BIO 104 4/16/96

Dr. Barstow began by going over exam #1
We are 20% done with Biology 104!
Chapter 32
There are 2 kinds of transport processes in plants
     1) transpiration=water
     2) translocation=products of photosynthesis
        What do plants need?
     1) CO2 and water are essential for photosynthesis
          -CO2 is .03% of the atmosphere
     photosynthesis supplies the plant with organic molecules such as
sugars, amino acids etc.

Macronutrients
     Carbon
     Hydrogen
     Nitrogen
     Oxygen
     Phosphorous
     Sulfur

     These are the components of all organic compounds.
     carbohydrates: C, H, O
     proteins: C, H, N, S
     lipids: C, H, O
     nucleic acids: C, H, O, N, P

     Calcium, Potassium, and Magnesium ions regulate osmotic and
other regulatory function
     -they can act as enzyme co-factors
     Magnesium ion found in chlorophyll

Fertilizer
10-10-10 is the NPK
This denotes how many part of nitrogen, phosphorous, and potassium is
in the fertilizer.

Micronutrients
     -these are required in minute quantities
1) Chlorine
2) Iron
3) Boron
4) Manganese
5) Zinc
6) Copper
7) Molybdenum

Worn out soil does not contain enough nitrogen

With the exception of Carbon dioxide everything else comes in through
the roots.
Acquisition of minerals
1) Active transport into the root hairs (ATP is required)
2) Transported through plasmodesmata
3) Active transport into root vascular cylinder
4) Diffusion into the xylem
     -water and minerals mainly transported into the xylem
     
Nitrogen
     Nitrogen gas makes up roughly 80% of the atmosphere
     NH4+=ammonia=which can move from soil to the roots
     NO3-=nitrate=transported in the plant
Rhizobium is a bacteria peanut farmers put on their peanut seeds.
     Nitrogen Fixation
          -takes N2 (nitrogen gas) to form nitrate          NO3
     Rhizobium is the bacteria that does this process in legumes   
               (clover, peas, beans, peanuts, and alfalfa)
          -infects root hairs and forms a root nodule (symbiosis        
     between bacteria and the root)
     
Mycorrhizae-fungus/root complex without it plants will not grow or at
least not grow well.

Transport of Water
Cohesion-Tension hypothesis
If you insert a celery stem without leaves in a glass of water and dye; the
water rises very minimally up the stem.  If you leave the leaves on the
celery the colored water will rise through the stem into the leaves
themselves.

A vacuum or pressure mechanism does not control the transport of water
in the plants - evaporation is the main mechanism - this requires:

1) capillarity= adhesion of water to the walls of thin tubes (Xylem)