Many native North American tap-rooted plants have served as a main staple for existence.Native Americans from the western portions of North America used one such species, Lewis’ bitterroot.Roots were also used for medicinal purposes including sore throat aid, poison ivy rashes, and heart pain.This important plant was introduced to Lewis and Clark on their famous expedition in the early 1800s.Named in honor of Lewis and its apparent ability to come back to life, this plants scientific name is Lewisia rediviva (rediviva is Latin for “brought back to life”).The tuberous potato ranks fourth as a major food staple globally, following only wheat, corn, and rice (grains) respectively.It is interesting to note that potatoes did not leave the Americas until just a few hundred years ago.Both plant species originated in the new world and have been widely cultivated for their important storage roots.True yams belong to a different genus, Dioscorea, and are grown primarily in Africa.How the Potato Changed the World An article from the Smithsonian magazine (November 2011) describes how the potato, brought to Europe from the New World by Spanish explorers, gave rise to modern industrial agriculture.Wild onions and garlic (right) have bulbs that can be enjoyed as a food source.The genus Allium, which includes the onion and its relatives, has been providing important food sources since before recorded time.Besides providing an aromatic food flavoring, most of the members of the genus have medicinal properties as well.The pungent quality common to the Alliums is tied to the volatile sulfur compounds that are released when the cells of an onion are ruptured.Early settlers or pioneers to the area were starving due to a large infestation of crop eating crickets. .
Root Vegetables Grow Underground
If you’ve only encountered potato in the form of French fries and chips, it might surprise you to know that it grows underground as do other root vegetables.My daughter could have said that potatoes are imported from Mars and her friend would probably have worn the same look of disbelief on his face.Sweet potato, yam, carrot, beet, radish, jicama, turnip, cassava, ginger, turmeric, galangal and parnsip are only some of them.Suffice to say that they are all root vegetables because the part of the plant that we eat grow in the soil rather than above it.Cooks who go for aesthetics prefer to peel and discard the skin (of potatoes and carrots, especially) to give the vegetables are cleaner look on the dinner plate.On the other hand, cooks who value nutrition over appearance say that we lose so much nutrients by discarding the skin of root vegetables.Other root vegetables especially cassava and yam, I prefer to peel before cooking. .
Are carrots and radish underground stems?
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How Potato Grows
As the potato plant grows, its compound leaves manufacture starch that is transferred to the ends of its underground stems (or stolons). .
Roots and Tuber Crops as Functional Foods: A Review on
Thus, they add variety to the diet in addition to offering numerous desirable nutritional and health benefits such as antioxidative, hypoglycemic, hypocholesterolemic, antimicrobial, and immunomodulatory activities.Tubers have an immense potential as functional foods and nutraceutical ingredients to be explored in disease risk reduction and wellness.They provide a substantial part of the world’s food supply and are also an important source of animal feed and processed products for human consumption and industrial use.Nutritionally, roots and tubers have a great potential to provide economical sources of dietary energy, in the form of carbohydrates (Table 1).However, high yields of roots and tubers give more energy per land unit per day compared to cereal grains .Similar to other crops, nutritional value of roots and tubers varies with variety, location, soil type, and agricultural practices, among others.Oxidative stress which would be harbored by both endogenous and exogenous factors contributes immensely to the etiology of NCDs as well as the aging process.The association between plant food intake and reduced NCDs episodes has been the main focus of a number of scientific investigations in the recent past.Several bioactivities, namely, antioxidant, immunomodulatory, antimicrobial, antidiabetic, antiobesity, and hypocholesterolemic activities, among others, are reported for tubers and root crops.They play an essential role in the diet of populations in developing countries in addition to their usage for animal feed and for manufacturing starch, alcohol, and fermented foods and beverages.Roots and tuber crops are important cultivated staple energy sources, second to cereals, generally in tropical regions in the world.An important agronomic advantage of root and tuber crops as staple foods is their favourable adaptation to diverse soil and environmental conditions and a variety of farming systems with minimum agricultural inputs.In addition, variations in the growth pattern and adopting cultural practices make roots and tubers specific in production systems.mandioca; kamoteng kahoy Elephant foot yam Amorphophallus paeoniifolius