Answer: Biology:
Metabolism includes assimilation and alienation.
Assimilation (also called anabolism) refers to the process that organisms transform nutrients obtained from the external environment into their own components and store energy.
Simply put, assimilation is to turn non-self into self.
Assimilation is an important process in biological metabolism, and its function is to recombine digested nutrients to form organic matter and store energy. Because the material elements in food are stored in the body, it is called "assimilation".
At the same time, assimilable organisms are divided into autotrophs and heterotrophs.
Autotrophic organisms: organisms that can synthesize their own organic matter from inorganic substances belong to autotrophs. Autotrophic organisms: cyanobacteria, nitrifying bacteria, green plants, etc.
Heterotrophs: Organisms that can only ingest ready-made organic matter from outside belong to heterotrophs. Heterotrophs: Most living things.
Generally speaking, digestion is a typical example of assimilation.
The same is true of photosynthesis, because in this process, plants use carbon dioxide and sunlight to make their own food (organic molecules) and store these organic molecules in the plants themselves.
Generally speaking, all higher plants and some lower plants, as well as a small number of bacteria can carry out photosynthesis.
(assimilation)
One of the important concepts in sociology and other disciplines. Assimilation is a physiological concept, which refers to the digestion process of food in the body. Sociology borrows this concept, which refers to the gradual or slow process in which different cultural units merge into a homogeneous cultural unit.
2. What is alienation?
A: Metabolism includes assimilation and alienation.
Simply put, alienation means turning yourself into someone else.
Alienation is the catabolism of organisms. It is a process in which organisms convert macromolecules into small molecules and release energy. Breathing is an important process in alienation.
Organisms can be divided into aerobic organisms, anaerobic organisms and facultative organisms according to whether they need oxygen for breathing.
The essence of alienation is that macromolecules in organisms, including protein, lipids and sugars, are oxidized and release energy in the process of oxidation. Part of the energy is absorbed by the reaction of converting ADP into ATP, and ATP is used as an energy storage material for other needs.
In aerobic alienation, sugars, lipids, protein, etc. Changing into compounds containing carboxyl groups and performing decarboxylation enzymatic reaction to generate carbon dioxide; Hydrogen, on the other hand, is activated by dehydrogenase, transmitted through respiratory chain in mitochondria, reduces substrate, gradually releases energy, and is oxidized to generate water.
Anaerobic alienation lacks oxygen as oxidant, which can not completely decompose macromolecules and release their energy.
3. Is it better to grow vegetables in greenhouse, because the more CO2, the weaker the respiration and the stronger the photosynthesis?
Please refer to: greenhouse vegetable cultivation techniques
I. Greenhouse construction
(1) Type and structure of scaffolding. There are many types and structures of plastic greenhouses. At present, there are two kinds of prefabricated galvanized thin-walled steel pipes (referred to as steel pipe greenhouses) and bamboo circular arch greenhouses widely used. It is mainly used for early-maturing cultivation in spring and delayed cultivation in winter of tomatoes, sweet (hot) peppers, eggplants and cucumbers in Natsuna, as well as seedling raising and hybrid seed production. There is also a bamboo shed, which is often used alone or in combination with a greenhouse (that is, a shed is built on the greenhouse) for seedling raising and early cultivation of eggplant and melon vegetables in winter and spring.
There are two specifications for steel pipe greenhouses: one is that the center is 2.2 meters high, the width span is 4.5 meters, the length is 20 meters, and the area is 90 square meters; The other is that the center is 2.5 meters high, 6 meters wide and 30 meters long, with an area of 180 square meters. The service life is generally 15 years.
In order to reduce the production cost, bamboo shed can also be used. Scaffolding is made of bamboo or small logs, about 2 meters high and 4-5 meters wide, with a general service life of 3 years.
(2) Covering materials: Greenhouse covering materials are as follows:
1. Ordinary membrane: made of polyethylene or polyvinyl chloride, with a thickness of 0. 1mm, colorless and transparent. The service life is about half a year.
