|OK my interpretation of those 2 posts is that these plants are #1 beginning to enter dormancy, and #2 grown indoors under artificial and natural light. Assuming that the indoor temps are "room temperature" (I dont know too many people that keep their houses in the 30's and 40's) that pretty much shoots the "temperature more important than light" theory right out of the water. |
I cant speak for maple trees in Pa. (I'm not even sure that is a very good comparison) but I can tell you that the mulbury tree in my next door neighbors yard is already beginning to lose its leaves as well. Again the only difference between September 15th (today) and August 15th is daylength.
2 lone indoor VFTs does not a theory break..
those VFTs could very well be entering dormancy because they have gone a LONG time without it..
in that case, time is the trigger, not temp or photoperiod.
I never said temp is the ONLY trigger of dormancy!
so my theory is far from "blown out of the water"
those 2 VFTs are far from a reliable experiement to what does or does not trigger dormancy..
If a tree is turning color this early (at least around here..no idea about California) it means the tree is stressed somehow.
usually drought or a very hot/dry summer.
again, I never said temp is the ONLY trigger of dormancy in trees either. all I said was its the "most important"..
you are starting to get snotty/sarcastic steve.
please keep it nice.
none of this is a personal attack against you..we are just debating here..
(I dont know too many people that keep their houses in the 30's and 40's) that pretty much shoots the "temperature more important than light" theory right out of the water.)
Scot your completely contradicting years and years of research by plant biologists that have proven over and over again that plant growth cycles are TRIGGERED by day length. (actually night length).. Flowering in plants, Induction of dormancy, Production of tubers and many other processes.
Because you can easily fool a plant into thinking it is now a differen't season based SOLELY on day length and it responds as it would naturally. THIS is how they get Pointsettia to flower for Valentines.. THIS is how they get easter lillies to flower for Easter. THIS is how they get christmas cactus to flower for Christmas.
I grow my VFT in the greenhouse all year long. The temperatures are actually WARMER at night during the Winter and the plants are absolutely without a doubt dormant. Summer leaves are now starting to die off and small traps with wide petioles are popping up. The greenhouse is the same temperature it has been all Summer. Sure isn't a change in temperature causing it. The only thing that has changed is daylength.
Is temperature important? SURE it is tied to the health of the plant and it's dormant state but it is not what triggers this state. A plant kept too warm after it has been triggered into dormancy by daylength will appear weak and sickly as you mention on the bonsai. The leaves were sickly looking because the plant was desperately trying to go dormant as the light signals it was receiving were telling it to do. It was not a nice lush actively growing and healthy plant as it would have if temperature was the deciding factor.
Is that a Nepenthes in your pocket or you just happy to see me?
VFT and Drosera lover
|Quote (scottychaos @ Sep. 15 2003,4:4[img]http://www.**********.com/iB_html/non-cgi/emoticons/alien.gif[/img]|
|you are starting to get snotty/sarcastic steve.|
please keep it nice.
none of this is a personal attack against you..we are just debating here..[/QUOTE]
Sorry.. *didnt intend to come across as snotty.. *maybe a little sarcastic [img]http://www.**********.com/iB_html/non-cgi/emoticons/wink.gif[/img] but certainly not in an offensive way. If thats the way I came across I apologize. I shall choose my words more carefully in the future. I never took any of this as any kind of personal attack. Im actually enjoying the debate here.
