Why is this in plants? (Botany question)?

I understand that chloroplasts make plants green, and are the chemical In a cell that help in the process of photosynthesis, but why are some plants (purple basil, Japanese maple, etc) reddish or purple in hue? Do they not have chloroplasts or is their another chemical or what. I was just wondering how that worked.

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  • 8 years ago
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    Yes, the plants have chloroplasts and they have chromoplasts.

    Chromoplasts contain pigments, just like chloroplasts, but the pigments are not photosynthetic. Their abundant pigments overwhelm the light reflected from the chloroplasts making the leaf another color. Chromoplasts are what color flowers, fruit and other plant parts. The function of chromoplasts pigments can be as a signal or protective.

    Chromoplast content in leaves varies naturally in plants. Plants with more chromoplasts can survive regions of marginal nutrient resources because they are better protected from both oxidative and UV stress. The green leaved sugar maple is more sensitive to nutrient stresses associated with low pH soils than the red maple Acer rubrum. Acidic soils are less fertile. 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...

    http://www.rsc.org/delivery/_ArticleLinking/Displa...

    Chromoplasts content in flowers signals to pollinators while in fruit it signals to seed dispersers when the plant is ready for them. Chromoplasts are not different organelles they are chloroplasts that continued to mature with regulation to produce more carotenoids or anthocyanins than chlorophylls.

  • 8 years ago

    Some varieties of plants have additional pigments in the tissues of the leaves. The purple or red colors you have mentioned are usually water soluble pigments similar to the pigment in beet roots. Some books mention the pigment, anthocyanin is used to protect the leaf cells from ultraviolet light that is paret of the radiation in the sun. The anthocyanin can be used as an acid/base indicator as well. Link to more info: http://en.wikipedia.org/wiki/Anthocyanin

    Source(s): Botanist
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