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8 Cards in this Set
- Front
- Back
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Why do simple solution cultures complicate studies?
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Because ions may be exhausted or the solution pH may change.
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What is the hydroponic approach? Is it always successful?
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Grow plants on an inert medium, such as quartz sand, to which a nutirent solution can be added. this solution can even be circulated through the medium. Not always, because it is difficult to find a true inert medium because traces of some minerals may exist which would be more than sufficient for plant growth.
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What are essential elements and how many are there?
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Essential elements whose absense prevents a plant form completing its life cycle, say through reproduction or essential metabolism. 17
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What is the critical concentration of a mineral nutrient?
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That which gives a 10% reduction in growth
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Why is the diagnosis of mineral deficiencies in soil-grown plants complex?
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1.) Multiple mineral deficiencies can occur.
2.) An imbalance in one nutrient can lead to imbalances in other nutrients. 3.)Symptoms related to nutrient defiecieny can resemble symptoms related to viral diseases 4.)Location of symptoms depends upon mobility of the nutirent within the plant. |
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Why is iron availibilty a significant problem for plants? What aids in keeping iron available for the plant?
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Because it has a tendency to form inorganic precipitates at neutral or basic pH values. Synthetic chelators, which form soluble ionic complexes.
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What are some forms of natural chelators?
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Porphyrins such hemes in cytochromes and organic phenolic acids, such as caffeic acid.
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What are two strategies applied by plants to combat iron deficiency?
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1.) Acidifying the soil surrounding the roots, keeping the iron (Fe3+) soluble until the iron can be chelated, reduced to Fe2+, and internalized by the plant.
2.) Secreting iron-binding organic compounds known as phytosiderophores into the soil, which then bind Fe3+ and are taken up as metal complexes by the plant. |
