hurricanes + Paph pod production

[Terry@PineRidgeOrchids]

I have a question / observation to put toward the Forum --- ever since the four hurricanes last year (the last of which was Hurricane Wilma on 10/24/2005 which produced wind gusts of 185 mph (83 meter/sec) on our property), I have notice a strange condition affecting my breeding program. On an average year, I might make 400 - 500 breeding attempts on my Paphs, usually resulting in sending over 100 - 150 mature pods to the labs. Our greenhouses were recovered with brand new polycarbonate sheets several months before the hurricane season and I converted all the greenhouses over to fan & cool pads instead of the original natural ventilation. I still use the rigid roof vents on our sawtooth design houses for the first three cooling stages. Further cooling involves the wet pads and high pressure fog. I replaced out 10 year old polycarbonate panels with new panels because of chemical deterioration due to a negligent farmer starting a forest fire on our property. The resulting 2 months of smoldering resulted in the polycarbonate turning quite yellow and extremely brittle (to the point that the greenhouse construction fell through the roof on 6 different occasions).
The changes in environmental conditions include more normal pre-burn light conditions and a more controllabletemperature during our long hot summers. Enclosing the side and end walls in polycarbonate also resulted in a stronger structure - the winds of Hurricane Wilma that caused over $100,000 in damage around our home resulted in one plant falling off the benches inside the greenhouse.
The question / observation --- I've made the normal quantity of Paph hybrids this last blooming season, but the success rate has fallen to possibly 20 or 25 pods actually germinating. This is not just a phenomenon affecting my greenhouse. I have spoken to several other Paph breeders in the Florida area that was affected by Wilma --- all of them, including the person that does a fair amount of our flasking, have reported the same thing --- lots of pods simply falling off orstaying on the plants the required amount of time, but totally empty. In my case, several of the grexes were exact replications of crosses I have done before with great germination rates - using the same plants. The only difference in the plant material is that the plants are older by one or two years, and if anything, even hardier and more robust. Chemical and fertilization histories are the same - no changes in media or anything else. RO water for irrigation w/ 6.5 - 8.5 ppm EC readings (before fertilizer injection. pH of 6.3 in the irrigation lines.
I am wondering if there could be some relationship between the extreme lows in barometric pressure and breeding potential of the Paphs - even after the storms have passed. Sounds improbable, but what other explanation is there???

Terry A. Glancy
Pine Ridge Orchids, Inc.
21100 SW 300 Street
Homestead, FL 33030
ph (305) 247-4839
(305) 247-3086
[email protected]
http://www.PineRidgeOrchids.com

 

[SlipperFan]

I saw Peter's reply to your post on the OGD. I was wondering about that also. Recently a friend of mine had to replace all his greenhouse roof panelling because it deteriodrated -- crumbled -- in the sun this summer. I don't know if he did any breeding during that time, but his plants suffered.

 

[littlefrog]

Terry,

This is completely anecdotal, but I had similar problems my first year in my greenhouse. I don't make nearly as many crosses as you, but the ones I did make were fairly successful at setting capsules for many years prior to building the greenhouse. I couldn't get anything to take that first year in the greenhouse, and I tried a lot. Now things have settled back down and I think I'm getting capsules again.

It could be (this is a guess) that your plants are responding to the new covering. It might not be enough of a change to affect flowering, but perhaps it is inhibiting their ability to carry a capsule? I wager that other growers in your area also had to replace their glazing, and/or lost shade from mature trees that came down in the storms? Or leaf cover that has subsequently grown back. The hypothesis here is that your plants are 'remembering' a drastic change in light levels (a stress), and that this stress has decreased fertility. How? No idea... Complete BS from this end! *grin*

 

[Leo Schordje]

Terry,
I do not know the answer. I doubt that barametric preasure could be the cause. Plants do not seem to have structures to directly detect preasure. But I don't know for sure. One potential cause I have not seen mentioned. The only scientific work I have seen, and frankly don't remeber clearly, is from work done with pine trees and maple trees.

A significant portion of the carbon fixed by photosynthesis by pine trees (and by extension, likely other major groups) is extcreted, gassed off, as volatile hydrocarbons. A significant percentage as sesquiterpines. Sesquiterpines can function as plant hormones. The key of the article was that through these volatile hydrocarbons the trees were sending chemical signals into the environment.
The article went on to propose that some (or certain) unrelated species of trees would also respond to the signals sent by the pines.
My annecdotal take on the article was that these chemical signals blowing in the breeze would explain why my Paphs from the southern hemisphere, under a constant day-night photoperiod that I do not vary through the year, would still seem to settle down after a couple years and always bloom on schedule. My thought is that the orchids do respond to the chemical signals coming to them from the surrounding environment. And if I read the paper right, the trees are gassing of tons of terpines per acre of wood lot.

So to Terry's problem, pod drop may be due to his orchids responding to the stress signals the surrounding forest is sending due to huricane damage.

I may be wrong, but this is a possibility worth considering, Terry is a skilled grower, his conditions are ideal, yet his plants are acting as if they were stressed. Thoughts anyone?
Leo

 

[Stephan]

Leo

I like your theory based simply on the fact that I know my plants respond to me - why not to their environment?

Cheers
Stephan

 

[Rick]

Given that several other breeders in the area are suffering similar problems to I also think there is an external environmental problem.

It could be pathogen or alergen related too. I would imagine with all the downed trees and other vegetation there could be allot more mold and pollen in the air.

Another possibility is that the water company has uped the chlorine concentration or changed the type of sterilant. THM (chloriform) levels could have gone up with more organic matter being chlorinated. Unlees he is on a well, Terry said his irrigation water was RO, but what about his wet pads and foggers releasing toxic aerosols?

Another thing that may be in common with several of these breeders is that there may be a big light bounce (analagous to a tree fall in the middle of a forest). There are anectdotal acounts of orchid population demographics changing in response to logging and natural tree reduction events.