PLEASE TRY!, to awnser ANY of the questions below.~What factors cause leaves to change colors. Where do these colors come from?~What are the names of the specific chemical pigments that cause the colors we see (reds, yellows, purples, browns, greens etc.) These are the same pigments (chemical that causes color) that give fruit their different colors.~What is the process (how it happens) that cause leaves to fall off of the branches. Explain at the cell level. (picture)Please try to awnser. Thanks.
Chlorophyll leaves and Tannin enters,depends on the temperature and seasons
1shorter days and cooler temperatures 2they emerge from being obscured by the more numerous chlorophyll 3carotenoids,etc 4 senescense then abscission.the abscission zone has thin-walled cells,plant hormones decrease,a separation layer forms,cells form suberin thus isolating leaf from stem,fall
1. Changes in pigment compsition is the primary reason for the changes in the colour observed during different developmental stages of leaves. 2. Each pigment has the property of absorbing light rays of certain wave lengths and reflecting rays of certain wave length. This is called chromatic property of the pigment. For example Chlorophyll absorbs all wavelengths and reflects green wave lengths. Hence it appears green in colour. Therefore the colour is in the light rays and not in the pigment. 3.Reds= Phycoerythrin; Yellows= Xanthophylls; Purples= Anthocyanins; Browns= different combinations of red and yellow pigments; greens= Chlorophylls; Blue= Phycocyanins. 4. Yes 5. The process of leaf fall is called Abcission. Leaf os an organ of definitive growth. It grows to its maximum size and becomes scenescent. Once scenescence sts in, all cellular materials that can be used elsewhere are translocated to other growing parts and the leaf becomes yellow. The water supply to the leaf is cut off. The phloem also becomes non-functional. At this stage a special layer called Abcission layer is formed at the base of leaf near the point of atachment to the stem. The abcission layer produces cork cells which plug the region. The layers of cells above the cork layer become deprived of water and food and die forming Separation layer. At this stage the leaf is attached to the base only by the xykem cells. By its shere weight the leaf breaks and falls. The most important point about abcission is that the exposed part of the leaf base is covered by cork layer which is impervious to entry of pathogens! Refer to any Plant Anatomy book for a diagram to show the longitudinal section of the abcission layer.
