I do not understand that the leaves of the alder remain green until they fall off. Doesn’t it take nutrients back into the stems? And how do the petioles break off the stem? Does he create a cork layer or does he create a more fragile cell structure?
Answer
The leaves of deciduous trees are all shed in a similar way in the fall. A cork layer is indeed created, so that the leaf will fall off after a while (or in some trees it can remain dried on the tree for a while).
The chlorophyll needed for photosynthesis is gradually broken down, but some residue is always left behind. Chlorophyll is a green dye and often dominantly present. But in many species, leaves also contain other dyes and these are often suppressed by chlorophyll.
Due to the reduced concentration of chlorophyll in the autumn, these other dyes often appear with sometimes beautiful color shades. However, the alder does not contain many of these other dyes, so that the leaves apparently remain green for much longer.
Answered by
ir Rudi Aerts
life sciences horticulture plant protection
http://www.thomasmore.be
.