The value of cereals. What is a living? The role of cereals in human life The value of cereals in nature
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Presentation on the topic: Cereals
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Cereals Cereals (lat. Gramíneae), or Meat aphids (lat. Poáceae) - a family of monocotyledonous plants, which includes such well-known and long-used plants in the economy as wheat, rye, oats, rice, corn, barley, millet, bamboo , sugarcane. Cereals in nature are settled on all continents (one species is found even in Antarctica). They make up a significant part of the phytomass in many biocenoses, and in the steppes and savannas - the vast majority.
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Cereal family (Poaceae, Gramineae). Cereals play an outstanding role in human life and occupy a dominant position in the formation of a number of types of herbaceous vegetation - meadows, steppes, prairies and pampas, as well as savannahs. Approximately 900 genera and up to 11,000 species of cereals are known. Over 1500 species of cereals belonging to 198 genera naturally grow and are cultivated in the CIS countries. The appearance of cereals is quite characteristic and they are recognized without much difficulty.
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Botanical characteristics As a rule, cereals are perennial herbs of dry treeless territories. According to the type of root system, they are divided into three forms: rhizomatous (wheatgrass), loose bush (red fescue) and densely sod (fescue). Shoots are annual, erect, unbranched, ending in an inflorescence. There is no mechanism for secondary thickening of the stem. Branching occurs in the tillering zone or in the region of the inflorescence. The leaves are alternate, two-row, narrow, with an open sheath.
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General characteristics of vegetative and generative organs of cereals. Cereals are a cosmopolitan family, equally well represented both in the tropics and in countries with a temperate and cold climate. All species of the family are not capable of secondary growth due to the absence of cambium, but in representatives of the bamboo subfamily (Bambusoideae), powerful stems are woody, reaching 25–30 m in tropical species. There are many annuals among cereals, but perennial rhizomatous species predominate. Branching is more often concentrated near the base, where the so-called tillering zone is located. Features of branching in the tillering zone determine the life form of a particular cereal. The stem of almost all members of the family is straw. In the nodes it is made and most often hollow in the internodes.
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Grass leaves are alternate, divided into an open or closed leaf sheath enclosing the stem and a linear, subulate or lanceolate blade with parallel venation. At the base of the leaf blade, a membranous outgrowth, called the tongue, or ligula, is very often located. On the rhizomes, the leaves are modified and are more or less leathery scales. The sheaths serve as a protection for the internodes, which retain the ability for intercalary or intercalary growth for quite a long time. The dead moisture of the lower leaves protects the bases of the shoots from excessive evaporation or overheating. Ligula prevents the penetration of water, and with it - pathogenic fungi and bacteria into the vagina.
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Flowers of cereals are usually bisexual. Dioecious flowers are rare, for example in corn (Zea). They are collected in complex botryoid inflorescences of various types - panicles, brushes, cobs or ears. The basis of all these inflorescences are elementary inflorescences very characteristic of the whole family - spikelets (Fig. 1). Each such spikelet can contain from one to many flowers. A typical multiflorous spikelet consists of an axis, near the base of which are located two scales that do not bear flowers in the axils. These are the so-called upper and lower glumes. Often at the tops they end with bristly outgrowths - awns. Spikelet scales are modified leaves, and their expanded part corresponds to the leaf sheaths, and the awn corresponds to the plates.
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Flowers are located on the axis above the spikelet scales. Their number is of great systematic importance. Each flower sits on its own short axis, which in relation to the axis of the spikelet can be considered a second order axis. The flower axes emerge from the axils of the lower lemmas. Above the base of the lower lemma, on the opposite side of the flower axis, is the upper lemma. It often has two longitudinal ribs - a keel and a more or less noticeable notch at the top. The lemmas are also considered to be modified leaves.
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Above the upper lemma on the axis of the flower are two small colorless scales called lodiculae. It is believed that these are the remains of a perianth. Most cereals have 3 free stamens, but some groups (rice - Oryza and bamboos - Bambusa) have 6 stamens. There are cereals with 8 (12) stamens. There is no consensus regarding the structure of the gynoecium. It is generally accepted that it is based on 3 fused carpels, forming a single-celled upper ovary with one ovule, i.e., the gynoecium in cereals is pseudomonocarpous. The column ends with two feathery stigmas. Sometimes, for example, bamboos have stigmas 3. Grasses are wind-pollinated plants. Cross pollination.
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The fruit of cereals is a pseudomonocarp: a caryopsis in which the membranous pericarp fits snugly to the seed and sometimes sticks together with the spermoderm (seed peel). Rarely (in some tropical bamboos), the caryopsis has a succulent or woody pericarp. Most of the single seed is the endosperm. The embryo is relatively small.
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Classification and significance of the cereal family Plants belonging to about 30 genera are of significant agricultural importance, and a brief description will be given to them. Corn (Zea mays) is an annual monoecious plant. Rodi on - Mexico. In recent centuries, it has spread throughout the globe.