Araceae White pot giant arum; stink lily.Potato is currently the fourth most important food crop in the world after maize, wheat, and rice, with a production of 368 million tonnes .The origin of sweet potato is Central America, but at present it is widely grown in many tropical and subtropical countries in different ecological regions.Sweet potato can be grown all around the year under suitable climatic conditions and complete crop loss under adverse climatic conditions is rare; thus it is considered as an “insurance crop.” The crop is particularly important in Southeast Asia, Oceania, and Latin America regions and China claims about 90% of total world production.The consumption of 125 g orange fleshed sweet potatoes, rich in carotenoids, improves vitamin A status of children, especially in developing countries .In addition, sweet potatoes are rich in dietary fibre, minerals, vitamins, and bioactive compounds such as phenolic acids and anthocyanins, which also contribute to the color of the flesh.Cassava plays an important role as staple for more than 500 million people in the world due to its high carbohydrate content .Yam is a member of the monocotyledonous family Dioscoreaceae and is a staple food in West Africa, Southeast Asia, and the Caribbean regions .Yam tubers have various bioactive components, namely, mucin, dioscin, dioscorin, allantoin, choline, polyphenols, diosgenin, and vitamins such as carotenoids and tocopherols [19, 20].Yams may stimulate the proliferation of gastric epithelial cells and enhance digestive enzyme activities in the small intestine .Colocasia, originating in India and Southeast Asia, is a staple food in many islands of the South Pacific, such as Tonga and Western Samoa, and in Papua New Guinea.The edible types of Canna edulis originated in the Andean region or Peruvian coast and extended from Venezuela to northern Chile, in South America.Arrowroot has been widely distributed throughout the tropical countries like India, Sri Lanka, Indonesia, the Philippines, and Australia and West Indies.They are derived from biosynthetic precursors such as pyruvate, acetate, a few amino acids, acetyl-CoA, and malonyl-CoA following the pentose phosphate, shikimate, and phenylpropanoid metabolism pathways.In plants, phenylalanine and to a lesser extent tyrosine are the two major amino acids involved in the synthesis of phenolic compounds .Saponins are high molecular weight glycosides consisting of a sugar moiety linked to a triterpene or steroid aglycone.Saponins having a steroid structure are precursors for the chemical synthesis of birth control pills (with progesterone and estrogen), similar hormones, and corticosteroids .According to recent findings steroidal saponins could be a novel class of prebiotics to lactic acid bacteria and are effective candidates for treating fungal and yeast infections in humans and animals .Dioscorin from fresh yam (Dioscorea batatas) exhibited DPPH radical scavenging activity  and showed beneficial effects in lowering blood pressure [19, 29].In addition, dioscorin demonstrated angiotensin converting enzyme (ACE) inhibitory and antihypertensive activities on spontaneously hypertensive rats [29, 30].The primary function of alkaloids in plants is acting as phytotoxins, antibactericides, insecticides, and fungicides and as feeding deterrents to insects, herbivorous mammals, and mollusks .The majority of carotenoids are unsaturated tetraterpenes with the same basic C 40 isoprenoid skeleton resulting from the joining of eight isoprene units in a head-to-tail manner with the exception of the tail-to-tail connection at the centre.In photosynthetic systems of higher plants, algae, and phototrophic bacteria, carotenoids participate in a variety of photochemical reactions .As reported by the 1983 Nutritional Food Survey Committee, potatoes serve as a principal source of vitamin C in British diets, providing 19.4% of the total requirement .The concentration of ascorbic acid varies with the species, location, crop year, maturity at harvest, soil, and nitrogen and phosphate fertilizers .Several authors reported that the peels of sweet potato possessed a potent wound healing effect, which appears to be related to the free radical scavenging activity of the phytoconstituents and their ability in lipid oxidation inhibition [46, 47].They further found that the rats treated with sweet potato fibre covering had reduced wound area compared to those of the control.Petroleum ether extract of sweet potato had shown significant closure of scar area for complete epithelialization compared to the control .Hsu et al.  studied the antioxidant activity of water and ethanolic extracts of yam peel on tert-butyl hydroperoxide (t-BHP) induced oxidative stress in mouse liver cells (Hepa 1–6 and FL83B).The administration of yams decreased the levels of γ-glutamyl transpeptidase (GGT), low density lipoprotein, and triacylglycerol in serum of rats in which hepatic fibrosis was induced by carbon tetrachloride .Using a rat model, it was shown that ethanolic extracts of purple fleshed potato flakes had effective free radical scavenging activity and inhibition of linoleic acid oxidation .Recently, Ji et al.
