Plant Structure And Growth The Plant Body is Composed of Cells and Tissues Tissue systems made up of tissues made up of cells Plant Tissue Systems (Functions) Ground Tissue System photosynthesis storage support Vascular Tissue System conduction support Dermal Tissue System Covering Ground Tissue System Different types of Ground Tissue Parenchyma Tissue Collenchyma Tissue Sclerenchyma Tissue Helpful hint: remember which ones are living or dead at maturity and which have only a primary wall and which have a secondary wall) Parenchyma Tissue Made up of Parenchyma Cells Living Cells at maturity Primary Walls Functions photosynthesis storage Collenchyma Tissue Made up of Collenchyma Cells Living Cells at maturity Primary Walls that are thickened Function Support Sclerenchyma Tissue Made up of Sclerenchyma Cells Usually Dead at maturity Primary Walls and Secondary Walls which are thickened with lignin There are two types Fibers (seen in the top picture - red cells on top and bottom) Sclerids (seen in the bottom picture) Function Support Vascular Tissue System Xylem (two types of cells) Tracheids Vessel Elements Phloem (two types of cells) Sieve-tube Members Companion Cells Xylem Tracheids Dead at maturity They have pits - water moves through pits from cell to cell Vessel Elements Dead at maturity They have perforations - water moves directly from cell to cell Phloem Sieve-tube Members alive at maturity lack nucleus at maturity Sieve plates - on end to transport food Companion Cells alive at maturity helps control sieve- tube member cell Dermal Tissue System Epidermis complex tissue usually transparent secretes cuticle Periderm replaces epidermis in woody plants protection Root System Tap Root Lateral Roots Shoot System Stems Nodes Internodes Leaves blades petioles Buds Terminal (apical) Axillary Plant Systems Plant Growth Meristematic Tissue generates cells for new growth apical meristems lateral meristems Apical Meristems increases length called primary growth Protoderm - gives rise to dermal tissue Ground Meristem - gives rise to ground tissue Procambium - gives rise to vascular tissue Lateral Meristems increases girth called secondary growth Vascular Cambium - produces secondary xylem and secondary phloem Cork Cambium - produces cork and phelloderm The Root System Functions anchor plant absorb minerals, water and nutrients store food Systems taproots - one large root with smaller lateral roots (dicots) fibrous roots - threadlike roots (monocots) Root Structure Four Regions Root Cap - protection Region of Cell Division - new cells Region of Elongation - cells get longer Region of Maturation - cells begin to specialize Root Tissue Protoderm - gives rise to the epidermis Procambium - gives rise to the stele xylem and phloem may include pith Ground Meristem Cortex Monocot vs. Dicot Root You will need to be able to recognize the difference between a monocot root and a dicot root Monocot Root (inside to outside) Pith Endodermis Xylem Casparian Strip made transport of suberin to regulate water water and minerals Phloem Passage Cells to allow transport water to pass through food Cortex Pericycle storage dividing cells Epidermis protection Monocot Root You will need to be able to recognize parts Epidermis Cortex Endodermis (red circle) Pericycle (one layer inside the red circle) Pith Xylem (red) Phloem (green) Dicot Root (inside to outside) Xylem Endodermis transport Casparian Strip made water of suberin to regulate water and minerals Phloem Passage Cells to allow transport food water to pass through Cortex Pericycle storage dividing cells Epidermis protection Dicot Root You will need to be able to recognize parts Epidermis Cortex Endodermis (red circle) Pericycle (one layer inside the red circle) Xylem (red) Phloem (green) No pith Modified Roots Food Storage carrots, sweet potatoes, yams Modified Roots Water Storage manroot, pumpkin family Modified Roots Propagative Roots which produce adventious buds cherries, pears Modified Roots Pnematophores Prop Roots mangroves Modified Roots Aerial Roots orchids, ivies Modified Roots Buttress Roots tropical trees Modified Roots Haustoria dodder Shoot System The Shoot System Made up of Stems, Leaves, Flowers, Fruits Stems - support, conduction, growth Leaves - photosynthesis Flowers - pollination Fruits - seed protection, dispersal Stems (Primary Growth) Protoderm - gives rise to the epidermis Procambium - gives rise to the stele xylem and phloem in vascular bundles dicots - found in ring monocots - scattered throughout includes pith in dicots Ground Meristem Cortex Vascular Bundle Parts Fibers Phloem Xylem Monocot vs. Dicot Stem You will need to be able to recognize the difference between a monocot stem and a dicot stem Monocot Stem (Inside to Outside) Ground Tissue Vascular Bundles Xylem Phloem Fibers Cortex Epidermis Monocot Stem You will need to be able to recognize parts Epidermis Cortex (very small) Ground Tissue Vascular Bundle Xylem (red) Phloem (green) Fiber (red) Dicot Stem (Inside to Outside) Pith Vascular Bundles Xylem Phloem Fibers Cortex Epidermis Dicot Stem You will need to be able to recognize parts Epidermis Cortex Pith Vascular Bundle Xylem (red) Phloem (green) Fiber (red) Roots vs Stems Roots have Endodermis / Stems Vascular Bundles Monocot Dicot Roots – has pith Roots – no pith Stems – No pith Stem – pith Vascular bundles in a ring Vascular bundles are scattered Stems (Secondary Growth) Occurs to increase girth (thickness) Vascular Cambium produces secondary xylem and phloem Cork Cambium produces cork and phelloderm together these structures are called periderm Secondary Growth Secondary Growth C – Vascular Cambian The vascular cambian goes through mitosis and D – Differentiated cell creates a cell (D) which on (will turn into another the inside of the plant type of cell) becomes a xylem cell. X – Xylem The next mitotic division produces another cell (D) P - Phloem which is on the outside and becomes a phloem cell Secondary Growth of a Stem You will need to know the parts Secondary Growth of a Stem Secondary Growth of a Stem (Inside to Outside) Pith Secondary Primary Phloem Xylem Primary Phloem Secondary Cortex Xylem Phelloderm (wood) Cork Cambium Vascular Cork Cambium Secondary Growth Periderm is cork cambium and cork Bark is everything outside the vascular cambium Wood (to a botanist) is secondary xylem Sap wood – still moves water Heart wood – no longer moves water, hardened now used for support Modified Stems Stolons - horizontal stems above the ground Modified Stems Rhizomes - horizontal stems below the ground Modified Stems Tubers - swollen areas of rhizomes Modified Stems Bulbs & Corms - vertical shoots under the ground Modified Stems Cladophylls - cactus pads Leaf Structure Simple leaf – one blade after axillary bud Compound leaf – multiple blades called leaflets Double Compound leaf – leaflets broken up into smaller leaflets Leaf Structure Leaves Epidermis Stomata - openings on underside of leaf Guard Cells - surround stomata Cuticle - waxy coating excreted by epidermis Mesophyll - middle of leaf Palisade layer - photosynthesis Spongy layer - gas exchange Modified Leaves Needles - reduce water loss Modified Leaves Tendrils - long thin leaves for clinging Modified Leaves Spines - protection Modified Leaves Succulents – water storage.