Spinescence (is a word)

Outdoor observation plus indoor enquiry  keep me supplied with so much new information that I'm impelled to communicate. Blippers end up being the passive recipients of my  discoveries. I know not everyone finds this stuff as fascinating as I do so feel free to pass on by.

While waiting for the dog to emerge from the undergrowth where she was noisily following a scent trail, I fell to musing on the comparitive spininess of holly leaves. It's common knowledge that they are prickly at the bottom of the tree  and smooth higher up because browsing animals that can only reach so far. The tree doesn't need to expend energy in making prickles where they're not needed.

I noticed though, that on this particular tree which grows on a bank beside an old lane between two farms, the lower leaves were very prickly on the lane side but not so much behind. A little research revealed an interesting explanation. Holly prickles are produced in response to browsing, they're not an in-built genetic feature. A study carried out in Spain found that trees munched on by deer were able to create  spinier leaves in response to the attack (via epigenetics whereby the DNA is modified but not permanently altered)  so effectively arming themselves for their own defence when needed.

I could easily see how this particular holly tree had been subject to regular munches from farm animals passing along the lane but they hadn't been able to get behind it. Not so many prickles were  needed there so the heavy armour had not been mobilised at the back.


See here for the science.


"The ability of plants to respond to environmental changes... makes  one  feel a bit more optimistic about plant survival in a quickly changing world."


[SciFi scenario:  the plant species we cultivate to eat turn themselves toxic...]