Why some fruits ripen on the branch

BANANAS, APPLES and avocados continue to ripen after they are picked. Cherries, blackberries and grapes do not. The difference between climacteric fruits (the former) and non-climacteric fruits (the latter) matters to fruit growers and greengrocers, who must make sure their wares are in tip-top condition when they arrive at the marketplace. But how those differences originally came about remains unclear.In a paper in , Fukano Yuya and Tachiki Yuuya of the University of Tokyo proffer a suggestion. Fruits, they observe, exist to solve a problem faced by all plants—how best to spread their progeny around. Wrapping their seeds in a sugary pulp, to provide a tasty meal, serves as a way to get animals to do this for them. They do, however, need to make sure that their fruits favour the animals most likely to do the distributing. Dr Fukano and Dr Tachiki propose that climacterism, or its absence, is a way to achieve this. If ground-dwelling animals are the main distributors, then the continuing ripening of fallen fruit (ie, climacterism) is beneficial. If, by contrast, those distributors are arboreal or aerial, and so can feed on unfallen fruit, then non-climacteric fruits will do well.