Plant Physiology - Musienko M. M. 2001

Chemical and molecular composition, structure, and functions of the plant cell
Golgi apparatus

Among the cytoplasmic structures of a membrane nature, the Golgi apparatus is of great importance. It is a multi-tiered system of flat, hollow, disc-shaped cisternae (dictyosomes) that thicken toward the periphery and form tubular outgrowths. This term is used to define all dictyosomes or Golgi membrane bodies within a Cell. Typically, a dictyosome contains several (4–8) flat membrane sacs or cisternae, with hyaloplasm located between them (Fig. 13).

Dictyosomes, as membrane complexes, possess a polar Structure. The diameter of dictyosomes ranges from 0.2 to 1.5 µm, and their total number in some plant Cells can reach several thousand. Numerous vesicles bud off from their edges. Furthermore, cisternae can form vesicles only on one side of the stack—the secretory side—and on this side, as vesicles are formed, the cisternae gradually disappear. On the opposite side (the regenerative side), new cisternae are formed.

During Cell wall formation, following the completion of nuclear division, Golgi vesicles gather at the new cell boundary and fuse to form the nascent cell wall—the middle lamella.

Proteins synthesized on the Ribosomes of The Endoplasmic reticulum enter the dictyosomes. The vesicle contents (hemicelluloses, Glycoproteins, Glycolipids) serve as material for The formation of the nascent wall, while the vesicle membrane, together with Regions of the endoplasmic reticulum, transforms into the Plasmalemma of the daughter cells. This is a prime example of membrane dynamics.

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Fig. 13. Three-dimensional model of the Golgi apparatus: 1 — flat membrane structures, 2 — reticular structure of membrane cavities, 3 — vesicular outgrowths

Another function of dictyosomes is the Synthesis and Secretion of various substances (mucilage, Essential Oils, sticky fluid in carnivorous plants, etc.). It is likely that secretion synthesis occurs during the formation of new cisternae on the regenerative side, while they are released during the budding of vesicles on the secretory side.

Dictyosomes reproduce through division and de novo formation. During division, their cisternae separate asynchronously with nuclear division. The endoplasmic reticulum is involved in the de novo formation of dictyosomes.

Thus, the Golgi apparatus plays a supply role in The Introduction/5.html">Eukaryotic Cell. Its main function is the transport and chemical modification of various substances. It collects, modifies, packages, and delivers molecules synthesized in certain cellular compartments to those where they are utilized.