Transcript OH Lecture
Ornamental Horticulture Unit: Seeds to Flowers Floral Design Miss. Perry Seeds – General Information • Mature, fertilized eggs contained inside fruit • Range in size from a few millimeters to a few inches • Can be flat, round or cylindershaped • Distributed by wind, water or animals Basic Parts of a Seed: • Seed embryo – complete miniature plant in a resting stage – Divided into the epicotyl and hypocotyl • Endosperm – stored food that contains sugars, proteins, and fats; used during the first stages of development • Seed coat – tissue that surrounds the embryo and the stored food; protects seed from H2O loss and injury Internal Parts of a Monocot 1 3 1.Seed coat 2.Cotyledons 3.Endosperm 2 5 4.Hypocotyl 4 5.Epicotyl Internal Parts of a Dicot 1.Seed coat 2.Cotyledons 3.Endosperm 4.Hypocotyl 5.Epicotyl Germination •The process of a seed developing into a plant • Requirements: Adequate moisture Oxygen Proper temperature Light Steps in Germination Process Seed absorbs water Water cracks the seed coat, activating growth Root shoot (hypocotyl) begins to grow downward Stem shoot (epicotyl) begins to grow upward Normal growth continues . . . Green leaves begin to develop BULBS What is a bulb? • An underground stem that contains an embryonic plant inside • Will begin to grow when the conditions are right • Scales: Modified leaves that overlap each other; gives the bulb a swollen, pearshaped look; protects the embryo inside • The base of the bulb is called the basal plate. It holds the bulb together and produces roots. • Bulbs can live for many years. • They will produce new, smaller bulbs from the basal plate. Buying & Planting Bulbs • Bulbs should be bought and planted during the dormant period Dormant period: the time period when plants are not actively growing (growth is slowed down – usually during winter) • Dormant bulbs will not have leaves or roots. • Look for plump, firm bulbs. A soft, mushy feel is an indication of rot. Where do you buy bulbs? Retail nurseries Mail order catalogs On-line resources Planting Bulbs • Soil – bulbs need good drainage (otherwise roots will drown and the bulb itself will rot) • Always determine proper planting depth. Different types of bulbs require different depths. • Water – Most bulbs need water from the moment they begin growing until after they flower Common Bulbs Crocus Tulips Gladiolus Common Bulbs Daffodils Iris Hyacinthus All About . . . Flowers! Functions of Flowers • Aid in sexual reproduction Contain reproductive parts Attract insects for pollination (bright colors, fragrant scents) Complete Flowers Made up of 5 parts: 1) Receptacle – the enlarged stem tip, to which other flower parts are attached 2) Sepals – form an outer circle of leaflike structures; collectively called the calyx Protect the flower bud 3) Petals – colorful parts of the flower; collectively called the corolla Some secrete sugary nectar Some secrete fragrant compounds 4) Stamens – male parts of the flower Located inside the petals Made of the filament and anther 5) Pistils – the female parts of the flower; located in the center of the pollen Made of 3 parts: Stigma – sticky surface that captures pollen Style – support structure that leads from stigma to ovary Ovary – enlarged part where seeds are formed Pistil Stamen Receptacle Sepal Petal Incomplete Flowers • Missing one or more of the 5 basic flower parts Perfect Flowers (Bisexual) • Have both male and female flower organs Imperfect Flowers (Unisexual) • Flowers that have either male OR female organs – not both Monecious Plants • Plants that bear both male and female flowers (capable of self-pollinization) Dioecious Plants • Plants that carry only male OR female flowers (not capable of self-pollinization)