2. Multifunctional long-life film: it is made by adding proper amount of anti-aging materials and surfactants during polyethylene blow molding. The multifunctional membrane produced by Zhejiang Guangxin Plastic Factory has a width of 7.5 meters and a thickness of 0.06 mm, its service life is twice as long as that of ordinary membrane, and the greenhouse temperature at night is higher than other materials 1-2℃. Moreover, the film is not easy to form water droplets, with good covering effect, low cost and high benefit.
3, grass quilt, grass fan: woven from straw, good thermal insulation performance, is a night thermal insulation material.
4. Polyethylene high foaming film: it is a white plastic film with many bubbles, with a width of 1 m and a thickness of 0.4-0.5 cm. It is light and can be rolled up, and its thermal insulation is similar to that of grass quilt.
5. Non-woven fabric: a kind of polyester filament, which is not woven or spun. There are two kinds: black and white. They have different densities and thicknesses. The common specification is 50g/? In addition to heat preservation, it is often used as a sunshade net.
6. sunshade net: a plastic woven net. Commonly used are black and silver gray, and there are several density specifications with different shading rates. It is mainly used for sun protection and rain protection in summer, and can also be used for thermal insulation and covering in winter.
(3) Greenhouse construction: choose a place with sufficient sunshine, shelter, high dryness, good drainage and no soil infectious diseases to build a greenhouse.
(4) Maintenance of plastic film: When the film is fastened, the mechanical damage of the shed film, especially the bamboo shed, should be avoided as far as possible. Before the film is buckled, the protruding part of the frame surface should be flattened or wrapped with old cloth. When fixed with a spring, the card slot should be padded with an old newspaper. In addition, attention should be paid to avoid long-term contact between old and new films, so as not to accelerate the aging of new films. Be careful when ventilating.
Film freezing or exposure will accelerate aging. When the steel pipe is exposed to the sun in summer, the temperature can rise to 60-70℃, thus accelerating the aging and crushing of the film.
In the process of using the film, it is inevitable that there will be holes, so it should be repaired with glue or tape in time.
Second, the environmental characteristics and supervision
Because the greenhouse is covered with plastic film, it forms a special microclimate which is relatively closed and different from the open field. In order to cultivate vegetables in greenhouse, we must master the characteristics of greenhouse environment and take corresponding control measures to meet the conditions of vegetable growth and development, so as to obtain high quality and high yield.
(1) Environmental conditions in the greenhouse:
1. illumination: it depends on the solar radiation intensity outside the shed, the optical characteristics of the covering material and the pollution degree. The light transmittance of new plastic film is 80-85%, and the light transmittance of old film polluted by dust and soil is often below 40%. The water droplets condensed on the film surface can reduce the illumination in the shed by 10%-20% due to the diffusion of water droplets. The shed frame, the film pressing line and the frame material of tall vegetables will be blocked, so the factors that weaken the light in the shed should be avoided and eliminated as far as possible in the management of the shed.
2. Temperature:
(1) Temperature variation law: The daily variation trend of temperature in greenhouse is the same as that in open field, but the temperature difference between day and night changes greatly. There is plenty of sunlight in the daytime. If the temperature in the film closed shed rises rapidly, the highest temperature can reach 40-50℃, which is more than 20℃ higher than that outside the shed. The effect of warming in rainy days is poor, and the lowest temperature in the shed at night is generally higher than that outside the shed 1-3℃. The ground temperature in the shed is more stable than the air temperature, usually 10-20℃. The temperature in the greenhouse also changes with different locations. The greenhouse is horizontally distributed with high middle and low sides, so the plants in the middle of the greenhouse are often higher than those on both sides. Greenhouse is vertically distributed. The sun shines during the day, and the temperature is high and low, but it is the opposite at night and cloudy days.
(2) Inversion phenomenon: In a polyethylene-covered greenhouse, there is a cool and sunny night in winter, and the temperature inside the greenhouse is sometimes lower than that outside the greenhouse. The reasons are as follows: at night, the temperature outside the shed is higher than that in the lower part. Due to the disturbance of wind, heat can be replenished from the high altitude outside the shed, but it can't be obtained in the shed because of the obstruction of shelter; It is cool during the day in winter, and the soil stores less heat. In addition, the polyethylene film has high long-wave emissivity, poor thermal insulation, large effective thermal radiation from the ground and much heat dissipation, which leads to the phenomenon that the temperature inside the shed is lower than that outside the shed.
