Question

Identify likely directions of sugar translocation and explain how it changes with time in these scenarios:

a. A tomato plant in the early stages of tomato development. Also explain why the common practice of removing emerging shoots at the base of mature leaves is done during fruit set.

b. About this time of the year in leafless maple trees: (I) non-photosynthetic buds growing (II), then breaking open revealing immature leaves that grow rapidly (III) mature leaves.

c. A germinating coconut on a beach in the Pacific Ocean

Answer 1

a. In the early stages of tomato development,sugar translocation occurs from the source i.e from leaves where photosynthates are produced by photosynthesis to the actively growing parts such as roots ,developing fruits,flowers etc.Here leaves act as source and developing fruits act as sink.

Removal of emerging shoots at the base of mature shoots is practised to ensure that majority of sugars and nutrients are translocated to the fruits instead of wasting on these shoots.These emerging shoots consume more photosynthates that are necessary for the development of fruits.

b. In leafless maple trees,roots are the only source of sugar.These storage sites now serve as sources ,while actively growing leaves serve as sink.In growing non photosynthetic buds,sugar translocation occurs from roots to the buds since the only source for sugar is now the roots.In immature leaves,roots act as the source for sugar.And while the leaves mature ,they will become the sources of sugar and act as the source of photosynthates.

c.In germinating coconut,the translocation of sugar occurs from the endosperm to the growing embryo.the endosperm is rich in carbohydrates and act as the source.