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Corn One of the largest herbaceous cereals, the stem reaches a height of 5 meters or more, the leaves are large, up to 12 cm wide; male flowers are collected in the apical inflorescence - panicle, consisting of spicate twigs (Fig. 3). Spikelets are located on branches in pairs; one on a leg, the second almost sessile. Each spikelet consists of 2 spikelet scales, between which there are 2 male flowers; glumes 2. Stamens, like the vast majority of cereals, 3.
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Female flowers are collected in axillary inflorescences - cobs. Each cob has a multi-layered sheath formed by leaf sheaths. One-flowered female spikelets with membranous spikelet and flowering scales are arranged in pairs along the cob in parallel rows. Of the two paired spikelets, one develops, the flower in the other spikelet remains barren. The style is long, filiform with a forked stigma. A bundle of columns protrudes from the cob by the time of flowering. The male flowers of this plant ripen a few days earlier than the female ones, which is how cross-pollination is achieved, carried out by means of the wind. Corn is a fodder, food and industrial crop. In terms of area occupied on the globe, it is second only to wheat. A huge amount of corn is grown for the preparation of si los. Stems, leaves and cobs of corn are rich in sugar and perfectly ensiled. Grain is used for livestock feed and for the production of a variety of foodstuffs. From corn stalks and corn cobs, the chemical industry manufactures a whole range of synthetic products. Dry leaves and stalks of corn are also used to make paper. Flower columns are harvested as a medicinal raw material (cholagogue). There are several varieties of corn and hundreds of varieties. Corn hybrids are distinguished by high yield.
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Sorghum (Sorghum) - 8 species grow in the CIS, of which only one is a perennial plant. All annual species are cultivated in culture. These are large plants with paniculate inflorescences. Sugar sorghum (S. caccharatum) - cultivated in Ukraine, the North Caucasus and the Lower Volga region. It reaches a height of over 2 m. The stem is filled with parenchyma rich in sugar. It is used for hay, green fodder, as a pasture plant and for silage. In young leaves, sometimes under conditions that impair growth, hydrocyanic acid accumulates, causing poisoning of animals. The grain is also used to feed livestock.
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Drought-resistant. Of great economic importance is the sorghum-huma hybrid, a perennial forage plant obtained by crossing sorghum with a perennial rhizomatous weed, humai (S. halepense). It is recommended for cultivation on the sandy lands of the arid zone. Sorghum drooping, or dzhugara (S. setiit), is cultivated in Central Asia as a grain crop. Grain is used for food and as a concentrated feed.
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The grass family (bluegrass) is a large family of monocots, including about 10,000 species. Cereals are evenly distributed throughout the globe, forming a grass cover. One species is found even in Antarctica. Mostly annual and perennial herbs. Shrub and tree forms (bamboo) are rare. This family includes the most important cultivated cereals - wheat, rye, rice, oats, corn, barley, millet, as well as many wild cereals - timothy, bluegrass, foxtail, etc.
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In addition, cereals include various types of reeds and bamboo.
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All types of cereals have a fibrous root system. The stem is a culm, hollow at the internodes and filled with tissue at the nodes. At the base of the internodes there is an educational tissue, due to which the stem grows in length. This growth of the stem is called intercalated. The leaves of cereals are narrow, simple, and consist of a long leaf blade and a sheath clasping the stem at the nodes. The leaf venation is parallel. Grasses branch by tillering, that is, they form new shoots in the lower part of the stem, near the ground. A cereal flower consists of two flowering scales - external and internal, which replace the perianth, three stamens with large anthers on long filaments and one pistil with two stigmas. One of the lemmas is sometimes elongated in the form of an awn.
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The structure of a cereal flower
Flower formula O2 + 2T3P1
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Flowers in cereals are collected in inflorescences - spikelets that make up complex inflorescences - a complex spike (rye, wheat, barley), panicle (millet), cob (corn), sultan (timothy grass) Spikelets consist of two spikelet scales covering one or more flowers.
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Cereals are pollinated by the wind, some (wheat) are self-pollinating. The fruit is a caryopsis. Cereals reproduce not only by seeds, they also have vegetative propagation by shoots and rhizomes.
lesson type - combined
Methods: partially exploratory, problem presentation, reproductive, explanatory-illustrative.
Target:
Students' awareness of the significance of all the issues discussed, the ability to build their relationship with nature and society based on respect for life, for all living things as a unique and priceless part of the biosphere;
Tasks:
Educational: to show the multiplicity of factors acting on organisms in nature, the relativity of the concept of "harmful and beneficial factors", the diversity of life on planet Earth and the options for adapting living beings to the entire range of environmental conditions.
Developing: develop communication skills, the ability to independently acquire knowledge and stimulate their cognitive activity; the ability to analyze information, highlight the main thing in the studied material.
Educational:
Formation of an ecological culture based on the recognition of the value of life in all its manifestations and the need for a responsible, careful attitude to the environment.
Formation of understanding of the value of a healthy and safe lifestyle
Personal:
education of Russian civil identity: patriotism, love and respect for the Fatherland, a sense of pride in their homeland;
Formation of a responsible attitude to learning;
3) Formation of a holistic worldview, corresponding to the current level of development of science and social practice.
cognitive: the ability to work with various sources of information, convert it from one form to another, compare and analyze information, draw conclusions, prepare messages and presentations.