(3) Temperature control: The temperature control of greenhouse is mainly carried out by ventilation and heating. Uncovering the film is the most commonly used method to reduce and control the air temperature in the shed during the day. The use of shading materials can reduce the amount of light received in the shed and prevent the air temperature in the shed from being too high.
In winter, in order to reduce heat loss and improve air temperature and soil temperature, the greenhouse film should be covered as tightly as possible. You can set up a wind wall around the greenhouse, build a small shed in the greenhouse, and then cover it with grass, non-woven fabric, foam plastic and other layers. Heating measures can also be taken to raise the temperature, such as using electric heating wires to raise the soil temperature, and areas with conditions can use the waste heat from factories, geothermal water or coal stoves to raise the temperature in the shed. Water bags (plastic bags filled with water) are built in greenhouses. Water bag takes advantage of the high specific heat of water, which absorbs a lot of solar energy during the day, converts it into heat energy and stores it, and gradually releases it at night, which can increase the temperature of greenhouse.
3. Air humidity control
(1) Variation law of air humidity in greenhouse: The plastic film is tightly sealed, which hinders the exchange between the air in greenhouse and the outside air, and the water vapor generated by soil evaporation and leaf transpiration is difficult to disperse. So the humidity in the shed is high. During the day, under the condition of ventilation, the relative humidity of air in the greenhouse is 70-80%. It can reach more than 90% in rainy days or after irrigation. The relative humidity of air in the shed decreases with the increase of temperature, and it is often 100% at night. The wet air in the shed condenses into water film or water drops when it is cold, and adheres to the inner surface of the film or plant.
(2) Control of air humidity: Excessive air humidity in the greenhouse not only directly affects the photosynthesis of vegetables and the absorption of mineral nutrients, but also facilitates the germination and infection of pathogen spores. Therefore, the relative humidity in the shed can be effectively reduced by ventilation to promote the exchange of high humidity air in the shed and low humidity air outside. Heating the hot wire in the shed can also reduce the relative humidity. Using drip irrigation technology combined with plastic film mulching cultivation to reduce soil moisture evaporation can greatly reduce air humidity (about 20%).
4. Air composition in the shed: The film coverage limits the flow and exchange of air in the shed. In the case of tall vegetables and plants and lush leaves, the concentration of carbon dioxide in the air in the shed changes greatly. Before sunrise in the morning, due to crop respiration and soil release, the carbon dioxide concentration in the shed is 2-3 times higher than that outside the shed (about 330 ppm); After 8-9 o'clock, with the enhancement of leaf photosynthesis, it can be reduced to below 100PPM. Therefore, ventilation should be carried out as appropriate after sunrise to replenish carbon dioxide in the shed in time. In addition, artificial carbon dioxide fertilization can be carried out, and the concentration is 800- 1000 ppm, which can be used after sunrise and before ventilation. Artificial application of carbon dioxide, in the case of weak light and low temperature in winter and spring, has a very significant effect on increasing production.
In the low temperature season, greenhouses are often sealed and insulated, and it is easy to accumulate toxic gases, such as ammonia, nitrogen dioxide, sulfur dioxide, ethylene and so on. When the ammonia gas reaches 5PPM in the greenhouse, the tip of plant leaves will be soaked in water, and then turn black and die; When nitrogen dioxide reaches 2.5-3 ppm, irregular green and white spots appear on the leaves, and in severe cases, all the leaves are bleached except the veins. The production of ammonia and nitrogen dioxide is mainly caused by improper use of nitrogen fertilizer. The production of carbon monoxide and sulfur dioxide is mainly caused by coal fire heating, incomplete combustion or poor coal quality. Because the aging of plastic film (plastic pipe) will release ethylene, which will lead to premature aging of plants, so excessive use of ethylene products is also one of the reasons.
In order to prevent the accumulation of harmful gases in the shed, fresh manure can not be used as base fertilizer or topdressing; It is forbidden to use ammonium carbonate for topdressing. When topdressing with urea or ammonium sulfate, water or cover the soil in time after acupoint application. Fertilization amount should be appropriate, not excessive; Proper ventilation is also needed in low temperature season to eliminate harmful gases. In addition, the coal used is of good quality and should be fully burned. If possible, use hot air or hot water pipe to heat it, and exhaust the burnt waste gas outside the shed.
