Pear and stone cells

I love apples, but they are not as emotion-laden as pear for me as there is a personal story. So without thinking about my childhood that was full of grit, I never take a bite of pear and hold it in my mouth.

 Pear flesh is infused with very fine grit, made of clusters of stone cells. Stone cells make up some other very hard tissues. I think making stone cells requires both energy and materials, so they probably serve some purpose in the life of a pear. Guarding against herbivores would be a reasonable guess, but I have never found any studies testing this idea. Related quinces also contain stone cells, along with bitingly astringent tannins that most certainly defend the fruits.