Root vegetables like carrots, beets or tuberous sweet potatoes are energy reservoirs. The plants store their power underground, packed into complex polysaccharides they can unpack and turn back into glucose.
Plants produce their own food as glucose through photosynthesis, using sunlight, water, and carbon dioxide. Glucose is a monosaccharide or simple sugar. It's easily absorbed by plants, microbes and other living organisms.
A plant can't turn CO2 directly into glucose. It goes through three stages collectively called the Calvin cycle: carboxylation, reduction reactions, and ribulose 1,5-bisphosphate (RuBP) regeneration.
During the second phase of photosynthesis, carbon dioxide from the atmosphere passes into the leaves through tiny openings. The chloroplasts use the stored chemical energy to transform carbon dioxide into glucose.
Fructose, another monosaccharide, is also produced in this phase. Then, glucose and fructose combine to form sucrose. Plants form chains of sugars and pack them as polysaccharides or complex carbohydrates.
If the plant needs to turn sucrose back into glucose and fructose, it uses the enzyme sucrase. When humans eat plants they use the enzyme amylase, present in saliva and the intestine, to break down starches.
The process of energy storage in sweet root veg is closely linked to their biological structure. The parenchymal cells store starch granules. The cells usually have thin cell walls; some are lignified.
Root veg include carrots, sweet potato, beets, turnips, rutabaga, radish, ginger, onion, garlic. All store starches and sugars in their roots and other parts such as tubers, which are underground parts of the stem.
Carrots
Carrots store energy as sugars, specifically sucrose. When a carrot is growing, it uses the sun's energy to turn carbon dioxide and water into glucose and fructose. They're converted to sucrose and stored in the root.
As carrots mature, leaves and stems produce more sugars. The sugars move down to the roots, where they're converted to starches for storage. Along the way some help nourish the plant. The root begins to enlarge.
The crude fiber in carrot roots is about 72% cellulose, 13% hemicellulose and 15% lignin. These give strength and some flexibility to the root.
Many root veg like carrots and turnips get sweeter after a frost. This happens because the conversion of starches to sugars automatically lowers the freezing point of plant cells.
Sweet Potatoes
Sweet potatoes hold up to 75% of their weight in glucose and starch. The primary components are starches, accounting for 53% of carbohydrate content.
Simple sugars like glucose, fructose, sucrose and maltose make up 32% of the carbohydrate content. Sweet potatoes also store energy as fiber.
There are two types of fiber in sweet potatoes. Pectin fibers absorb water, soften and swell, creating a gel-like consistency. Indigestible fibers pass into the intestine.
Sweetness of sweet potatoes comes from the action of the enzyme amylase breaking down starches. In these tuberous roots the enzyme activates in cooking temperatures between 57 and 77°C (135 and 170°F).
Sugar Beets
Sugar beets store energy in the form of both sugars and starches. The sugar beet's root is rich in sucrose, which is extracted and refined to make table sugar. The root also contains starch, which the plant uses for energy.
These energy reserves not only facilitate plant growth and development but also prepare them to coast through tough conditions like drought or cool temperatures.
Energy Use During Growth
When conditions are good for growth, root vegetables use stored energy. Carrots convert their sugar reserves into energy quickly, allowing them to prosper even in poor soil conditions.
Sweet potatoes often retain higher starch levels throughout the growing season. This strategy supports larger tuber development, with a yield of 15 to 25 tons per acre in well-maintained agricultural fields.
In the dark, plants release sucrose into from their starch reserves for continued energy. The plant also taps into its energy reserves in periods of stress, such as:
Overwintering: Many root vegetables are biennials, meaning they live for two years. The stored energy helps them survive the harsh winter months, allowing them to regrow in the spring and produce flowers and seeds.
Regrowth: Damaged or stressed plants can rely on the stored energy in their roots to regenerate new shoots and leaves.
Reproduction: When it's time to reproduce, the plant mobilizes the stored starch and converts it back into glucose, providing the energy needed to produce flowers, fruits, and seeds.
In the first season, carrots grown from seeds develop leaves, stems, and roots. They're usually harvested when the roots are young. If left in the ground for an additional season, the plants have a growth spurt.
Their stems extend, flowers bloom and seeds form. Wild carrots also don't flower in the first year and young growth is often unnoticed in meadows.
Deep rooting vegetables help improve soil structure and prevent erosion by stabilizing the soil. As they grow, die and decay they replenish organic matter in the earth.
Their nutrients improving soil fertility and supporting growth of other plants. Sugars of the roots provide food for billions of organisms in the soil, and new plants.
Non-Fiction Books:
Fiction Books:
READ: Lora Ley Adventures - Germanic Mythology Fiction Series
READ: Reiker For Hire - Victorian Detective Murder Mysteries