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1989
Journal Article
Titel
Ion composition of tobacco cells cultured under sulfur deficiency.
Alternative
Ionen-Zusammensetzung von Tabakzellen die unter Schwefelmangel kultiviert wurden
Abstract
In both photoheterotrophic and heterotrophic tobacco cells a reduced supply of sulfate in the medium did not alter the rate but the duration of exponential growth. The higher the sulfate supply in the medium the longer exponential growth proceeded. However, the ion composition of photoheterotrophic and heterotrophic cells was affected by sulfur deficiency in completely different ways. The dynamics in the K plus minus, Na plus minus, Mg2 plus minus, nitrate-, phosphate-, and malate-contents of photoheterotrophic cells during growth were not at all, or only slightly changed, when the sulfate supply in the medium was reduced from 1.8 mM to 1.2 mM, 0.6 mM, or 0.3 mM. In heterotrophic tobacco suspensions, however, severe sulfur deficiency caused K plus, Na plus, Mg 2 plus, and malate to accumulate and nitrate to begin to accumulate earlier inside the cells. Addition of sulfate after 4 days to heterotrophic suspensions grown under sulfur-limiting conditions prevented the accumulation of thes e cations and anions. During the initial period of growth also phoshate accumulated inside heterotrophic tobacco cells to amounts found to be the higher the smaller the sulfate-content of the media. Apparently, in photoheterotrophic tobacco cells the ion composition can homeostatically be regulated independent from the cells' sulfate supply, whereas the ion composition of heterotrophic tobacco cells appears to be highly dependent on the sulfate supply of the cells.
Language
English