Botany Midterm PDF

3 BASIC PARTS - roots - stem - leaves FUNCTIONS absorb water and nutrients from the soil acts as storage of food for the plants holds plants in its place produces plant hormones that regulates plant growth and development PLANT HORMONES AUXIN elongation in response to a s...

3 BASIC PARTS - roots - stem - leaves FUNCTIONS absorb water and nutrients from the soil acts as storage of food for the plants holds plants in its place produces plant hormones that regulates plant growth and development PLANT HORMONES AUXIN elongation in response to a stimuli apical dominance GIBBERELIN seed germination stem elongation CYTOKININ cell division ensure same growth rate for roots and shoots growth of fruits secondary (lateral) growth ETHYLENE maturation and aging ripening of fruits ABSCISIC ACID inhibits cell division deaths of leaves (abscission) seed dormancy stress response closing of the stomata ROOT SYSTEM TAPROOT SYSTEM - root growth of dicots and gymnosperms - has large main root ( taproot) - penetrates deep into soil - primary root remain - can store food - develops from a radicle FIBROUS ROOT SYSTEM - root growth of monocots and seedless vascular plants - no large main root - does not penetrate deeply into soil (shallow) - primary root does not remain - cannot store food - develops from the stem STRUCTURES ROOT CAP - contains amino plus starch grains - region of cell division - apical meristem, root cap - region on elongation - cells become longer and larger - region of maturation ( root hair zone) - cells mature vascular ENDODERMIS - single layered cylinder of compactly arranged cell whose primary cell walls are impregnated by suberin that if found on the cortex of the root CASPARIAN STRIPS - suberin band which prevents water from passing through the permeable (porous) cell wall of the epidermis. PASSAGE CELLS - thin walled endodermal cell which serves as the passage way of the material between the cortex and the vascular bundle. VASCULAR CYLINDER - a collective core of tissues ( primary phloem and xylem) that lies inside the endodermis which may conduct water or food in solution. PERICYCLE - region where lateral roots arise in which their cells continue to divide even after maturation. SPECIALIZED ROOTS PROP elaborate set of aerial prop roots. adventitious roots that arise near the base of the stem and provide additional support. HAUSTORIA parasitic plants whose roots penetrate the host plant tissues and absorb water and dissolved minerals from the hosts xylem. BUTTRESS support plants in shallow wet soil. AERIAL ROOT  roots of climbing plants. may be photosynthetic. EPIPHYTE long, hanging aerial roots that eventually reach the ground and anchor the plant to the soil. CONTRACTILE adjust the depth of and corm in the soil. PNEUMATOPHORE (breathing roots) breathing roots produced by certain trees living in habitats facilitates gas exchange between the atmosphere and submerged roots. SUCKERS above ground stems that develop adventitious buds and roots. Each sucker grows additional roots and becomes an independent plant when plant dies. FUNCTIONS OF STEMS - stem transports water and nutrients from the roots. - acts as storage of food and nutrients for the plants. - holds other plant parts such as the leaves, flowers, and buds. - the apex of the shoots contains the apical meristem which makes new tissue. EXTERNAL STRUCTURES TERMINAL BUDS - grows stem that bear leaves and flowers at the tip of the stem. BUD SCALES - protects dormant terminal buds. BUD SCARS - left after bud scales fall off. AXILLARY BUD ( aka LATERAL BUDS ) - grows stem that bear leaves and flowers found in the axis. - develop above the leaf scars. LEAF SCARS - shows where the leaf was attached to the stem. INTERNAL STRUCTURES EPIDERMIS - outer covering that provides protection by producing CUTICLE, a fatty substance that reduces water loss. CORTEX  - thick cylinder that makes up the plant’s ground tissue system which functions as storage, support, and photosynthesis. STELE - the central cylinder of the stem which is composed of the vascular bundle. VASCULAR BUNDLE ( Primary Phloem ) PRIMARY XYLEM PITH - ground tissue composed of large - thin walled parenchyma cells that function primarily for storage VASCULAR CAMBIUM - cells divide to produce daughter cells in two directions INSIDE THE RING OF VASCULAR CAMBIUM - to become the secondary xylem or wood OUTSIDE THE RING OF VASCULAR CAMBIUM - to become secondary phloem or inner bark. one of the daughter cells remain meristematic (remains as a part of the vascular cambium) WOOD SAPWOOD - functioning secondary xylem HEART WOOD - non functioning secondary xylem - provides structural support CORK CAMBIUM - continuous cylinder of dividing cells that makes up periderm (outer bark) - periderm replaces the epidermis as it matures - like the vascular cambium, cork cambium also divides to form new tissue in two directions CORK CELLS (outside) - are dead at