Question 1:A The root system is a basic part of a plant. It is below the ground.The root of a plant has two main functions:- it take in water and minerals from the soil.- it hold the plant firmly in position in the soil.B The root hairs are single cells near the tip of each root.C: - sugar beets and carrot can store food in the their roots.- leguminous plants have special bacteria on their roots.Question 2:A The shoot system is a basic part of plant. It is above the ground: it consists of stem, leaves, flowers and fruits.B - The stem supports the plant. It enables water, mineral to pass up from the roots to the leaves and flowers the stem to the roots.- leaves make food for the plant.- The flower contains the reproductive organs of the plant.- The fruit encloses the seeds and protects them while they are developing.Question 3 :A Germination is the first stage of the life cycle of a typical annual plant.B The seeds only germinate if: + The seeds must be alive + The amount of moisture and the temperature level are right- If the temperature is too high, the seeds are died because the water content in the seeds is reduced too much, and certain essential proteins are destroyed.- If the soil is too cold, germination will not occur because of lacking oxygen.- If dry seeds are planted in a dry soil, they will not germinate because there is not enough water.- If there is too much water in the soil, the seeds will not germinate because of lacking oxygen.Question 4:A: In the first stage of germination:- The primary root emerges- The stem appears above the surface of the soil.- The root system grows downward to spread through the soil.-Leaves are produced, the seedling begins photosynthesis.B: In the rapid growth:- Plant begins to grow to its full size.- When it is mature enough, it flowers.- Pollination and fertilization are ready to take place.Question 5:A - Light quantity refers to the intensity of sunlight and varies with the season of the year.- The maximum is present in the summer and the minimum in the winter.B - Light quantity can be decreased in a garden or greenhouse by using shade – cloth or shading paint above the plants.- Light quantity can be increased by surrounding plants with white or reflective material or supplemental lights.Question 6:A - Light quality refers to the color or wavelength reaching the plant surface. There are 7 color : red, orange, yellow , green, blue, indigo, and violet.B - Red and Blue light have the greatest effect on plant growth. Blue light is primarily responsible for vegetative growth or leaf growth. Red light when combined with blue light, encourages flowering in plants.C : Green light is least effective to plants because most plants reflect green light and absorb very little.Question 7: how does high temperature affect plant growth? Give an exampleA. - high temperature afftects the productivity and growth of a plant.- high tempertures cause increased respiration sometimes above the rate of photosynthesis. This means that the products of photosynthesis are being used more rapidly than thay are being produced.- for growth to occur, photosynthesis must be greater than respiration.B. for example:Question 8: How does low temperature affect the plant growth ?How does too low temperature affect the plant growth ?A . - low temperature affects the productivity and growth of a plant.- low temperatures can result in poor growth. Photosynthersis slows at low temperatures. Since photosynthesis is slowed, growth is sslowed and this results in lower vields.B. – If temperatures drop too low during the winter, entire trees of some species are killed because plant cells and tissue are frozen.Question 9: What are the rotes of the water in plant growth ?Water is one of the mót esential factors required in growth of plant.- water is a primary component of photosynthesis. Water mainains the turgor pressure or firmness of tissue and transports nutrients throughout the plant.- water is the major constituent of the protoplasm of a cell.- water provides the pressure to more a root through the soil.- water helps stabilize plant temperature- water reguiates the opening and closing of the stomata, thus regulating transpiration.Question 10: Where are 16 essential nutrient elements from ?what are factors that affect the amount of nutrient absorption ?A . plant need 16 essential nutrient elements for their growth and development:- Carbon, hydrogen, and oxygen are drived from the atmosphere and soil water.- The remaining 13 essential elements ( nitrogen, phosphorus, potassium, calcium magnesium, sulfur , iron, zinc, manganese, copper, boron, molyndenum , chlorine) are supplied either from the soil minerals and soil organic matter or by organic or inorganic fertilizers.B: the factors that affect the amount of nutrient absorption are:- the type of ion - soil ph- solubility of ion pairs - soil water- soil oxygen - sugar supply- plant stress- temperatureQuestion 11:what are fertilizers and why are they added to the soil ?Fertilizers are more concentrated, inorganic chemical substances.They may be grouped as nitrogenous fertilizers, phosphatic fertilizers, potassic fertilizers and so on.- nitrogenous fertilizers encourages rapid vegetative growth and gives plant a healthy green colour.- phosphatic fertilizers stimulates the formation of a plant’s roots and promotes fruit and seed production.- potassic fertilizers makes the plant tissues stronger.Question 12: What are manures and why are they added to the soil ?Manures are bulky, organic materials. There tow kinds of manures:A. farmyard manure contains of a mixture of litter, solid excreta and urine. Manure is added to the soil for several reasons.- It improves the physical condition of the soil.- It also keeps up the level of humus in the soil, and maintains the best conditions for the activities of soil organisms.- It make up for the plant nutrients which have been removed by crops or lost by leaching and soil erosion.B. Green manure includes leguminous crops which grow quickly such as clover and lucerne , Green manure supplies additional nitrogen as well as organic matter.
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