Term
|
Definition
-Growth toward a light source
-Experiments done by Darwin & Darwin, Boysen-Jensen, and Frits Went
- Tip of coleoptile mmust produce a water-soluble chemical(auxin) that promotes shoot growth
-Increased concentrations of auxin lead to greater cell elongation on dark side |
|
|
Term
| Darwin and Darwin experiment |
|
Definition
-Light sensed in tip of coleoptile and signal transmitted downward
-Covered stem, tip, clear, opaque |
|
|
Term
|
Definition
-Showed that the light sensing "signal" is a water soluble chemical
-Cut off tip and placed either agar or mica between tip and stem |
|
|
Term
|
Definition
-Term for any chemical substance that promotes the elongation of coleoptiles
-Have multiple functions in monocots and eudicots
-Most common form is IAA(indoleacetic acid) |
|
|
Term
|
Definition
1. Auxin stimulates proton pumps, acidifying cell walls
2. Cell walls become more plastic and stretch more easily
3. Water moves into cell, pushing out and expanding cell wall |
|
|
Term
| What does Auxin Do in Plants? |
|
Definition
-Promotes shoot elongation
-Suppresses shoot branching
-Inhibits root elongation
-Promotes root branching
-Promotes growth of Fruit
-Regulates development through interaction with other hormones |
|
|
Term
|
Definition
-Plant Hormone
-promotes lateral growth of shoots, promotes cell division and differentiation
-Works with auxin for elongation |
|
|
Term
|
Definition
-Plant Hormone
-Promote Cell Division
-Stimulate fruit development(with auxin)
-Breaks seed dormancy |
|
|
Term
|
Definition
-Plant Hormone
-Maintains seed dormancy
-Promotes drought resistance
-Opens potassium channels in guard cells |
|
|
Term
|
Definition
-Plant Hormone
-Reaction to mechanical stress
-Promotes leaf abcission
-Apoptosis
-Fruit ripening |
|
|
Term
|
Definition
1. Texture: General structure
2. Composition: organic and inorganic |
|
|
Term
| How much mass of top soil is lost each year? |
|
Definition
| 1700-5000 tons per square kilometer |
|
|
Term
|
Definition
-Few grasslands/monocot soils left alone
-wind and water erosion
-single species grazers
-salination
-desertification
-sodication |
|
|
Term
|
Definition
-9 Macronutrients and 8 Micronutrients
-Most important Macronutrients are Potassium, Nitrogen, and Phosphorous
-Without these three visible deficiencies |
|
|
Term
| Most important Plant Nutrient |
|
Definition
-Nitrogen
-Needed for proteins, nuclei acids, chlorophyll, enzymes(rubisco), etc. |
|
|
Term
|
Definition
| Nitrogen fixing bacteria that live in the root nodules of legumes; mutualistic relationship |
|
|
Term
|
Definition
| Rotate nitrogen adding and nitrogen extracting crops |
|
|
Term
| Adaptations to Water Stress |
|
Definition
1. Mesophytes
2. Xerophytes
3. Hydrophytes
4. Halophytes |
|
|
Term
| Environmental Control of Stomatal Density |
|
Definition
| During development if light intensity increase and carbon dioxide levels decrease than stomatal density will increase |
|
|
Term
|
Definition
-Guard Cells change turgor pressure by uptake and loss of potassium ions
-Driven by active transport of protons in membrane(creates a membrance potential)
-Accumulation of K+ lowers water potential and resutls in water gain through osmosis, so opens stoma |
|
|
Term
| Cues for Stomatal opening and closing |
|
Definition
1. Bluelight receptors; stimulates the proton pumps of K+
2. Depletion of CO2 in leaf
3. Internal clock/Circadian Rhythm
4. Environmental stresses (close during day) |
|
|
Term
|
Definition
-Rubisco+3 CO2+RuB)
-6 3-carbon compounds
-Energy rearranged into higher energy G3P
-G3P used to build glucose
-One of six used to build and the rest used to regenerate RuBP |
|
|
Term
| Photorespiration and Photosynthesis |
|
Definition
| -Rubisco catalyzes two competing and opposite reactions |
|
|
Term
| C4 Photosynthetic Pathway |
|
Definition
-Increases CO2 concentration about rubisco, which eliminates photorespiration
-Takes extra energy
-Only beneficial at high temperatures(unlike the C3 mechanism which favors lower temperatures) |
|
|
Term
|
Definition
-The enzyme C4 plants use in the mesophyll
-Has a much higher affinity for CO2 than rubisco |
|
|
Term
| Advantages of C4 at higher temperatures |
|
Definition
1. More efficient use of light energy
2. Higher Water Use efficiency
3. Higher Nitrogen Use Efficiency(reduces leaf litter nitrogen quality)
-C4 dominate in summer and hot grasslands
-Advantages negated at high CO2 concentrations |
|
|
Term
|
Definition
-Different times of the day
-Hot and Dry climates: succulents, pineapples and cacti |
|
|
Term
| Other Adaptations to Environmental Stress |
|
Definition
1. Dry condition lead to suppresion of shallow roots
2. Aerial roots
3. Ethylene leads to air pockets that act as "snorkels"
4. Heat Shock Proteins for enzymes
5. Antifreeze, by high solute concentrations |
|
|
Term
|
Definition
1. Allelopathy (biotic)
2. Physical Structures (biotic)
3. Secondary Compounds(biotic)
4. Direct competition with neighbors |
|
|
Term
|
Definition
-First defense: Physical structures; trichomes, spines, etc.
-Second defense: Chemical Poisons; allelopathy |
|
|
Term
| Types of Secondary Compounds |
|
Definition
1. Terpenes: St John's Wort
2. Phenolics: Tannins and Lignans; flavaonoids
3. Alkaloids: Psychoactive; Nitrogen containing compounds; active on nervous sytem |
|
|
Term
| How to compete with neighbors |
|
Definition
1. Grow faster above ground and monopolize light resources
2. Grow faster below ground and monopolize soil resources
3. Poison: Allelopathy |
|
|
Term
|
Definition
-Most often inhibit seed germination or seedling growth
-May act directly on competing plants or inhibit growth via effects on soils |
|
|
