Sorry for the "vacation" so to speak but I return to the FES with hopefully what you will find to be a much more advanced addition to my previous research on the biological effects of moonlight. In the other thread, I have a very broad scope of things underlined and there were also many advanced effects on a cellular level. I was able to research such occurences yet only had the resources and ability to test vital signs of myself and others (which I will post in the near future). However, relying on others' research for ceullar events does NOT suffice! With this thread I hope to shed some more light on the harm to metabolic processes through once again my own independent research.
I hope to discuss CAM plants on a later date but I devised such an elegantly simple procedure to show the taxing results of moonlight. In the experiment such factors were put into to play so that exemption of minimal practice could be taken into account. Sunlight, artificial light imitating both celestial bodies and moonlight were used in the experiment. I only tested dicots in this instance for the uniformity is much greater in samples of given stem tissue. So much of programmed predictability, that environment influences could easily be observed.
In addition to CAM plants, I would also like to discuss photoperiodicity in more detail on a later date. Goldenrods have been found to rely on flowering during a time when the day is dominated slightly by more darkness. Darkness that, without interuption will not hinder the growth of the goldenrod plant. However, it has been shown again and again that exposure to a full moon intensely illuminating the scenery with naught but minimal cloud cover, will initiate an interruption of severe consequence that in turnn, the plant will not flower. I have interesting reactions and results recorded from such events and surprising phtochrome findings. However, this was not the focus of my own experiment in this particular thread and I will now shift focus.
My friends the key to observing the stress of plants is simple: COLLENCHYMA
One previous study of the Rural University of Pernambuco showed this reading of collenchyma with no liming in toxic conditions
The results showed that the structural changes observed in maize leaves were not only a response to the Cd-induced stress but also a cellular mechanism to reduce the free Cd<sup>+2</sup> in the cytoplasm. However, this mechanism seems to be efficient only up to a Cd concentration in leaves between 27 and 35mgkg<sup>−1</sup> for soils without and with liming, respectively. The cellular response varied with both the Cd concentration in soil and liming. For limed soil, Cd was preferentially accumulated in the apoplast while for unlimed soils Cd was more evenly distributed into the cells. The ability of Cd accumulation depended on the leaf tissue considered. The apoplast collenchyma presented the highest Cd concentration followed by the endodermis, perycicle, xylem, and epidermis. On the other hand, symplast Cd accumulated mainly in the endodermis, bundle sheath cells, parenchyma, and phloem. Based on the structural changes and growth reduction, the critical toxic concentration of soil Cd to maize plants is between 5 and 10mgkg<sup>−1</sup>.
As one can see, collenchyma was known to present the highest Cd concentration. Other experiments point to collenchyma production in plants as a response to stress induced by being subjected to harmful wind conditions. This is common knowledge among active researchers of plants even plants that grow too fast are forced to collenchyma production:
In many rapidly growing organs (i.e. leafstalks), the outer epidermal wall is supported by a thickened inner epidermal wall and by thick-walled subepidermal collenchyma tissue. Owing to the turgor pressure of the cells the peripheral walls are under tension, while the extensible inner tissue is under compression. As a corollary, the longitudinal tensile stress of the rigid peripheral wall is high whereas that of the internal walls is lowered. The physical stress between the tissues has been described by Sachs in 1865 as 'tissue tension'. The term 'tissue stress', however, seems to be more appropriate since it comprises both tension and compression. Hitherto no method has been developed to measure tissue stresses directly as force per unit cross-sectional area. One can demonstrate the existence of tissue stresses by separation of the tissues (splitting, peeling) and determining the resulting strain of the isolated organ fragments. Based on such experiments it has been shown that rapid growth is always accompanied by the existence of longitudinal tissue stresses.
In my experiment, the knowledge that collenchyma growth is a plant's response to stress was vitally stressed. The sample prepared from moonlight exposure was very hard to make presentable as a picture. A precise razor-like device had to be used multiple times along with advanced multiples (Didn't want lignin of fibers hogging the color!)
In the picture you can clearly see this is the vascular bundle of a dicot stem in this case towards perenchyma formation nearer to medulla or pith would be Amaranthus. Everything is as it should be. Clearly the vessel elements of xylem are relatively large and healthy for water transport, the band of procambium reaching across between vascular tissues also appears strong (and will eventually turn to beautiful secondary growth!), the phloem is in good shape above the procambium and in the cortal region, scherenchyma fibers took up the red dye (L factor) and is extremely strong. The rest of the cells for the most part are the average perenchyma. Look upon the surface however, and you willl quickly see the problem. Epidermal tissue takes the outermost layer but what is below it?
FIVE LAYERS OF COLLENCHYMA The key indicator is the excreted cell walls. In this plant, normal growth only yields 2 ( maybe 3) layers of collenchyma. This is made even more important since plants have such a predictable life growth and the green house used was climate controlled and protected from wind and other environment facotrs that could factor into upsetting the control. This theme was consistent throughout the 3 runs of the experiment completed and obviously shows moonlight alone results in damage to plants.
Collenchyma's preciseness is also due to the large amount of energy required for the cell types production following the exodus from meristematic beginnings. This comparatively large amount of energy required to make these specific cells takes a heavy toll on the overall metabolic state of the plant. Therefore, if it can be avoided, a plant will always make as few collenchyma as possible.
Reference List
Cunha K, Nascimento C, Pimentel R, Ferreira C. Cellular localization of cadmium and structural changes in maize plants grown on a cadmium contaminated soil with and without liming. Journal of Hazardous Materials [serial online]. December 15, 2008;160(1):228-234.
Kutsehera U. Tissue stresses in growing plant organs. Physiologia Plantarum [serial online]. September 1989;77(1):157-163.