REPRODUCTION IN SEED PLANTS – CH.24

1. REPRODUCTION IN SEED PLANTS – CH.24

2. COMPLETE (PERFECT) FLOWERS • COMPLETE FLOWERS HAVE 4 TYPICAL FLOWER PARTS: STAMENS, PISTILS, SEPALS, AND PETALS. • THE BASIC STRUCTURE OF A TYPICAL FLOWER IS MADE UP OF FOUR CONCENTRIC WHORLS (CIRCLES) IN ORDER FROM OUTER PART TO INNER PART: • CALYX – OUTERMOST WHORL – MADE UP OF ALL OF THE SEPALS • COROLLA – NEXT WHORL – MADE UP OF ALL OF THE PETALS • ANDROECIUM – NEXT WHORL – MADE UP OF ALL OF THE STAMENS • GYNOECIUM – INNERMOST WHORL – MADE UP OF ONE OR MORE PISTILS

3. The Structure of a Flower Stamen Carpel Stigma Anther Style Filament Ovary Petal Ovule Sepal Section 24-1

4. ESSENTIAL FLOWER PARTS (REQUIRED FOR REPRODUCTION) • PERFECT FLOWERS: BOTH KINDS OF REPRO PARTS (BISEXUAL); MAY HAVE SELF OR CROSS POLLINATION **MOST FLOWERS (EG. ROSES, GLADIOLUS, BUTTERCUPS) • IMPERFECT FLOWERS: ONLY ONE KIND OF REPRO PART (UNISEXUAL); CAN ONLY HAVE CROSS POLLINATION 1. STAMINATE FLOWERS: MALE – STAMENS ONLY (MAKE POLLEN) *TASSEL OF CORN PLANT 2. PISTILLATE FLOWERS: FEMALE – ONLY HAVE PISTILS (MAKE EGGS) *SILK PART OF CORN PLANT MONOECIOUS PLANTS: IMPERFECT FLOWERS- MALE & FEMALE FLOWERS ON THE SAME PLANT (EG. CORN, SQUASH, CUCUMBER, PUMPKIN, WALNUTS) DIOECIOUS PLANTS: IMPERFECT FLOWERS- MALE & FEMALE FLOWERS ON TWO DIFFERENT PLANTS (EG. DATES, PLUMS, ASH, MAPLES, SPINACH)

5. NONESSENTIAL FLOWER PARTS (NOT INVOLVED IN REPRODUCTION) • SEPALS – OUTERMOST WHORL OF LEAF-LIKE PARTS, USUALLY SMALL & GREEN. ALL OF THE SEPALS MAKE UP THE CALYX • PETALS – NEXT WHORL OF LEAF-LIKE PARTS, USUALLY LARGE, COLORFUL, AND FRAGRANT. ALL OF THE PETALS ON ONE FLOWER MAKE UP THE COROLLA *IN SOME FLOWERS THE SEPALS LOOK EXACTLY LIKE THE PETALS IN SIZE, SHAPE, & COLOR (EG. LILY), BUT THE OUTERMOST WHORL (CALYX) IS STILL MADE UP OF ALL OF SEPALS *IN SOME ATYPICAL FLOWERS THE SEPALS AND PETALS DO NOT LOOK “TYPICAL” – NOT COLORFUL OR LARGE AT ALL (EG. WEEDS LIKE JOHNSON GRASS), BUT THESE TWO PARTS STILL MAKE UP THE OUTER 2 WHORLS (CALYX & COROLLA)

6. Stamen Carpel Stigma Anther Style Filament Ovary Petal Ovule Sepal REPRODUCTIVE PARTS – MALE (ESSENTIAL PARTS) STAMEN – MALE REPRODUCTIVE ORGAN. MADE OF: 1. ANTHER: ENLARGED TIP THAT PRODUCES POLLEN – EACH POLLEN GRAIN HAS 2 HAPLOID (N) NUCLEI (1 IS THE TUBE NUCLEUS, OTHER THE GERM NUCLEUS) 2. FILAMENT:STALK-LIKE PART THAT SUPPORTS THE ANTHER

