Why are Jerusalem artichoke leaves not sweet in taste, unlike tubers?

Jerusalem artichoke leaves, unlike its tubers, do not have a sweet taste because there is no glucose in the leaves. Moreover, Jerusalem artichoke leaves, as well as all other plants, serve not for the accumulation of various substances in them, but for completely different purposes: they participate in the process of photosynthesis, in the process of respiration, in the process of water exchange (moisture evaporation). On the contrary, the sweet taste of Jerusalem artichoke tubers is explained by the high content of glucose and other substances such as inulin in them.