Have you noticed that pears can sometimes have a gritty texture compared to apples? This comes from stone cells, which develop in pears as they ripen on the tree. ... They are protective for the fruit, but not necessarily what humans want, so pears are picked when mature, but not ripe, to avoid excess stone cells.

What causes stone cells in pears?

The fruit of pears always has stone cells scattered through it. ... Stress may come from poor ripening, from pears left on the tree too long, or from lack of water during the time when the fruit was growing. Since this was a particularly dry summer, insufficient water is a likely cause of your stone cell clusters.

What are the stones in pears?

Stone cells (sclereids), heavily lignified cells present in fruit flesh, serve as a distinctive trait of pear fruits. Stone cells are characterized by thickening and lignified cell walls, and their development is closely associated with lignin metabolism.