Plant Growth and Development Part I Levels of Organization Whole Plant Organs Tissues Cells Organelles Macromolecules Levels of Organization Whole Plant Organs Tissues Cells Organelles Macromolecules 1
Plant Cells Differentiation in Cells Refers to the process by which distinct plant cells arise from precursor cells and become different than each other Unique adaptation of plants Levels of Organization Whole Plant Organs Tissues Cells Organelles Macromolecules 2
Plant Tissues Xylem and Phloem = xylem Transports water and minerals from the roots to the plant parts Moves only in one direction = phloem Moves photosynthates (sugars) throughout the plant Moves both directions These internal tissues are also important for supporting the plant. Movement of water through the plant: Transpiration Stomata microscopic openings, usually on the bottom of a leaf, important for gas exchange and transpiration http://www.fairchildgarden.org/eduprofdev/leaf_anatomy.html Heat Vascular cambium Vascular cambium Located between the xylem and phloem Produces new xylem and phloem tissue Responsible for increasing stem diameter. 3
Phloem, Xylem and the Cambium Layer Knowing the cambium layer is important when looking at wood boring insects and disease such as mountain pine beetle Knowing the Cambium Layer is Important for Plant Grafting Or, why leaving trees tied for too long or Why letting the 13 year old weed whip around trees Is a bad thing 4
VASCULAR BUNDLE PHLOEM XYLEM CAMBIUM PITH EPIDERMIS http://www.fairchildgarden.org/eduprofdev/leaf_anatomy.html Vascular Bundle Arrangement Understanding Crop Production, Stoskopf., 1981 Monocot (grass) Dicot (broadleaf) Levels of organization Whole Plant Organs Tissues Cells Organelles Macromolecules 5
Vegetative Organs (plant parts) Stem Leaf Root Shoot Bud Asexual (vegetative) Reproduction Asexual Reproduction Offspring arise from a single parent The Function of Stems Mechanical support and display Movement of water and minerals up to the leaves Movement of photosynthates (sugars) to other parts of the plants Asexual propagation Storage http://www.gimcracker.com/blab/archives/2002 12.html 6
Modified Stems Can grow above and below ground Crown Stolon Rhizome Corm Bulb Tuber Spur Woody Stems Shoot Soft young stem with leaves Twig Dormant stem one year old Branch Stem over one year old Trunk Main stem of a woody plant 7
The Parts of a Woody Stem 22 Parts of a Plant Shoot Leaf primordia Shoot apex The tip of the shoot Axillary bud Parts of a Plant Shoot Node Area on the stem where a leaf, another stem, or flower bud is located Internode Space between the nodes on a stem 8
Vegetative Buds A bud is an undeveloped shoot that produces leaves and/or flower parts Determining One Year s Growth A Plant s Life Cycle Annuals Annuals Completes life cycle in 1 year Grow, mature, bloom, produce seed and die Summer annuals complete their life cycle in spring and summer Winter annuals complete their life cycle during the fall and winter. Usually easy to pull out of the ground 9
Summer Annual Weeds Black medic Pigweed Pineapple weed Purslane Chickweed Henbit Penny cress Winter Annual Weeds A Plant s Life Cycle Biennials Biennials Requires all or part of 2 years to complete its life cycle Vegetative 1 st year Overwinters Flowers and fruits 2 nd year Bolting (flowering in one year) may occur in extreme environmental conditions 10
A Plant s Life Cycle Perennials Perennials Live for many years Woody Trees and shrubs Herbaceous Die back to the ground in Montana What are the issues with reading about herbaceous perennials on the Internet or in popular publications? How about leaves? Dartmouth.edu The inside story http://www.fairchildgarden.org/eduprofdev/leaf_anatomy.html 11
Functions of Leaves Food manufacture photosynthesis Functions of Leaves Protection of delicate tissues like buds Bud scales Floral bracts Sepals Storage Cotyledons, bulbs Plant Identification Key 12
Leaf Structure Blade (lamina) Apex Vein Margin Base Petiole Types of Leaves Venation Monocot (grass) Dicot (broadleaf) Types of Leaves Simple Leaves 13
Types of Leaves Compound Leaves Leaf Arrangement Opposite Whorled Alternate Leaf Shapes and Margins 14
Plant Identification Key Roots Anchorage Nutrient and water absorption Storage Aerial support Propagation (sometimes) Roots that are not growing cannot absorb nutrients Cross Section of a Root Root cap Protection Apical meristem region Cell division Elongation Pushes root through soil Differentiation Root hairs and secondary roots Root hairs Absorb water and nutrients 15
Roots Modified Roots Swollen root Prop roots Radicle Flowers Fruits Flower buds Seeds Reproductive Organs Sexual Reproduction 16
Parts of a Flower Sepal Usually green; protect the flower when it is in bud Petal Attract pollinators Pistil Stigma Pollen falls and develops Style Stalklike part between the stigma and ovary Ovary Enlarged part of the Pistil that containing ovules Stamen Anther The part of the stamen that contains the pollen Filament Stalk of the stamen Parts of a Flower -Pistil Stigma Style - Stamen Anther Filament How about flowers... My squash is putting out a lot of flowers, but I am not getting any fruit 17
How about flowers... How about flowers... Not all flowers have both male and female parts Some plants may contain only male or female flowers We will discuss this more in following classes Composite Flowers 18
Inflorescence (Flower) Types Plant Identification Key Questions? 19