I need to write a paragraph about this for my science homework and I don't understand a thing :( Please help!! I heard that red pigments mask the green chlorophyll, but I don't understand it well enough.
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Many photosynthetic plants do not appear green. They have chloroplasts with abundant chlorophyll pigment in photo reaction centers to carry out normal amounts of photosynthesis. They also contain nonphotosynthetic plastids, called chromoplasts, because they are colored by various pigments usually yellow xanthophyll and/or yellow-gold to red carotenoids. Copper beech leaves or red maple leaves have another pigment, an anthocyanin they synthesize in their chromoplasts.
Chromoplasts contain pigments, just like chloroplasts, but the main pigments are not photosynthetic. Their abundant pigments overwhelm the light reflected from the working chloroplasts making the leaf another color. Chromoplasts are what color flowers, fruit and other plant parts like leaves. The function of chromoplasts can be as a signal in flowers or protective in leaves. Chromoplasts protect leaves from oxygen causing free radical damage and protect from UV damage to reduce their stress. The free oxygen comes from chloroplast's photosynthesis.
Chromoplast content in leaves varies naturally in plants. Plants with more chromoplasts can survive regions of marginal soil nutrient resources because they are better protected from the additional harm from other stresses. The green leaved sugar maple (Acer saccarum) is more sensitive to nutrient stresses associated with low pH soils than the red maple Acer rubrum because they also struggle with UV and their own O2 causing free radicals. The increase in chromoplast content can mediate the negative effects of nutrient imbalances on red maples by relieving their UV & oxidative stress. Red maples can out compete other green leaved maples for nutrient poor acidic soil habitats by having more chromoplasts.
Photosynthesis results in plants having the highest internal oxygen concentrations of any organism. Free O2 is highly reactive & causes free radical damage. Anthocyanins prevent charged radicals from attacking cells. Another important physiological function of xanthophyll pigments is as an internal light screen and/or light trap to stop UV from damaging the plant. Light must enter cells for them to use visible spectral wavelengths but UV can destroy the photoreaction center in chloroplasts or DNA in the nucleus. Plants under this stress switch on the expression of anthocyanin and carotenoid xanthophyll biosynthetic genes during the chloroplast to chromoplast transition.
http://www.ingentaconnect.com/content/bs…
http://www.vivo.colostate.edu/hbooks/pat…
http://link.springer.com/content/pdf/10.…
Chromoplasts contain pigments, just like chloroplasts, but the main pigments are not photosynthetic. Their abundant pigments overwhelm the light reflected from the working chloroplasts making the leaf another color. Chromoplasts are what color flowers, fruit and other plant parts like leaves. The function of chromoplasts can be as a signal in flowers or protective in leaves. Chromoplasts protect leaves from oxygen causing free radical damage and protect from UV damage to reduce their stress. The free oxygen comes from chloroplast's photosynthesis.
Chromoplast content in leaves varies naturally in plants. Plants with more chromoplasts can survive regions of marginal soil nutrient resources because they are better protected from the additional harm from other stresses. The green leaved sugar maple (Acer saccarum) is more sensitive to nutrient stresses associated with low pH soils than the red maple Acer rubrum because they also struggle with UV and their own O2 causing free radicals. The increase in chromoplast content can mediate the negative effects of nutrient imbalances on red maples by relieving their UV & oxidative stress. Red maples can out compete other green leaved maples for nutrient poor acidic soil habitats by having more chromoplasts.
Photosynthesis results in plants having the highest internal oxygen concentrations of any organism. Free O2 is highly reactive & causes free radical damage. Anthocyanins prevent charged radicals from attacking cells. Another important physiological function of xanthophyll pigments is as an internal light screen and/or light trap to stop UV from damaging the plant. Light must enter cells for them to use visible spectral wavelengths but UV can destroy the photoreaction center in chloroplasts or DNA in the nucleus. Plants under this stress switch on the expression of anthocyanin and carotenoid xanthophyll biosynthetic genes during the chloroplast to chromoplast transition.
http://www.ingentaconnect.com/content/bs…
http://www.vivo.colostate.edu/hbooks/pat…
http://link.springer.com/content/pdf/10.…