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Unformatted text preview: short and slender, and anthocyanin discoloration occurs on stems, petioles, and lower leaf surfaces. Phosphorusdeficient plants are often stunted, with leaves turning a characteristic dark green, often with the accumulation of anthocyanin. Typically, older leaves are affected first as the phosphorus is mobilized to young growing tissue. Iron deficiency is characterized by chlorosis between veins in young leaves. 2. The word exhibit in the passage is closest in meaning to
spread 3. According to Paragraph2, which of the following symptoms occurs in phosphorusdeficient plants but not in plants deficient in nitrogen or iron?
Chlorosis on leaves
Change in leaf pigmentation to a dark shade of green
Short, stunted appearance of stems
Reddish pigmentation on the leaves or stem 4. According to Paragraph2, a symptom of iron deficiency is the presence in young leaves of
Deep red discoloration between the veins. 182
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White or yellow tissue between the veins.
Dead spots between the veins.
Characteristic dark green veins. Paragraph3: Much of the research on nutrient deficiencies is based on growing plants hydroponically, that is, in soilless liquid nutrient solutions. This technique allows researchers to create solutions that selectively omit certain nutrients and then observe the resulting effects on the plants. Hydroponics has applications beyond basic research, since it facilitates the growing of greenhouse vegetables during winter. Acroponics, a technique in which plants are suspended and the roots misted with a nutrient solution, is another method for growing plants without soil. 5. The word facilitates in the passage is closest in meaning to
focuses on 6. According to Paragraph3, what is the advantage of hydroponics for research on nutrient deficiencies in plants?
It allows researchers to control what nutrients a plant receives.
It allows researchers to observe the growth of a large number of plants simultaneously.
It is possible to directly observe the roots of plants.
It is unnecessary to keep misting plants with nutrient solutions. 7. The word suspended in the passage is closest in meaning to
hung Paragraph5: Scientists have known for some time that certain plants, called hyper accumulators, can concentrate minerals at levels a hundredfold or greater than normal. A survey of known hyper accumulators identified that 75 percent of them amassed nickel, cobalt, copper, zinc, manganese, lead, and cadmium are other minerals of choice. Hyper accumulators run the entire range of the plant world. They may be herbs, shrubs, or trees. Many members of the mustard family, spurge family, legume family, and grass family are top hyper accumulators. Many are found in tropical and subtropical areas of the world, where accumulation of high concentrations of metals may afford some protec...
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- Fall '13