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Unformatted text preview: (enzymatic degradation activated by ethylene) Leaf abscises The hormones (which will be discussed later) involved in leaf abscission are: Auxin Ethylene Associated with abscission, and occurring prior to the loss of the leaf, is a process that involves degrading and moving a number of solutes, minerals and other substances from the leaf tissue into the stem and roots. The degradation of chlorophyll and change in leaf color which results, is often referred to as "fall color". As chlorophyll degrades the natural carotenoids become prominent. In addition, some leaves may accumulate anthocyanins in their vacuoles, adding reds or bluish reds to the fall color. Photoperiod is important in triggering the fall change in pigmentation. Summer moisture also affects fall color. There are a number of web sites that discuss fall color....
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- Fall '09