Section 6 Dendrology: The Scientific Study of Trees

Chapter 19 Classification and Anatomy of Trees

Dendrology The scientific study of trees is known as Dendrology Anatomy: study that examines structure of an organism Arrangement and relationship of organs/parts to other organs Physiology: the branch of biology that deals with the life functions and processes of living organisms

Tissue Systems of Tree Tissue systems perform specialized functions Ground tissue system: much of material in plant leaves, roots, stems, fruit Vascular tissue system: moves nutrients Dermal tissue system: protects against loss of fluids Meristem tissue: rapidly dividing, causes plants to grow

Tissue Systems of Tree (Continued) Organ: several tissues that function as single unit Vegetative organs Reproductive organs

Vascular Tissue Xylem: water-conducting woody tissue carrying nutrients from roots to stems to leaves Important components of xylem: Tracheids and vessel elements, once they become dead and hollow End-to-end vessels: more efficient than tracheids Vessel element: A hollow tube where nutrients pass

Vascular Tissue (Continued) Phloem: vascular tissue located in the interior layer bark, stems and roots. Sugars flow from high concentration to low concentration

Annular Rings Annular Rings consist of new later of woodt xylem tissue that has been deposited each year. (determine age, conditions, weather) Spring wood Often a smaller darker ring Summer wood Larger and lighter color More favorable growing season

Dendrochronology

How old is this tree? (Core 1) 6. How do the banding patterns of the two cores compare?

http://scied.ucar.edu/tree-ring-interactive

Cambium-located between the phloem and xylem that contains a dividing mass of cells. Vascular Ray-transport dissolved materials across the woody section (xylem) between the phloem and the pith. Pith- is located in the center of the stem and primarily stores plant food. Heartwood- older xylem filled with tannins bums and resins, which becomes darker in color and no longer conducts water. Sapwood-lighter colored wood through which water still moves.

Dermal Tissue System Dermal tissues protect plants from loss of fluids and keep harmful microorganisms out of the cells Epidermis: protective outer layer of cells of leaves, stems, flowers, seeds, and roots Cuticle: The waxy material covering plants

Plant Tissues

Dermal Tissue (Continued) Meristem: rapidly dividing mass of cells that causes plants to grow Apical meristems: at ends of branches, twigs, roots Cambium layer: between phloem and xylem layers of roots and stems When a cell in the cambium divides one cell remains until it divides again. The other cell becomes part of the xylem or phloem tissue. Cell division increases diameter of stem or root (Xylem) Forms vascular rays that transport materials across woody section of stem

External Parts of Tree Leaf Petiole: point of attachment to tree Vascular tissues for transporting nutrients to leaf cells Blade Midrib: gives shape, distributes nutrients Spines: function like midrib Veins: distribute material to and from leaf cells Margin: useful for tree identification

Taproots and Fibrous Roots Trees have either a taproot system or a fibrous root system A taproot system has a primary root that grows much larger and deeper than the other roots A fibrous root system does not have a large dominant root Primary root branches out just below the soil surface and the main roots are near the same size

Taproots and Fibrous Roots (Continued) Many trees have taproots during the seedling stage, but in some species, the taproot gives way to a fibrous root system as the tree matures

Root Systems

Anatomy of Tree Root Plant roots: specialized organs that anchor trees in soil and transport nutrients and water into plant Fungi that attach to a plant’s roots, dissolve nutrients making it available to the plant Epidermis: protects root, absorbs water and nutrients, includes root hairs Root hairs- increase surface area for water and minerals absorption.

Secondary Root Tissues Secondary tissues develop from meristem tissue, or vascular cambium, and provide secondary growth Secondary xylem and secondary phloem add thickness

Basic Parts of Flower Female flower parts constitute pistil Stigma: pollen receptor Ovary: produces egg cell; seed forms in ovule Style: connects stigma to ovary Male flower parts compose stamen Anther: pollen grains develop here

Basic Parts of Flower (Continued) Filament: connects anther to receptacle or base of flower Petals: color attracts pollinators Sepals: leaflike, protects flower

Anatomy of a Flower

Perfect (bisexual flowers)- Containing both male and female reproductive flowering parts. Imperfect Flowers- Some broad leaf trees are unisexual male (staminate) and female (pistillate) Flowers. These may be born on the same plant like oaks and hickories or on separate trees as in hollies. A few trees have both perfect and imperfect flowers intermixed

Tree Types Gymnosperms bear seeds in cones Pines, spruces, cedars Slow movement of dissolved plant materials through tracheid cells Angiosperms produce seeds inside ovary, or fruit Plant materials transported rapidly through tracheid and vessel elements