5, soil moisture and salt:
The distribution of soil moisture in greenhouse is uneven. The soil near the two sides of the shed has more water infiltration outside the shed, and the water droplets flowing on the shed film have higher humidity. The middle of the shed is relatively dry. Cucumber and eggplant planted in greenhouse in spring, especially those cultivated with plastic film, often have insufficient soil moisture, which seriously affects the quality. It is best to lay a hose drip irrigation belt and fertilize water at any time according to actual needs, which is an effective measure to increase production. Due to the long-term coverage of greenhouses, the rainwater leaching is insufficient, and the salt moves from bottom to top with groundwater, which is easy to cause excessive accumulation of salt in cultivated soil and cause salinization. Therefore, we should pay attention to proper deep ploughing and application of organic fertilizer to avoid long-term application of fertilizers containing chloride ions or sulfate ions. Topdressing should be light, and it is best to test soil and fertilize. Every year, there must be a certain period of time without plastic film, or in summer, only the sunshade net is covered for shading cultivation, so that the soil can be leached by rain. When soil salinization is serious, flooding can be used to suppress salt, and the effect is very good. In addition, using soilless culture technology is the fundamental measure to prevent soil salinization.
Three Cultivation Techniques of Greenhouse Vegetables in Dalangdian Township
Third, the annual stubble arrangement of greenhouse vegetables
Greenhouse only has early cultivation of eggplant in spring, which only takes 4-5 months a year, so the utilization rate and benefit are not high. If the greenhouse is also used for autumn, winter and Xia San cultivation, seedling raising and seed storage, the production benefit can be improved.
(1) seedling type; It is characterized by seedling raising in winter → early maturity cultivation in spring → seedling raising in summer → autumn and winter cultivation. In winter, seedlings are usually raised from June 1 1 to the middle and late March of the following year, and seedlings of solanaceous fruits, melons and beans are cultivated. Sow in the middle and late March and cultivate early in spring. Raise seedlings in summer from June to August, such as cabbage, cauliflower and tomato. Plant autumn tomatoes, cucumbers, leafy vegetables, celery, onions and garlic in autumn and winter.
(2) Cultivation type: mainly cultivated vegetables, combined with seedling raising. There are two main forms: one is to plant eggplant, tomato, cucumber and pepper in early spring, fast-growing vegetables in summer, cucumber, tomato, cabbage and cauliflower in autumn, celery, spinach, lettuce and onion and garlic in winter; The second is intercropping, in which tomatoes and peppers are planted in early spring, and loofah is planted next to the arch pole in the greenhouse in April-May, so that it can climb along the arch pole, or in the later stage of tomato growth, wax gourd is planted in the border, and vines are climbed by tomato brackets; Planting lettuce and cabbage in autumn; Seedling raising is carried out in winter.
(3) Seed-keeping: There are two main ways: one is to keep seeds of eggplant and melon in spring, and the stubble-keeping way is to raise seedlings in winter → keep seeds in spring → cultivate celery and cabbage in autumn; One is to collect and reserve seeds mainly from Cruciferae self-incompatibility in winter and spring, raise seedlings in summer and cultivate eggplant and melon vegetables in autumn.
Four, several forms of greenhouse vegetable cultivation
(1) Early Spring Cultivation in Natsuna
Early-maturing cultivation of eggplant and melon vegetables is the most common project in greenhouse cultivation. Open field cultivation is generally sown in late March to mid-April, and harvested in early May to July. Greenhouse cultivation can be planted1-March in advance and harvested from late March to July. Early listing, high yield, long flowering and fruiting period and obvious economic benefits. In addition, according to market demand, warm green leafy vegetables such as amaranth, auricularia auricula and water spinach can be planted in advance and listed in advance.
1. Variety (combination) selection: early-maturing tomato varieties are Zaofeng, Japanese Red× Aihong; Zheza No.5, Su Kang No.4 and No.5 were selected as mid-mature varieties, and the excellent varieties with early maturity, disease resistance, high yield and marketability were selected as sweet pepper. Pepper: chicken feet × Jilin F 1, Zaofeng1; Sweet pepper: add No.3; Eggplant: Fujian eggplant 1, Pingtung eggplant; Cucumber: Jinchun No.2 and No.3, etc.
