A little light on the science, but still an interesting episode of SciShow.
The pigments that plants use to protect against harmful damage are flavonoids, with multiple subgroups of pigment, including Phytochrome, Carotenoids, Flavins, and Cryptochrome.
Flavonoids serve multiple purposes:
This is an interesting look at this topic. I have personally heard the warnings of mid-day watering but have never experienced the negative side effects from it; However I have had leaf scorch from spraying pest management solutions such as Neem or other Oil based products during the sun light hours. I typically use best practice of spraying during lights out hours and doing a leaf rinse before daytime temperatures rise. In the video posted it says scientists have determined the leaf scorch is not due to the prism effects from droplets but I wonder if that is only the case with Water?
Pretty likely that they were only looking at water. There’s so many different substances out there they could test, it would be difficult to say with absolute certainty. That said, I doubt the prism effect is strong enough with most commonly found liquids – acting like a magnifying glass at that close of a distance requires some interesting refractive properties.
