New Grower 4 Weeks Into First Grow. Droopy And Unhappy Plants.

[AutoLowRyder]

The reason for the flop is, "The Calvin Cycle / Light" & "CAM Cycle / Dark", the RuBisCon phos fixation & crassulacean acid metabolism, redirects vascular presure, which makes the leaves flop...... like low systolic blood pressure in the xylum and pheolum Trunk & Bow Structures, the cappiliary actioned, fluid, liquid nute highway in the plant inner structure....... the generation of ATP & NADPH......... is an energy expensive process......

There are three phases to the light-independent reactions, collectively called the Calvin cycle: carbon fixation, reduction reactions, and ribulose 1,5-bisphosphate (RuBP) regeneration. This process occurs only when light is available. Plants do not carry out the Calvin cycle during nighttime. They instead release sucrose into the phloem from their starch reserves. This process happens when light is available independent of the kind of photosynthesis (C3 carbon fixation, C4 carbon fixation, and crassulacean acid metabolism); CAM plants store malic acid in their vacuoles every night and release it by day to make this process work. They are also known as dark reactions........

Photosynthesis occurs in two stages in a cell. In the first stage, light-dependent reactions capture the energy of light and use it to make the energy-storage and transport molecules ATP and NADPH. The Calvin cycle uses the energy from short-lived electronically excited carriers to convert carbon dioxide and water into organic compounds that can be used by the organism (and by animals that feed on it). This set of reactions is also called carbon fixation. The key enzyme of the cycle is called RuBisCO. In the following biochemical equations, the chemical species (phosphates and carboxylic acids) exist in equilibria among their various ionized states as governed by the................. "pH"...............ALR

 

[Waira]

Thanks ALR, you have me really dusting off the old brain cells that logged all this stuff in decades ago!
...RuBisCo, I thought they only made snack crackers?

....so I'm not quite following mate, you say it's when the Calvin cycle starts to wind down as whole PS process does as darkness increases, that there's a lowering of vascular pressure ("root pressure?"),... Is it related to the closing of stomata at this time, or is it linked to respiration physiology?

 

[AutoLowRyder]

darkness increases, that there's a lowering of vascular pressure (

it is a long sequence to get a handle on the P680 reaction centre !........... but essentially yes, vascular pressure drops, the plant can tell time to with a minute,......... so just priori to the shut down, she begins to flop, as in the time lapes shots, up down up down of the leaves.............. it's like a swallow before the dark sequence set in......... co2 taken in and o2 given out, the reverse in the light period.............. th whole resperation cycle is linked, as ATP is made ans shifted up............

To get the full picture study the P700 & P680 reaction centres, and the Calvin light cycle and the CAM dark cycles............... and ATP & NADP transport systems................. the flop happens in between the two... ALR