методичка. Агрономического профиля
 Скачать 254.22 Kb.
|
|
Parts of flower A complete flower is made up of four principal parts, namely a) sepals, b) petals, c) stamens and d) a pistil. The number and position of the floral parts vary in different species and it frequently happens that one or more of them is missing, in which case the flower is said to be incomplete. The flowers of the small grain lack both petals and sepals, and thus they are incomplete. Neither sepals nor petals are directly involvedin seed production. The former comprise the outermost part of the flower, protecting and supporting the other parts. They are usually green and leaf-like. Sometimes, however, they are brightly colored rather than green but it is not true for common cereals. The petals are located immediately to the inside of the sepals and unlike the latter they are generally bright-colored but it is not true for grasses, including the common cereals. When taken together the petals are referred to as the corolla. The two remaining parts of the flower, namely, the stamens and the pistil, form the reproductive organs of the flower and are both absolutely essential for reproduction and seed production. It is in the stamens that the pollen grains which are necessary for fertilization are produced. The pistil should be looked for in the center of the flower. It consists of the style bearing on its top the stigma and a swollen base which is referred to as ovary. Within the ovary there are the egg-cells. Pollination and Fertilization For fertilization to occur the egg-cells must be fertilized by the pollen grains. The transfer of pollen from the stamens to the stigma of the pistil is spoken of as pollination. In self-pollinated flowers pollination results from close proximity of stamens and stigma. In some cases pollination occurs before the flower opens, as in most of the cereals and in some grasses; as a more general rule, however, flowers are pollinated from the flowers of other plants of the same species. Such plants are spoken of as cross-pollinated. Pollination is effected in some plants by wind while others have insect pollination. After the pollen has been transferred to the stigma some further processes take place which result in the fertilization of the egg-cells. The latter then develop into seeds. Notes: In addition – кроме того, к тому же, вдобавок so as (to + Inf.) – для того, чтобы (to) be involved – участвовать в, быть связанным с … but it is not true for common cereals – но этого не бывает у обычных злаковых (to) be referred to as – называться; упоминаться как (to) result from – происходить от; получаться из (to) result in – приводить к; давать в результате 3. Find in the text the following word combinations: производить семена, процесс размножения, части полного цветка, самая наружная часть цветка, листоподобный, ярко окрашенные лепестки, перекрестноопыляющееся растение, растения, опыляемые насекомыми. 4. Fill in the blanks with appropriate words and word combinations from the text. 1. A seed is always preceded by a … . 2. A complete flower is made up of four … parts: …, …, … and … . 3. The flowers of … lack both … and … . 4. Taken together the … are referred to as the … . 5. Commonly flowers are … from the flowers of other plants of the same … . 6. The … are located immediately to the inside of the … . 5. Agree or disagree with the following statements (True or False). 1. The transfer of pollen from the stamens to the stigma of the pistil is pollination. 2. Within the ovary there are the egg-cells. 3. The pistil is in the center of the flower. 4. The petals taken together are referred to as the corolla. 5. The stamens and the pistil form the reproductive organs of the flower. 6. Sepals comprise the outermost part of the flower. 7. The flowers of the small grain have both petals and stamens. 8. A complete flower is made up of 5 principal parts. 9. The number and position of the floral parts vary in different species. 10. A flower is preceded by a seed. 11. The flower is the part of the plant which is formed for leaf production. 6. Say it in English using words from the vocabulary list. 1. Цветок – самая заметная часть растения. 2. Цветы различаются по цвету, размеру и форме. 3. Все растения, образующие семена, имеют цветки. 4. Некоторые цветки очень простые, они имеют только основные части. 5. Цветы необходимы, чтобы образовывать семена. 6. Основные части цветка это: лепестки, чашелистики, тычинки и пестик. 7. Чашелистики покрывают цветковую почку и защищают ее от насекомых. 8. Термин чашечка включает все чашелистики цветка. 9. Лепестки часто бывают ярко окрашены, чтобы привлекать насекомых. 10. Тычинки являются мужским органом цветка, а пестик – женским. 7. Answer the following questions. What is a flower? 2. What is a seed usually preceded by? 3. By what means do most plants reproduce? 4. What is a complete flower made up of? 5. What flower is incomplete? 6. What parts do the flowers of the small grains lack? 7. Are sepals and petals involved in seed production? 