Regulatory: the ability to organize independently the execution of tasks, evaluate the correctness of the work, reflection of their activities.
Communicative: Formation of communicative competence in communication and cooperation with peers, older and younger in the process of educational, socially useful, teaching and research, creative and other activities.
Planned results
Subject: know - the concepts of "habitat", "ecology", "environmental factors" their influence on living organisms, "connections of living and non-living";. Be able to - define the concept of "biotic factors"; characterize biotic factors, give examples.
Personal: make judgments, search and select information; analyze connections, compare, find an answer to a problematic question
Metasubject:.
The ability to independently plan ways to achieve goals, including alternative ones, to consciously choose the most effective ways to solve educational and cognitive problems.
Formation of the skill of semantic reading.
Form of organization of educational activities - individual, group
Teaching methods: visual and illustrative, explanatory and illustrative, partially exploratory, independent work with additional literature and textbook, with DER.
Receptions: analysis, synthesis, conclusion, transfer of information from one type to another, generalization.
The economic importance of cereals is very high. Almost all cereal plants belong to this family.
Independent work of students with a textbook
Using the text of the textbook (textbook by I.N. Ponomareva § 45; textbook by V.V. Pasechnik § 53), write down all the main plants of the cereal family used in human life and economic activity, and indicate the area of \u200b\u200btheir use
(About 5 minutes are allotted to complete the task, after which the students take turns calling one of the plants of this family, give its brief description and indicate the areas of its application. After completing this task, you can listen to the reports of some students.)
Oral reports of schoolchildren
(Several students prepare mini-reports in advance for 2-3 minutes about one of the most interesting representatives of the cereal family. The rest of the students draw up the information received in the form of a short summary or a small table.)
Plants of the grass family
| Plant | Characteristics of the plant and its scope |
| Wheat | About 20 species and a large number of varieties are known, in Russia there are about 10 species. Hard and soft varieties are common. Used in baking, as well as for the production of semolina, pasta, food alcohol |
| Barley | There are 26 species (of which 8 are in Russia), as well as a large number of varieties. Found wild in the southern regions of the country. Two types of barley are mainly cultivated: two-row barley and common barley. Used in brewing, for the manufacture of pearl barley and barley groats, as well as a fodder plant |
| Rye | About 8 species are known, in the flora of Russia 4. It is distributed and cultivated mainly in temperate regions and semi-mountainous regions of the Northern Hemisphere. Sowing rye is mainly grown as a spring (one-year) and winter (biennial) crop. Used in baking for the manufacture of black bread, for the production of food alcohol |
| oats | About 30 species, in Russia - about 15. Distributed mainly in the Mediterranean countries. The inflorescence is complex. Simple spikelets are collected in a sprawling panicle. Oats are cultivated as the most valuable food (groats) and fodder crops. |
| Millet | About 400 species are known, in Russia there are only 4. It grows mainly in tropical and subtropical zones. Has an inflorescence panicle. Unlike many cereals, its stems not only bush, but also branch. Drought-resistant non-frost-resistant plant. Millet is cultivated as a cereal plant, from which cereals (millet) and flour are obtained. Straw is used as feed and bedding for livestock, and also goes to the production of lower grades of paper. |
| Corn
| One species, subdivided into 8 subspecies. Not found in the wild. Flowers are heterogeneous. Male flowers are collected in a panicle inflorescence at the top of the stem, female flowers are in an ear inflorescence in the axils of the leaves. Monoecious plant. The stems can reach a height of 2-3 m. It is cultivated in southern and moderately warm latitudes on all continents. It is grown for grain, flour (in some countries it is used for making bread). It is used as a fodder plant, as well as for the manufacture of starch, alcohol, fiber, paper. In addition, it is an oilseed crop, used in medicine as a diuretic and choleretic agent (columns with stigmas) |
| Rice | There are 24 species and about 2000 varieties. In Russia, only 2 species are found. Widespread in tropical and sub-tropical countries. Hydrophytic plant. Spikelets are collected in paniculate inflorescences. Cultivate mainly two species, the most important is sowing rice. It is eaten, used as a raw material for the preparation of starch, alcohol, etc. Rice straw is used for making paper, as well as in applied arts |
| Sorghum | About 40 species are known, in Russia 3 (cultivated and weed). Drought tolerant plant. Distributed in tropical countries, mainly in Africa. Common sorghum is a plant up to 6 m high. It is cultivated as a grain, fodder and industrial crop. Grain is processed into starch, sugar, alcohol |
| Sugar cane | 15 species are known, they are not cultivated in Russia (in the former USSR - in the south of Tajikistan). Distributed in the tropics and subtropics of both hemispheres. Stems contain up to 15-20% sugar. Used to produce sugar, rum, alcohol, molasses |
Continuation of the teacher's story with elements of conversation
In addition to these plants, the family of cereals includes many cultivated food plants that are important in human life and economic activity. Let's list
just a few of them: French reygrass (a relative of oats), mogar, boron (Italian millet), gomi, chumiza, paidza (related to millet), as well as dzhugara (cultivated in Central Asia as a grain, fodder and industrial crop).
