十万个为什么·科学阅读30篇（4）

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香蕉在紫外灯下为什么会发蓝光？

Bananas emit faint blue fluorescence when exposed to UV light due to chlorophyll breakdown products.
As bananas ripen, chlorophyll degrades into fluorescent catabolites that absorb UV and re-emit blue light.
These compounds accumulate in the peel’s cell walls and remain stable longer than the original pigment.
The bluer the glow, the more advanced the ripening stage—even before yellow color fully develops.
Other fruits like pears and apples show weaker versions, but banana fluorescence is unusually strong and consistent.
Scientists use this property to monitor fruit quality non-invasively during transport and storage.
UV-induced fluorescence doesn’t harm the fruit or affect taste, nutrition, or safety.
It’s visible only under blacklight; normal sunlight contains too much competing visible light to see it.
This natural phenomenon inspired new biosensors that detect plant stress or disease early.
Interestingly, some insects see UV light and may use banana fluorescence to locate ripe fruit.