At the base of their stem (referred to as the petiole), leaves have a zone called the abscission layer, located near the branch to which they are attached. Figure 2.

As this abscission layer forms, it gradually chokes off the flow of minerals and nutrients between the leaf and its branches. ( More from World Science Festival : How quantum computing could ...

In most deciduous trees, a group of cells grows between the branches and the leaves, called the abscission layer, and acts as a sort of off-valve for water and nutrients once daylight begins to wane.

However even with this partial abscission layer junction, the seeds still tend to fall easily in a natural environment. Credit Ishikawa et al. (2022) PNAS Plant Breeding Lab. Graduate School of ...

Due to the disruption of the abscission layer, the dried brown leaves can cling on to the twigs for a long period (and are now called marcescent leaves) until a strong wind or under the weight of ...

However, in cultivated rice (japonica), the abscission layer isn’t formed at all. Credit Plant Breeding Lab. Graduate School of Agricultural Science, Kobe University ...

The annual antler cycle. At the end of mating season, usually in late winter, male deer, or bucks, shed their antlers thanks to an abscission layer that forms between the antlers and the skull ...

This abscission layer, when it spans the entire stem, causes the leaf to fall off the tree. This helps protect these trees from losing water from their leaves during the winter (an extremely dry ...

In fall, however, cooler and shorter days trigger an end to auxin production, allowing the abscission layer to grow and cut off the circulation of water, nutrients and sugar to the leaves.

But in marcescent trees, the abscission layer doesn’t form until spring and that’s when their leaves finally fall to the ground. Scientists aren’t sure why certain tree species hold their ...