种子与果实 seeds & fruit

4. ________ – also a fleshy fruit with a tougher outer rind All member of the squash family: pumpkin, melons, cucumbers
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Simple fleshy fruit: pome
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C. Multiple fruit
Multiple fruit develops from ovaries of several flowers borne/fused together on the same stalk For example: ____________
Simple dry fruits
Simple dry fruits that do NOT open at maturity include Caryopsis: seed coat is fused to the ovary wall (cereal grains like ____________________) Nuts: single-ovary wall and seed coat remain separate, ovary wall is very hard (acorns)
Seeds and Fruits
Types & Dispersal
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Seeds and Fruit
• Fruits are formed by seed plants to aid in dispersing seeds • A seed contains the developing plant embryo in a protective coat (testa) • Seeds form from ovules fertilized in the ovary • Ovaries with seeds ripen into dry or fleshy fruits
DICOT
Parts of a Seed
MONOCOT
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Parts of a Seed
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Gymnosperm Seed
• A single fertilization produces the diploid (2n) embryo • The food source is the haploid megagametophyte
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B.
_____________
__________ fruit develops from one flower with many separate pistils/carpels, all ripening simultaneously Examples: strawberry, raspberries, blackberries
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Simple dry fruit: capsule
Simple dry fruits are dry (not fleshy) at maturity. Simple dry fruits that open at maturity include: capsules and legumes Capsule – fruit is dry at maturity and splits open along several seams Example: Cotton
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Animal dispersal
Some dry fruit attach and cling to animals (they hitchhike on the animals) Some have Velcro-like hooks that cling to animal fur (burdock, cockleburs) Others have sticky substances that stick to host (mistletoe)
B. Wind dispersal
Fruit and seeds may have special devices for wind dispersal Plumes catch wind currents: Dandelion Trees take advantage of their great heights for wind dispersal. Fruits with wings are used to slow the descent to land: maple, ash fruit
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What is the purpose of the fruit?
The main function of the fruit is to disperse the seeds Dispersal is important because 1. It spreads the progeny in order to colonize new environments 2. Reduces ______________ for resources with parents 3. Reduces the chances of predators destroying all of the plant’s yearly seed production Four types of seed dispersal: A. Self dispersal B. ______ dispersal C. Water dispersal
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C. ___________ Dispersal
Fruits and/or seeds use flotation devices to travel by water (in rivers, oceans, etc.) Fruit may have air spaces and corky floats: for example ________________
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D. Animal dispersal
Plants have _____________ with animals to accomplish seed dispersal Many plants depend on animals for seed dispersal; they may offer a nutritional reward Animals learn to recognize ripened fruit colors Fleshy fruits eaten and dispersed with feces
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Self dispersal
The peanut plant sows (buries) its own seeds! Geocarpic: carpel grows inside the earth (ngale
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Simple fleshy fruit
1. Berry – entire fruit wall is soft and fleshy at maturity. Inside is slimy. For example, grapes, tomato, etc.
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Flowering plant seed
In angiosperms (flowering plants) there is DOUBLE _______________ Which produces a diploid ________(2n) and, A triploid (3n) __________ Endosperm is the food source
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A. Simple fruit
A. Simple fruit – develops from a ______ ovary of a single flower. Simple fruits can be either fleshy or dry when mature Simple fleshy fruit 1. __________ 2. _________
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• • • •
External seed coat or testa Developing plant embryo Stored food called endosperm Seeds may be in one part (monocot) or two parts (dicots)
3. _______ type – outer part of fruit wall is soft and fleshy, inner part is hard and stony For example: ______________________
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Simple fleshy fruit: pepo
2. _______________ is a berry with tough, leathery rind (peel) Examples: oranges, lemons, other citrus.
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Simple fleshy fruit: drupe
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A. Self dispersal
Plants disperse their seeds by forceful ejection – explosive fruits! Witch hazel, squirting cucumber (jet propulsion)
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Dicot vs. monocot seed
Dicot has two cotyledons (like bean) Endosperm (food) is kept in the _________ Monocot has one __________ which absorbs the endosperm tissue during germination (corn)
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Simple dry fruit: Legumes
Legumes are dry at maturity and split open along _______ seams Examples: pea pods, bean pods, peanut
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5. Pomes: most of the fleshy part of pomes develops from the enlarged base of the perianth (corolla and calyx) that has fused with the ovary wall Pomes include ___________________
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Fruit
In flowering plants – Fruit is a mature, ripened o_____ that contains the seeds Pericarp – the ovary wall
ovary
Fruit types A. Simple B. Aggregate C. Multiple