we are talking over white leds?
the blue emitters works at about 440-460nm. this is in the PAR range(400-700nm)
One peak of chlorophyll a sits also at ~430nm.
i don´t believe that a plant starts in this range with photoprotective mechanisms.
the energie overhead in the blue range (400-500nm) disappears in form of heat...don´t know if that helps?
Probably you're right about it ....
Most probably is the wls under 400nm causing plants to protect themselves ....
Still ...Do you remember at one of your grows ,that a lot of trich production was evident ,
at one really resinous plant ?
With one panel having a 460 ( orwas it 470 nm ? ) nm led at the center ....
It might be true also ,that those high -energy blue photons -if maybe so in an increased flux ,
maybe do cause some photoprotection procedures in plants ...
The light absorption of non-intact leaves ( solution of chlorophyll )
do indeed present two main peaks ,one at blue wls -one at red wls ...
( different for each Ch type ) ....
That means that Ch as a
chemical molecule
(
not as a part of complete PS system inside living intact leaves ...),
"favors " absorption of certain photons ,instead of others .....
So now I ask .....
That means what exactly ?
Note : Both Ch types are same almost on all higher plants ....
No matter if perennial ,annual ,winter plants ,summer plants ,etc ....
All plants have to use light -no matter of season ,part of day ,weather ,etc -
at the most efficient way in order to live and produce energy ....
At summer ,there is no need for producing heat ....
Or open stomatas is not the best water preservation policy ....
I strongly think that Ch absorption is strongly "biased " towards one peak or another ,
by the rest of PS apparatus ....
A Ch molecule ,during noon at summer ,will benefit more the plant ,
by collecting/harvesting deep red photons than blue ones ...
At winter ,probably ,the opposite,will benefit a plant ,
as it needs the heat from the blue photons and already it's metabolism is rather "slow " ..
No need of plenty photons ...
Dunno ....
We do not have a solid indication in our hands ,that rules out ,blue wls as 'oxidising' ones ...
Wls that cause damage ....
Afterall almost all accessory photoprotective pigments do present peaks at blue wls ...
Favoring absorption of these blue photons .....
And they are many such pigments for few available blue photons ......
Maybe by regulating the amount of accessory pigments ,plants 'manipulate' main PS pigments absorption peaks ......
If ,for example there's a lot of Zeaxanthin ...
Most of the( few at sunlight ) blue photons ,are absorbed by it ....
What is left over for the two chlorophylls is the rest of the photons ....
While maybe at wintertime ,there's not a accessory pigment photoprotection mechanism (s) present ....
Or is (are ) diminished ....
Larger-Wider (than red ) blue absorption peaks of chlorophylls then ,
do indicate the
inclination towards collection/harvesting of blue photons ,rather than reds ...
Or at least do ,indeed, favor the absorption of blue photons ..
" A bit of energy to convert into biomass at slow metabolic rates ...
Lots of heat produced ...Cause 'outside' has pretty cold weather ...."
Pretty complex matter I guess ...
What is known ,is that
when overall light power* increases equally-evenly ,
More & more green-yellow-amber photons are being used for PS
and
more photoprotective accessory pigments are being made ..
.....
Which ,most of them ,do not PROTECT from red,
amber or even yellow /green photons but from blue ones ....
As most of them ,do absorb light at blue/violet ( or uv ) range .....
Though ,more or less ,through a variety of different mechanisms ,
all photons do aid at biomass/chemical energy production ..
Still the ones used least for PS -when light levels are high - are the blue photons .....
Their RQE is also rather low ,compared to the rest of photons ....
That's why I insist on that blue leds ,although most efficient at led technology world ...
Are kinda "too much " in horticulture world ....
At least in our case of a plant ....
Covering them with the 'right' phosphor or 'phosphor blend' ,
presents lots of improvements towards growing plants ....
Especially mj ....
A 'summer-loving' plant .....
A plant that needs lots of light power* ,to thrive ...
(
......Some, will understand the '*' "
hidden " clue ......
Mj reveals by it's
energy/light power needs ,what kind of spectrum she likes .....
More or less ....)
If it was to grow lettuce ,a winter '
greenie-leafie' ,I'd rather use just red & blue leds ....
They are enough for that kind of a plant....
And indeed ,those leds ,are going to grow some high quality ,super-nutritional lettuce ..
A plant ,where flowering is considered " unwanted " ....
Depending on the variety and time of year, lettuce generally lives 65–130 days from planting to harvesting. Because lettuce that flowers (through the process known as "
bolting")
becomes bitter and unsaleable, plants grown for consumption are rarely allowed to grow to maturity. Lettuce flowers more quickly in hot temperatures, while
freezing temperatures cause slower growth and
sometimes damage to outer leaves
https://en.wikipedia.org/wiki/Lettuce
Blue leds used for high nutrient content and producing internal heat ,
Red leds for PS and
Cold temps to prevent flowering ...
That in a large scale led-assisted greenhouse ...
Not in my mj grow-tent ....
There I need lots of light power per square meter -or as much as possible-
and thus ,a whole lotta wider 'availability' of different photons ...
Blue & reds ,will still do the job ,but not as great ...
Or quite far from what is expected ,in analogy to their "efficiency",at general** ....
They seldom reach up to their 'myth' ....
Proven ,plenty of times ,by now ...
**(Usual exceptions to the rule ,have all in common ,their low/mid light power output and high quality leds and/or top bins used )
