중복수정

1. 중복수정

2. 복습-체세포 분열과 생식 세포 분열 1 4 반 생장

3. 꽃에서 열매로 http://mcintosh.botany.org/bsa/misc/mcintosh/mcinto01.html

4. 1. The McIntosh apple begins in late Winter when the stem tips or "buds" are still in their dormant condition. 2. In early Spring each bud begins to swell and turn green, bending back the tough bud scales.

5. 3. Continued growth expands the bud still more. 4. Gradually the fresh young leaves open

6. 5. The young leaves expand into the typical shape and size of apple leaves. 6. Several additional days of growth allow the tightly closed, hairy flower buds in the center to be visible.

7. 8. The red parts (the petals) enlarge from behind the five green, hairy parts (the sepals). 7. The flower buds continue to swell as the parts inside the bud grow

8. 10. The flower buds are beginning to break open. 9. The individual flower stalks get longer and the flower buds swell.

9. 12. The stamens flare out from the center and we can see their nearly white stalks (filaments) each topped with a tiny yellow anther which contains pollen. Even though we cannot see it, there is sweet nectar at the base of the petals and the apple blossoms will be visited by honey bees that gather the nectar then carry it to their hives to produce honey. 11. Finally one of the flowers bursts open, revealing the parts inside. The petals are white on the inside with a tinge of pink on the outside!.

10. 14. Soon the petals fall off. If you were in the the apple orchard at this time, you might think the thousands of petals drifting through the air look like falling snow! Notice that the small green sepals are still attached. 13. While gathering the nectar, the bees move the pollen from one tree to the blossoms of another tree where they rub it on another structure in the center of the flower, the stigmas on the very tip of a long styles that are attached to an ovary far below the attachment point of the petals. The movement of this pollen is called "pollination" and without it the fruit and the seeds would not develop on the apple tree.  After shedding their pollen, the anthers darken and begin to shrivel up while the petals begin to wilt. If we look closely, we can see the stigma, the pronged structure in the center of the blossom where the pollen was deposited.

11. 16. The fruit begins to enlarge very rapidly below the sepals which stay the same size as always but seem to be getting smaller by comparison. 15. The ovary now begins to enlarge, turning the sepals upright from their former flared position. We can see the stamens beginning to shrivel and dry up.

12. 17. The apple is fuzzy at this stage from a covering of very soft hairs. The stamens continue to dry up and disappear beneath the enfolding sepals. 18. After several weeks the soft hairs disappear from the surface of the developing fruit, which looks more and more like an apple.

13. 19. Summer sun and rain allow the apple tree to produce lots of sugar, which it stores in the expanding apples. The added weight of the growing apple causes it to hang down and the cool, sunny days of Autumn bring a blending of nice hues of red and yellow to the skin of the apple. 20. Now the fruit is ripe and ready for us to pick!If we cut the fruit lengthwise, we will see that there are seeds inside! They are in what we call the "core" of the apple. Notice that the stalk of the flower is now the stalk of the fruit and is at the top. Looking carefully at the bottom of the apple, we can find the five sepals of the flower forming a star-like pattern. If we gently pry up the sepals we will see some of the dried, shriveled stamens underneath!

14. 중복수정 http://bcs.whfreeman.com/thelifewire/content/chp39/3902001.html

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