I have a mandarin tree that produces lots of fruit. Last year some of its fruit had pips but the rest contained none. This year I couldn’t find pips in any of the fruit. What causes these pips to form, or not?
• The short answer is plant hormones. The growth of each part of a plant depends on sensitive and complex feedback that controls several different kinds of hormones. In the case of fruit, structured tissues grow quickly and then die in a certain manner. Anything that affects the controls on this process can make it go wrong, whether…
