just came back from a vacation that included a brief stay in the Okanagan. Among the treasures from that visit were two containers of delicious fresh apricots and cherries, courtesy of a friend who owns an orchard near Oliver.
The amount of fruit produced by the trees of the Okanagan Valley alone is staggering: everywhere you look, it seems, peaches, apples, cherries, grapes and other delectable delicacies are growing. Which, naturally, got me wondering: what is fruit, and how is it grown in such abundance?
There are actually three definitions of fruit. According to the strict botanical definition, the fruit of a flowering plant (and only flowering plants, or angiosperms, produce fruit) is its mature, swollen ovary, which contains one or more of the plant’s seeds. That’s a rather broader definition than we commonly use, however, because it includes everything from nuts to coffee beans to wheat (which would presumably make Saskatchewan, not B.C. or Ontario, Canada’s major fruit-growing province!).
Horticulturally, fruits are the seed-bearing product of a perennial plant, which makes tomatoes, cucumbers and string beans vegetables, even though botanically, they’re fruit. However, that definition also makes melons vegetables.
That brings us to the what most of us mean by the term fruit, which is the succulent, edible fruits of woody plants (apples, apricots, peaches, pears, etc.), as well as melons and such small fruits as strawberries, grapes, raspberries and blueberries.
Fruit, whether you use the broad botanical or narrow common definition, have developed to promote the dispersal and sprouting of the plants seeds. Fruits taste good as a way of encouraging animals to eat them and the seeds they contain. The animal may then either spit out or excrete the seeds in a new location. Fruits that fall to the ground eventually decay, enriching the soil and providing a boost to the seeds inside.
From our point of view, fruits are good to eat both because of their taste and because of their nutritional benefits, although those vary widely. A ripe tomato, for example, contains very few calories because it’s 97 percent water. Many other fruits also contain a lot of water. However, they also contain starches, sugars, valuable vitamins and other useful nutrients. Most fruits, for instance, contain considerable quantities of vitamin A and B. Orange and yellow fruits like cantaloupes and persimmons contain beta-carotene, which helps prevent cancer and heart disease. Kiwi, strawberries and oranges are particularly high in vitamin C. Strawberries are also valuable sources of vitamin E and other nutrients. In general, if you want to eat something that’s good for you, reach for fruit. (Ideally it should be fresh fruit, however; fruits lose vitamins in storage, unless they’re frozen.)
Although fruits can be divided and sub-divided into many different types, they all have a common structure, although it’s hard to believe when comparing, say, a coconut and a grape. As a plant’s ovary matures into a fruit, its wall develops into what’s called the pericarp, which is divided into three layers, which, from the outside in, are called the exocarp, mesocarp and endocarp. The exocarp is usually a single, skin-like layer, while the thickness and fleshiness of the mesocarp and endocarp vary greatly. In the aforementioned coconut, for instance, the exocarp, mesocarp and endocarp together make up the husk, while the entire edible portion, including the “milk,” is the seed. In a grape, on the other hand, the exocarp is a thin skin, the fleshy, juicy, delicious part is the mesocarp, and the endocarp is a thin layer immediately surrounding the seeds.
Some fruits contain additional parts left over from the flower. The apple, for intance, includes a “receptacle” for the seeds (the apple core) which is made up of fused parts of the apple flower. A strawberry really consists of a bunch of tiny individual fruits on a fleshy receptacle: in other words, technically, the part of the strawberry we most enjoy eating isn’t really “fruit” at all!
Where and how successfully you can grow fruit depends to a great degree on climate. Tropical fruits such as bananas and pineapple grow from evergreen plants that are seriously damaged or killed by freezing, so you won’t be seeing banana plantations around here any time soon, unless global warming really gets out of control. Sub-tropical fruits such as citrus fruits, however, actually benefit from cool (though still above-freezing) temperatures in winter, but require warm weather for proper growth. Warm-temperate regions (which includes the sunny and, at least when I was there, blazingly hot Okanagan) grow deciduous fruit-bearing plants such as apricots, peaches, plums, almonds, and, of course, grapes. These plants require a long warm growing season, but also require a period of low temperatures in order to flower. Finally, there are cool-temperate species of fruit, such as apple, pear, cherry, strawberry, raspberry and currant, that can withstand more severe winter temperatures by becoming dormant. They, too, require a certain number of hours above freezing but below seven degrees Celsius before they’ll properly blossom.
Fruit ripens in response to hormones, which cause the fruit tissues to soften, starches to be converted to sugar (making the fruit sweeter to the taste) and pigments to change, altering the fruit’s color (a signal to animals that the fruit is ready to eat–and the plant’s seed are ready to be spread around!). Ripening fruits also produce small quantities of a gas called ethyene, which can be used to hasten the ripening of other fruits. Fruits are difficult to transport or store for long because even after they’re picked, they continue to use oxygen, give off carbon dioxide and generate heat. This consumes the food and water stored in the fruit and leads to an ongoing breakdown of the fruit tissues, until the fruit is too soft and shrivelled to be good to eat. Refrigeration helps delay this process; in some storage rooms, the oxygen level is reduced and the carbon dioxide level boosted to slow the process further.
Of course, fruits can also be preserved by freezing, drying and canning.
Tree fruits are grown in orchards, artificial stands of fruit-bearing trees. Artificial is definitely the word: most people don’t realize, when looking at an apple orchard, for instance, that what they’re really seeing are hybrids–each tree is really made up of parts of two or more trees. Growers start with a rootstock, a strain of the tree that grows well in the local soil and is resistant to local root-destroying diseases and insects. Then they graft onto that cuttings or buds from different strains of the tree chosen for the quality of fruit they produce.
Now, in many orchards, the trees don’t even look like we think fruit trees should look like. Growers are now growing trees in higher and higher densities by using very slender root stocks (the root stock determines how big the tree will grow) and planting the trees closer together. The result is a row of apple “trees” that really look more like skinny, almost branchless saplings, grown on poles and supporting strings. The fruit pops out all over the skinny, upright part of the tree; the result, according to one grower I talked to, is a “wall of fruit,” easy to pick and easy to prune (pruning forces the tree to concentrate on growing fruit instead of wood; it’s usually done in the winter because a little bit of extra wood and leaves helps to prevent the sun from scalding the fruit). This method is called “spindle” or “super spindle,” depending on how close together the trees are. In addition to reducing labor, this method, though expensive to implement, pays for itself quickly: the trees produce fruit in their third year, instead of their fifth or sixth.
The new methods of growing fruit continue to be refined, but whatever the trees look like, one thing hasn’t changed: the combination of water and sunshine peculiar to the Okanagan continues to produce some of the best-tasting fruit in the world. After several hours in a car with fresh cherries and apricots just an arms-length away, I can personally attest to it.
