how are photosynthetic process different in plants that are red shifted? e.g. red maple.?

Question

What is the relative effenciency of plant processes in red shifted plants as opposed to their more conventional green cousins?

Answer 1

The red leaf coloration is not due to the chloroplasts but to the chromoplasts in the leaves. Chromoplasts also contain pigments but are not photosynthetic. Their pigments overwhelm the light reflected from the chloroplasts, however if you look at a leaf in the shade that red colouration thins out, and you can see the green chlorophyll showing through.
Chromoplast content varies naturally in plants. Plants with more chromoplasts can survive regions of marginal resources where they are better protected from both oxidative and UV stress. Oxygenic photosynthesis results in plants with the highest internal oxygen concentrations of any organism. Plants under oxidative stress switch on the expression of carotenoid biosynthetic genes during the chloroplast to chromoplast transition. An important physiological function of pigments is as an internal light screen and/or light trap to stop UV from damaging the plant.
The green leaved sugar maple is more sensitive to nutrient stresses associated with low pH soils than the red maple Acer rubrum. An increase in chromoplast content can mediate the negative effects of nutrient imbalances on maples by relieving UV & oxidative stress. Red maples can out compete other maples for nutrient poor acidic soils by having more chromoplasts. http://www.ingentaconnect.com/content/bsc/pce/2005/00000028/00000007/art00005
Chlorophyll is unstable and must continually be replaced. Light is only one essential for chlorophyll manufacture. Marginal quantities of Mg, Fe, or nitrogen strongly limit the rate that chlorophyll can be manufactured. Weathered acid soil is a poor habitat for nitrifying bacteria, that are sensitive to low pH, so less nitrogen is available to the plants. Fe becomes soluble as pH increases so is lost. Then Mg is leached out of the soil due to excess hydrogen, aluminum, and iron, which compete for cation exchange sites as pH drops. This reduces the rate of chlorophyll production so the plant grows slower. More chromoplasts relieve the plant of oxidative stress and protect it from UV allowing it to use marginal habitat.
http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=PP&Year=2005&ManuscriptID=b417802e&Iss=4

Answer 2

Plants with red leaves still uses the exact same chlorophyll as other green plants for photosynthesis. The red pigment is contained in the cytoplasm, and the red colour mask the chlorophyll in the chloroplasts. The effect is that photosynthesis is reduced because less light reaches the chloroplast, the site for photosynthesis because of the filtering caused by the pigment.