BIOL 1108 Chapter Notes - Chapter 32: Rafflesia, Symbiosis, Xylem
Document Summary
Plants can provide a habitat for other plants and even viruses, bacteria, and protists. Plants can sense danger and deploy defense mechanism that include physical and chemical ones. Epidermis is the plant"s first line of defense. Some diseases enter through wounds in the tissue/cuticle. Some pathogens release chem to prevent its closure. Come secret chem to weaken epidermis/cell walls. Can travel from cell wall to cell wall, through plasmodesmata, through vascular system. Biotrophic pathogens- obtain resources from living cells. Most release chem to stimulate release of nutrients. Necrotrophic pathogens- kill cells before exploiting them. E. g. some mistletoes are xylem parasites and do not need to produce roots to get nutrients and water. Rafflesia is a lrg parasitic flower and gets all carbs/sugar from host. Virulent pathogens- can overcome the host"s defenses and lead to disease. Avirulent pathogens- damage only a small part of the plant b/c the host plant is able to contain the infection.