2. Planting: 65,438+00 days before planting, cover the shed with plastic film. 3000 kg of manure or decomposed garbage manure, 2000 kg of human excrement and urine, and 50 kg of compound fertilizer are applied per mu, which are applied in deep ditches or in the whole layer and turned into the soil. Tomato is planted in two rows, with the border length of 1.5m, the row spacing of 75cm and the plant spacing of 20-30cm, with 2500-3000 plants per mu. There are 3000 peppers per mu. Eggplant spacing is 40-50 cm, and 2,000-2,400 plants are planted per mu. Plant 2000-2400 cucumbers per mu.
3. On-site management:
(1) Temperature management: No ventilation is needed for one week after planting, mainly heat preservation, especially for eggplant and cucumber, so as to keep a high temperature to facilitate the seedlings to turn green. After returning to seedlings, keep the temperature high. The optimum temperature for tomato seedling growth is 20-25℃ during the day and 10- 15℃ at night. The optimum temperature for eggplant growth is 20-30℃. When the temperature is lower than 15℃, it will cause poor pollination and fertilization. The optimum growth temperature of sweet (spicy) pepper is 25-28℃; The temperature of cucumber is 28-30℃, and the temperature at night shall not be lower than 10℃. The temperature rises gradually in the middle and late May, and the skirt film can be gradually removed. After 9: 00 pm-10 and 16: 00 pm, the cover should be closed.
(2) Fertilizer and water management: after sowing and returning seedlings, use dilute human excrement or livestock fertilizer to raise seedling fertilizer. Tomato, ① the first ear fruit expansion stage, compound fertilizer 10kg/ mu; The fruits of the 2nd-3rd ear began to swell, and the compound fertilizer was 30kg/mu; The 4th-5th ear fruit began to swell, and the compound fertilizer was 20kg/mu. (2) After the sweet (spicy) pepper seedlings are fertilized, the field should be kept moist, not dry and stagnant, and thin fertilizer should be applied frequently during the whole growth period. Generally, topdressing once every two harvest seasons, compound fertilizer 10 kg/mu, and the amount of fertilizer applied at full fruit stage increased by 20 kg/mu. Eggplant topdressing is similar to pepper, and cucumber topdressing is done every two harvest seasons.
(3) Erection and pruning: tomatoes and cucumbers should be supported by bamboo, and the vines should be put on the shelves, which is beneficial to the results. Tomatoes should be trimmed in parallel bars, the first lateral bud above the first flower spike should be kept, and the axillary buds and branches below should be removed. The first flower and the 1 branch under the eggplant fruit were left, and the others were removed. Sweet (spicy) peppers blossom and bear fruit regularly. When the growth, flowering and fruiting are too vigorous and the plant growth potential is small, the upper flowers and fruits should be removed to facilitate the normal growth of the lower flowers and fruits.
(4) flower protection and fruit protection: when the temperature is low in spring, tomatoes and the first and second ears need hormones to protect flowers and fruits to increase the early yield, and 40PPM anti-falling agent is used to spot pedicels; Eggplant should be sprayed with 1-2 days before flowering (trumpet-shaped) or 15PPM anti-falling agent; Peppers can also be sprayed with anti-fall agents.
The flower and fruit protection treatment should be carried out below 65438 05℃ and above 65438 05℃. If there is plenty of sunshine, it should not be treated. The concentration should be strictly controlled and not too high to avoid side effects.
(2) Delayed cultivation in autumn and winter in Natsuna.
The general harvesting period of delayed cultivation in autumn and winter in Natsuna is 10 ~ 12. If preserved, it can last until the Spring Festival with high economic benefits.
1, cultivation season and variety:
(1) Tomato, sown in early July, 30 days old, sown from late August to September, harvested from 10 to 65438+February. The varieties are Zheza 7 and Zaofeng.
(2) Cucumber: direct seeding from the end of July to mid-August, and harvesting from September to165438+1October. The varieties are Jin Yan No.4, Jinchun No.4, Autumn Cucumber 1, Xia Feng and so on.
