Pollen Study II
- Subject: Pollen Study II
- From: H* E* P*
- Date: Sun, 25 Jul 1999 21:44:07 -0700
To: Pumpkins
cc: Microscope
SHOULD PUMPKINS BE POLLINATED AT SUNSET?
Twenty minutes before sunset tonite, I picked a typical male Atlantic
Giant pumpkin flower which would have opened tomorrow morning. I
immediate removed the petals and examined at 7X and found 2% of the
pollen ridges had split open to release the pollen grains.
Using a fine sewing needle, I teased the unopened ridges and found the
pollen grains are fully formed and piled loosely within the ridges like
BBs in a tube of shot. I compared the grains with pollen grains on a
male flower which has been on the lab table from 3 days earlier (I had
stripped the petals from it 3 days ago. I saw no difference in the
pollen grains at 15X. Does someone on Microscope@onelist.com know of a
stain which tests viability of pollen grains?
The best way to test viability is to apply the pollen to a female
flower and I will do so if I have the opportunity. I fear dry weather
and vine borers have ended my 2000 crop.
The 3 day old anther body which has been in the lab (80 F) without
water has dried down to 1/4 the original diameter, but the pollen looks
normal and is much easier harvested. Perhaps, someone can let an anther
dry without petals for a day and use this day old pollen to fertilize an
unneeded female flower.
Blackberry and strawberry breeders normally pollinate females 24 hours
before the flower would open normally. Such flowers are mostly covered
with the green sepals, but show streaks of white. They remove the
sepals+petals as a unit and place that in a dry dish for 24 hours in lab
so the anthers will open. This pollen is used to pollinate females. Thus
females are pollinated one day ahead of Nature's date with pollen that
is of Nature's date. Actually pollen days or years old can be be used if
stored in dry in home freezer.
I scraped the anther body of this sunset unopened male flower and
examined the scraping at 15X and found no evidence of damage to the
pollen grains.
I examined 3 day old pollen by attempting to crush it with a needle,
but did not succeed. I then used the flat surface of a scapel and found
pollen grains of AG make good ball bearings between paper and a hard
flat surface, but some were crushed. I also examined fresh pollen and
guessed that pollen grains obtained by scraping the anther ridges of an
open male flower are study and should be suitable for use. However it
would be much easier to use pollen from day earlier male flowers kept at
room temperature or in refrigerator.
CAN ONE POLLINATE AG DURING THE COUPLE HOURS BEFORE SUNSET?
1. I have not tested this in the garden and have no flowers to test.
2. Since many people say pollination tends to fail when done in the
morning and day temperature rises above 90 F, I think sunset may be the
ideal time to pollinate pumpkin flowers. Pollen germinates rapidly. The
two nuclear divisions take place in the pollen tube as the tube grows
toward the egg. Recall in corn that distance is 3 inches or so and one
can see the tube growing down the style by using a microscope. Any corn
can be used, but the inbred KYS is said to be best for use by students.
3. I don't expect to be able to do this experiment during 1999. I hope
someone can try sunset pollination using pollen from male flowers picked
24 hours earlier and stored in water or kept dry. Store them like cut
flowers, do not get the anther wet! Please report the results on
pumpkins@mallorn.com
--
Harold Eddleman Ph.D. Microbiologist. i*@disknet.com
Location: Palmyra IN USA; 36 kilometers west of Louisville, Kentucky
http://www.disknet.com/indiana_biolab/pk.htm
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