Question

(HOMEWORK HELP)

Is fruit ripening different once it's detached from the plant? If the bananas were still attached to the plant, would the results differ?

Answer 1

Fruit ripening involves various physiological, biochemical and developmental changes that occur in a coordinated and genetically regulated manner. Fruits, in general, show two distinct respiratory patterns during ripening and on this basis they are categorized into climacteric and non-climacteric groups.

Many fruits that belong to climacteric group enter the climacteric phase soon after harvest but they might not ripen for weeks if left on the tree. The best example for such a differential behaviour is of banana fruit. bananafruit (in most of the varieties) do not ripe or partially ripe or undergo climacteric change if remain attached to the plant. To explain this, it has been proposed that a substance of unknown nature enter the fruit from the tree and this inhibits ripening. It was also hypothesized that ethylene is rendered ineffective by this hypothetical ripening inhibitor (which is supposed to be supplied by parent plant) and harvesting the fruit removes it from the source of this inhibitor i.e., the parent plant. Further, it was suggested that endogenously synthesized ethylene is not the direct cause of climacteric rise.

Evidences have suggested that the hypothetical inhibitor is transported through the phloem from leaf to fruit. So, proposed that the inhibitor prevented the auto-induced production of ethylene. But, further it was suggested that this inhibitor either inhibits ethylene production or raises the threshold value at which ethylene becomes physiologically active in promoting the process of ripening. With this background, an attempt has been made in this article to understand the ripening behaviour of different fruits if they remain attached to the parent plant or they are detached and then undergo the process of ripening during storage.