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Fig. 8.7
Structure of Flowers
• Outermost whorl typically consists of three to five sepals. Sepals (calyx) may be fused together.
• Next whorl consists of three to many petals (corolla). Calyx and corolla form the perianth.
Structure of Flowers
• Several to many stamens are attached to the receptacle around the base of the pistil. Each stamen consists of a filament with an
anther at the top.- Pollen grains developed and
disseminated in anthers.
Structure of Flowers
• Pistil consists of Stigma, Style, and Ovary. Superior Ovary - Calyx and corolla are
attached to the receptacle at the base of the ovary.
Inferior Ovary - Receptacle grows up and around the ovary.
- Calyx and corolla appear to be attached at the top.
• Inflorescences - Group of several to hundreds of flowers.
Generalized Flower
Fruits
• Fruit is an ovary and its accessory parts that have developed and matured. Usually contains seeds. All fruits develop from flower ovaries and
accordingly are found exclusively in flowering plants.
Fruits
• Fruit Regions Exocarp - Skin Endocarp - Inner boundary around seed(s). Mesocarp - Fleshy tissue between exocarp
and endocarp.- Three regions are collectively called the
pericarp.
Regions of a Mature Peach
Fruits
• Fleshy Fruits Simple fleshy fruits develop from a flower
with a single pistil.- Drupe - Simple fleshy fruit with a single
seed enclosed by a hard, stony endocarp, or pit. Copyright © McGraw-Hill Companies Permission Required for Reproduction or Display
Fig. 8.9
Fruits
• Berry - Usually develops from a compound ovary and often contains more than one seed. True berry is a fruit with a thin skin and a
relatively soft pericarp. Pepos - Relatively thick rinds (Pumpkins). Hesperidium - Leathery skin containing oils
(Citrus). Copyright © McGraw-Hill Companies PermissionRequired for Reproduction or Display
Fig. 8.10a
Fruits
• Pomes - Bulk of flesh comes from enlarged floral tube or receptacle that grows up around the ovary. (Apples)
Copyright © McGraw-Hill Companies PermissionRequired for Reproduction or Display
Fruits
• Dry Fruits That Split at Maturity (Dehiscent) Follicle - Splits along one side or seam. Legume - Splits along two sides or seams. Silique - Splits along two sides or seams,
but seeds are borne on central partition exposed when the two halves separate.
Capsules - Consist of at least two carpels, and split in a variety of ways.
Copyright © McGraw-Hill Companies PermissionRequired for Reproduction or Display Copyright © McGraw-Hill Companies Permission
Required for Reproduction or Display
Copyright © McGraw-Hill Companies PermissionRequired for Reproduction or Display
Copyright © McGraw-Hill Companies PermissionRequired for Reproduction or Display
Fig. 8.12
Fig. 8.14b
Fig. 8.14a
Fig. 8.15
Fruits
• Dry Fruits That Do Not Split at Maturity (Indehiscent) Achene Nut Grain Samara Schizocarp
Copyright © McGraw-Hill Companies PermissionRequired for Reproduction or Display
Fig. 8.16
Fig. 8.17
Fruits
• Aggregate Fruits Derived from a single flower with several to
many pistils.- Individual pistils mature as a clustered
unit on a single receptacle Raspberries, Strawberries.
• Multiple Fruits Derived from several to many individual
flowers in a single inflorescence. - Pineapples, Figs
Fig. 8.19
Fig. 8.19b
Fig. 8.20
Fig. 8.21
Fruit and Seed Dispersal
• Wind Dispersal Small and Lightweight seeds.
• Animal Dispersal Seeds pass through digestive tract. Fruits and seeds catch in fur or feathers. Oils attract ants.
• Water Dispersal Some fruits contain trapped air.
• Mechanical Ejection of Seeds
Fig. 8.22
Fig. 8.23
Seeds
• Structure Cotyledons - Food storage organs that
function as first seed leaves. Plumule - Embryo shoot. Epicotyl - Stem above cotyledon. Hypocotyl - Stem below attachment point. Radicle - Stem tip developing into a root.
Dormancy
• Coat Imposed Dormancy Prevention of Water Uptake Mechanical Constraint Interference with Gas Exchange Retention of Inhibitors Production of Inhibitors
Dormancy
• Embryo Dormancy High levels of GA and ABA
Dormancy
• Primary vs Secondary dormancy
• Release from Dormancy Afterripening Chilling (stratification) Light
Germination
• Germination is the beginning or resumption of seed growth. Seed must be viable.
- Favorable Environmental Factors- Imbibe water
Fig. 8.28b
Fig. 8.29
Longevity
• Viability of most seeds is significantly extended when the seeds are stored under conditions of low temperatures and kept dry. A few species produce seeds with no
period of dormancy.- Vivipary
Box Fig. 8.1
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