In addition to cultivated plants used by humans, many cereals are also environment-forming species (edificatory species) in plant communities of meadows, steppes and forest-steppes. (Some representatives of wild plants of the cereal family can also be introduced using the material presented in the reports of schoolchildren.)
quotation broad-leaved and water-leafed (Canadian rice) are bred in lakes and reservoirs as a protective and fodder plant for waterfowl.
Different kinds feather grass are often the main ones in the vegetation cover of the steppes. Many of them are valuable fodder plants (Lessing's feather grass), and some can cause serious injuries and even loss of livestock (hairy feather grass, or tyrsa), spoil animal hair.
canary canary found in the middle lane and in the south of Russia in the wild. It is bred as a fodder plant for many species of indoor birds (“canary seed”).
The most common wild plants of the grass family are meadow timothy, meadow foxtail, soddy meadow grass (soddy pike), team hedgehog, meadow bluegrass, meadow fescue, awnless bonfire, chicken millet, green foxtail. Almost all of them are specially grown as valuable fodder plants.
A relative of oats is the wild oat weed, which not only litters the grain, but also dries up the soil. Couch grass is a hard-to-kill weed (but the roots of couch grass are used in medicine), as well as Aleppo sorghum (Johnson's grass), chicken millet, etc.
stems of plants such as cane ordinary, veynik ground, used as fuel, raw material for the production of paper, mats are woven from them, mattresses are stuffed with them, and they are also used for buildings (roofs are covered).
Some plants of the family, such as the Cylindrical Emperor, the Large Shaker, are grown in decorative purposes (mainly for dry bouquets). Tolevitsa white, some bluegrass make out lawns.
A great contribution to the formation of modern ideas about the origin of cultivated plants was made by the Russian biologist N.I. Vavilov. He substantiated the theory of centers of origin cultivated plants, according to which the greatest variety of natural forms (species and genera) is located in the centers of their origin. N.I. Vavilov identified 5 main centers of origin of cultivated plants.
Frontal survey
Answer the questions.
What family name is similar to the name "cereals"?
What features are characteristic of plants of the cereal family?
What life forms are represented by plants of this family?
Name a plant of the grass family that has a lignified trunk.
What plants of this family are used by humans as food?
List the wild forage plants of the grass family.
Why are there no honey plants among the plants of this family?
Give examples of plants of the grass family that are medicinal.
What parts of these plants are used in medicine?
What is the name of the cereal fruit?
What is its difference from other dry one-seeded fruits?
What inflorescences are typical for plants of the grass family?
What is the name of the stem of cereals, what are its main features?
What pollination methods are typical for plants of this family?
What is the difference between species and variety?
What type of root system is typical for plants of the grass family?
Creative tasks.
Determine from which plants of the cereal family do semolina, oatmeal, millet, pearl barley, barley groats, from which - flour, pasta, bake oatmeal cookies? What other cereal seeds are used as food? What other plants of the cereal family do humans use as food? What cereals are made from plants of other families?
Assemble a collection of various rice seeds commercially available in your area (usually at least 5 types). Measure and describe each of the samples. Indicate its color, shape, transparency and other characteristic features. Find on the package information about the area of growth of this rice variety.
Assignments for students interested in biology.
Collect information about N.I. Vavilov. Find out from which regions of the globe various types of cereals cultivated by man originated. Map the centers of origin of various types of cereals
Prepare a report on interesting families of the monocot class that were not considered in the lessons.
Department of angiosperms. Cereal family. Variety of plants of the grass family
food plants. General characteristics of the families of cultivated plants.
food plants. Cereals. Wheat, rye, barley, oats, corn, rice, millet, etc. Part 1
FamilyCereals(bluegrass). Theory and practice of the Unified State Examination / OGE 2017. Biology.
Resources:
I.N. Ponomareva, O.A. Kornilov, V.S. Kuchmenko Biology: Grade 6: a textbook for students of educational institutions
Serebryakova T.I., Elenevsky A. G., Gulenkova M. A. et al. Biology. Plants, Bacteria, Fungi, Lichens. Trial textbook for grades 6-7 of high school
N.V. Preobrazhenskaya Biology workbook for the textbook by V. V. Pasechnik “Biology Grade 6. Bacteria, fungi, plants
V.V. Pasechnik. Manual for teachers of educational institutions Biology lessons. 5th-6th grades
Kalinina A.A. Lesson developments in biology Grade 6
Vakhrushev A.A., Rodygina O.A., Lovyagin S.N. Verification and control work to
textbook "Biology", 6th grade
Presentation Hosting
The importance of cereals in human life is so great and varied that it deserves special consideration. In the first place should be placed grain and cereal crops, of which wheat, rice and corn are rightly considered the main food plants of mankind. In terms of the area occupied by their crops - according to 1980 data, about 225 million hectares - wheat occupies the first place among all cultivated plants. Although it is mainly an extratropical crop, the development of a number of new varieties (especially Mexican ones) has significantly expanded the area occupied by this crop within the tropics.
