1. Acetylcholine is the most common. Neurons that release it are called cholinergic. Cholinergic neurons include all preganglionic neurons of the autonomic nervous system, postganglionic neurons of the parasympathetic nervous system and some postganglionic neurons (sweat glands) of the sympathetic nervous system.cetylcholine is the most common. Neurons that release it are called cholinergic. Cholinergic neurons include all preganglionic neurons of the autonomic nervous system, postganglionic neurons of the parasympathetic nervous system and some postganglionic neurons (sweat glands) of the sympathetic nervous system.
Translocation is the movement of materials from leaves to other tissues throughout the plant. Plants produce carbohydrates (sugars) in their leaves by photosynthesis, but nonphotosynthetic parts of the plant also require carbohydrates and other organic and nonorganic materials.t is pressure, generated in the sieve elements and companion cells in source tissues. In leaves, sugar is synthesized in mesophyll cells (the middle layer of the leaf), and is then actively pumped into the phloem, using metabolic energy.
During the plant's growth period, usually during the spring, storage organs such as the roots are sugar sources, and the plant's many growing areas are sugar sinks. The movement in phloem is multidirectional, whereas, in xylem cells, it is unidirectional (upward).