(3) Autumn tomatoes, flowers that bloom before mid-September, often fall off because of the high temperature at night, while flowers that bloom after 10 are not easy to bear fruit because of the low temperature. Therefore, it is necessary to spray flowers with10-15 ppm anti-falling agent, or to coat pedicels with 40PPM concentration to prevent flowers from falling and fruits from falling.
(3) Planting leafy vegetables
In the greenhouse, in addition to tall vegetables such as melons and eggplants, there are leafy vegetables with high economic value, such as fungus, water spinach, celery and lettuce. It can be cultivated in advance in spring and overwintering in autumn to avoid freezing injury, promote growth, increase production and supply, and go on the market out of season, with good economic benefits.
Leafy vegetables, such as auricularia auricula and water spinach, which like temperature and heat resistance, can be planted in greenhouse in September and June of 10, covered with heat preservation in the later period, put on the market in advance, and cultivated conventionally, basically reaching the annual supply. Lettuce and other vegetables that like cold but are not frost tolerant are most suitable for sowing in the open field in late August to early September and March to April in spring. If the seeds are sown from June 165438+ 10 to March of the following year, they will be cultivated in greenhouse.
(4) Shading and rainproof seedling raising in summer.
From late June to early August, strong light, high temperature, thunderstorm and typhoon rainstorm in southern China seriously affected vegetable production and early autumn vegetable seedling. In recent years, the application of sunshade nets and non-woven fabrics has promoted the role of greenhouse in seedling cultivation in summer.
1, the role of shading and mulching in greenhouse
(1) Shading function: Shading net significantly reduces the light intensity in the shed. The greater the density specification, the better the shading effect. The shading effect of black with the same specification is better than silver gray. Generally, the shading rate of black is 42%-65%, and the shading rate of silver gray is 30%-42%.
(2) Cooling effect: due to the shading net covering, the temperature in the greenhouse is reduced, especially on the surface and the soil plough layer. From 10 in the morning to 2: 00 in the afternoon, the temperature in the upper part of the greenhouse is as high as 37-40℃, while the temperature around the surface plants is 22-26℃ and the soil temperature is 18-22℃, which is suitable for crop growth.
(3) Moisture conservation and rainstorm prevention: evaporation in the shed is reduced, soil water content is higher than that in the open field, and the topsoil is moist. Because the sun-shading net has a certain mechanical strength and is relatively dense, it can decompose the rainstorm into Mao Mao rain, and prevent vegetable leaves from being damaged by the rainstorm, and the soil is not easy to harden, with large porosity and good air permeability. It is best to cover the sunshade net with plastic film in the greenhouse.
2. Matters needing attention in shading and covering cultivation
(1) Choose a sunshade net with appropriate specifications according to the types of vegetables. Usually, green leafy vegetables are covered with black shading nets for a short period in summer and autumn, and silver-gray shading nets are used for seedling raising in autumn and winter and summer to avoid aphids. Eggplant should be planted or cultivated later, and it is best to use net film together.
(2) Coverage period: usually in July-August, the light intensity is suitable for vegetable growth at other times, and it is not necessary to cover if there is no rainstorm.
(3) Sunshade management: Sunshade nets cannot be covered on scaffolding for a long time, especially black sunshades. Only at noon on a sunny day in summer and autumn will the light intensity under the net reach near saturation. It is best to cover it at 10 am- 1 1 am and uncover it at 4-5pm. 3-4 days before uncovering the net, the time for covering the net should be gradually shortened, so that the seedlings and plants can gradually adapt to the open environment.
(5) Soilless cultivation of greenhouse vegetables
Local successful experience: soilless cultivation of leafy vegetables, annual cultivation of lettuce, 8-9 crops a year, yield per mu 1 10,000 kg. The growth period is from high to low with the temperature, generally about 20-40 days. Tomatoes can be planted in spring and summer in a year, and the yield per mu can reach 654.38+00,000 Jin. Cucumber can be cultivated all year round with good economic benefits.
Verb (abbreviation of verb) prevents (corrects) pests and diseases and physiological obstacles.
