Why Are Plants Exposed To Light
Why did plants exposed to no light grow better than the plants exposed to light? The plants exposed to no light performed better than those exposed to light is most likely caused by the plants exposed to no light having more water than those in light. Even though the amount and frequency of water added to all plants were kept the same, the amount of water the plants in no light had access to was more than the amount of water the plants in light had. This is due to two reasons: a) because the plants exposed to no light, the sun couldn't evaporate water from the plant, and b) the plastic container placed on top of the plant trapped and contained what little water did evaporate, therefore letting the plants reuse water that was given to it.
Why did the plants exposed to no light look less healthy than those exposed to light? The sickly pale color seen in plants 4, 5, and 6 is most likely attributed to the fact that, without sunlight, plants are not able to create sugars to nourish itself. Sugar is vital for the healthy …show more content…
growth of the plant, and by ceasing to provide the plant with sunlight would ensure that the plant wouldn't be able to produce the sugars needed.
1. Page 535/561 g/a) The NPK value of fertilizer did not drastically influence the growth rate of the plants. If compared to plants of the same lighting, the different amounts of NPK did not have a drastic effect on the height of the plant relative to each other. For example, by the end of the last day of observations, the difference between the tallest and the shortest plants that were exposed to light was merely 2.3 cm. The difference in heights of the plants that were exposed to light saw an even small difference, with only a 1.8cm difference between the tallest and shortest plant. The lighting that the plant was exposed to were the opposite of expectation and revealed that when plants are not exposed to light, they grow taller than if they had been exposed to light. To see an explanation as to why his might have happened, please see the Why did plants exposed to no light grow better than the plants exposed to light? section of discussions. i/b) A farmer growing crops and an operator of a greenhouse would find this information useful because it would assist them in determining which NPK ratio and what lighting environment would develop the plant the fastest. Both the operator and the farmer would find the NPK ratio useful for the growth of their plants, but only the greenhouse operator would find what lighting environment produces the tallest plants. This is because the farmer would not have the ability to change the lighting that the plants are exposed to. e/k) It was important to have more than one seed in each container because if only one seed was added to a container, that one seed wouldn't necessarily survive the growing process. I would suggest adding 4 seeds into each container. This is because 4 seeds would allow the researcher to have a reasonable window of error when it comes to unsuccessful seeds as well as not providing an overabundance of seeds which would require more water nutrients, thusly being less healthy. f/l) Primary growth caused by apical meristems would be both the most convenient and most valid measure of growth. Primary growth is more valid and convenient than secondary growth caused by lateral meristems due to the circumference of the cat grasses stem being too thin to accurately measure. m/g) One possible improvement that could have been implemented in the experiment was the addition of a control group. This control group would consist of two plant containers with no fertilizer; one in complete darkness under the plastic container and the other outside the box and in light. This would help determine how much better (or worse) the plants performed while exposed to fertilizer.
2. Canada's fruit and vegetable industry primarily "products are canned, frozen or otherwise preserved fruits and vegetables, vegetable and fruit juices, soups, pickles, jams, jellies and marmalades, cider, sauces and vinegar" (1). Canada's agriculture and agri-food industry contribute a large sum towards Canada's overall GDP, at over $100 billion annually (2). Considering Canada's 2015 GDP was $1.552 trillion (3), that means the agriculture and agri-food industry represented approximately 6.4% of Canada's total GDP in 2015. Apart from contributing to Canada's GDP, Canadian companies that process fruits and vegetables sell over $6.5 billion dollars worth of products every year, 30% of which is exported to other countries (2). The importance of agriculture to Canada is also echoed through the fact that Canada is the 5th largest exporter of agriculture in the world as well as providing 1 in 8 Canadians with a job (2).
3. Crop rotation is the rotation of plant families from one spot to another . The main purpose people rotate crops is to "help maintain the balance of nutrients, organic matter, and microorganisms necessary for healthy soil" (4). When a large number of the same plants occupy the same location, it results in the nutrients in the soil being depleted . When this happens, crop rotation is implemented so that instead of the same plant depleting certain nutrients from the soil, a different plant with different nutritional needs would then be rotated to take the place of the first plant. Apart from preventing nutrients from being depleted, crop rotation "also offers an excellent defense against all kinds of pests" (5). For example, a fungus that targets potatoes could infest a crop of potatoes one season. If potatoes are planted the next season, then the fungus will come back and most likely affect the newest batch of potatoes; however, if a new plant was planted in that location instead, the host for the fungus (in this case potatoes) would be cut off from the fungus; therefore, killing it off.
