Plant Parts and their Functions 13.00 Describe principles of plant science as related to horticulture 14.00 Compare the anatomical parts and distinguishing characteristics of horticultural 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 Parts Leaves Stems Roots Flowers
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
Leaves-External
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
Leaves-Internal
Leaves-Internal
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 Sapwood Cambium 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
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
Flowers
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
What are the functions of these plant 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