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The number of wheat species (Fig. 215) in their narrowest scope reaches 20-27, the vast majority of which are known only in cultivation. The most ancient and, apparently, ancestral for all other wheat species are wild diploid (with 2n = 14) einkorn wheats: Boeotian (Triticum boeoticum) and Urartu (T. urartu), common in Southwest Asia (including in Southern Transcaucasia), in the Crimea and on the Balkan Peninsula and having spikes that easily break up into single-spike segments. In addition, the grains of these wheats are tightly enclosed in lemmas and are threshed out of them with great difficulty. In the process of cultivation of Boeotian wheat, einkorn wheat (T. monococcum) was formed, which differs from it in non-decaying ears, but still retains poorly threshed, so-called filmy grains, with a small number of them per spikelet (1, rarely 2). It was the grains of this wheat with a small admixture of the grains of its ancestor - Boeotian wheat - that were found during archaeological excavations in Iran and Turkey, dating back to the 65-54th century. BC e. It is assumed that much more productive tetraploid (with 2n = 28) and hexaploid (with 2n = 42) wheats arose not only as a result of the continued cultivation of einkorn wheats by ancient farmers, but also as a result of their hybridization with diploid species of the closely related genus Aegilops ( Fig. 215, 10). At the same time, tetraploid wheats were first formed, which are divided into a group of two-grain, or spelled, and a group of durum wheats, which got their name because of the glassy consistency of the protein-rich endosperm of caryopses. Among the spelt there are still wild-growing species with decaying ears: two-grain wheat (T. dicoccoides) and Ararat wheat (T. araraticum). The once widely cultivated emmer wheat (T. dicoccon) is now only occasionally sown as a cereal crop and in experimental plots. Durum wheat includes only cultivated species durum wheat (T. durum), from the grains of which a protein-rich flour is obtained, which is used to prepare high-quality pasta, fat wheat (T. turgidum), some varieties of which have branched ears (the so-called branched wheat) , and other, much less commonly cultivated species. If spelled still have filmy grains, then durum wheats already belong to the number of naked wheats with easily threshed grains.
The most "young", hexaploid wheats are represented by exclusively cultivated species, of which spelled wheat (T. spelta) and macha wheat (T. macha) are the oldest and still retained membranous grains. Like spelt, they are currently cultivated mainly in experimental plots. Finally, naked hexaploid soft wheat, or summer wheat (T. aestivum), which is a kind of pinnacle of wheat evolution, is the most productive and is cultivated almost throughout the globe. It is currently represented by more than 400 cultivated varieties, the number of which is increasing due to the ongoing selection of this wonderful crop in almost all countries. It should be noted that the experimental plots of the All-Union Institute of Plant Growing (Leningrad) have the richest living collection of wheat species and varieties, begun on the initiative and with the participation of the outstanding Soviet biologist N. I. Vavilov.
Like wheat, such important grain and cereal crops as rye, barley and oats originate from the Mediterranean countries, although they have retained closer ties with their wild relatives than cultivated wheat. Sowing rye (Secale cereale, Fig. 213) has been known in cultivation since the end of the Bronze Age, and currently occupies relatively large areas in Eurasia, North and South Africa, North America, southern South America and Australia. It is believed that rye was introduced into the culture by man due to a kind of natural selection. As wheat crops moved northward and into higher mountain regions, it often died and was replaced by more cold-resistant field weed rye (S. segetale), which had previously been a weed in wheat crops. Farmers were forced in such cases to collect grains of brittle-eared weed-field rye, from which later, through unconscious selection, sowing rye with non-decaying ears was formed. In addition to the two species of rye mentioned, several closely related perennial species, often combined under the name mountain rye (S. montanum), are found in the mountainous regions of the Mediterranean and Western Asia, including the Caucasus. It should be noted that recently obtained stable hybrids between rye and wheat - triticale (Triticale), which open up new opportunities for breeding these crops. Cultivated common barley (Hordeum vulgare, Fig. 213, 6-11) and two-row barley (H. distichon) are not only food (giving barley and barley groats, flour, as well as raw materials for the brewing industry), but also the most important fodder plants . The closest ancestor and probable ancestor of both cultivated barleys is wild barley (H. spontaneum) with ears splitting into segments during fruiting, distributed on stony and fine-earth slopes of the countries of the Eastern Mediterranean and Western Asia, often found there as a weed in crops of cultivated barley. In the archaeological finds of barley of the most ancient age (about 7000 years BC) in the territories of Jordan and Iran, only wild barley grains are found. Later, forms with partially decaying ears begin to occur, and then grains of the two-row barley that arose in the culture. Common barley, or multi-row barley (all 3 spikelets in groups of 3 spikelets are sessile and fully developed), which is economically the most valuable, apparently originated from two-row barley by mutation in a relatively more humid climate. At present, over 200 varieties of cultivated barley are known, the main areas under crops of which are in Eurasia, North Africa, North America and Argentina, and in Tibet barley is cultivated up to an altitude of 4600 m.
