Cucumber (Cucumis sativus) is a widely-cultivated creeping vine plant in the Cucurbitaceae family that bears usually cylindrical fruits, which are used as vegetables. Considered an annual plant, there are three main varieties of cucumber — slicing, pickling, and burpless/seedless — within which several cultivars have been created.
In this post, Pritish Kumar Halder illustrates Cucumber, a member of the Cucurbitaceae family.
The cucumber originates from South Asia, but now grows on most continents, as many different types of cucumber are traded on the global market. In North America, the term wild cucumber refers to plants in the genera Echinocystis and Marah, though the two are not closely related.
The cucumber is a creeping vine that roots in the ground and grows up trellises or other supporting frames, wrapping around supports with thin, spiraling tendrils. The plant may also root in a soilless medium, whereby it will sprawl along the ground in lieu of a supporting structure. The vine has large leaves that form a canopy over the fruits
The fruit of typical cultivars of cucumber is roughly cylindrical, but elongated with tapered ends, and may be as large as 62 centimeters (24 in) long and 10 centimeters (4 in) in diameter.
Cucumber fruits consist of 95% water (see nutrition table). In botanical terms, the cucumber is classified as a pepo, a type of botanical berry with a hard outer rind and no internal divisions. However, much like tomatoes and squashes, it is often perceived, prepared, and eaten as a vegetable.
Flowering and pollination
Most cucumber cultivars are seeded and require pollination. For this purpose, thousands of honey beehives are annually carried to cucumber fields just before bloom. Cucumbers may also be pollinated via bumblebees and several other bee species. Most cucumbers that require pollination are self-incompatible, thus requiring the pollen of another plant in order to form seeds and fruit. Some self-compatible cultivars exist that are related to the ‘Lemon’ cultivar.
A few cultivars of cucumber are parthenocarpy, the blossoms of which create seedless fruit without pollination, which degrades the eating quality of these cultivar. In the United States, these are usually grown in greenhouses, where bees are excluded. In Europe, they are grown outdoors in some regions, where bees are likewise excluded.
Traditional cultivars produce male blossoms first, then female, in about equivalent numbers. Newer gynoecia’s hybrid cultivars produce almost all female blossoms. They may have a pollinizer cultivar interplanted, and the number of beehives per unit area is increased, but temperature changes induce male flowers even on these plants, which may be sufficient for pollination to occur.
In 2009, an international team of researchers announced they had sequenced the cucumber genome.
Nutrition, aroma, and taste
Raw cucumber (with peel) is 95% water, 4% carbohydrates, 1% protein, and contains negligible fat. A 100-gram (3+1⁄2-ounce) reference serving provides 67 kilojoules (16 kilocalories) of food energy. It has a low content of micronutrients: it is notable only for vitamin K, at 16% of the Daily Value.
Depending on variety, cucumbers may have a mild melon aroma and flavor, in part resulting from unsaturated aldehydes, such as (E,Z)-nona-2,6-dienal, and the cis- and trans- isomers of 2-nonenal. The slightly bitter taste of cucumber rind results from cucurbitacins.
In general cultivation, cucumbers are classified into three main cultivar groups: slicing, pickled, and seedless/burpless.
Cucumbers grown to eat fresh are called slicing cucumbers. The main varieties of slicers mature on vines with large leaves that provide shading.
Slicers grown commercially for the North American market are generally longer, smoother, more uniform in color, and have much tougher skin. In contrast, those in other countries, often called European cucumbers, are smaller and have thinner, more delicate skin, often with fewer seeds, thus are often being sold in plastic skin for protection. This variety may also be called a telegraph cucumber, particularly in Australasia.
Pickling with brine, sugar, vinegar, and spices creates various flavored products from cucumbers and other foods. Although any cucumber can be pickled, commercial pickles are made from cucumbers specially bred for uniformity of length-to-diameter ratio and lack of voids in the flesh. Those cucumbers intended for pickling, called picklers, grow to about 7 to 10 cm (3 to 4 in) long and 2.5 cm (1 in) wide. Compared to slicers, picklers tend to be shorter, thicker, less-regularly shaped, and have bumpy skin with tiny white or black-dotted spines. Color can vary from creamy yellow to pale or dark green.
Gherkins, also called cornichons, or baby pickles, are small cucumbers, typically those 2.5 to 12.5 centimetres (1 to 5 in) in length, often with bumpy skin, which are typically used for pickling. The word gherkin comes from the early modern Dutch gurken or augurken (‘small pickled cucumber’). The term is also used in the name for Cucumis anguria, the West Indian gherkin, a closely related species.
Burpless cucumbers are sweeter and have a thinner skin than other varieties of cucumber. They are reputed to be easy to digest and to have a pleasant taste. They can grow as long as 60 centimeters (2 ft), are nearly seedless, and have a delicate skin. Most commonly grown in greenhouses, these parthenocarpic cucumbers are often found in grocery markets, shrink-wrapped in plastic. They are marketed as either burpless or seedless, as the seeds and skin of other varieties of cucumbers are said to give some people gas.