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  3. About fifty years ago, plant physiologists set out to grow roots by themselv

About fifty years ago, plant physiologists set out to grow roots by themselv

游客2025-01-29  0
问题     About fifty years ago, plant physiologists set out to grow roots by themselves in solutions in laboratory flasks. The scientists found that the nutrition of isolated roots was quite simple. They required sugar and the usual minerals and vitamins. However, they did not require organic nitrogen compounds. These roots got along fine on mineral inorganic nitrogen. Roots are capable of making their own proteins and other organic compounds. These activities by roots require energy, of course. The process of respiration uses sugar to make the high energy compound ATP, which drives the biochemical reactions. Respiration also requires oxygen. Highly active roots require a good deal of oxygen.
    The study of isolated roots has provided an understanding of the relationship between shoots and roots in intact plants. The leaves of the shoots provide the roots with sugar and vitamins, and the roots provide the shoots with water and minerals. In addition, roots can provide the shoots with organic nitrogen compounds. This comes in handy for the growth of buds in the early spring when leaves are not yet functioning. Once leaves begin photosynthesizing, they produce protein, but only mature leaves can "export" protein to the rest of the plant in the form of amino acids. [br] Where is this passage most likely to be published?
选项 A、In a letter.
B、In a scientific novel.
C、In a scientific journal.
D、In a scientific advertisement.
答案 C
解析 根据本篇文章的结构和文体可知，它不符合信件的格式，排除A；不是一篇科幻小说的内容，排除B；也没有广告的文体特征，排除D；只可能是发表在一本专业刊物上的文章，所以选项C为答案。
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