I agree that 2 VFTs are hardly a "theory breaker" *especially given that I have no other background on these specific plants beyond what I posted. I just posted that as another example of plants that were not triggered by temperature. My personal experience/ observation, combined with information I have gathered from other growers simply does not support the theory that "Temperature is FAR more important than photoperiod/amount of light..". Thats all I am trying to say. Bear in mind that this is all simply my theory on this subject, supported solely by my own personal observation. I could be completely off base here and just rambling on and on to eventually be proven wrong. (wouldnt be the first time.. *and most likely not the last either [img]http://www.**********.com/iB_html/non-cgi/emoticons/tounge.gif[/img] ) lol
Sorry again if I offended anyone
There are only 2 infinite things... the universe and human stupidity, and I'm not too sure about the universe.
while not actual scientific papers/experiments, it is some more personal experiences:
"Aquatic Utricularia love warmth! However for a variety of reasons such as algal and bacterial blooms at high temps, and dormancy, the best range would be from between 20-25°C. Below 18°C, and the plants begin developing turions. I have experimented with U. macrorhiza, and have found that temperature and not photoperiod is the key factor to turion production. My personal experiences with other temperate species suggest the same. I would think that tropical species would do poorly indeed below 18°C, and would perhaps die at 15°C."
An I hesitate to post this one, because I am firmly NOT a believer in (man-made) global warming!
but..ironically it does kinda prove my point! [img]http://www.**********.com/iB_html/non-cgi/emoticons/rolleyes.gif[/img]
(it seems warmer average temps, from year to year, are causing trees to break dormancy earlier..for the sake of this thread, we will ignore the topic of WHY global temps are increasing! [img]http://www.**********.com/iB_html/non-cgi/emoticons/wink.gif[/img] *totally different topic!
but..regardless of the reason, its obvious that warmer temps earlier in Spring = earlier dormancy break and flowering..photoperiod is unchanged.
has to be ONLY the temp doing it! the photoperiod CANT change!
Ah! here is some good info..
this says photoperiod is more important when *entering* dormancy..and warmer temps are more important when breaking dormancy:
The main environmental signal which triggers the onset of dormancy is daylength. *For most temperate woody plants, long days promote vegetative growth and *short days trigger dormancy. *As days begin to get shorter in later summer growth slows, and eventually a dormant bud develops. *You may recall from an earlier biology class that it is actually the length of the night that is critical, not the length of the day. *Short nights stimulate growth, long, uninterrupted nights stimulate dormancy. Daylength of course is a very reliable environmental signal since it is perfectly stable from year to year and trees will not be tricked into growing longer because of an abnormally warm fall. Daylength then is the primary trigger that results in the changes in growth regulator production which in turn results in dormancy development. *The growth regulator abscisic acid (ABA) apparently plays a role in dormancy development and has been found to build up to high levels in the fall.
INFLUENCE OF TEMPERATURE
Decreasing temperatures also play a role in dormancy development. *Short days cause the plant to enter pre-dormancy (and maybe even true-dormancy). *It is believed by some researchers that cool temperatures are needed for the plant to enter true-dormancy. *Whatever the specific case, dormancy in many temperate woody plants develops more quickly when *short days occur in combination with cool temperatures.
INFLUENCE OF WATER AND NUTRITION
Both water supply and mineral nutrition also interact with dormancy induction. *Water stress will deepen dormancy and if severe enough will result in a resting bud and defoliation in some trees. *High mineral nutrition can result in delaying dormancy. *This is particularly true with the mineral nitrogen. *High levels of nitrogen should never be given to plants in late summer or early fall since they may actually flush and resume growth. *For the deepest dormancy, nurserymen will reduce day length, reduce temperatures, cut back on fertilization and mildly water stress plants.
RELEASE FROM DORMANCY
RELEASE FROM DORMANCY
Temperate woody plants once in true-dormancy require chilling to enter post-dormancy. *Temperatures above freezing and in the range of 2° to 4° C are considered best. *The amount of accumulated hours at these temperatures varies but is typically between 500 and 2,000 hours. *Often species or seed sources form more northern climates require more hours but this is not a perfect rule. Fruit growers and nursery managers will often keep track of these so called chilling hours so they know when their trees have entered post-dormancy.
RELEASE FROM DORMANCY
Some researchers believe that during short days in the fall ABA builds up to high levels and induces dormancy. *Chilling may be responsible for the breaking down of ABA. *Until enough hours have accumulated to remove the inhibitory effect of ABA the plant will not break bud. *At the same time when the soil begins to warm promoters of growth such as gibberellin and cytokinins build up signaling the bud to resume growth.
