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How does ethylene promote fruit ripening?
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plant development
The life cycle of the fern. (1) Clusters (sori) of sporangia (spore cases) grow on the undersurface of mature fern leaves. (2) Released from its spore case, the haploid spore is carried to the ground, where it germinates into a tiny, usually heart-shaped, gametophyte (gamete-producing structure), anchored to the ground by rhizoids (rootlike projections). (3) Under moist conditions, mature sperm are released from the antheridia and swim to the egg-producing archegonia that have formed on the gametophyte's lower surface. (4) When fertilization occurs, a zygote forms and develops into an embryo within the archegonium. (5) The embryo eventually grows larger than the gametophyte and becomes a sporophyte.
Ethylene acts as a vital plant hormone that signals and regulates the ripening process in fruits. When fruit tissues are exposed to this gaseous hormone, it triggers a series of physiological changes that transform the fruit's texture, composition, and appearance.12
Specifically, ethylene promotes ripening through the following mechanisms:
- Breakdown of Acids: Ethylene initiates the degradation of acids within the fruit, which reduces tartness and contributes to a sweeter flavor profile.1
- Softening: The hormone facilitates the breakdown of structural components, causing the fruit to become softer and less firm.1
- Pigment Transformation: Ethylene triggers the degradation of chlorophyll, the pigment responsible for the green color in unripe fruit. As chlorophyll breaks down, it is replaced by other pigments, such as the yellow hues seen in bananas.1
- Enzymatic Activity: Ethylene stimulates the synthesis of specific enzymes that catalyze these metabolic changes.2
The sensitivity of fruit tissues to ethylene can also be influenced by other growth-regulating hormones, such as auxin, which help coordinate the timing of the ripening process.2