7. Stamen Carpel Stigma Anther Style Filament Ovary Petal Ovule Sepal REPRODUCTIVE PARTS – FEMALE (ESSENTIAL PARTS) PISTIL – FEMALE REPRODUCTIVE ORGAN (ALSO CALLED CARPEL) MADE OF: • STIGMA: STICKY PART AT TOP – MAY HAVE ONE TO SEVERAL DISTINCT LOBES – CONTAINS MOISTURE & SUGARS NEEDED FOR POLLEN GRAIN GERMINATION AFTER POLLINATION • STYLE: STALK-LIKE PART THAT SUPPORTS THE STIGMA- POLLENTUBE WILL GO DOWN STYLE TO OVARY. AT THE TOP PART OF THE STYLE, MITOSIS OF GERM NUCLEUS WILL FORM 2 SPERM NUCLEI & THESE WILL BE CARRIED TO THE EGG BY THE POLLEN TUBE. THE POLLENGRAIN AND POLLEN TUBE COMPLETELY ELIMINATE THE NEED FOR H20 FOR SWIMMING SPERM THAT LIMITED MOSS & FERN REPRO. • OVARY: ENLARGED BASE AT BOTTOM OF PISTIL OVULE (EMBRYO SAC): FEMALE GAMETOPHYTE – WILL PRODUCE 8 HAPLOID NUCLEI WHICH POSITION THEMSELVES AS ANTIPODALS/POLAR NUCLEI/SYNERGIDS/EGG. THE EGG & POLAR NUCLEI WILL BE INVOLVED IN DOUBLE FERTILIZATION FORMING THE ZYGOTE (EMBRYO) & THE ENDOSPERM (STORED FOOD) INSIDE THE DEVELOPING SEED PERICARP: OUTER WALL OF OVARY THAT WILL ENLARGE WHEN MATURE, FORMING FRUIT CARPELS: SECTIONS W/IN THE OVARY WHERE DEVELOPING SEEDS WILL BE FOUND. THE # OF CARPELS OFTEN EQUALS THE # OF LOBES FOUND MAKING UP THE STIGMA

8. FLOWER CLASSIFICATION • MONOCOTS – FLOWER PARTS IN 3’S OR MULTIPLES OF 3 (LILY) • DICOTS – FLOWER PARTS IN 4’S OR 5’S OR MULTIPLES OF 4 OR 5 (BUTTERCUPS OR ROSES)

9. ANGIOSPERM LIFE CYCLE

10. Video Video • Click the image to play the video segment. Life Cycle of Angiosperms

11. MICROSPOROGENESIS (IN ANTHER – POLLEN FORMATION) • MICROSPORE (POLLEN) MOTHER CELL (2n) UNDERGOES 1 MEIOTIC DIVISION TO PRODUCE 4 MICROSPORES (n) • 4 MICROSPORES (n) UNDERGO 1 MITOTIC DIVISION TO PRODUCE 4 HAPLOID POLLEN GRAINS WITH 2 NUCLEI EACH (GENERATIVE NUCLEUS & TUBE NUCLEUS). • POLLEN GRAIN (IN ANTHER AWAITING ITS RUPTURE) IS THE MALE GAMETOPHYTE!!!

12. GERMINATING LILY POLLEN GRAIN

13. MEGASPOROGENESIS (IN OVARY) EMBRYO SAC FORMATION 1.MEGASPORE MOTHER CELL (2n) UNDERGOES 1 MEIOTIC DIVISION TO PRODUCE 1 HAPLOID CELL (OTHER 3 DISINTEGRATE) 2.1 MEGASPORE UNDERGOES 3 MITOTIC DIVISIONS TO PRODUCE 1EMBRYO SAC THAT HAS 7 CELLS IN IT: 3 ANTIPODALS (n), 2 SYNERGIDS (n), 1 EGG CELL (n) & 1 POLAR NUCLEI CELL (2n). 3. EMBRYO SAC IS THE FEMALE GAMETOPHYTE! *BOTH THE POLLEN GRAIN AND THE EMBRYO SAC ARE: 1. MICROSCOPIC 2. INCONSPICUOUS 3. SHORT-LIVED 4. DEPENDENT

14. EMBRYO SAC

15. POLLINATION TO SPOROPHYTE

16. POLLINATION FOLLOWED BY FERTILIZATION 1.POLLEN GRAIN LANDS ON THE STIGMA & GERMINATES, FORMING A POLLEN TUBE (FROM TUBE NUCLEUS) THAT CARRIES SPERM NUCLEI THROUGH THE STYLE INTO THE OVARY 2. WHILE IN THE POLLEN TUBE, THE SPERM NUCLEUS (n) DIVIDES (MITOSIS) TO PRODUCE 2 SPERM NUCLEI (n)

