Sugars, which are formed by the plant during photosynthesis, are an essential component of plant nutrition. Like water, sugar (usually in the form of sucrose, though glucose is the original photosynthetic product) is carried throughout the parts of the plant by the vascular system. Phloem, the vascular tissue responsible for transporting organic nutrients around the plant body, carries dissolved sugars from the leaves (their site of production) or storage sites to other parts of the plant that require nutrients. Within the phloem, sugars travel from areas of high osmotic concentration and high water pressure, called sources, to regions of low osmotic concentration and low water pressure, called sinks. (Osmotic concentration refers the concentration of solutes, or sugars in this case; where the concentration of solutes is highest, so is the osmotic concentration).
<span>When a testcross between f1 dihybrid flies produces
more offspring with both traits like those of one parent, or the other than
offspring with recombinant-type traits are produced means that the two genes are
link. The reason that linked genes are inherited together is that they are
located on the same chromosome.</span>
