Investigations with a home microscope! - PEARS

Have you ever wondered, "what makes pears so gritty compared to other fruits?" Me too.

Luckily, I bought a home microscope recently to see first hand. 

It turns out that there is a specific type of cell, called a sclereid cell, which is ubiquitous inside the fruit. The spots are actually clusters of stone cells, which make really hard tissues in nature, like nut shells. Basically the cell is made for structural support, and a very large portion of the cell is cell wall. 

I can't find convincing evidence for why these clusters evolved in pears, but it seems likely that it is a defense against the wrong kind of eater. In the same way that tannins can make certain plants less digestable and bitter tasting, perhaps the sclereid cells make the pear less appealing to certain animals. Apparently, humans have been changing pears to produce less of these things because they are more pleasant to eat without those hard cells scattered throughout.