« Back to Glossary Index

Leaves, fruits, flowers, and other parts of plants contain a layer of cells called an “abscission layer” or “abscission zone” which are cells that are meant to weaken and expand to push – or cut – part of the plant away from the base. This is seen in deciduous trees at the base of the petiole, and is responsible for leaves falling in autumn.

A phytohormone called ethylene is largely responsible for leaf abscission, especially in conjunction with auxin. Loss of auxin makes the plant more susceptible to the effects of ethylene.

Pests, temperature, changes in chlorophyll, as well as other phytohormones may be responsible for abscission depending on the plant type and environment.

When abscission cells are triggered, they begin to push against the healthy cells, halting the transport of nutrients and severing their connection with the plant’s base. Over a few days to a few weeks, these abscission cells grow and push the leaf, fruit, flower, or other organ away from the base.

Related Articles:
  • Why Do Leaves Change Color in the Fall?
    This process takes place across the globe, but climates that receive a healthy mix of all seasons are the most likely to have “peak fall foliage.” Areas with mild winters are less likely to have colors as vibrant as leaves need less preparation for the cold weather. So, why do leaves change color in the fall for these peak foliage areas of the world?
  • Glossary: Deciduous
  • How Plants Reach for the Sun: Phototropism
    One of the earliest questions in botany was how plants knew where the sun was, and how they grew towards the light. With more attention on the plant world, it was found that all plants - not just sunflowers - reached for the sun. This phenomenon is called phototropism, and in this HerbSpeak article, you will learn why plants experience phototropism, how it works, the effects of different types of light, and much more.
  • How to Propagate Pothos
    Pothos is a great beginner plant and it is easy to propagate, but many people overlook how difficult first-time propagations can be. Find the right answers and the most efficient way to propagate your houseplant in this in-depth guide.
  • Do Plants Die From Old Age?
« Back to Glossary Index
Related Terms: