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  3. Mineral deficiencies can often be detected by specific symptoms such as chlorosis(loss of chlorophyll resulting in yellow or whi

Mineral deficiencies can often be detected by specific symptoms such as chlorosis(loss of chlorophyll resulting in yellow or whi

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问题     Mineral deficiencies can often be detected by specific symptoms such as chlorosis(loss of chlorophyll resulting in yellow or white leaf tissue), necrosis(isolated dead patches), anthocyanin formation(development of deep red pigmentation of leaves or stem), stunted growth, and development of woody tissue in an herbaceous plant. Soils are most commonly deficient in nitrogen and phosphorus. Nitrogen-deficient plants exhibit many of the symptoms just described. Leaves develop chlorosis; stems are short and slender; and anthocyanin discoloration occurs on stems, petioles, and lower leaf surfaces. Phosphorus-deficient 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.
According to paragraph 2, a symptom of iron deficiency is the presence in young leaves of
选项 A、deep red discoloration between the veins
B、white or yellow tissue between the veins
C、dead spots between the veins
D、characteristic dark green veins
答案B
解析
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