Botanical Adaptation Notes

Introduction: What is an adaptation? Characteristic that helps organism survive Why adapt? Increase reproductive fitness (# of successful offspring) Taxonomy: Plants with similar adaptations are grouped together. For example, peas, beans, lupine (Lupinus arboreus) all part of the Leguminosae family (Legumes)

Adaptations: Photosynthetic pathways: What is photosynthesis? Conversion of light energy into chemical energy (6CO2 + 6H2O + light => C6H12O6 + 6O2)

C3 Adaptations: Who does it? Photosynthetic pathways: Most plants (dicots) Where in the leaf does it occur? Mesophyll (leaf cells) What enzyme is used to help the reaction occur? Rubisco - can’t tell the difference between CO2 and O2 When does it work well? Moderate temperatures. At high temperatures energy is wasted on photorespiration (O2 used instead of CO2 ) so plants must keep stomatae open (see below) to take in more CO2 (and lose H2O :( ) Adaptations: Photosynthetic pathways:

C4 Adaptations: Photosynthetic pathways: Who does it? Grasses (monocots) Where in the leaf does it occur? Bundle sheath (surround plant “veins”) What enzyme is used to help the reaction occur? PEP- can tell the difference between CO2 and O2 When does it work well? High temperatures and dry. Can close stomatae (no H2O loss :) ) and still recognize CO2 inside leaf

CAM Adaptations: Photosynthetic pathways: Who does it? Succulents, pineapple Where in the leaf does it occur? Mesophyll (same as C3) What enzyme is used to help the reaction occur? PEP (same as C4) When does it work well? Stomatae open at night and CO2 stored for use in dark reaction when sun is out. Keeps stomatae closed in day (no H2O loss :) ) Photosynthetic pathways:

Seeds and Fruits Adaptations: Structures: (See prior studies) A epicotyl B radicle C cotyledon D seed coat Seeds used to disperse plant species. Monocots-one cotyledon Dicots- two cotyledons

Flowers Adaptations: Structures: Sexually reproductive structures which allow for the recombination of gametes (pollen and ova) to form fertilized seeds/fruits and increase variation. Monocots-stamen, other parts in multiples of 3’s Dicots-stamen, other parts in multiples of 4’s or 5’s, easy to identify sepal

Stems Adaptations: Structures: Xylem: H2O up plant (like a vein) Phloem: food down plant (like an artery) both are examples of “vascular” tissue (tubes) Monocots-xylem and phloem in separate bundles Dicots- xylem and phloem organized in rings (see diagram)

Leaves: Adaptations: Structures: External: stomatae (pores) C3, C4 open in day, close when hot, CAM open at night Middle: mesophyll (C3, CAM occurs here) Internal: bundle sheath (C4 occurs here), vascular system Monocots-parallel leaf veins Dicots- networked leaf veins (see diagram)

Other modified structures: Adaptations: Structures: Other modified structures: Modified leaves: bulbs Modified stems: corms, rhizomes, tubers Modified roots: storage roots, (i.e. Carrots)

Heat, dryness-C4 and CAM photosynthesis High light-Modify leaf shape Adaptations: Other Adaptations For dealing with… Heat, dryness-C4 and CAM photosynthesis High light-Modify leaf shape Salt-Dilute salt with water, remove it mechanically Flooding-Plants accumulate ethylene to avoid drowning, Specialized roots Defenses and Competitive Mechanisms Structures, chemicals, reproductive timing, etc. (more on this later)