|Plant Physiology (Biology 327) - Dr. Stephen G. Saupe; College of St. Benedict/ St. John's University; Biology Department; Collegeville, MN 56321; (320) 363 - 2782; (320) 363 - 3202, fax; email@example.com|
is sensitive to a variety of internal and external parameters.
The plant requires this tight control of stomatal aperture in order to
regulate the rates of photosynthesis/ transpiration; that is, the entry and exit
of water and gases from a leaf. Since
the stomata are so sensitive, they provide good indication of a plant's
physiological state. To measure the aperture:
a drop of immersion oil on a microscope slide.
an epidermal strip and immediately place it
cuticle side up in the drop of oil.
the forceps, carefully distribute some of the oil on top of the strip.
smooth out the strip if necessary and over with a cover glass.
the slide with the high power objective (430X) and measure the aperture with
a calibrated ocular micrometer. Measure
the stomata at the widest point from the inside wall of one guard cell to
the inside wall of the other.
10 stomata in 5 fields per strip. Repeat
with 4 other strips.
Record your data in a table and then calculate the mean aperture.
The oil serves to fix the stoma. Alternate techniques are available for fixing (i.e. immersion in alcohol; preparation of silicon rubber replicas)
Apertures should be measured within an hour of strip preparation.
Do not measure stomata in areas that were crushed by the forceps during stripping.
01/07/2009 � Copyright by SG