17. FERTILIZATION • TUBE NUCLEUS DISINTEGRATES ONCE POLLEN TUBE PUNCTURES THE OVULE (IN OVARY) • FERTILIZATION! SPERM (n) + EGG(n) = EMBRYO (2n) • SPERM (n) + 2 POLAR NUCLEI CELLS(n) = ENDOSPERM (3n) • SYNERGIDS & ANTIPODALS DISINTEGRATE

18. DOUBLE FERTILIZATION(CHARACTERISIC OF ANGIOSPERMS) 1. SPERM + EGG = EMBRYO(2n) 2. SPERM + 2 POLAR NUCLEI CELLS = ENDOSPERM (3n)

19. SEED/FRUIT FORMATION • OVULE WALL HARDENS TO FORM SEED COAT – SURROUND/PROTECT EMBRYO & ENDOSPERM • OVARY WALL GETS THICKER TO FORM FRUIT WHICH ENCLOSES SEEDS

20. SEEDS IN A POD

21. SEEDS 3 PARTS • EMBRYO – YOUNG PLANT • ENDOSPERM – STORED FOOD • SEED COAT - PROTECTION

22. GYMNOSPERMS (CONIFERS) HAVE CONES DRY SEEDS ARE EXPOSED ON SCALES OF CONES (NOT ENCLOSED) EG. PINE, SPRUCE, FIR, CEDAR ANGIOSPERMS (FLOWERING PLANTS) PRODUCE FRUIT SEEDS ENCLOSED (PROTECTED) BY FRUIT EG. ROSE, LILY, TULIP, DAISY, SUNFLOWER VEGETABLES: TOMATOES, BEANS, SQUASH, WATERMELON TREES: MAGNOLIA, FRUIT UNUSUAL FLOWERING PLANTS (ATYPICAL FLOWER PARTS) TREES: PECAN, OAK VEGETABLES: CORN GRASSES: CEREALS, GRAINS, WEEDS REPRODUCTION IN HIGHER PLANTS

23. STEPS IN PLANT REPRODUCTION • FORMATION OF EGG & POLLEN (SPERM) • POLLINATION (TRANSFER) • POLLEN TUBE FORMATION (GROWING DOWN STYLE) • FERTILIZATION/FUSION (OVARY) • FRUIT FORMATION (BASE OF FLOWER) • SEED DEVELOPMENT (INSIDE FRUIT) • SEED DISPERSAL (SPREADING) • SEED GERMINATION (SPROUTING) • GROWTH OF PLANT • FORMATION OF FLOWER/CONE (MALE & FEMALE GAMETOPHYTES)

24. ASEXUAL OFFSPRING FORMED FROM 1 PARENT – NO VARIATION, OFFSPRING IDENTICAL TO PARENT-ONLY SOURCE OF VARIATION: MUTATION EXAMPLES: MITOSIS- “COPIES” OF PARENT CELL SPORES – CELL ENCLOSED IN PROTECTIVE WALL, UNDER FAVORABLE CONDITIONS WILL RUPTURE, GROW, FORM NEW ORGANISM VEGETATIVE PROPAGATION- PLANT REPRO WITHOUT SEEDS – PART OF PARENT CAN FORM OFFSPRING LEAVES: AFRICAN VIOLETS, CHICKENS & HENS, BEGONIA STEMS: ROSES, STRAWBERRIES, BLACKBERRIES, PEARS, PEACHES, APPLES, POTATOES BUDDING – OUTGROWTH ON PARENT BREAKS OFF & FORMS WHOLE NEW ORGANISM (EG. SPONGE, HYDRA, YEAST) FRAGMENTATION – CELLS BREAK OFF PARENT TO FORM NEW ORGANISM (EG. BLUE-GREEN ALGAE, SPONGES, COELENTERATES (SEA ANEMONE) SEXUAL UNION OF 2 TYPES OF CELLS (2 SETS OF DNA) VARIATIONS: OFFSPRING DIFFER FROM PARENTS FERTILIZATION: UNION OF GAMETES AFTER MEIOSIS MEIOSIS: HAPLOID GAMETES THAT MAINTAIN SPECIES CHROMOSOME # - FERTILIZATION RESTORES SPECIES # EXAMPLES (ALL CAN FORM GAMETES): SPONGES COELENTERATA PLATYHELMINTHES ALL OTHER HIGHER ANIMALS SOME TYPES OF ALGAE (RED, BROWN, GREEN) REPRODUCTION: BASIC PROPERTY OF ALL LIFE, MAINTAINS THE SPECIES – 2 METHODS: