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.
(1) From the phloem sieve tubes (Pc), carbohydrates can move by diffusion via plasmodesmata into the symplastic storage compartment (S) (e.g. ray cells or phloem parenchyma). Carbohydrates can diffuse through the cell membrane (2) into the apoplast (A) or (3) into the storage compartment.irst, the phloem protects the plant by its high turgor pressure and concomitant high sugar concentration in the SECCCs (Turgeon, 2010a). When a sieve tube is wounded, pressure release causes surging and forces cellular debris into the sieve pores, sealing the phloem (e.g. Ehlers et al., 2000).