Leaves from the maidenhair tree (Ginkgo biloba) developing their autumn colour. The yearly colour change & leaf fall among such deciduous trees results from a combination of leaf senescence (death) & abscission (fall). Lipid droplets build up in the chloroplasts (photosynthetic bodies in the cell,containing the green pigments,chlorophyll). As photosynthesis slows due to shorter daylight hours & lipid production increases,colour changes occur. The production of ethylene stimulates the secretion of enzymes in the abscission zone (the point where the leaf breaks from the stem) which weakens the cell walls to allow the leaf to fall | |
Licence : | Droits gérés |
Crédit: | Science Photo Library / Bernard, George |
Taille de l’image : | 3620 px × 2480 px |
Model Release : | Non requis |
Property Release : | Non requis |
Restrictions : | - |