CAM photosynthesis

[Dusted]

From what I can tell my plants use both the C3 and C4 metabolic pathways. They actually transpire more water during the 12 hr dark cycle than during the day. My estimate is 2 litres per plant per night and 1 litre each during the day. They are under a fairly good breeze all the time, and a 1000 w mh. I have always wondered what the change in odor given off by the plants when the lights go off was. I suspect this may have something to do with the change in metabolic pathways. I’m still trying to wrap my head around how this can influence our plants

 

[TorturedSoul]

Interesting. I never bothered to track transpiration rates vis-à-vis day vs. night lighting. I did notice quite some time ago that a fan during the lights-off period can be a very good idea, lol.

I had assumed that any additional(?) signs of moisture over "night" was due to lower relative humidity - that the cooler air wouldn't support the same amount of evaporated moisture and, therefore, that a portion was merely precipitating out. If anything, I would have expected less gross transpiration during lights-off, not more. (Again, an assumption.)

I do know that plants' stomata will close in very high temperatures, and that can skew things. Are your peak lights-on temperatures extreme?

I do not know one way or the other, but I wouldn't be all that surprised if too much airflow can have a detrimental effect on transpiration rates, kind of a moisture-saving defense mechanism. However, even if this turned out to be the case, I'd expect the airflow required to attain such a state to be enough to cause uneven growth (in much the same way that single, exposed trees at higher elevations might have zero or little branch growth on the windward side).

 

[Dusted]

It surprised me too, which is why I mentioned it. Light period temperature is 27 C. Night time probably 18-20 C. RH is below 50%. It’s not as though my fan is bending the plants over, but all the leaves do russle.

A lot of plants do have the gene for CAM photosynthesis, but don’t utilize it unless they are heat or drought stressed. I’m trying to figure out how the carbon utilization and storage could work if both C3 and C4 pathways are used. I guess I better goggle it.

 

[Gazoo]

Just throwing this into the mix

 

[Dusted]

Just throwing this into the mix/QUOTE]

That is interesting. I do run a metal halide lamp which is high in blue spectrum. Thanks for that

 

[Dusted]

I bought a RH/temperature logger for the grow room. It samples every minute and downloads data to iPad. My plants have a definite twice daily transpiration cycle. It is lowest at dawn and dusk, and peaks at midday and midnight (plant time). I can also use the sensor (3.5 cm diameter) to monitor RH in my cure jars. I’m going to buy another one.

 

[TorturedSoul]

How much did it cost? Is it able to communicate with other sorts of devices? (Wired, WiFi, Bluetooth, or...?) A lot of people might be interested in such a thing, especially if it's pretty inexpensive (and accurate, of course).

 

[Gazoo]

How much did it cost? Is it able to communicate with other sorts of devices? (Wired, WiFi, Bluetooth, or...?) A lot of people might be interested in such a thing, especially if it's pretty inexpensive (and accurate, of course).

As soon as I read the post i looked them up here is the one I am looking at
it also does C02 and incidentally all the CO2 monitors I have looked are about
the same price so I can get more info using one of these

Thanks for the heads up
Dusted

EDIT: Just downloaded the PDF instruction file and see this make DOES NOT
download to any device, its history is held within the unit. OH and found another
seller at 77.00 bin

 

[TorturedSoul]

A little rich for my blood, but that thing does look nice, especially if someone is thinking about CO₂ supplementation (or is wondering if their "Get Mad Amounts of CO₂" product is actually benefiting their garden - or ought to be relegated to late-night infomercials, to be sold by the ShamWow guy.

Maybe the Arduino route is the way to go. Or a Raspberry Pi (although it seems that the former has more "industry standard" components available for it).

 

[Dusted]

Smart Sensor IBS-TH1 | INKBIRD

This is $35 CAN on Amazon.

Smart Sensor IBS-TH1 Mini| INKBIRD

 

[TheFertilizer]

Just throwing this into the mix

I was going to venture a guess that VPD had something to do with it.

 

[Gazoo]

I was going to venture a guess that VPD had something to do with it.

