1. what is ‘selfing’? why is it disadvantageous for a plant? What are some of the mechanisms that have evolved to prevent selfing? “Selfing” is the mechanism of self-fertilization by a flower. There are preventative measures that angiosperms perform in order to ensure that the sperm and egg come from different parents. Some plants mature the stamen faster than the carpel, or vice versa, so that an animal pollinator cannot transfer pollen between the two reproductive organs. Self-incompability is the ability of the plant to reject its own pollen. There are genes that are recognized when the pollen lands on the stigma of the same flower. Chemical blocks are stimulated to prevent the “selfing”. There is also sporophytic self-incompatibility where the block is released by cells of the stigma. 2. define these terms: perfect flower, unisexual flower, monoecious plant, dioecious plant, hypocotyls, radicals, scutellum, coleoptile, imbibition, callus A perfect flower has both reproductive units, the stamen and carpel. A
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This note was uploaded on 09/27/2011 for the course BIOL 101 taught by Professor Fevzidaldal during the Fall '08 term at UPenn.