 reported the contents of phenolic compounds and glycoalkaloids of 20 potato clones and their antioxidant, cholesterol uptake and neuroprotective activities in vitro.Chlorogenic acid (50–70%) and anthocyanins, namely, pelargonidin and petunidin glycosides, were identified as major phenolic compounds present in potatoes.Kim et al.  showed that butanol fraction of sweet potato could be a better source for treating gastric ulcers induced by excessive alcohol intake.It is important to find ways to reduce and prevent the risk of cancer through dietary components, which are present in plant foods.Root and tuber phytochemicals have demonstrated anticancer effects in several types of carcinoma cell lines and animal models.Furthermore, two anthocyanin pigments, namely, 3-(6,6′-caffeylferulylsophoroside)-5-glucoside of cyanidin (YGM-3) and peonidin (YGM-6), purified from purple sweet potatoes effectively inhibited the reverse mutation induced by mutagenic pyrolysates of tryptophan (Trp-P-1, Trp-P-2) and imidazoquinoline (IQ) in the presence of rat liver microsomal activation systems .There are several groups of saponins, namely, cycloartanes, ammaranes, oleananes, lupanes, and steroids, demonstrating strong antitumour effect on different types of cancers.For instance, cycloartane saponins possess antitumour properties in human colon cancer cells and tumour xenografts .They downregulated expression of the hepatocellular carcinoma (HCC) tumour marker α-fetoprotein and suppressed HepG2 cell growth by inducing apoptosis and modulating an extracellular signal-regulated protein kinase- (ERK-) independent NF-κB signaling pathway .Glycoalkaloids showed antiproliferative activities against human colon (HT-29) and liver (HepG2) cancer cells as assessed by the MTT assay .Extract of water yam contains a homogenous compound with a single copper-binding site and also is a good natural, safe (redox inactive) copper chelator.It was found that dioscorin stimulated RAW 264.7 cells to produce nitric oxide (NO), in the absence of lipopolysaccharide (LPS) contamination.Furthermore, the released cytokines may act synergistically with phytohemagglutinin (PHA) which is a lectin found in plants that stimulate the proliferation of splenocytes .In vitro cytotoxic activity of mouse splenocyte against leukemia cell was increased in the presence of YMP of Dioscorea batatas at 10 μg/mL .Mice which were fed with a Dioscorea extract recovered damaged bone marrow progenitor cell populations that had been depleted by large doses of 5-fluorouracil (5-FU).In addition, it was found that the specific antibodies rapidly responded against foreign proteins (or antigens) in the presence of yam mucilage.Yams (Dioscorea esculenta) showed anti-inflammatory activity on carrageenan induced oedema in the right hind paw of Wistar rats .Phytochemical screening of D. esculenta confirmed the presence of saponins, β-sitosterol, stigmasterol, cardiac glycosides, fats, starch, and diosgenin, which could be responsible for the observed activity .The results showed that the consumption of pigmented potatoes was responsible for elevated antioxidant status and reduced inflammation and DNA damage, which was observed through the reduction of inflammatory cytokine and C-reactive protein concentrations .Authors indicated that the presence of steroids and flavonoids in A. campanulatus (Suran) tuber may be responsible for the observed immunomodulatory activity .The methanolic extracts from D. hirtiflora demonstrated antimicrobial activity against all tested organisms, namely, Staphylococcus aureus, E coli, Bacillus subtilis, Proteus mirabilis, Salmonella typhi, Candida albicans, Aspergillus niger, and Penicillium chrysogenum.Diabetes mellitus is a chronic disorder marked by elevated levels of glucose in the blood and life-threatening complications that can untimely lead to death.In addition, blood triacylglycerol (TG), free fatty acid (FFA), and lactate levels were also lowered by the oral administration of WSSP.In histological examinations of the pancreas of Zucker fatty rats, remarkable regranulation of pancreatic islet B-cells was observed in the WSSP and troglitazone groups after 8 weeks of treatment.In support of these observations, ingestion of 4 g of caiapo, the extract of WSSP, per day for 6 weeks reduced fasting blood glucose and total as well as low density lipoprotein (LDL) cholesterol in male Caucasian type 2 diabetic patients who were previously treated by diet alone .Later Ludvik et al.  confirmed the beneficial effects of caiapo on glucose and serum cholesterol levels in type 2 diabetic patients treated by diet alone for 3 months after administration for the study.External agents possessing anticholesterolemic activities continuously show beneficial effects on risk reduction and management of the disease conditions.In agreement with this finding, several studies showed that diosgenin, in some Dioscorea, could enhance fecal bile acid secretion and decrease intestinal cholesterol absorption [82, 83].They further suggested that the increased viscosity of the digest and the thickness of the unstirred layer in the small intestine caused by Tainung number 2 yam fibre (or/and mucilage) decreased the absorption of fat, cholesterol, and bile acid.Short term (3-week) consumption of 25% Tainung number 2 yam in the diet could reduce the atherogenic index but not total cholesterol level in nonhypercholesterolemic mice.Furthermore, short term