Vegetables are planted in greenhouses most of the time, especially in winter, which provides suitable ecological conditions for the overwintering reproduction of diseases and insect pests, making vegetable diseases and insect pests and physiological obstacles more and more serious. Therefore, the prevention and control of pests and diseases and overcoming the physiological obstacles of crops are the key to the success of greenhouse vegetable cultivation.
In addition to timely control of pests and diseases of various cultivated varieties and periods, chlorothalonil is fumigated irregularly to eliminate germs. Control of underground pests with carbofuran.
(A) the physiological obstacles of greenhouse cultivation and its corrective measures
1. Physiological obstacle of high temperature: it mainly affects flower bud differentiation, such as the increase of male flowers and the decrease of female flower differentiation in cucumber under high temperature and long sunshine; Tomato and pepper meet high temperature during flower bud differentiation, which leads to small flowers and poor development.
① Sunburn: Main symptoms: At the initial stage, the leaves turn milky white after fading, and finally turn yellow and die.
(2) Falling flowers and fruits lead to fruit deformity. High temperature, especially at night, not only delayed the differentiation of female flowers in the first inflorescence of tomato, but also affected the normal physiological function of stamens, which could not be pollinated normally, resulting in falling flowers and fruits.
③ Affect the normal pigment formation: The high temperature hazard at fruit maturity is poor coloring. When tomatoes are ripe, the formation of lycopene is slow when the temperature exceeds 30℃. When the temperature exceeds 35℃, lycopene is difficult to form, and several yellow and red variegated fruits appear.
Preventive measures: mainly to strengthen ventilation, so that the leaf surface temperature drops. Cover with sunshade net, or spray with cold water to reduce the shed temperature.
2, toxic gas physiological disorder
Ammonia poisoning: When the concentration of ammonia in the air reaches 0. 1%-0.8%, it can harm vegetables. If the temperature is high in sunny days and the concentration of ammonia volatilization is high, cucumber plants will die within 1-2 hours.
Prevention and control measures: organic fertilizer should be fully decomposed and applied, and chemical fertilizer should be applied less.
(2) Typical physiological disorder symptoms of cucumber and tomato and their corrective measures:
1, cucumber vines are long; At the top of the flower, the internode near the growth point is shortened to form a hybrid flower cluster, and the top of the melon seedling does not produce a heart leaf but presents a flower with a head flower; Leaves turn yellow and wilt severely.
Reason: Partial application of nitrogen fertilizer. In early spring, the temperature is low, the temperature difference between day and night is large, the sunshine is insufficient, the root activity is poor, and the soil nutrients are insufficient when raising seedlings.
Prevention and control measures: transplant in time, build a small arch shed early to raise the temperature. Strengthen ventilation, apply fertilizer correctly, and manage moisture, temperature and sunshine well.
2, cucumber, tomato deformed fruit
There are too many nutrients and too many nitrogen and phosphorus fertilizers in tomato flowering period, especially in winter or early spring. Before and after flower bud differentiation, abnormal fruit will appear when it encounters low temperature of 6-8℃ for several days. When the temperature is too high, or the temperature is too low during the treatment, the air is dry due to insufficient illumination, or the nutritional conditions are extremely poor, the flowers that should have fallen are treated with hormones, which inhibits the falling, but the obtained photosynthetic products form less granular fruits, pointed fruits and sour berries.
The leaves haven't seen the light for a long time. Why is chlorophyll filtrate too light green?
Please refer to: After leaf injury, H in vacuole permeates into cytoplasm, replacing Mg in chlorophyll molecule to form pheophytin, so leaves often turn brown. When preparing soaked plant specimens, plants were treated with copper acetate, and Cu replaced Mg to form more stable green pheophytin, which kept the specimens green for a long time, but the optical properties of chlorophyll were lost.
5. Why is the absorption of inorganic salts by plants related to cell respiration?
Please refer to: judging that the power of plants to carry out life activities mainly comes from the energy released by respiration.
Can't say 100% right or wrong.
Most of the energy released by plant respiration is used for plant life activities (such as absorbing inorganic salts, transporting organic matter, cell division, growth and reproduction, etc.). ), and a small part of it is converted into heat energy and dissipated.