The economic use of cultivated oat species, of which the most important is sowing oats (Avena sativa), is in many respects similar to barley. In addition to such valuable dietary products as oatmeal, oatmeal and oatmeal, oats provide the best concentrated pet food. In addition, like barley, it is often sown in mixtures with or without legumes to obtain a very valuable forage green mass. Of approximately 25 wild-growing species of oats, wild oat (A. fatua), a common weed in oat crops, is closest to and, apparently, its ancestor. It is distinguished by an axis of spikelets that easily breaks up into segments along the joints and much more developed, articulated awns (Fig. 212, 1-4). It is likely that, like rye, oats entered cultivation as a weed in the earliest cultivated wheat species. Currently, oats are widely cultivated in Eurasia (in the north to 69.5 ° N) and North America.
Sowing rice (Oryza sativa, Fig. 196, 1-5) is the most important food plant in tropical and subtropical countries. How great its importance can be judged already because it serves as the main food for about 60% of the total population of the Earth. The areas occupied by this crop are especially large in East, Southeast and South Asia, which is probably the birthplace of sowing rice, since it has been known here since the Stone Age. In the oldest written sources of China, it is mentioned that already in 2800 BC. e. rice was widely cultivated and was listed among the 5 sacred plants, which also included millet, wheat, barley and soybeans. The ancestors of rice for sowing, probably, were species of this genus with spikelets falling off at the fruit at the joints, for example, wild rice (O. rufipogon) - a malicious weed of cultivated rice crops. Rice provides cereals and flour, as well as raw materials for the production of starch, beer, rice oil and other products. Rice straw is used for various crafts and paper making. Thanks to the development of new, early-ripening varieties, it became possible to expand the rice culture on the territory of the USSR. It began to be cultivated in the Kuban basin, in the Crimea, in the Volga delta, in the south of the Far East.
Rice is a moisture-loving plant, as a result of which its fields must be periodically flooded with water. True, there are also so-called upland varieties, but they are much less productive.
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Another most important food and fodder crop of mankind is corn, or maize (Zea mays, Fig. 209). Maize crops are found in almost all tropical, subtropical and warm temperate regions of both hemispheres, but the main areas of its cultivation are Central and South America, the USA, South and Southeast Europe, China, India and South Africa. Unlike all other cultivated cereals, corn is of American origin. In the southwestern United States, in Mexico, Central America, Peru and Chile, it has been known since ancient times, being one of the objects of worship (Fig. 216). The remains of cobs from the caves of Mexico and adjacent countries have an age of 3400-5000 years, determined using the radiocarbon method. The cobs of that time were small (often 5-7 cm long), the grains in them were also small and dressed with well-developed lemmas (i.e. membranous). Obviously, corn has since gone through a long evolutionary path towards increasing yields through unconscious, and then conscious selection. With regard to the origin of corn, not everything is clear yet, but it is very likely that its immediate ancestor or one of the ancestors is a weed plant common in Mexico (often a weed of corn crops) Mexican teosinte (Euchlaena mexicana, Fig. 209, 4-5) outwardly similar to corn, but having not cobs in the axils of the upper stem leaves, but two-row ears with an axis splitting into segments. The genus teosinte, which includes 4 species, of which 2 are perennials, is undoubtedly the closest relative of corn and often even joins this latter genus. In addition, Mexican corn and teosinte have the same number of chromosomes (2n = 20) and easily interbreed with each other. It is assumed that the evolution of maize could be constantly promoted by introgressive hybridization of its primary forms with teosinte species, and possibly with species of another closely related genus Trypsacum (Tripsacum, Fig. 209, 7).
It is worth noting that only recently in a remote mountainous region of Mexico, an American-Mexican expedition discovered a second perennial species of teosinte, called “diploid perennial corn” (Zea diploperennis; its author, X. Iltis, combines the genus teosinte with corn ). This species, in contrast to the previously known perennial teosinte - Euchlaena (or Zea) perennis - with 2n = 40, like cultivated corn, has a diploid number of chromosomes - 2n = 20. Thus, this finding opens up the possibility of successful crossing of corn with its perennial relative in order to create perennial cultivated corn, as well as to give corn other useful properties, in particular, greater cold resistance, since diploid perennial corn can grow at altitudes up to 3000 m. The economic use of corn is very diverse. Flour and cereals are obtained from its grains, and not quite mature grains and whole cobs are eaten both directly and in boiled form or in the form of canned food. In addition, corn starch is obtained from grains - a valuable raw material for the production of alcohol, glucose and other products, as well as corn oil. Corn cobs and green mass, both fresh and ensiled, are the best pet food. According to the structure and consistency of grains, numerous varieties and varieties of corn are divided into a number of groups that have different uses: siliceous, dentate, starchy, sugary, waxy, etc. A small-fruited group of varieties, the so-called "bursting" corn, is used to obtain a special treat called " snowflakes." Especially high yields of corn are obtained when sown with seeds of intervarietal and interlinear hybrids.