4. Biofuels, like bio diesel, was mainly created to reduce greenhouse gas emissions and to mitigate the effects of global warming produced by fossil fuels (6). Though created for a righteous purpose, biofuels also have some other, unintended impacts on water, biodiversity, and land . For example, The State of Food and Agriculture 2008 report says "Depending on the methods used to produce the feedstock and process the fuel, some crops can even generate more greenhouse gasses than do fossil fuel," (6). The production of biofuels also requires a large amount of water. Water is used for the washing of plants and seeds, as well as evaporative cooling; however, the biggest impact on water availability comes from the fact that plants like sugar cane, oil palm, and maize have "relatively high water requirements and are best suited to high-rainfall areas" (7). Biofuels also impact biodiversity in a negative way. For example, wild biodiversity is impacted by "habitat loss following land conversion for crop production" (7). What this means is that biodiversity will be negatively affected by the loss of habitat due to land being used for crops used in biofuels. In conclusion, biofuels, though in theory a clean and eco-friendly alternative to fossil fuels like gasoline, are not worth the negative impact on water and biodiversity, as well as the fact that the creation of these fuels could create more greenhouse gasses than fossil fuels.
5. In 2004, scientists were able to utilize a "large chloroplast... genomic dataset" to estimate when the monocot-dicot split occurred (8). From their results, they concluded monocots diverged from dicots 140-150 million years ago (8). This estimate is at least 50 million years younger than estimates based upon " the molecular clock hypothesis" (8).
Structure Monocot Dicot
# of Cotyledon 1 Cotyledon 2 Cotyledon
Veins in leaves Parallel (9) Net like (9)
Flower pedals Multiples of 3 Usually in fours of fives
Vascular bundles Scattered (10) In a ring (10)
Roots Fibrous Roots (11) Tap Roots (11)
6. Angiosperm Gymnosperm
Seeds Usually enclosed within a fruit (12). Bare, unenclosed and found on scales, leaves or as cones (12).
Pollination Pollinated by the wind and by animals (13). Pollinated primarily by wind blowing pollen to other plants (13).
Fertilization When pollen comes into contact with the stigma, a pollen tube is sent down into the ovary (14). Two sperm cells are then released; one fuses with an egg and creates a diploid zygote and the other fuses with the fusion nucleus to form a triploid nucleus (14). Egg cells develop and originate in the archegonia, which is found in the female gametophyte (14). Fertilization occurs when pollen from the male gametophyte is blown into the open end of an ovule (14).
7. Two forms of asexual reproduction that plants utilize are vegetative reproduction and apomixis (15). Apomixis is " an asexual mode of seed formation that produces clonal progeny with a maternal genotype" (16). Apomixis works by the maternal tissues of the ovule of a plant forming a seed without the use of meiosis and fertilization (17). Vegetative reproduction is a " form of asexual reproduction of a plant " and where only " one plant is involved and the offspring is the result of one parent " (18). Plants have multiple ways of performing vegetative reproduction, two of them are through the use of stems and root. Vegetative reproduction through stems work by using special stems called runners that grow horizontally above the ground. All the across the runner, there are small nodes where buds form, and eventually grow into new plants. Vegetative reproduction through roots work by having new plants grow out of special roots called tubers. Like vegetative reproduction through stems, buds grow between the stem and the tubers and create new plants that way.
8. (19) In order for sexual reproduction of plants to occur, pollen from a different plant has to reach the stamen of another plant (20). This is usually done by either the wind blowing pollen from one to plant to another or by insects like bees taking advantage of the nectar the plant produces. If a grain of pollen from one plant is able to reach a " compatible stigma", a pollen tube will start growing (20). Eventually, the egg cell (which is hidden away inside the embryo sac) will be able to be fertilized. After fertilization, the ovule of the plant is then referred to as the seed.
9. Xylem and phloem tissue are both part of the vascular tissue system, however, they have very different functions within the plant. The xylem tissue of the plant carries water and minerals from the root of the plant, up to the stems and leaves. Xylem tissue is formed when certain plant cells thicken and when dead, the strong cylinders that are left behind still function. In contrast to xylem, phloem tissue transports organic materials that include nutrients and hormones across the plant. Phloem is formed from cells that contain living tissue. People are still not sure how xylem and phloem transport materials, but there are theories that help explain possible ways xylem and phloem work.
The three main theories as to how xylem transports water and minerals are root pressure, capillary action, and cohesion-tension/transport pull. The root pressure theory works by the water being pumped into xylem tissue. Then, the minerals and ions absorbed with the water then get pumped up the root. The water then follows the ions and minerals up the xylem, and throughout the plant. Capillary action works by relying on the adhesive properties of water. Because the polarity of the capillary walls attracts water molecules, water sticks to the sides of the tube, therefore, causing the water to move up the tube. Cohesion-tension or transpiration pull works by the water from the leaves being evaporated caused by the heat of the sun. This then causes a change in pressure which moves the water up from the
roots. The main theory surrounding how the phloem works is the mass-flow theory. The theory is that osmosis caused by the plant keeping the ratio of water to ions equal creates a pressure that then moves minerals throughout the plant. This theory is widely accepted as correct, however, there is still debate over how the internal pressure of the plant should be higher than it actually is. Mass-flow theory also can't account for the speed and the distance in which phloem transport occurs, nor does it explain the change in speed caused by low oxygen levels and low temperature.
