Sensitivity of Nostoc commune UTEX 584 (Cyanobacteria) to water stress |
| |
Authors: | Malcolm Potts Mark A Bowman |
| |
Institution: | (1) Cyanobacterial Research Group, Department of Biological Science, Florida State University, 32306 Tallahassee, FL, USA |
| |
Abstract: | Cells of Nostoc commune UTEX 584 from liquid cultures expressed an upshift in nitrogenase activity when immobilised on inert supports and exposed to matric water potentials between -1.10 and -99.5 MPa. Cells incubated at 0.10 MPa (aw=c 1.0) maintained increased activity for at least 48 h following immobilization. At water potentials below -23.1 MPa (aw=0.85), the upshift was transitory. Nitrogenase activity decreased rapidly when immobilised cells were incubated at lower values of m.Desiccated cells stored at -99.5 MPa (aw=0.50) underwent an upshift in nitrogenase activity, and in the size of the intracellular ATP pool, when rewetted with either distilled water or liquid MBo medium ( o =-0.18 MPa). The upshift in nitrogenase activity was chloramphenicol-sensitive and was preceeded by a lag. The duration of the lag depended on the time taken to equilibrate cells to-99.5 MPa, the time desiccated, and the conditions of storage and rewetting. Cells that had no, or very low, nitrogenase activity when rewetted in air, showed a marked stimulation of nitrogenase activity in the presence of 5% v/v CO2 under both aerobic and anerobic conditions.When rewetted in the presence of 1% w/v glucose ( o =-0.14 MPa), vegetative cells remained intact, but heterocysts underwent autolysis and nitrogenase activity was not detected, even in the presence of 5% v/v CO2.Abbreviations TTC
2,3,5-triphenyl-2-tetrazolium chloride
- m
matric water potential
- o
osmotic water potential
- aw
water activity |
| |
Keywords: | Cyanobacteria Immobilised cells Desiccation Water stress Nitrogenase ATP pool Photooxidation |
本文献已被 SpringerLink 等数据库收录! |
|