Again, we are looking for some organ called "brain" in plants because we (assume to) experience sentience through this organ. I agree that plants are not exact copy of humans or animals, and that's why they are called plants. But that doesn't mean they need a organ called "nose" to breathe, "eyes" to see or "liver" to digest food. They have got their own ways to do things.
E.g. even if plants don't have eyes, they have got photoreceptor cells. Most of our conscious vision stems from photoreceptors in the retina in our eyes. But how about extraocular photoreceptors? Plants have got it.
Visual cells in animals detect light using a proteins, called opsin. But recently, a a second class of light-sensitive molecules called cryptochromes was discovered.. And they were at first discovered in plants! And they have a distinct evolutionary history. While plant cryptochromes have ancient evolutionary history whereas animal crptochromes evolved relatively recently. Check the whole paper here. Cryptochromes are named so because their functions and methods of action are still poorly understood. So who knows what they can do for plants!
I don't disagree about what you experience under anesthesia or without anesthesia. But that is what YOU experience. This doesn't imply anything about plants as what they would be experiencing with or without anesthesia.
So to your question, why we should expect sentience from plant, I'd like to say because of the fact that plants are a different creature altogether. They have got different systems and since it's not similar to us, it's not sufficient reason to not to expect sentience from them.
You know, plants don't have legs and thereby can't move? This was the very ground to term them non-living objects earlier. According to your logic it was fair enough as we see all living beings (except plants) have ability to move but plants do not. So why consider them living beings!
I completely agree @xyzashu! There is a growing body of evidence to show that even without what we would traditionally call a brain, plants actually experience all the same senses humans do and are able to understand what is being done to and around them. In other words, they are scientifically aware and can make logical decisions based on that awareness. By logical decisions, I mean that they do not just take the first option given to them, but they actually weigh the options and choose, all this without a brain! As you so clearly states, humans use a brain to do this, cephalopods use a combination of detached nervous system and brain, plants use neuron-like receptors in the roots and who know what else, since we are just starting to understand how they think.
One study I think both of you might find interesting, given that @teamsteem speaks about anesthesia, is that it has been shown that plants are affected to anesthesia in a way that is comparable to the way humans react. A study published in the Annals of Botany suggests that the action of anesthetic at cellular and organ levels are similar in plants and animals, which opens to new questions on sentience. Read the study here.
As a researcher on plant intelligence and plant music and communication currently studying under Prof. Stefano Mancuso, the scientist that coined the term plant neurobiology as is leading the way in proving scientifically plant intelligence, I am thrilled to see this conversation. Excited to see where it goes....
Yes and I think I've covered a bit about the effects of anesthesia on plants in this post. But thanks a lot for pointing to the exact study.
I found your blog & your research field interesting. Following you now to read more about this field from your own experiences and discoveries 😊
Thank you! Following you, as well. You did a great job bringing together the research.