Why did the plants exposed to no light look less healthy than those exposed to light? The sickly pale color seen in plants 4, 5, and 6 is most likely attributed to the fact that, without sunlight, plants are not able to create sugars to nourish itself. Sugar is vital for the healthy …show more content…
growth of the plant, and by ceasing to provide the plant with sunlight would ensure that the plant wouldn't be able to produce the sugars needed.
1. Page 535/561 g/a) The NPK value of fertilizer did not drastically influence the growth rate of the plants. If compared to plants of the same lighting, the different amounts of NPK did not have a drastic effect on the height of the plant relative to each other. For example, by the end of the last day of observations, the difference between the tallest and the shortest plants that were exposed to light was merely 2.3 cm. The difference in heights of the plants that were exposed to light saw an even small difference, with only a 1.8cm difference between the tallest and shortest plant. The lighting that the plant was exposed to were the opposite of expectation and revealed that when plants are not exposed to light, they grow taller than if they had been exposed to light. To see an explanation as to why his might have happened, please see the Why did plants exposed to no light grow better than the plants exposed to light? section of discussions. i/b) A farmer growing crops and an operator of a greenhouse would find this information useful because it would assist them in determining which NPK ratio and what lighting environment would develop the plant the fastest. Both the operator and the farmer would find the NPK ratio useful for the growth of their plants, but only the greenhouse operator would find what lighting environment produces the tallest plants. This is because the farmer would not have the ability to change the lighting that the plants are exposed to. e/k) It was important to have more than one seed in each container because if only one seed was added to a container, that one seed wouldn't necessarily survive the growing process. I would suggest adding 4 seeds into each container. This is because 4 seeds would allow the researcher to have a reasonable window of error when it comes to unsuccessful seeds as well as not providing an overabundance of seeds which would require more water nutrients, thusly being less healthy. f/l) Primary growth caused by apical meristems would be both the most convenient and most valid measure of growth. Primary growth is more valid and convenient than secondary growth caused by lateral meristems due to the circumference of the cat grasses stem being too thin to accurately measure. m/g) One possible improvement that could have been implemented in the experiment was the addition of a control group. This control group would consist of two plant containers with no fertilizer; one in complete darkness under the plastic container and the other outside the box and in light. This would help determine how much better (or worse) the plants performed while exposed to fertilizer.
2. Canada's fruit and vegetable industry primarily "products are canned, frozen or otherwise preserved fruits and vegetables, vegetable and fruit juices, soups, pickles, jams, jellies and marmalades, cider, sauces and vinegar" (1). Canada's agriculture and agri-food industry contribute a large sum towards Canada's overall GDP, at over $100 billion annually (2). Considering Canada's 2015 GDP was $1.552 trillion (3), that means the agriculture and agri-food industry represented approximately 6.4% of Canada's total GDP in 2015. Apart from contributing to Canada's GDP, Canadian companies that process fruits and vegetables sell over $6.5 billion dollars worth of products every year, 30% of which is exported to other countries (2). The importance of agriculture to Canada is also echoed through the fact that Canada is the 5th largest exporter of agriculture in the world as well as providing 1 in 8 Canadians with a job (2).
3. Crop rotation is the rotation of plant families from one spot to another . The main purpose people rotate crops is to "help maintain the balance of nutrients, organic matter, and microorganisms necessary for healthy soil" (4). When a large number of the same plants occupy the same location, it results in the nutrients in the soil being depleted . When this happens, crop rotation is implemented so that instead of the same plant depleting certain nutrients from the soil, a different plant with different nutritional needs would then be rotated to take the place of the first plant. Apart from preventing nutrients from being depleted, crop rotation "also offers an excellent defense against all kinds of pests" (5). For example, a fungus that targets potatoes could infest a crop of potatoes one season. If potatoes are planted the next season, then the fungus will come back and most likely affect the newest batch of potatoes; however, if a new plant was planted in that location instead, the host for the fungus (in this case potatoes) would be cut off from the fungus; therefore, killing it off.