maturity and have heavily suberized, or waterproof, walls - protect the woody stem against mechanical injuries, mild fires, attacks by insects and fungi, temperature extremes, amd water loss  - impermeable to water and gases - stomata are replaced by lenticels - stopper bottles, floats for fishing lines, flooring, insulation CORK PARENCHYMA (inside) - stores water and food (starch granules) BARK PERIDERM (outer bark) - cork cells (phellem) - cork cambium (phellogen) - cork parenchyma (phelloderm) SECONDARY PHLOEM ( inner bark ) SPECIALIZED STEMS CORM - a short thickened underground stem specialized for food storage and reproduction. - resembles a bulb - storage organ for a corm is a thickened - underground stem covered by papery scales - crocus, gladiolus, cyclamen BULB - a rounded, fleshy underground bud that consist of a short stem with fleshy leaves - forms bulblets - lily, tulips, onion, daffodil RHIZOME - horizontal underground stem that often serves as a storage organ and a means of reproduction - may or may not be fleshy, fleshiness indicates that the stem is used for storing food materials such as starch - resembles roots but they are really stems indicated by the presence of scalelike leaves, buds, nodes, and internodes - iris, bamboo, ginger, grasses TUBER - the thickened end of a rhizome that is fleshy and enlarged for food storage - “eyes” of a potato are axillary buds, evidence that a tuber is a stem rather than a root - white potatoes STOLON/RUNNER - an aerial horizontal stem with long internodes  - often forms buds that develop into separate plants - strawberry FUNCTIONS OF LEAVES - give the plant its identity through shapes and color - major site of photosynthesis in plants PARTS OF LEAVES LAMINA/ BLADE - broad flat portion of the leave PETIOLE - stalk that attaches the leaf to the stem STIPULE - leaf - like outgrowth at the base of the petiole TYPES OF LEAVES SIMPLE - single blade COMPOUND - two or more divided leaflets COMPOUND LEAF PINNATELY COMPOUND - leaflets are borne on an axis that is a continuation of the petiole PALMATELY COMPOUND - leaflets arise from a common point at the end of the petiole ARRANGEMENT ALTERNATE - one leaf at each note OPPOSITE - two leaves grow at each node WHORLED - three or more leaves grow at each node VENATION PARALLEL - primary veins run approximately parallel to one another along the leaf’s long axis with smaller veins forming connections between the primary veins.  - characteristic of monocots RETICULATED/ NETTED - smaller veins branch off larger veins that resembles a net - characteristic of eudicots PINNATELY NETTED - major veins branch off along the entire length of the midvein PALMATELY NETTED - several major veins radiate from one point STRUCTURES DERMAL TISSUE SYSTEM (epidermis) - provides protection ( cutin, trichomes, stomata ) - prevents water loss ( cutin, trichomes, stomata ) - gas exchange ( stomata ) - temperature control ( trichomes ) GROUND TISSUE SYSTEM PALISADE MESOPHYLL - toward upper epidermis - columnar cells stacked closely together - main site of photosynthesis in leaf - have additional layers of mesophyll for adaptation purposes SPONGY MESOPHYLL - toward lower epidermis - cells are loosely and irregularly arranged - primary function is the diffusion of gas particularly carbon dioxide VASCULAR TISSUE SYSTEM XYLEM - located at the upper side of the vein toward the upper epidermis PHLOEM - confined to the lower side of the vein toward the lower epidermis EUDICOTS - have blades and petiole - netted venation - have distinct areas of palisade and spongy mesophylls - guard cells shaped like a kidney bean MONOCOTS - have blades but lack petiole - parallel venation - have no distinct area of palisade and spongy mesophylls - guard cells shaped like dumbbells LEAF ABSCISSION - abscission is the normal (usually seasonal) falling off of leaves or other plant part, such as fruit or flower IMPORTANCE OF LEAF ABSCISSION - survival of trees in temperate forest to low temperature - during winter the plants metabolism, including its rate of photosynthesis, slows down or halts temporarily - winter inhibits absorption of water mainly because the ground is frozen ABSCISSION ZONE - the area where a leaf petiole detaches from the stem - as autumn approaches, a protective layer of cork cells develop on the stem side of the abscission zone 1. cell wall sare impregnated with suberin 2. enzymes dissolve the middle lamella in the abscission zone 3. leaf detaches from the stem 4. leaf scar forms SPECIALIZES LEAVES BRACT - a modified leaf associated with a flower or inflorescence but not part of the flower itself BUD SCALES - a modified leaf that covers and protects the winter buds BULB - a rounded fleshy bud that consist of short stem with fleshy leaves SPINE - a modified leaf for protection TENDRIL - a leaf or stem that is modified for holding on or attaching to objects CARNIVOROUS PLANTS - PITCHER PLANT - VENUS FLY TRAP - SUNDEW