Growth
Hyphae grow at their tips. During tip growth, cell walls are extended by the external assembly and polymerization of cell wall components, and the internal production of new cell membrane. The spitzenkörper is an intracellular organelle associated with tip growth. It is composed of an aggregation of membrane-bound vesicles containing cell wall components. The spitzenkörper is part of the endomembrane system of fungi, holding and releasing vesicles it receives from the Golgi apparatus. These vesicles travel to the cell membrane via the cytoskeleton and release their contents outside the cell by the process of exocytosis, where it can then be transported to where it is needed. Vesicle membranes contribute to growth of the cell membrane while their contents form new cell wall. The spitzenkörper moves along the apex of the hyphal strand and generates apical growth and branching; the apical growth rate of the hyphal strand parallels and is regulated by the movement of the spitzenkörper.
As a hypha extends, septa may be formed behind the growing tip to partition each hypha into individual cells. Hyphae can branch through the bifurcation of a growing tip, or by the emergence of a new tip from an established hypha.
Read more about this topic: Hypha
Famous quotes containing the word growth:
“The risk for a woman who considers her helpless children her “job” is that the children’s growth toward self-sufficiency may be experienced as a refutation of the mother’s indispensability, and she may unconsciously sabotage their growth as a result.”
—Letty Cottin Pogrebin (20th century)
“The quality of American life is an insult to the possibilities of human growth ... the pollution of American space, with gadgetry and cars and TV and box architecture, brutalizes the senses, making gray neurotics of most of us, and perverse spiritual athletes and strident self-transcenders of the best of us.”
—Susan Sontag (b. 1933)
“Rights! There are no rights whatever without corresponding duties. Look at the history of the growth of our constitution, and you will see that our ancestors never upon any occasion stated, as a ground for claiming any of their privileges, an abstract right inherent in themselves; you will nowhere in our parliamentary records find the miserable sophism of the Rights of Man.”
—Samuel Taylor Coleridge (1772–1834)