Allelopathy

Allelopathy is understood to mean the influence exerted by fruits and vegetables on other plants through the gases they emit, such as carbon dioxide (CO2), ethylene (ethene, C2H4), and aromatic substances which reach their peak at the climacteric (time of maximum respiration). A concentration of 0.02% ethylene in air may accelerate the ripening process by 4-10 times. Therefore, it is essential that unripe fruit at the pre-climacteric stage is NOT stowed together with ripe fruit. If one piece of produce begins to excrete ethylene, a whole cargo may begin the increase in respiration associated with the climacteric. In simpler terms: If one item is ripe and emits this substance it can cause a rapid increase in the ripening process for everything near it.

It should be noted this does not only apply to fruit and not only to the same type/species of plant that may be stored together. Different fruits have this effect on each other, as do fruits and vegetables. For example, apples excrete large amounts of ethylene, which may cause potatoes to sprout prematurely. Cucumbers turn yellow when exposed to ethylene from apples or tomatoes. Fruit and vegetables species produce different amounts of ethylene and exhibit different levels of sensitivity to other ethylene producers, as is clear from the tables below. On the other hand, allelopathy may be used to one's advantage in warehouses to bring about ripening at the desired time.

Click here for more information about Allelopathy Ethylene Production Rates and Ethylene Sensitivity.

Ethylene Production Rates Products
[ μL / (kg * h) ]  
Zero 0 Chinese artichoke, Japanese radish, prickly pear, Florence fennel, cassava, pak-choi cabbage, cranberry, black salsify
Very Low 0.01-0.1 Pineapple, artichoke, cauliflower, broccoli, watercress, mushroom, chicory, Chinese cabbage, date, endive, pea, Jerusalem artichoke, grapefruit, curly kale, ginger, carrot, potato, cherry, garlic, celeriac, kohlrabi, lime, sweetcorn, mandarin, horseradish, orange, parsnip, parsley root, chanterelle, leek, radish, rhubarb, Brussels sprout, beetroot, red cabbage, turnip, green cabbage, asparagus, spinach, rutabaga, celery, sweet potato, tangerine, taro, grape, white cabbage, lemon, onion
Low 0.1-1.0 Winter cherry, aubergine, egg-plant, berries, bitter squirting cucumber, Seville orange, bean, clementine, persimmon, iceberg lettuce, baby sweetcorn, pomegranate, guava, cucumber, starfruit, kiwifruit, coconut, cabbage, lettuce, kumquat, pumpkin, limequat, olive, sweet pepper, chili pepper, quince, garden radish, satsuma, watermelon, courgette, zucchini
Moderate 1.0-10.0 Banana, fig, feijoa, honeydew melon, Jack fruit, lychee, mango, mangosteen, plum, tomato
High 10.0-100.0 Apricot, avocado, tamarillo, pear, papaya, peach/nectarine
Very High >100.0 Apple, cherimoya, passion fruit
Ethylene Sensitivity Products
Zero Seville orange, Chinese artichoke, clementine, fennel, kumquat, pak-choi, cabbage, chanterelle, cranberry, garden radish, satsuma
Low Pineapple, winter cherry, artichoke, aubergine, egg-plant, berries, bitter squirting cucumber, date, Jerusalem artichoke, fig, feijoa, baby sweetcorn, pomegranate, ginger, prickly pear, starfruit, carrot, cherry, garlic, celeriac, coconut, pumpkin, sweetcorn, cassava, horseradish, sweet pepper, parsnip, chili pepper, parsley root, radish, rhubarb, beetroot, turnip, black salsify, rutabaga, sweet potato, taro, grape, watermelon, onion (dry)
Moderate Tamarillo, bean, mushroom, endive, pea, Jack fruit, grapefruit, guava, potato, cabbage, lettuce, lime, lychee, mandarin, olive, orange, leek, asparagus, celery, tangerine, lemon, courgette, zucchini, onion (green)
High Apple, apricot, avocado, banana, pear, cauliflower, broccoli, watercress, cherimoya, chicory, Chinese cabbage, persimmon, iceberg lettuce, curly kale, cucumber, honeydew melon, kiwifruit, mango, mangosteen, papaya, passion fruit, peach, plum, quince, Brussels sprout, red cabbage, spinach, tomato, white cabbage, savoy cabbage