4. Biofuels, like bio diesel, was mainly created to reduce greenhouse gas emissions and to mitigate the effects of global warming produced by fossil fuels (6). Though created for a righteous purpose, biofuels also have some other, unintended impacts on water, biodiversity, and land . For example, The State of Food and Agriculture 2008 report says "Depending on the methods used to produce the feedstock and process the fuel, some crops can even generate more greenhouse gasses than do fossil fuel," (6). The production of biofuels also requires a large amount of water. Water is used for the washing of plants and seeds, as well as evaporative cooling; however, the biggest impact on water availability comes from the fact that plants like sugar cane, oil palm, and maize have "relatively high water requirements and are best suited to high-rainfall areas" (7). Biofuels also impact biodiversity in a negative way. For example, wild biodiversity is impacted by "habitat loss following land conversion for crop production" (7). What this means is that biodiversity will be negatively affected by the loss of habitat due to land being used for crops used in biofuels. In conclusion, biofuels, though in theory a clean and eco-friendly alternative to fossil fuels like gasoline, are not worth the negative impact on water and biodiversity, as well as the fact that the creation of these fuels could create more greenhouse gasses than fossil fuels.
5. In 2004, scientists were able to utilize a "large chloroplast... genomic dataset" to estimate when the monocot-dicot split occurred (8). From their results, they concluded monocots diverged from dicots 140-150 million years ago (8). This estimate is at least 50 million years younger than estimates based upon " the molecular clock hypothesis" (8).
Structure Monocot Dicot
# of Cotyledon 1 Cotyledon 2 Cotyledon
Veins in leaves Parallel (9) Net like (9)
Flower pedals Multiples of 3 Usually in fours of fives
Vascular bundles Scattered (10) In a ring (10)
Roots Fibrous Roots (11) Tap Roots (11)
6. Angiosperm Gymnosperm
Seeds Usually enclosed within a fruit (12). Bare, unenclosed and found on scales, leaves or as cones (12).
Pollination Pollinated by the wind and by animals (13). Pollinated primarily by wind blowing pollen to other plants (13).
Fertilization When pollen comes into contact with the stigma, a pollen tube is sent down into the ovary (14). Two sperm cells are then released; one fuses with an egg and creates a diploid zygote and the other fuses with the fusion nucleus to form a triploid nucleus (14). Egg cells develop and originate in the archegonia, which is found in the female gametophyte (14). Fertilization occurs when pollen from the male gametophyte is blown into the open end of an ovule (14).
7. Two forms of asexual reproduction that plants utilize are vegetative reproduction and apomixis (15). Apomixis is " an asexual mode of seed formation that produces clonal progeny with a maternal genotype" (16). Apomixis works by the maternal tissues of the ovule of a plant forming a seed without the use of meiosis and fertilization (17). Vegetative reproduction is a " form of asexual reproduction of a plant " and where only " one plant is involved and the offspring is the result of one parent " (18). Plants have multiple ways of performing vegetative reproduction, two of them are through the use of stems and root. Vegetative reproduction through stems work by using special stems called runners that grow horizontally above the ground. All the across the runner, there are small nodes where buds form, and eventually grow into new plants. Vegetative reproduction through roots work by having new plants grow out of special roots called tubers. Like vegetative reproduction through stems, buds grow between the stem and the tubers and create new plants that way.
8. (19) In order for sexual reproduction of plants to occur, pollen from a different plant has to reach the stamen of another plant (20). This is usually done by either the wind blowing pollen from one to plant to another or by insects like bees taking advantage of the nectar the plant produces. If a grain of pollen from one plant is able to reach a " compatible stigma", a pollen tube will start growing (20). Eventually, the egg cell (which is hidden away inside the embryo sac) will be able to be fertilized. After fertilization, the ovule of the plant is then referred to as the seed.
9. Xylem and phloem tissue are both part of the vascular tissue system, however, they have very different functions within the plant. The xylem tissue of the plant carries water and minerals from the root of the plant, up to the stems and leaves. Xylem tissue is formed when certain plant cells thicken and when dead, the strong cylinders that are left behind still function. In contrast to xylem, phloem tissue transports organic materials that include nutrients and hormones across the plant. Phloem is formed from cells that contain living tissue. People are still not sure how xylem and phloem transport materials, but there are theories that help explain possible ways xylem and phloem work.
The three main theories as to how xylem transports water and minerals are root pressure, capillary action, and cohesion-tension/transport pull. The root pressure theory works by the water being pumped into xylem tissue. Then, the minerals and ions absorbed with the water then get pumped up the root. The water then follows the ions and minerals up the xylem, and throughout the plant. Capillary action works by relying on the adhesive properties of water. Because the polarity of the capillary walls attracts water molecules, water sticks to the sides of the tube, therefore, causing the water to move up the tube. Cohesion-tension or transpiration pull works by the water from the leaves being evaporated caused by the heat of the sun. This then causes a change in pressure which moves the water up from the
roots. The main theory surrounding how the phloem works is the mass-flow theory. The theory is that osmosis caused by the plant keeping the ratio of water to ions equal creates a pressure that then moves minerals throughout the plant. This theory is widely accepted as correct, however, there is still debate over how the internal pressure of the plant should be higher than it actually is. Mass-flow theory also can't account for the speed and the distance in which phloem transport occurs, nor does it explain the change in speed caused by low oxygen levels and low temperature.