Plant structure and function
Plant growth is accomplished by both mitotic division of cells, and increase of cell size.
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Primary growth lengthens roots and shoots by division at the apical meristem, which is typically dominant over axillary buds -
Secondary growth increases the girth of woody and other plants. Lateral meristems divide to produce vascular and cork cambium; the latter eventually generates cork and bark. -
Sapwood contains active vascular elements, and eventually gets filled in with resin to become heartwood
Plant reproduction
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Pollen and embryo sacs represent the male and female gametophyte stages, respectively. Pollination is followed by a double fertilization to produce the zygote (2n) and endosperm (3n).This ensures development only happens in ovules containing a fertilized egg -
Fertilized ovules develop into seeds with an embryo surrounded by food reserves and a hard exterior capsule. -
Ovaries develop into fruit by a variety of methods: simple (growth of the ovary), aggregate (multiple carpels), and multiple (fusion of clustered flowers). -
Seeds germinate when they take up water, send down an embryonic root, and send up the embryonic shoot. -
Asexual reproduction produces plant clones; agriculture takes advantage of this process to propagate desirable varieties.
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