BIOL 1002 Chapter : Chapter 25
Document Summary
Sexual reproduction: two parent plants give rise to genetically variable offspring, involves meiosis, gamete formation, and fertilization, allows offspring to cope with a changing environment or invade different habitats. Plant life cycle is characterized by alteration of generations: multi cellular diploid plants (sporophytes) and multicellular haploid plants (gametophytes) take turns producing each other. Pollen is the male gametophyte: pollen develops within anthers of diploid sporophyte plants, pollen grains have a tough protective coats that exhibit species- specific shapes and patterns. Mature pollen is dispersed: pollen sacs of anthers split open when male gametophytes are mature, pollen is dispersed by either animal pollinators or wind currents, grass is an example of wind pollinated flower. Pollination does not ensure fertilization: pollination will not lead to fertilization if, the tube cell fails to grow properly, the embryo sac has no egg, sperm from another pollen grain has already fertilized the egg.
