A tuber is a part of a plant that stores energy for later, and which plays a role in asexual vegetative reproduction. Strictly speaking, it is the tip of an underground stem, also called a rhizome, that swells with unused nutrients. Many types are edible, and people around the world easily grow different varieties as major crops or supplements to their general diet. Probably the best-known varieties are potatoes and Jerusalem artichokes. Some people also use this word when talking about plants with roots that look and perform in a similar way, but this is not really proper.
Main Functions
One of the main things this growth does for a parent plant is to keep food available for the future, much like a seed does. The plant uses this stored energy to get through tough times or to support new shoots, thereby ensuring that the species survives even if the parent plant dies off. They also help to anchor the plant in the ground to some degree, just like roots do.
Primary Characteristics
This structure is distinguishable from many bulbs and corms in that it doesn't have a tunic, which is a very thin outer covering that prevents the excessive loss of moisture. It also has no flat basal plate, which is what usually sends off roots. Some areas on a tuber are capable of growing into a new plant, and people usually call these spots buds or eyes — these are easy to see on potatoes that have been stored a little too long. An additional trait is that, generally, one gets bigger and bigger from year to year and doesn't split.
Propagation
Growing tubers is generally very easy, as they are specifically designed to generate new plants. In fact, this sometimes can be a problem — if a single potato is left behind in a garden bed, for example, it will produce more plants the next year, whether or not a gardener wants them. They are also famous for propagating in compost piles. The large number of kinds means that people can grow them around the world, although a person has to identify which species likely would do best in the climate and soil his area has.
The basic technique for propagation is very similar to planting a seed, except that a person first has to cut the main tuber into pieces. Each cut section should have at least one eye on it and should be almost completely covered with soil. New sprouts should appear within one to three weeks, although this depends on the variety of plant, the quality of the soil and the availability of sufficient sunlight and water. Most people find that giving them a drink roughly every 1 - 3 days works just fine.
Use as Food
The amount of carbohydrates or starch, vitamins and minerals tubers contain usually is extremely high, given that plants use them as an energy source as needed. They are an excellent addition to the human diet as a result, which is likely a primary reason they have become so important in many regional cuisines. People also can prepare them in a wide variety of ways, such as baking or frying, and individuals have the option of flavoring them with an array of spices, herbs or sauces, making them extremely flexible additions to the kitchen.
Many types are very tasty on their own, but generally, people pair them with other foods, particularly meats. Two big reasons for this is that tubers often are not ideal sources of protein, and because preparing them in combination generally provides a more balanced variety of nutrients. Another factor is that they are not always available in large amounts, depending on the variety, and some types have a flavor that is powerful enough to require just a small amount in a recipe.
Even though they work well as a food source for most people, they aren't right for everyone to eat. Diabetics, for example, have trouble with them because of the high carbohydrate levels. Some individuals also have allergies to certain varieties, so this occasionally limits what kinds someone can eat raw or use in cooking. Since tubers are typically low to moderate in calories, they also are not always the best choice for people who need to gain weight, such as people who have been severely sick.
Differentiation
Sometimes, people mistakenly use the word "tuber" to reference plants that technically are in a different class. The roots of these plants are unusual in that they are specialized and can store food. They are known as "root tubers" or "tuberous roots" because their function is so similar to a true tuber that forms from an underground stem or rhizome. Two common examples of this type of plant are the dahlia and cassava.