The cereals also include a number of crops that are of great nutritional and fodder importance. In the USSR, the most famous of them is sowing millet (Panicum miliaceum), apparently originating from the inland regions of Asia, where the weed subspecies of this species is predominantly distributed with spikelets falling off at the fruit at the joint - probably the direct ancestor of cultivated millet. In food, millet is used mainly in the form of cereals (millet), which is also an excellent concentrated feed. In South Asia, another species is used for the same purpose - Sumatran millet (P. sumatrense). Suitable for human nutrition, cereals and valuable concentrated food are also provided by many types of sorghum (Sorghum), the culture of which is especially common in Africa, South and East Asia, mogar, or chumiza (Setaria italica), African millet (Pennisetum americanum), caracana, or dagussa (Eleusine caracana), teff (Eragrostis tef), some species of barnyard grass (Echinochloa), rosichki (Digitaria) and buckwheat (Paspalum), already mentioned above in a brief review of the tribes. Apparently, the grains of many other cereals are also suitable for food, from which, through selection, new economically valuable crops can be obtained.
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Of the cereals in which other parts of the plant are not used as food, the first place is undoubtedly occupied by sugar cane (Saccharum officinarum, fig. 210, 1, 2, tab. 45, 1), which gives more than half of the world sugar production. The homeland of cultivated sugar cane has not been precisely established, but it is most likely that it was first introduced into cultivation in India. In Europe, they learned about sugar cane only after the campaign of Alexander the Great in India. In Asia (including Central Asia), the most common wild relative of sugar cane is wild sugar cane, or kalam (S. spontaneum), which is probably its ancestor. In East, Southeast and South Asia, young shoots of many bamboo species are of significant nutritional value. Thus, one of the factories on the island of Taiwan receives about 150 tons of shoots daily. Young shoots, zizania, cane and some other cereals are also used as a vegetable.
In second place in importance can be put the use of cereals as fodder plants for domestic animals. It has already been noted that many food grains, especially corn, oats and barley, provide excellent concentrated fodder and high quality green mass. In addition, cereals are the main components of natural hayfields and pastures, especially meadows and steppes of various types. The best wild-growing species in terms of their fodder qualities are not only introduced into the culture, but also represented by a number of cultivar varieties. Especially widely cultivated are meadow timothy grass, cocksfoot, meadow and reed fescue, awnless rump, perennial and many-flowered tares, meadow foxtail, giant bent grass, meadow bluegrass, high ryegrass, and in forest-steppe and steppe regions - comb, desert and brittle wheatgrass. Among fodder cereals introduced into cultivation in tropical and subtropical countries, naturally, species from the tribes of millet, sorghum, and hogweed predominate.
Many of the forage grasses listed above are also used in ornamental gardening as lawn plants. In the USSR, lawns made from species of chaff, fescue, bent grass, wheatgrass, ryegrass, and bluegrass are especially common. In the parks of the subtropics, such species that form dense mats as a one-sided narrow-furrow (Stenotaphrum secundatum) with blunt or even notched leaves at the top and fine-leaved zoysia (Zoysia tenuifolia) with very narrow bristle-like leaves are very good for arranging lawns. Large densely soddy species - pampas grass, Chinese miscanthus, whose shiny, pinnate feather grass, etc. - are planted in single plantings in parks, squares, gardens, and roadsides. Large moisture-loving cereals - reed, manna, zizania, etc. - are suitable for planting along the banks of reservoirs. Many of the ornamental grasses have variegated varieties (usually leaves with white longitudinal stripes), of which a variety of meadow grass cane (Phalaroides arundinacea) is especially often cultivated in the USSR, the shoots of which are added to bouquets. Especially for making dry bouquets, maned barley (Hordeum jubatum) with drooping long-awned ears, ovoid haretail (Lagurus ovatus) with hairy hairy ellipsoidal or ovate spike-shaped panicles, golden lamarckia (Lamarckia aurea) with one-sided golden panicles, large shaker (Briza maxima) are cultivated. , slightly swollen spikelets in a panicle and some other species. Some wild-growing cereals with beautiful panicles are also suitable for bouquets, for example, types of shaker and bison, winding Lerchenfeldia (Lerchenfeldia flexuosa), etc. For the manufacture of beads and other ornaments in South and Southeast Asia, the common cob (Coix lacryma-jobi, rice 210, 7-9). Beads made from its false fruits are found during excavations in Central Asia.
In gardens and parks of tropical and subtropical regions, as well as in greenhouses, bamboo culture is very common. In the USSR, on the Black Sea coast of the Caucasus and Crimea, species of phyllostachys, Japanese pseudosaza, bluish bamboo, and species of perennial are especially often cultivated.
Cereals are also used to fix moving sands, various kinds of embankments, and mine dumps. On the coastal dunes of Northern Europe, long-rhizomatous species are usually planted for these purposes - sandy sandy (Ammophila arenaria) and sandy grate (Leymus arenarius), and in the sandy deserts of Central Asia - cystic grate (L. racemosus) and selin species. The most “active” and unpretentious cereals with long rhizomes are suitable for fixing embankments and dumps of mines, especially creeping wheatgrass, awnless rump, ground reed grass, and in subtropical regions - pig fingered.
