BOTANY WITH THE BASICS OF HYDROBOTANY (AQUATIC PLANTS OF UKRAINE) - B.Ye. Yakubenko - 2011

V. CYTOLOGY. THE CONCEPT OF THE CELL

Structure of the Plant Cell

Microtubules

Straight cylinders up to several micrometers in length and 24-25 nm in diameter. The microtubule wall consists of 13 cylindrical structural units, each 5 nm in diameter. Microtubules are formed by molecules of the globular protein tubulin, which is composed of two subunits.

Three types of microtubules occur in plant Cells: microtubules that form the nuclear spindle apparatus during mitosis, microtubules found in the Cytoplasm, and microtubules that serve as Structural components of flagella and cilia.

Microtubules can degrade into the protein tubulin and re-form According to the scheme: microtubule tubulin free tubulin molecules. This equilibrium can be altered by the action of the Alkaloids colchicine, vinblastine, and vincristine. Thus, colchicine, by preventing The formation of nuclear spindle microtubules from tubulin, destroys the mitotic spindle, which causes polyploidy. A similar effect is also characteristic of vinblastine and vincristine, which block Cell Division and are used to treat rapidly growing cancerous tumors.

Cytoplasmic microtubules are involved in orienting Cellulose microfibrils during their deposition in The Cell wall. The destruction of cytoplasmic microtubules by colchicine leads to the chaotic arrangement of cellulose microfibrils and the formation of an abnormal cell wall Structure.



Last update: 07/08/2026

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