8. Where are petals located? 9. What is the corolla? 10. What are the reproductive organs of the flower? 11. Where are the pollen grains produced? 12. What does the pistil consist of? 13. Where are egg-cells produced? 14. What process is known as pollination? 15. What plants are spoken of as cross-pollinated? 8. Choose 8–10 key sentences from text A and retell it using them. Text B 1. Get acquainted with text B and find in the text answers to the following questions: What is the biological function of the flower? 2. What do seeds serve for? 3. How are the groupings of flowers called? 4. What are the means of pollen transfer from one flower to another? 5. In what way have modern flowers been influenced by humans? 6. How do people beautify their life? 7. What do flowers provide man with? 8. What flower vegetables do you know? 9. Name some edible flowers. Functions of Flowers A flower, also known as a bloom or blossom, is reproductive structure found in flowering plants. The biological function of a flower is to mediate the union of male cells with female cells in order to produce seeds. The process begins with pollination, is followed by fertilization, leading to the formation and dispersal of the seeds. For the higher plants, seeds are the next generation, and serve as the primary means by which individuals of a species are dispersed across the landscape. The grouping of flowers on a plant is called the inflorescence. In addition to serving as the reproductive organs of flowering plants, flowers have long been admired and used by humans, mainly to beautify their environments but also as the source of the food. Each flower has a specific design which best encourages the transfer of its pollen. Some flowers attract and use insects, birds to transfer pollen from one flower to the next. Flowers also attract pollinators by scent and color. Some species of orchids, for example, produce flowers resembling female bees in color, shape, and scent. Flowers are also specialized in shape and have an arrangement of the stamens that ensures that the pollen grains are transferred to the bodies of the pollinator when it lands in search of its attractant (such as nectar, pollen, or a matte). Flower evolution continues to the present day; modern flowers have been so much influenced by humans that many of them cannot be pollinated in nature. The transition to flowering is one of the major phase changes that a plant makes during its life circle. Flower formation is initiated at the ends of stems and involves a number of different physiological and morphological changes. The first step is the transformation of the vegetative stem primordial into floral primordial. People grow flowers around their homes, dedicate entire parts of their living space to flower gardens, pick wildflowers or buy flowers from florists. Flowers provide less food than other major plants parts (seeds, fruits, roots, stems and leaves) but they provide several important foods and spices. Flower vegetables include broccoli, cauliflower, and artichoke. The most expensive spice, saffron, consists of dried stigmas of a crocus. Other flower spices are clovers and capers. Hundreds of flesh flowers are dipped in bread crumbs and fried. Edible flowers include nasturtium, chrysanthemum, carnation, cornflower, canna and sunflower. Flowers can also be made into herbal teas; they are infused into tea both for their fragrance and medical properties. Notes: inflorescence – соцветие saffron – шафран capers – каперсы 2. Skim the text again and: a) find the sentence in the text, which enumerates the functions of the flower; b) describe the process of pollination; c) say, what attracts pollinators to the flower; d) say, who takes part in the process of pollination; e) say, how is flower produced. 3. Make up the plan of text B and retell it. Unit 5 Grammar Revision: Infinitive (Part I) Text A: Seed Text B: Seedbed Preparation Инфинитив (Infinitive) Инфинитив (the Infinitive) – это неличная форма глагола, которая называет действие. Инфинитив является основной (или I) формой глагола и представляет глагол в словаре. Признаком инфинитива является частица to: to help – помогать, to read – читать. Инфинитив употребляется без частицы to в следующих случаях: You had better go now. –Лучшеуйди / идисейчас. Imustseeyouatonce. – Мне надо сейчас же встретиться с тобой. Таблица 4 –Формы инфинитива
