and minerals from roots up to the leaves and move food from the leaves down to the roots • Supports branches, leaves, flowers, fruits and seeds
Functions of Roots • Absorption-take water and nutrients from the soil and conduct them to the stem • Anchor the plant and hold it upright • Store food for plant use • Asexual reproduction in some plants
Functions of Flowers • Produce seeds used for sexual reproduction • Attract insects for pollination (Pollination is the transfer of pollen from anther to stigma.) • Produce fruit to protect, nourish and carry seeds
Objective 3.03 • Discuss floriculture and landscape plants
Taxonomy • The science of classifying and identifying plants • Scientific names are used because the same common name is used for different plants in different areas of the world.