consumption (3-week) of 25% uncooked keelung yam effectively reduced total blood cholesterol levels and the atherogenic index in mice.It was shown that the levels of serum estrogen and sex hormone binding globulin (SHBG) increased significantly after subjects had been on a yam diet for 30 days.Furthermore, three serum hormone parameters measured, namely, estrogen, estradiol, and SHBG, did not change in those who were fed with sweet potatoes as the control.Authors further showed that high SHBG levels had a protective effect against the occurrence of type 2 diabetes mellitus and coronary heart diseases in women .Sporamin did not exhibit any cytotoxic activity toward the model cell line 3T3-L1 preadipocytes which have frequently been used to study differentiation of adipocytes in vitro.Anthocyanin fractions of purple sweet potato inhibited hepatic lipid accumulation through the induction of adenosine monophosphate activated protein kinase (AMPK) signaling pathways.These authors further suggested that anthocyanin fraction may improve high fat diet induced fatty liver disease and regulate hepatic lipid metabolism .Tuber crops are processed in a number of ways before they are consumed and these include hydrothermal treatments such as boiling, frying, baking and roasting, dehydration, and fermentation.Those fermented foods from cassava include gari, fufu, lafun, chickwanghe, agbelima, attieke, and kivunde in Africa, tape in Asia, and “cheese” bread and “coated peanut” in Latin America .Greater yams (Dioscorea alata L.), commonly known as ube in the Philippines, are utilized in sweetened food delicacies due to their attractive violet color and unique taste.Processing conditions, such as peeling, drying, and sulphite treatment, could change physiochemical properties and nutritional quality of sweet potato flour .Peeled and unpeeled sweet potato flour with or without sulphite treatment showed higher browning indices at 55°C and decreased with increasing drying temperatures .Total phenolic content decreased at a higher drying temperature for peeled and unpeeled sweet potato flour without sulphite treatment.Methanolic extracts of sweet potatoes increased the proliferation of the lectin concanavalin A (Con A) stimulated splenocytes of BALB/c mice in a concentration dependent manner.The reported losses in phenolic contents could be due to a combination of degradation caused by leaching into water, heat, and polyphenol oxidation [10, 98].Different processing methods decreased the anthocyanin content due to the effect of high temperature, enzyme activity, change in pH, and presence of metallic ions and proteins [101, 102].Fang et al.
 identified the major phenolic compounds in Chinese purple yam and their changes during vacuum frying (Table 4).Chen and Lin  also reported the negative impact of temperature on the content of phenolic compounds and dioscorin and antioxidant activities of yam cultivars.In addition to the main role as an energy contributor, they provide a number of desirable nutritional and health benefits such as antioxidative, hypoglycemic, hypocholesterolemic, antimicrobial, and immunomodulatory activities.Tubers may serve as functional foods and nutraceutical ingredients to attenuate noncommunicable chronic diseases and to maintain wellness. .
plant - Gymnosperms
Along with other features, angiospermy, the enclosed condition of the seed, gave the flowering plants a competitive advantage and enabled them to come to dominate the extant flora.Flowering plants have also fully exploited the use of insects and other animals as agents of pollination (the transfer of pollen from male to female floral structures).Classification of angiosperms Many of the flowering plants are commonly represented by two basic groups, the monocotyledons and the dicotyledons, distinguished by the number of embryonic seed leaves (cotyledons), number of flower parts, arrangement of vascular tissue in the stem, leaf venation, and manner of leaf attachment to the stem.Other angiosperm groups, such as the Magnoliids, do not fit the traditional paradigm of monocot and dicot and are considered to have more-ancient lineages.The epicotyl (region above the cotyledon) gives rise to the stem and leaves and is covered by a protective sheath (coleoptile).Herbaceous plants have soft, flexible aerial portions and commonly die back each year.Encyclopædia Britannica, Inc. Another system of classification, based on the duration of the life history, is particularly applicable to angiosperms of the temperate region.Beets, celery, cabbage, carrots, and turnips are biennials, but their flowers are rarely seen because they are harvested during the first season.
For instance, a potato isn’t a root; it’s actually a “tuber.” Peanuts are “technically” Root Vegetables, because they are tubers that grow off a rhizome underground, but they are treated as a nut (and so would you be, if you went looking for them next to the parsnips.).Technically, to be a “true” Root Vegetable, the vegetable should meet two conditions: grow underground and play the role of a root for the plant, absorbing moisture and nutrients from the ground.They are actually the taproot of the plant, which is formed from the very first root that the seed put out.Most hearty eaters, though, love their “root veg”, as they affectionately refer to them.Adherents of the Jainism religion do not eat any Root Vegetables, because harvesting them requires killing the whole plant. .