Plant Body Shoot system = leaves + stem Root system Meristem = cells that divide for life of plant, can give rise to all plant structures 3 BASIC Organs Roots Stems Leaves
Division of Meristem Cells Causes Plant Growth Apical Meristem tips of root and shoot increase in height (called primary growth) Lateral Meristem cylinders within plant body increase in width (called secondary growth) Only in woody plants
2 BASIC Systems BOTH SYSTEMS DEPEND ON THE OTHER Root System (roots) receive sugars and other nutrients from photosynthetic parts Shoot System (leaves and stems) depends on water & minerals absorbed from the soil by roots.
The plant body cells tissues organs A tissue = group of cells with a common structure and function An organ = several types of tissues that work together to carry out particular functions
Tissue Types in Vascular Plants Dermal Tissue Covers/ protects plant Makes cuticle on stems/ leaves Allows for better H 2 O absorption (root hairs) Make guard cells Vascular Tissue (xylem & phloem) Transport and support Throughout the plant Called “ veins ” in leaves Called the “ stele ” in stem or root Ground Tissue Between dermal and vascular tissues Storage Photosynthesis (makes sugars) Support
Plant Body- ROOTS Functions: 1.Anchors plant in soil 2.Takes up water and minerals from soil 3.Store Food
Roots Tissues Epidermis-outer layer of root that protects the underlying tissues of the root. Cortex-the inner side of the epidermis. Allows diffusion of water, mineral salts, and oxygen from the root hairs. Stores foods, especially starch. Endoderims-Active mineral uptake Epidermis-outer layer of root that protects the underlying tissues of the root. Cortex-the inner side of the epidermis. Allows diffusion of water, mineral salts, and oxygen from the root hairs. Stores foods, especially starch. Endoderims-Active mineral uptake
Modified Roots Some plants have modified roots Adventitious roots arise aboveground spread over large areas Storage roots hold “food” called root tubers
Plant Body-STEM Stem: series of nodes and internodes Functions Support for the plant body Holds leaves up to light Transports nutrients throughout plant Xylem conducts water and minerals Phloem transports sugar
Tissue Organization of Stems Pith: in young stems, the pith stores food. The pith disappears in older stems. Cambium: during growing season, cambium produces new phloem to the outside and new xylem to the inside. Vascular Tissue: Xylem on inside Phloem on the outside
Two Kinds of Plant Vascular Tissue Xylem Carries H2O, dissolved nutrients. Generally upward movement. Dead at maturity. Phloem Carries products of Photosynthesis. Alive at maturity Generally downward movement
Woody Stem Growth The Stem has three areas: Bark Wood Pith The Stem has three areas: Bark Wood Pith CORK-protects the outer part of the bar SPRING WOOD (early wood): the part of an annual ring of wood, characterized by large, thin-walled cells, formed during the first part of the growing season. SUMMER WOOD (late wood): the part of an annual ring of wood, characterized by compact, thick-walled cells, formed during the later part of the growing season.
What makes up a leaf? Cuticle Epidermis Mesophyll Layer Vascular System Stomata
Leaf Structure-Dermal layers Cuticle-The thin waxy covering on the outer surface. prevents water loss within the leaf. (Plants that live entirely within water do not have a cuticle). Directly underneath the cuticle is a layer of cells called the epidermis (upper and lower) protect inner layers
Leaf Tissues Mesophyll Tissue between upper and lower epidermis Two types: Palisade parenchyma (mesophyll) cells Lots of chloroplasts in these cells Most photosynthesis occurs here Spongy parenchyma (mesophyll) cells Lots of air spaces where O 2 and CO 2 circulate Near stomata (Think: sponges have lots of air spaces) Veins Xylem and phloem are continuous from roots through stem to leaves
Stomata and Guard Cells The underside portion of a leaf has stomata and is the site of transpiration (water movement) and gas exchange.
Stomata help regulate the rate of transpiration Guard cells 2 cells on either side of stomata (surrounds stomata) regulate water loss What conditions will promote closing of guard cells? Hot, dry, windy conditions
Flowering Plant Reproduction Flowers are modified leaves, specialized for reproduction (where pollination takes place). Flower parts undergo meiosis to produce haploid products pollen grain ovule (contains egg cell)
Flowers, Fruits, and vegetables A fruit is the part of the plant that develops from a flower. It's also the section of the plant that contains the seeds. (Protects the seeds). The other parts of plants are considered vegetables. These include the stems, leaves and roots — and even the flower bud.
Dead Center sits the tomato. Why? Botanically speaking, a tomato is a fruit because it is a seed-bearing structure that develops from the ovary of a flowering plant. In the culinary world sweet = fruits and savory = vegetables: this includes botanical fruits as eggplants, bell peppers, and tomatoes.