Re: Re: HYB: thermo-hygrometer

In a message dated 8/18/2002 9:17:15 AM Central Daylight Time, 
neilm@charter.net writes:


> In Western Idaho in late May the humidity was rarely above 30% during 
> iris bloom season except early some mornings.  We had Taylor 
> Instruments Hygro-thermographs in the orchards, so could track 
> conditions there.
> 
> Typically, the daytime percentage as I recall was lower than that on 
> most days, more like 20%.  My experience there was about the same as 
> here--the condition of the stigma and the pollen were what was 
> important, not so much the weather.  Fresh blooms, fluffy pollen have 
> their own humidifiers built in.  There is a microclimate within the 
> well-protected part of the flower were the pollen makes contact that 
> raises the chances for sucess.
> 

Your micro climate comment has merit and a degree of support from some of the 
data iris-talk generates. Most accept the concept that only one stigma need 
be pollinated to set pods as do biology texts. Conversely, most people also 
accept the principle that higher pod set is achieved by pollinating all three 
stigmas. Both are true by consensus.

I suspect more often than not, failure to set pods is a result of pollen 
failure than a blooms (stigmas) response to weather conditions. While this is 
conjecture on my part it has some basis in fact. If one assumes iris pollen 
has roughly the same viability subjected to the natural environment as 
daylily pollen then maximum viability is about 24 hours. We are able to 
extend the life of both pollens by artificially controlling it's environment 
(refrigeration or freezing). In all three instances (natural, refrigeration, 
freezing) the pollen viability degrades over time. We also know from 
experience that moisture is the enemy of pollen.

The term "weak pollen" implies that individual pollen grains are not 
particularly virile. I believe more appropriately, the term should be used to 
designate a high percentage of dead, dying or infertile pollen grains 
relative to the total number. And, vise versa for "good" or viable pollen.

The instant the anther is removed from the bloom it's micro climate no longer 
exists and the ultimate death of pollen grains is accelerated. This is not 
immediately of extreme importance because there are so often so many pollen 
grains. It becomes exponentially important over time.

Revisiting the moisture issue, we often see pollen sacs on the anthers fail 
to open in low light, high humidity times. Additionally, we often see them 
open in periods of high humidity and produce little pollen. Too, we see them 
open and produce gummy tacky pollen in elevated humidity conditions. None of 
these situations are conducive to a high rates of pod set. Attention to the 
treatment/condition/control of pollen can conceivably do more for pod set 
than any other factor under the direct influence of a hybridizer.

Accepting as fact that moisture on the stigmatic lip is necessary for a 
successful pollen strike (Wilkerson post), under any given weather conditions 
it is more important to apply pollen at a time the lip is producing stigmatic 
fluid than a certain time of day or certain climatic conditions. There 
appears to be observable difference among cultivars as to when this fluid is 
produced relative to initial bloom opening.

The above situations make setting seed pods like shooting basket ball. The 
more you shoot the more times the ball will get through the hoop (you don't 
quit because you miss, nothing will go through the hoop if you do not shoot, 
three shots will produce more pods). There is no need to shoot when the net 
is tangled ( lip is not producing stigmatic fluid) You can improve your game 
keeping the right amount of air (humidity/temperature) in the ball (pollen).

I do not know the correct air pressure for a basketball or the best humidity 
for maximum pollen viability but expect lower is better relative to pollen. I 
do suspect the hydrometer would see better use as a measuring device for a 
bloom environmental chamber (constructed maybe from an aquarium) than from 
use to measure overall weather conditions.

Shootin' hoops poorly here and thinkin'  50% is an astronomical percentage of 
takes,
Bill Burleson 7a/b
Old South Iris Society


[Non-text portions of this message have been removed]


------------------------ Yahoo! Groups Sponsor ---------------------~-->
4 DVDs Free +s&p Join Now
http://us.click.yahoo.com/pt6YBB/NXiEAA/Ey.GAA/2gGylB/TM
---------------------------------------------------------------------~->

 

Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
Other Mailing lists | Author Index | Date Index | Subject Index | Thread Index