Autumn Gold is a photograph by Darren Fisher which was uploaded on September 30th, 2014.
Autumn Gold
A beautiful yellow leaf backlit agains the beautiful blue sky. I have used a texture along with effects to give the photo a painterly look.... more
Title
Autumn Gold
Artist
Darren Fisher
Medium
Photograph - Photography/ Digital Art
Description
A beautiful yellow leaf backlit agains the beautiful blue sky. I have used a texture along with effects to give the photo a painterly look.
In late summer, as daylight hours shorten and temperatures cool, the veins that carry fluids into and out of the leaf are gradually closed off as a layer of special cork cells forms at the base of each leaf. As this cork layer develops, water and mineral intake into the leaf is reduced, slowly at first, and then more rapidly. It is during this time that the chlorophyll begins to decrease.
Often the veins will still be green after the tissues between them have almost completely changed color.
A lot of chlorophyll is located in Photosystem II (Light Harvesting Complex II or LHC II), the most abundant membrane protein on earth.[citation needed] LHC II is where light is captured in photosynthesis. It is located in the thylakoid membrane of the chloroplast and it is composed of an apoprotein along with several ligands, the most important of which are chlorophylls a and b. In the fall, this complex is broken down. Chlorophyll degradation is thought to occur first. Recent research suggests that the beginning of chlorophyll degradation is catalyzed by chlorophyll b reductase, which reduces chlorophyll b to 7-hydroxymethyl chlorophyll a, which is then reduced to chlorophyll a.[7] This is believed to destabilize the complex, at which point breakdown of the apoprotein occurs. An important enzyme in the breakdown of the apoprotein is FtsH6, which belongs to the FtsH family of proteases.[8]
Chlorophylls degrade into colorless tetrapyrroles known as nonfluorescent chlorophyll catabolites (NCCs).[9] As the chlorophylls degrade, the hidden pigments of yellow xanthophylls and orange beta-carotene are revealed. These pigments are present throughout the year, but the red pigments, the anthocyanins, are synthesized de novo once roughly half of chlorophyll has been degraded. The amino acids released from degradation of light harvesting complexes
Uploaded
September 30th, 2014