Only a few types of cereals contain aromatic substances used in perfumery, food industry and medicine. In the USSR, the best-known coumarin-containing bison (Hierochloe) and fragrant spikelet (Anthoxanthum) species are used to flavor various drinks. Essential oils used in perfumery and medicine (as an antiseptic) are obtained from species of vetiver (Vetiveria zizanioides), lemon beard (Cymbopogon citratus) and white beard (C. nardus) widely cultivated in the tropics. If in vetiver the essential oil - vetiverol - is found mainly in the roots, then in species of shuttle beard the essential oil with a strong citrus smell is found mainly in the leaves and scales of spikelets. All 3 species were originally introduced into cultivation in South and Southeast Asia (India, Burma, Sri Lanka, Malaysia), and the lemon beard is not known in the wild. Stigma branches of corn, rhizomes of couch grass and some other cereals are also used as medicines.
The technical application of cereals is very diverse. Durable and light bamboo stems are widely used as a building material and for various crafts in tropical and subtropical countries. Often they are used even as water pipes and other pipes. In the USSR, in Western Transcaucasia, there are also small plantations of leaf-grass, the stems of which are used mainly for the manufacture of ski poles and fishing rods. In non-tropical countries, reed stalks are used as a building material for small buildings, both directly and in the form of a compressed mass called "reeds". Reed stalks are also suitable for various crafts, in particular as a material for weaving. In addition, the fast-growing stalks of bamboo, reeds, and some other large grasses growing in large thickets are an excellent raw material for papermaking, replacing the more valuable wood of slow-growing trees. Paper of especially high quality is produced from the stems of the Western Mediterranean esparto feather grass (Stipa tenacissima), the fibers of which are also used to make ropes, ropes and coarse fabrics, and more recently also artificial silk. Other large cereals with very tough stems and leaves can be used similarly, such as koi shiny, Ravenna woolflower (Erianthus ravennae), cylindrical imperial, etc. Some varieties of sugar sorghum (Sorghum saccharatum) with fan-shaped panicles, sometimes distinguished as a special type of technical sorghum (S. technicum) are widely cultivated in many countries, including the USSR for the production of brooms. The very strong roots of some grasses, especially the Central American long-tailed epicampes (Epicampes macroura) and the Mediterranean cycad (Chrysopogon gryllus), are used to make brushes.
Cereals also have some negative significance in human life, although, of course, it is completely incommensurable with the benefits they bring. Among the cereals, there are many weeds of crops and plantations of various crops that cause significant damage to them. In non-tropical countries, the most common field weeds include creeping wheatgrass, rye brome, wild oats, field broom (Apera spica-venti), species of foxtail, blackberry "chicken millet" (Echinochloa crus-galli), annual bluegrass. Rice crops are often severely damaged by specialized weeds such as rice barnyard grass (Echinochloa oryzoides) and woolly hairy weed (Eriochloa villosa). In the fields and plantations of tropical and subtropical regions, the number of weed grasses increases significantly. The most famous of them are Aleppo sorghum, or gumai, Alang-alang emperor, pig fingered, two-eared buckwheat, Indian Eleusina (Eleusine indica), many types of foxtail, barnyard and millet. Some damage to forestry is caused by ground reed grass and reed reed grass growing on forest fellings. The "weeds" of our northern meadows are considered to be of little nutritional value, soddy pike (Deschampsia caespitosa) and white-beaked pike.
Plant life: in 6 volumes. - M.: Enlightenment. Under the editorship of A. L. Takhtadzhyan, editor-in-chief corr. USSR Academy of Sciences, prof. A.A. Fedorov. 1974 .
What is the meaning of the cereal family in nature and human life, you will learn from this article.
The value of cereals
Grasses are perennial (rarely one- or two-year-old plants). Underground shoots sometimes change into rhizomes. For example, in bamboo, the stem is woody. Most cereals are characterized by the structure of a hollow stem in the internodes - a culm. Sugarcane and corn have loose stems with storage tissue. Almost every stem has intercalary growth. In cereals, the leaves are sessile, elongated, simple, alternate, with parallel venation. The root system is fibrous.
The value of cereals in human life
Representatives of cereals are excellent fodder grasses. They play an important role in pastures and grasslands. Meadow fescue, couch grass, awnless bonfire are especially valued. There are also such cereals that animals do not like to eat - white-bearded and pike. The economic importance of cereals for humans is determined by their nutritional value. They are considered important food and cereal plants. The most important of them are rice, corn and wheat. Pasta and bread products, cereals are made from their grains. In tropical countries, sugar cane is grown, the elongated stems of which contain up to 20% sugar. In subtropical and tropical countries, bamboo is grown, which is used as a building material. It is used to make decorative items and furniture. High quality oil is produced from corn kernels. Rice grains are not only eaten due to the presence of starch in the composition, but also refined varieties of powder are produced from them. Hats, baskets, the best grades of paper, and furniture are made from rice straws. Many cereals are ornamental plants.
The value of cereals in nature
Cereals are specially grown in beams and ravines to fix sands and prevent soil shedding. With their roots, they loosen and enrich the soil. Also, cereals play a negative role: among them there are weeds - foxtail, wild oat, wheatgrass. They have a well-developed rhizome and reproduce vegetatively. Therefore, crops of cultivated plants can be drowned out in the shortest possible time.
