Bio 201 S12 Lect 13(True v3

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Unformatted text preview: temps –  ice crystals damage Essues •  adaptaEon: cold hardening –  takes several days –  increases unsaturated faNy acid content in membranes •  preserves fluidity •  see next slide •  anEfreeze proteins –  prevent ice crystals from forming hNp:// content/uploads/2009/12/plants- in- snow.jpg fat •  Lipid - general term for fats, fat- like molecules •  Fat - a class of lipids, produced by plants and animals, density lower than water, insoluble in water –  Fats that are liquid at room temperature = “oils” •  Triglycerides - a main component of natural fats •  FaNy acid - a carboxylic acid O –  with a long hydrocarbon chain || •  Saturated - no C- C double bonds in chain •  Unsaturated - has C=C double bonds in chain - C- O- H •  Polyunsaturated - has >1 C=C double bonds in chain –  Cis - most common in unprocessed food –  Trans - common in processed food R1 H! \ /! C = C! / \! H R2! R1 R2! \ /! C = C! / \! H H! salt •  the most restricEve substance to plant growth •  saline (=salty) environments –  oceans –  river estuaries going into ocean –  soil near estuary, river delta areas •  salinizaEon of soil = growing problem hNp:// ricebreedingcourse/image46.jpg also: textbook menEons geneEcally modified tomatoes that express high levels of a gene whose product causes salt to be stored in vacuoles – greatly increasing salt tolerance in salty environments halophytes = plants adapted to salty environments salt glands – excrete salt to outside and excreted salt in bladders in some plants can help leaves get water from roots and prevent water loss due to transpiraEon •  high negaEve water potenEal in environment –  water moves toward negaEve potenEal •  plant cells need even more negaEve water potenEal to preserve water –  otherwise, wilEng due to water loss •  also: Na+ and Cl- ions can be toxic to plants halophytes and xerophytes share: •  succulence - thick, watery Essue –  conserves water; stored water can vary in daily cycles in salt marshes •  •  succulents oren use: Crassulacean Acid Metabolism (CAM) (see later slides) other adaptaEons: high raEo of root to shoot Essue, sunken stomata, thick cuEcles (already discussed for xerophytes)...
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This note was uploaded on 10/02/2013 for the course BIO 201 taught by Professor True during the Spring '08 term at SUNY Stony Brook.

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