السؤال 70

In translocation, sugar travels from a source to a sink. In a leafy plant in midsummer, which movement fits that description?

From a photosynthesising leaf to a growing root tipالإجابة الصحيحة
From a root upwards to a leaf that is making sugar
Between two leaves of exactly the same age and size
From the soil into a root hair and on up to the shoot

الشرح

A source is a part that releases sugar into the transport tissue, and in midsummer a lit leaf is doing exactly that, while a growing tip consumes what arrives and therefore acts as a sink. Reversing the pair puts the supply where the demand is, and a root in midsummer makes no sugar at all, so it cannot be the part that loads the tissue.

الشرح

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