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רבייה זוויגית בצמחים
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מחזורי חיים ספורופיט הפלואידי דיפלואידי נבגים יצור הפלואידי גמטופיט
גמטות גמטות הפרייה מיוזה זיגוטה דיפלואידי ספורופיט
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בעלי חיים ספורופיט הפלואידי דיפלואידי גמטות גמטות גמטות הפרייה מיוזה
זיגוטה דיפלואידי ספורופיט
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ממלכת הצמחים חסרי מערכת הובלה בעלי מערכת הובלה טחבים בעלי זרעים חסרי זרעים שרכים מכוסי זרע חשופי זרע בעלי פרח מחטניים
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מבנה הפרח 1. עילי 2. צלקת 3. עמוד עילי 4. שחלה 5. אבקן 6. זיר 7. מאבק
8. עלה כותרת 9. עלה גביע
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Male Reproductive Structure
The stamen consists of two parts: Anther and Filament The anther is where meiosis occurs to produce haploid pollen The filament is a stalk that supports the anther
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Female Reproductive Structure
The pistil consists of the stigma, style and ovary The sticky stigma receives the pollen from the anther The pollen grows a tube down through the style Meiosis occurs in the ovary to produce haploid ovules
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גמטופיט נקבי
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הפרייה כפולה
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Fertilization After pollen lands on stigma, a pollen tube grows down through the style to ovary Tube contains two sperm nuclei In ovary, there is one egg or ovule nucleus and two polar nuclei Double fertilization occurs: one sperm nucleus fertilizes the egg, the other the two polar nuclei
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Result of Double Fertilization
The sperm nucleus and egg nucleus join to form a 2n (diploid) embryo The other sperm nucleus and the two polar nuclei join to form a 3n (triploid) endosperm. The endosperm is the food supply for the embryo.
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Accessory Structures The calyx consists of all the sepals, which protects the flower before it opens The corolla consists of all the petals, which serve to attract pollinators through color and scent
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Pollination Wind, insects or other animals transfer pollen from the anther of one flower to the stigma of another Flowers vary depending on pollination mechanism
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Pollination Vectors Wind Pollination: Dull, scentless
flowers with reduced petals Bees/Butterfly Pollination: Bright color, nectaries, scent. They sip nectar, get pollen on coats, transfer pollen from flower to flower
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Bird Pollination: Nectaries, bright
colors, tube-like flowers Moth Pollination: White petals, open at night Fly Pollination:Rank odor, flesh colored petals
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Seed and Fruit Development
After fertilization, the petals and sepals fall off flower Ovary “ripens” into a fruit The ovule develops into a seed
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Seed Dispersal Mechanisms- Allow plants to colonize new areas and avoid shade of parent plant
Wind Dispersal - Flight mechanisms, like parachutes, wings, etc. Ex. Dandelion, maples, birch Animal Dispersal - Fleshy fruits which animals eat, drop undigested seeds in feces or burrs which stick to animals’ coats
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Gravity Dispersal - Heavy nuts fall to ground and roll
ex. acorns Water Dispersal - Plants near water create floating fruits ex. coconuts
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Monocot Seed Germination
Monocots grow straight up with coleoptile sheath covering shoot One embryonic leaf Seed remains underground
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Dicot Seed Germination
Curved stem comes up out of soil Two embryonic leaves Seed goes above soil
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Parts of the Embryo Epicotyl - Grows into the leaves of the plant
Hypocotyl - Becomes the stem Radicle - Becomes the root
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