题目选项分析

In an attempt to produce a coffee plant that would yield beans containing no caffeine. the synthesis of a substance known to be integral to the initial stages of caffeine production was blocked either in the beans, in the leaves, or both. For those plants in which synthesis of the substance was blocked only in the leaves. the resulting beans contained no caffeine. Any of the following. if true, would provide the basis for an explanation of the observed results EXCEPT:

【选项】In coffee plants. the initial stages of caffeine production take place only in the beans, but later stages depend on another substance that is synthesized only in the leaves and does not depend on the blocked substance.