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Angiosperm Reproduction Angiosperms have 3 unique features:-Flowers, Fruits, double Fertilization (by 2 sperm) Pollination = transfer of pollen from anther to stigma-some plants are self-pollinated-cross-pollinated plants: -self-incompatibility: plant rejects own pollen or closely related plant -maximize genetic variability Fruit:-egg cell à plant embryo-ovules inside ovary à seeds-ripe ovary à fruit-fruit protects enclosed seed(s)-aids in dispersal by water, wind, or animals-types of fruit: simple (pea), aggregate (raspberry), multiple (pineapple), accessory (apple) Seeds:-mature seed à dormancy (resting)-low metabolic rate-growth and development suspended-resumes growth when environmental conditions suitable for germination-dispersal by wind (dandelion, maple), water (coconut), animal (in poop, hoarding, travel) Germination:-seed take up water (imbibition) à trigger metabolic changes to begin growth-root develops à shoot emerges à leaves expand and turn green (photosynthesis)-very hazardous for plants due to vulnerability – predators, parasites, wind Plant Reproduction-Sexual Reproduction: flower à seed. Genetic diversity. More complex and hazardous for seedlings. Advantage in unstable environments-Asexual (vegetative) reproduction: runners, bulbs, grafts, cuttings, vegetative fragmentation. Clones. Simpler (no pollinator needed). Suited for stable environments. Humans Modify Crops-Artificial selection of plants for breeding-Plant Biotechnology:--genetically modified organisms ex: golden rice – engineered to produce beta carotene (vit. A)ex: Bt corn – transgenic – expresses Bt (bacteria gene) à produces protein toxic to insects --Biofuels: reduce CO2 emissions ex: biodiesel: vegetable oils ex: bioethanol: convert cellulose into ethanol
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