Ch 8 Part 2

1. Ch 8 Part 2

2. Fruits • Fruit- Matured ovary and its accessory parts • Contains seeds • All fruits develop from flower ovaries and accordingly are found exclusively in flowering plants. Tomato fruit

3. Fruits • Fruit Regions • Exocarp - Skin • Endocarp - Inner boundary around seed(s) • Mesocarp - Tissue between exocarp and endocarp Peach fruit • Three regions collectively called pericarp.

4. Fruits • Variability of fruits • Can consist of only ovary and seeds • Can include adjacent flower parts • May be fleshy or dry at maturity • May split or not split • May be derived from a one or more ovaries

5. Fruits • Fleshy Fruits - Mesocarp at least partly fleshy at maturity. • Simple fleshy fruits develop from flower with single pistil. • Drupe - Simple fleshy fruit with single seed enclosed by hard, stony endocarp (pit) Drupes: peaches, almonds, olives

6. Fruits • Simple fleshy fruits • Berry • From compound ovary, with more than one seed, and with fleshy pericarp • True berry - With thin skin and relatively soft pericarp • Tomatoes, grapes, peppers, blueberries, bananas • Pepo - Relatively thick rind • Pumpkins, cucumbers Grape berries

7. Fruits • Berry • Hesperidium - Leathery skin containing oils • Citrus • Pome- Flesh comes from enlarged floral tube or receptacle that grows up around ovary. • Endocarp papery or leathery • Apples, pears - Core and a little of adjacent tissue is from ovary; remainder is from floral tube and receptacle Apple pomes

8. Fruits • Dry Fruits - Mesocarp dry at maturity • Dehisicent or indehiscent • Dehiscent fruits - Split at Maturity • Follicle - Splits along one side • Larkspur, milkweed, peony • Legume - Splits along two sides • Legume family: peas, beans, lentils, peanuts Milkweed follicle Legumes

9. Fruits • Dehiscent fruits • Siliques and silicles - Split along two sides, but seeds on central partition, which is exposed when two halves separate. • Silique - More than three times longer than wide • Silicle - Less than three times longer than wide • Mustard family: broccoli, cabbage Silicle Silique

10. Fruits • Dehiscent fruits • Capsules - Consist of at least two carpels, and split in a variety of ways • Irises, poppies, violets, snapdragons Capsules

11. Fruits • Dry Fruits • Indehiscent Fruits - Do Not Split at Maturity • Single seed united with pericarp • Achene - Base of seed attached to pericarp. • Sunflower seed, buttercup, buckwheat • Nut - Similar to achene, but larger, with harder and thicker pericarp, and a cluster of bracts at base • Acorns, hazelnuts, hickory nuts Inside of sunflower achene Acorn

12. Fruits • Indehiscent Fruits • Grain (Caryopsis) - Pericarp tightly united with seed • Grasses: corn, wheat, rice, oats, barley • Samara- Pericarp extends as wings for dispersal. • Maples, ashes, elms Corn section • Schizocarp - Twin fruit that breaks into one-seeded segments called mericarps Samaras • Parsley family: carrots, anise, dill Schizocarp of mericarps

13. Fruits • Aggregate Fruits • Derived from single flower with several to many pistils • Individual pistils mature as clustered unit on single receptacle. Blackberry aggregate fruits • Raspberries, blackberries, strawberries • Multiple Fruits • Derived from several to many individual flowers in single inflorescence • Mulberries, Osage orange, pineapples, figs Osage orange multiple fruit

14. Fruit and Seed Dispersal • Dispersal by Wind • Fruits: Samaras, plumes or hairs on fruit • Seeds: Small and lightweight, or with wings

15. Fruit and Seed Dispersal • Dispersal by Animals • Seeds pass through digestive tract. • Fruits and seeds adhere to fur or feathers. • Oils attract ants. • Elaiosomes on bleeding hearts used as food by ants. Seeds from bleeding hearts. Elaiosome is white. • Water Dispersal • Some fruits contain trapped air for floatation.

16. Seeds • Structure • Ovules develop into seeds. • Cotyledons - Food storage organs that function as “seed leaves” • Embryo = cotyledons and plantlet • Plumule - Embryo shoot • Epicotyl - Stem above cotyledon attachment • Hypocotyl - Stem below cotyledon attachment • Radicle - Tip of embryo that develops into root Bean seed

17. Seeds • Epigeous germination • Hypocotyl lengthens, bends and becomes hook-shaped. • Top of hook emerges from ground, pulling cotyledons above ground. Epigeous germination • Hypogeous germination • Hypocotyl remains short and cotyledons do not emerge above surface.

18. Germination • Germinationis beginning or resumption of seed growth. • Some require period of dormancy. • Brought about by mechanical or physiological factors, including growth-inhibiting substances present in seed coat or fruit • Break dormancy by mechanical abrasion, thawing and freezing, bacterial action, or soaking rains. • Scarification - Artificially breaking dormancy • After ripening - Embryo composed of only of few cells when fruit ripens; seeds will not germinate until embryo develops.

19. Germination • Favorable environmental factors needed for germination. • Water and oxygen • Light or its absence • Proper temperature range • Enzymes in cytoplasm begin to function after water is imbibed.

20. Longevity • Seed viability varies, depending on species and storage conditions. • Viability extended: • At low temperatures • When kept dry • Vivipary - No period of dormancy; embryo continues to grow while fruit is still on parent. Vivipary in red mangrove