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FRUITS AND SEEDS Competency Identify the pats of the fruits and seeds and its classifications Pre-Activity: Short clip Film Showing Guide Questions: 1. What is a fruit? What is a seed? 2. What are its parts? 3. What are its types? Fruits Part of sexual reproduction unique to angiosperms Develops from fertilized ovary Protect the enclosed seeds and aids in seed dispersal Widely utilized as a significant food source Fruit wall or Pericarp Develops from the ovary wall Composed of three layers outer exocarp middle mesocarp inner endocarp Appearance of these three layers varies among different fruit types Fruit Types I: Simple Fruits Derived from the ovary of a single carpel or several fused carpels Can be fleshy or dry Type I.a: Simple fleshy fruit Derived from the ovary of a single carpel or several fused carpels Often soft and juicy Seed dispersal occurs when an animal eats the fruit Types of simple fleshy fruits BERRY DRUPE -HESPERIDIUM -POME -PEPO Berry Thin exocarp Soft fleshy mesocarp Endocarp with one to many seeds Tomatoes, grapes and dates Hesperidium Berry with a tough leathery rind Oranges, lemons, and other citrus fruitS Pepo Tough outer rind that has both receptacle tissue and exocarp Mesocarp and endocarp are fleshy All members of the squash family (pumpkins, melons, and cucumbers) Drupe Thin exocarp Fleshy mesocarp Hard stony endocarp which encases the seed Cherries, peaches, and plums Exocarp Mesocarp Endocarp Pome Fleshy part develops from the enlarged base of the perianth (calyx and corolla) that is fused to the ovary wall Apples and pears Type I.b: Simple dry fruits Derived from the ovary of a single carpel or several fused carpels Pericarp may be tough and woody or thin and papery Two types: dehiscent indehiscent Dry dehiscent fruits Split open at maturity to release seeds Wind often aids seed dispersal Types characterized by how they open: * Follicle - splits open along one seam (magnolia and milkweed) * Legume - splits open along two seams (beans and peas) * Capsule - several pores or slits (cotton and poppy) Legume - pea Legume pod splits along two seams to disperse seeds Capsule Cotton fruit is a capsule splitting open along five lines Seeds are covered with long hairs (trichomes) which are the commercial cotton fiber Indehiscent fruits Do not split open to release seeds Common types Achene Samara Grain Nut ACHENES SAMARAS One-seeded fruit Pericarp free from the seed Sunflower “seeds” Winged achenes Dispersed by wind Fruit in maple trees and ash trees Grains Also called caryopsis Single seeded fruits Pericarp fused to seed coat Fruits of all cereal grasses: wheat, rice, corn and barley Wheat grain Fused seed coat and ovary wall layers Nuts One-seeded fruits Hard stony pericarps Hazelnuts, chestnuts, and acorns Other things commonly called nuts that are not true nuts but are actually seeds Fruit Types II: Aggregate fruits Develop from a single flower with many separate carpels Raspberries and blackberries Strawberries also contain accessory tissue Seeds on the surface are actually separate achenes inserted on the enlarged, fleshy, red receptacle Raspberries and Blackberries Aggregate-Accessory Fruit Strawberries also contain accessory tissue Seeds on the surface are actually separate achenes on enlarged, fleshy receptacle Fruit Types III: Multiple fruits Result from the fusion of ovaries from many separate flowers on an inflorescence Figs and pineapples are examples of multiple fruits one of many ovaries that are fused together Seed Structure and Germination Seeds Develop from the fertilized ovules Include an embryonic plant and some form of nutritive tissue within a seed coat Because of the stored nutrients many seeds are valuable foods SEED – matured ovule Parts: Embryo – rudimentary plants – zygote plumule – rudimentary shoot, bud radicle – rudimentary root hypocotyl – attachment of cotyledon and stem epicotyl – attachment of cotyledon and plumule Seed Coats – derived from the integuments of ovule. testa – outer seed tegmen – inner coat Hilum – point at which the seed was attached to the fruit. Look like a scar indicating the point of attachment. Raphe – ridge formed by stalks Micropyle – small opening in the seed which is close to the end of the hilum. pore Chalaza – upper end of raphe Endosperm – daughter nuclei • • • • Parts of a Seed External seed coat or testa Developing plant embryo Stored food called endosperm Seeds may be in one part (monocot) or two parts (dicots) DICOT MONOCOT copyright cmassengale Parts of a Seed copyright cmassengale Dicots and monocots Refers to the number of seed leaves or cotyledons present in the seed Dicot seeds have two cotyledons Monocots have one cotyledons Dicot seed Cotyledons attached to and enclose the embryonic plant Cotyledons occupy the greatest part of the seed Cotyledons have absorbed the nutrients from the endosperm which may be entirely used up Dicot seed - Lima bean Thin seed coat Hilum and micropyle visible on surface * Hilum - attachment * Micropyle - opening in the integuments If the seed coat is removed the two large food-storing cotyledons are visible Dicot embryo Consists of : Epicotyl - part that develops into the shoot; typically has embryonic leaves - also called a plumule Hypocotyl - portion of embryo between cotyledon attachment and radicle (between stem and root) Radicle - the embryonic root Monocot seed Cotyledon transfers food from the endosperm to the embryo In several monocot families large amounts of endosperm are present Seed germination Absorption of water Emergence of the radicle Shoot emerges: In dicots the hypocotyl elongates and breaks through the soil In monocots the coleoptile emerges protecting the epicotyl tip Soon after the tissues are exposed to sunlight, they develop chlorophyll and begin to photosynthesize Classify the types of fruits (flesh or dry , multiple, aggregate Types of simple fleshy fruits and its specifics): BERRY -HESPERIDIUM 1. mango -PEPO - DRUPE -POME 2. alligator pear SIMPLE DRY Dehiscent 3. jackfruit Types characterized by how they open: 4. grapes * Follicle - splits open along one seam 5. lemon (magnolia and milkweed) 6. coconut * Legume - splits open along two seams (beans 7. banana and peas) * Capsule - several pores or slits (cotton and 8. pineapple poppy) 9. guava 10. melon Indehiscent fruits: Do not split open to release seeds Common types: Achene; Samara; Grain; Nut
