Senescence
/sɪˈnɛsəns/
Definition
Senescence is the genetically regulated aging process in plant cells, organs, or whole plants that leads to a gradual decline in function and, often, death of the tissue. It commonly appears in leaves, flowers, fruits, and annual plants as chlorophyll breaks down, nutrients are moved to other parts, and the tissue yellows, dries, or drops. Unlike sudden injury or disease, it is a normal developmental stage.
Biological Role
- Nutrient recovery: Before leaves, petals, or whole annual plants die, senescence helps move nitrogen, phosphorus, and other mobile nutrients into seeds, storage organs, or younger tissues.
- Hormone control: Ethylene, abscisic acid, and other plant signals can promote senescence, while favorable growth conditions and some hormones can delay it in certain tissues.
- Visible plant changes: Chlorophyll breaks down during senescence, so green color fades and yellow or brown pigments become more noticeable, especially in aging leaves.
- Gardening relevance: Drought, low light, root stress, and natural aging can all trigger earlier senescence, so timing and pattern help distinguish normal decline from disease or care problems.
Related Terms
Abscission
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Leaf abscission
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Dormancy
Dormancy is a temporary resting state in which a plant, seed, bulb, tuber, or bud greatly slows growth and metabolism…
Ethylene
Ethylene is a gaseous plant hormone, meaning a chemical signal that helps regulate growth and development. Plants…
Chlorosis
Chlorosis is a plant condition in which leaves lose green color because chlorophyll, the pigment used in…
Leaf
Leaf refers to a plant organ, usually flat and green, that grows from the stem or a branch and is specialized for…
Flower
Flower is the reproductive structure of a flowering plant, usually containing stamens, which produce pollen, and one or…
Fruit
Fruit, in botany, is the mature ovary of a flower, sometimes with nearby tissues attached, that develops after…