I don't know how they know, but they know.

[jackb]

In an attempt to keep the olive trees from blooming indoors in the winter and let them bloom in the spring outdoors I kept the photoperiod to the daylight hours of the winter solstice.

In spite of my efforts, they are beginning to bloom anyway.

In their natural environment, they bloom in late spring, however, each year my trees bloom in late January or early February.

The trees are not exposed any natural light, as they are in grow tents, so all I can think of is that they must have some internal trigger that tells them it is time bloom. It is not an aberration, as the varieties I have are from several parts of the world and mostly all are beginning to bloom.

So, I guess the answer is to increase the light cycle to 16 hours per day, grab a brush, and hand pollinate them.

Not complaining, just an observation that we will never understand plants completely.

jackb

 

[Ridgerunner]

Do you think temperature has something to do with it?

 

[jackb]

Do you think temperature has something to do with it?

No, I do not. I monitor the temperature and it has been pretty constant around 55 - 60 in the tents. I have a friend who is a bonsai guru and has had a greenhouse for many years. She has always said that the plants know when the solstice has occurred and begin to perk up a few days after it has passed. She travels the world teaching bonsai, so she definitely knows what she is talking about. If you appreciate bonsai here is a link to her collection.

http://pfmbonsai.com/PersonalCollection/

 

[Ridgerunner]

I'm not into bonsai but some of those photos are beautiful.

I think that magic is just technology that we don't understand yet, but I agree with you. Some things we will never understand. We can try to understand but sometimes just appreciate the wonder.

 

[digitS']

I wonder if pre-solstice conditions have something to do with it. For example, solar light loss occurs at nearly the same rate of solar light gain. The the new cycle is baked in before dormancy.

Age and health of the organism might play an important role.

Biomes have long had quite a bit of attention in the ecologist's world view. These days, the "microbiome" is gaining the layman's attention. Measurements of the seasonal units of environmental change play into the plans of the botanist and the entomologist, etc. Life exists in a complex world of connections. The olive tree must have those relationships, just as we do.

Marmots are supposed to communicate using 4 different calls. There's no doubt in my mind that if a rodent can do this, other lifeforms can too and that they respond, not only within a species but between species. The olive's microbiome may have sat down at the kitchen table and decided that it was time to wake the host ... Or, one of them caught the sound of a different birdcall outside your greenhouse and woke up to its seasonal task of teasing the tree into bloom.

Steve
Man has to awaken to wonder - and so perhaps do Peoples. Science is a way of sending him to sleep again. ~ Ludwig Wittgenstein

 

[Larisa]

All plants have a genetic memory and the individual. Moreover, genetic memory, is expressed in the commitment to the daily rhythm, stronger.

I raised the small bush from seeds (legume family). Seeds collected in the country of "eternal summer". Therefore leaves persist throughout the year. This plant closes leaves every evening and open every morning. It stands on a shelf with lighting. I have long noticed that the leaves are opened and closed independently of the light. I do not turn off the lamp, but the plant has leaves folded. That's work it's biological clock. This genetic memory.

I also grow Amorphophallus. His genetic memory tells him that he has to sleep in the winter and wake up in the summer. However, when I bought a small tuber, I could not put the plant at the right time. I made a serious failure in its genetic memory. Now Amorphophallus third year wakes up in the fall. But I want to include hereditary memory and working on it. I like that the water droplets appear at the end of its leaves before the summer rain.

For some plant genetic memory can be broken if the changes in the conditions if desired. For example, now my tulips and crocus have buds after I alternated temperature conditions.
The work of the biological clock is determined by the rotation of the Earth, which makes a certain rhythm to the seasons, night and day, light levels and temperature, atmospheric pressure, humidity ...
The same plant will have different biological clocks in different conditions.

Swedish scientist Carl Linnaeus XVIII century studied the behavior of flowering plants and called it "a dream of flowers." He studied the laws of this phenomenon and created a flower clock.

On a bed flowers were planted, blossoming in a strict sequence. The dial is made of different kinds of plants. Hours unmistakably showed the exact time and worked flawlessly. Each flower opens in a certain hour. However, in good weather.

Copy watches have appeared in other European cities.
But mechanical copying is not retained accuracy Linnean hours, because their creators did not take into account the spatial, temporal and environmental conditions of flowering plants.

 

[jackb]

Whatever turns on the blooming is internal. Their environment has been pretty constant for months, light cycle, temperature, and watering. There is no chance that they receive any natural light, as they are below ground level enclosed in lined tents. It is like they have a calendar that only they can sense. Fascinating.

 

[valley ranch]

Yes, it is Fascinating!

Jack & Steve, I have a: How do they know that if I'm less lazy I may post, it has bothered or had me wondering for years.

 

[jackb]

In previous years I increased the photoperiod little by little to coincide with the increased daylight hours after the solstice. This year I kept the photoperiod the same as it was on December 21 to see if I could retard blooming. Their little biological clocks kept on ticking right along, as usual, photoperiod be damned.

 

[baymule]

There is no chance that they receive any natural light, as they are below ground level enclosed in lined tents.

I read this and started laughing. Basically you have then in a dungeon, albeit a sufficiently warm and lit dungeon, yet they defy you and light up their dungeon with their blossoms.