Hormone effects on Cosmarium botrytis cell division

Area of Science:

• Phycology
• Plant Physiology
• Cell Biology

Background:

• The synchronous generation time of Cosmarium botrytis is influenced by environmental factors like pH.
• Understanding factors affecting algal cell division is crucial for optimizing cultivation and biotechnological applications.

Purpose of the Study:

• To investigate the effects of plant growth regulators, specifically kinetin and indole-acetic acid (IAA), on the synchronous generation time of Cosmarium botrytis.
• To determine optimal concentrations and application methods for these regulators to enhance algal cell division.

Main Methods:

• Culturing Cosmarium botrytis under controlled conditions (21°C, 15h light/9h dark cycle) at different pH levels (5.3 and 8.0).
• Applying varying concentrations of kinetin and IAA to the algal cultures at the beginning of the light cycle.
• Monitoring cell division rates, lag phase duration, and generation times.

Main Results:

• Kinetin (0.01–1.0 mg/ml) eliminated the lag phase and resulted in a 24-hour division cycle at both pH 5.3 and 8.0.
• IAA (0.03–0.06 mg/ml) decreased the lag phase, particularly at pH 5.3, and eliminated it at pH 8.0.
• Daily combined application of IAA and kinetin maintained the accelerated 24-hour division cycle for up to 14 days. Kinetin was lethal at 3 mg/ml and IAA at 0.05 mg/ml.
• No synergistic or additive effects were observed with combined IAA and kinetin treatments. Cell numbers did not correlate with optical density at 678 nm. Medium pH dropped during cell division.

Conclusions:

• Kinetin and IAA are effective in significantly shortening the generation time of Cosmarium botrytis.
• Optimized application of these plant growth regulators can lead to a consistent and rapid cell division cycle, beneficial for mass cultivation.
• Further research is needed to understand the precise physiological mechanisms underlying the observed effects and the lack of synergistic interactions.