Plant Growth and Development Level 2 Part II Toby Day MSU Extension Horticulture Associate Specialist Pages 24-48 Montana Master Gardener Handbook
Vegetative parts of a plant
Definitions Apical bud or terminal bud Dominant bud Apical dominance due to auxin Blade Broad portion of the leaf Petiole Stalk attaching the leaf blade to the stem
Definitions Node Part of the stem where a leaf or a branch grows Internode Portion between two nodes Axillary bud A bud at the axil of the leaf that is capable of developing into a leaf, shoot or flower
Definitions Stem Plant axis that bears buds and shoots Comprised of xylem and phloem Lateral root Extend from the primary root Primary root Originates from the radicle of the embryo Taproot
Definitions Lateral bud In a dormant twig it is synonymous with axillary bud Bud scale scar Scars left behind by terminal buds Leaf scar Scar left where a leaf fell off
Definitions Bundle scar Markings on a leaf scar where a vein was once connected Lenticels Openings that allow gases to be exchanged between the air and the tissues of the plant Sometime used for tree ID
Lenticels
Parts of a Root The cortex lies just inside the epidermis and contains food and water. The inner layer of the cortex makes up the endodermis. The core of the root is surrounded by pericycle cells that surround the xylem and phloem
Parts of a Flower
Complete Flowers Having all its parts Stamens Pistils Petals Sepals Incomplete Flowers Types of Flowers Missing one of the parts
Types of Flowers Perfect Flowers Contains functional stamen and Pistil Examples: dandelion, lilies, tomatoes, roses, peas Imperfect Flowers Missing either the stamen or the pistil Examples: hops, boxelder, corn, squash Female Male Fruit
Monoecious vs. Dioecious Monoecious Has both male and female flowers on the same plant Example: corn, squash Dioeciousi Having male and female organs on separate and distinct individuals Example: Holly, poplars, buffaloberry, spinach
Dioecious Asparagus Males Live longer Emerge earlier Does not have fruits that compete for nutrients Does not seed Female asparagus Male asparagus Seeded plants are inferior
Inflorescence A cluster of flowers and their arrangement on a floral stem Peduncle Stem of the inflorescence Pedicel Stem that connects the individual flowers to the peduncle
Indeterminate Inflorescence Types Inflorescence Spike Spikelet Raceme Panicle Description an elongate, unbranched, indeterminate inflorescence with sessile flowers. a small spike, characteristic of grasses and sedges. an elongate, unbranched, indeterminate inflorescence with pedicelled flowers. a branched raceme. Corymb Ccompound Corymb a flat-topped raceme with elongate pedicels reaching the same level. a branched corymb. Umbel Compound Umbel Capitulum (or head) Thyrse a flat-topped or rounded inflorescence with the pedicels originating from a common point. Umbels can be determinate or indeterminate. a branched umbel, with primary rays arising from a common point, and secondary umbels arising from the tip of the primary rays. a dense vertically compressed inflorescence with sessile flowers on a receptacle and subtended by an involucre of phyllaries, characteristic of the Asteraceae. Heads can be determinate or indeterminate. a many-flowered inflorescence with an indeterminate central axis and many opposite, lateral dichasia; a mixed inflorescence, with determinate and indeterminate i t shoots.
Indeterminate Inflorescence Types
Indeterminate Inflorescence Types
Determinate Inflorescence Type Inflorescence Description Simple Cyme or Dichasium a determinate inflorescence with 2 dichotomous lateral branches and pedicles of equal length. Compound Dichasium a branched dichasium Compound Cyme a determinate thyrse. Helicoid Cyme (or bostryx) a determinate cyme in which the branches develop only on 1 side, due to the abortion of opposing paired bud, the inflorescence thus appearing simple. Cincinnus Scorpioid Cyme (or rhipidium) a tight, modified helicoid cyme in which the pedicels are very short. a zig-zag zag determinate cyme with branches developing alternately on opposite sides of the rachis, due to abortion of opposing paired bud.
Determinate Inflorescence Type
Pollination How Seeds are Formed The transfer of pollen from anther to stigma Wind
Pollination How Seeds are Formed The transfer of pollen from anther to stigma Insects
Pollination How Seeds are Formed The transfer of pollen from anther to stigma Mammals
Fertilization How Seeds are Formed Pollen lands on stigma Stigma causes pollen to produce pollen tube Sperm cell is released Union of sperm nucleus and egg produce zygote
Seeds After the seed is fertilized, the embryo is formed Contains 3 or 4 parts: Seed coat Embryo Endosperm (many times consumed during embryo development Dicots) Cotyledons One (monocots) grasses Two (dicots) broadleaf plants
Contains: Cotyledon(s) Dicot Seed and Embryo Food storage for embryo Plumule (Epicotyl) Meristematic region that produces leaves and buds Hypocotyl Stem portion of seedling Radicle Germinates and produces root system First to appear
Seed Coat Pericarp Monocot Seed and Embryo Wall of a ripened ovary Endosperm Food source for embryo Cotyledon Coleoptie Protective sheath covering emerging shoot Epicotyl Hypocotyl Radicle
Seed Coat Protects against pests and slows water penetration and premature germination Scarification External dormancy Seeds with hard seed coats may need to be nicked, sanded or even soaked in acid to germinate
Internal dormancies Other Dormancies? Prevents seeds of many species from germinating g when environmental conditions are not favorable for seedling survival Stratification Some plants may need a period of warmth or cold to y induce germination
Simple Fruits Ripening of a simple or compound ovary but with one pistil Drupes (cherry), pomes (apple), true fruit (tomato) Aggregate Derived from a single flower with numerous ovaries Strawberry or raspberry Multiple l Derived from a cluster of flowers Mulberry Not common in Montana
Questions? End