Инфинитив в форме действительного залога обозначает действие, произведённое лицом, выраженным в предложении подлежащим, а в страдательном залоге – действие, направленное на это лицо. Iliketohelp. – Я люблю помогать. Ilike tobehelped. – Я люблю, когда мне помогают. Инфинитив в Indefinite Active обозначает действие, не уточняя характер его протекания. Инфинитив в Continuous Active подчеркивает длительность действия. Shelikes towrite letters. –Она могла писать письмо. Shemust be still writing.– Она, должно быть, все еще пишет. Неперфектный инфинитив выражает действие, одновременное с действием глагола-сказуемого (или следующее за ним). Перфектный инфинитив выражает действие, предшествующее действию, выраженному глаголом-сказуемым. I am glad to study at the University. – Ярад, чтоучусьвуниверситете. I am glad to have studied at the University.– Ярад, чтоучилсявуниверситете. 1. Read and translate the following sentences paying attention to the different forms of Infinitive and their meaning. 1. I’d like to go home early today. 2. It’s nice to be sitting here. 3. I’m glad to have left school. 4. He doesn’t like to be interrupted while he’s working. 5. I remember to have been asked this question. 6. I’d like to have been sitting there when she walked in. 7. She asked me not to forget to post the letter. 8. I was sorry not to have phoned you. 9. We must make careful plans. 10. I would rather go by myself. Translate the following sentences. Pay attention to difference in the translation of attributes, expressed by Participle constructions and the Infinitive. 1. The soil to be used as a seedbed should be warm, moist mellow. 2. The soil cultivated when it is too wet will not provide conditions for normal plant growth. 3. Seed planted deep enough will have a sufficient supply of moisture and nutrients. 4. Developing a new variety to be cultivated in a given area one should know its soil and climatic requirements. 5. We were given the seed to be used for sowing. 6. The seedbed prepared in spring is to provide the proper environment for seed germination. 7. Fertilizers to be applied must be of highest quality. 8. The yield of root crops produced last year was rather low. 9. The yields to be obtained on our farm greatly depend on soil conditions. 10. The increase in corn yield to be produced greatly depends on the amount and quality of fertilizers added to the soil. Text A Vocabulary list reproductive part – репродуктивная часть embryonic plant – зародышевое растение generation – поколение seed coat – семенная кожура germ – зародыш dormant state – состояние покоя food supply – запас питательных веществ endosperm – эндосперм seed leaves – семенные листочки to germinate – прорастать viability – жизнеспособность viable – жизнеспособный storage conditions – условия хранения to mature – созревать to swell – набухать clover – клевер pressure – давление to cause – заставлять, вызывать stands – всходы germination – прорастание cereal – злак 1. Translate the following word combinations into Russian: embryonic plant, new generation, plant in a dormant state, dry seeds, to germinate properly, high viability, food supply, the amount of required heat, reproductive part, storage conditions, air-dried seeds, seed coat, the kinds of seeds, moisture content, to retain vitality. 2. Read and translate text A. Seed Ordinarily the plant is divided as follows: the root system, stems and leaves and, the reproductive part made up of flowers, fruits and seeds. Seed A seed must be looked upon as an embryonic plant of the new generation with enough stored food to start it off in life and seed coats for protection. Thus a seed consists of: a) the embryonic plant in a dormant state known also as the embryonic or germ; b) the food supply stored either inside the embryo or, as with the cereals, around it on the outside, in which case it is called the endosperm, c) one or more seed coats surrounding and protecting the other parts. Some seeds as those of the legumes do not contain an endosperm, the entire supply of food in them being stored inside the embryo in its seed leaves or cotyledons. Thus, in the seed the plant stores up food to be used at some future time. It is on this stored food that the young plant feeds until it is sufficiently developed to provide food for it. Germination The dry seeds being placed under favorable conditions; the young dormant plant begins to grow. This change from a dormant state to one of activity is known as germination. For seeds to germinate well they should be well developed and have high viability. The length of time during which the seed remains viable depends on the species and the storage conditions as well, the maximum period for most species varying from 2 to 10 years. The main factor affecting the viability of seeds is their moisture content. For seeds to retain their vitality well they should be thoroughly air-dried as soon as mature and kept in dry place. For germination to occur three conditions are necessary: sufficient heat, moisture and air should be present. Unless all three of these conditions are met, the seed will not germinate properly. The amount of required heat will vary with the kinds of seeds. Some seeds, as those of clover and oats, will grow at rather low temperature while the requirement of corn seeds is higher. 3. Find in the text the following word combinations: запасать питательные вещества, благоприятные условия, зародышевое растение, хранить в сухом месте, семенная кожура, высокая жизнеспособность, хорошо прорастать, растение в состоянии покоя, содержание влаги. |