RELEASE FROM DORMANCY
Once adequate chilling has occurred and the plant is in a post-dormant condition, warm temperatures and increasing day lengths are required for normal shoot expansion. *Warm temperatures are probably the most critical environmental factor at this point. *Trees of the same species growing in the north will break bud later than the ones growing in the south. *However, research has also shown that plants kept under warm temperatures but short day lengths broke bud later than plants kept in warm temperatures and long daylengths."
So what does all this say? we need BOTH!
[img]http://www.**********.com/iB_html/non-cgi/emoticons/rolleyes.gif[/img] *well..we knew that already.
well..it also says that photoperiod *triggers* dormancy..and cold temps *keep* dormancy..which makes sense..
all plants go into dormancy very slowly..over a period of 2 or 3 months..so you need that photoperiod to begin the process, then cold completes the cycle and the plant enters true dormancy..short photoperiod without following cold wont be true dormancy..(the indoor bonsai..they night have started to think about dormancy, but didnt get the conditions necessary to complete the job..)
and conversly, just instant cold without long preparation (photoperiod and coolere temps) also wouldnt work..(like instantly sticking your VFT into the fridge in July![img]http://www.**********.com/iB_html/non-cgi/emoticons/wink.gif[/img]
so..to KEEP and hold a true dormancy, once the process has begun, you need to maintain the cold temps..(bringing us back to mid 40's for the VFT![img]http://www.**********.com/iB_html/non-cgi/emoticons/wink.gif[/img]
to *trigger* dormancy in the first place, you need decreased photoperiod..(and cooler temps? probably..)
which bring us (well..me anyway) full circle..
give Cps a good natural cool crisp autumn, keep them outdoors straight through late October, so they naturally, slowly, go dormant..then..once its TOO cold for them outdoors (if you live in the north) bring them indoors, and KEEP them cold all winter!
(45 degrees average! [img]http://www.**********.com/iB_html/non-cgi/emoticons/wink.gif[/img] )
[img]http://www.**********.com/iB_html/non-cgi/emoticons/biggrin.gif[/img] *[img]http://www.**********.com/iB_html/non-cgi/emoticons/wink.gif[/img] *[img]http://www.**********.com/iB_html/non-cgi/emoticons/confused.gif[/img] *[img]http://www.**********.com/iB_html/non-cgi/emoticons/rolleyes.gif[/img]
|Quote (Tony Paroubek @ Sep. 15 2003,8[img]http://www.**********.com/iB_html/non-cgi/emoticons/wow.gif[/img]3)|
|Is temperature important? *SURE it is tied to the health of the plant and it's dormant state but it is not what triggers this state. *A plant kept too warm after it has been triggered into dormancy by daylength will appear weak and sickly as you mention on the bonsai. *The leaves were sickly looking because the plant was desperately trying to go dormant as the light signals it was receiving were telling it to do. *It was not a nice lush actively growing and healthy plant as it would have if temperature was the deciding factor.|
I totally agree with that analysis of the Bonsai..
they were *trying* to go dormant! the photoperiod told them it was time to go dormant..but the air stayed too warm! so the "dormancy cycle" didnt complete, and the plants didnt enter true dormancy at all..kinda like being really tired, and WANTING to fall asleep, but not being able to do it!
"It was not a nice lush actively growing and healthy plant as it would have if temperature was the deciding factor."
but temperature WAS the deciding factor!
it was temperature alone that prevented the trees from going dormant..they needed cool/cold temps to go dormant, they didnt recieve those temps, and because of that *alone* they couldnt go dormant..
that makes temp the only deciding factor in *completing* dormancy..maybe not *triggering* dormancy..but without the cold temps, you get no dormancy at all!
I think we are both right, we just arent talking about exactly the same thing!