I agree will have to read the article again to see if they eliminated that variable ?
Its all related but if the stomata can be stimulated to open a little more using the Blue Light
I suspect it can be used to our advantage ?

 

[TorturedSoul]

Perhaps. Are you speculating that there is insufficient transpiration or gas exchange in the plants as things are now? If so, then probably (if it works).

 

[Gazoo]

Perhaps. Are you speculating that there is insufficient transpiration or gas exchange in the plants as things are now? If so, then probably (if it works).

I was thinking it would work better to do Foliar under Blue light if the Stomata was opened wider.
Just thinking out loud, I forget others dont hear the voices in my head

 

[TorturedSoul]

I wasn't disputing your theory, lol. And as for voices... An ex- that I was with for some years was afflicted with schizophrenia (et al) - so don't worry too much about it. It's not the "really weird stuff" that you have to worry about; it's when it becomes subtle enough that it starts making sense that you enter the danger zone.

Oh, wait...

 

[TheFertilizer]

I agree will have to read the article again to see if they eliminated that variable ?
Its all related but if the stomata can be stimulated to open a little more using the Blue Light
I suspect it can be used to our advantage ?

I think it would be hard to measure the specific spectrum's influence on it without having really tight controls over the PAR levels.

Kind of weird you'd mention it... Right now I'm running kind of an odd-ball light setup. I have a T5 with 6400K bulbs in it side-lighting my tent, with a 3100K CMH HID above.

I notice that the plants that are closer to the T5 are drying their pots out a lot faster than those further way from it. I had just figured it was because they were photosynthesizing more, and thus using up more water. It would be interesting if they were transpiring more because of the light spectrum.

(The T5 is just out of frame but you can see the light emanating from it)

IMG_20181115_130647.jpg

• TheFertilizer
• Nov 15, 2018

 

[Gazoo]

I think it would be hard to measure the specific spectrum's influence on it without having really tight controls over the PAR levels.

Kind of weird you'd mention it... Right now I'm running kind of an odd-ball light setup. I have a T5 with 6400K bulbs in it side-lighting my tent, with a 3100K CMH HID above.

I notice that the plants that are closer to the T5 are drying their pots out a lot faster than those further way from it. I had just figured it was because they were photosynthesizing more, and thus using up more water. It would be interesting if they were transpiring more because of the light spectrum.

(The T5 is just out of frame but you can see the light emanating from it)

IMG_20181115_130647.jpg

• TheFertilizer
• Nov 15, 2018

Interesting, I also use Side T5s but with HID above. My tent is to small 2 x 4 so I have never noticed any difference
I have noticed a lot more trichomes under the T5 Full Spectrum UVA/B bulbs, It was very noticeable
at the start of flower

 

[TheFertilizer]

Interesting, I also use Side T5s but with HID above. My tent is to small 2 x 4 so I have never noticed any difference
I have noticed a lot more trichomes under the T5 Full Spectrum UVA/B bulbs, It was very noticeable
at the start of flower

Yeah my last run of Panama x Malawi, I ran a set of clones in each of my 4x4 tents, one tent had the T5 as overhead lighting, and the other my CMH. The ones under the T5 seemed to have much more pronounced trichome production.

But the curious thing about that is that 3100K CMH lighting isn't really very low on the UV spectrum, so you should expect to see the same kind of increased trichome production in CMH vs HPS if it was a matter of UV, but I didn't really see a huge difference between 3100K CMH and 2100K HPS .

But I have heard from a lot of people in the past that "blue light makes them stickier" and I also experienced that. I've talked to a lot of old-school growers who complain that, "All the sticky weed is gone now days," and I think it might have something to do with the common wisdom having switched over to suggesting that red spectrum are the best for flowering.

 

[TorturedSoul]

Some people still switch back to MH as a finisher, and I've heard of some using bulbs with higher than "the usual 6500K" Kelvin numbers.

 

[Dusted]

Some people still switch back to MH as a finisher, and I've heard of some using bulbs with higher than "the usual 6500K" Kelvin numbers.

I am a fan of mh for the entire cycle. I just figured the PAR was better with mh even though the listed lumens are higher on hps