Abstract
The effects of monosulfuron on growth and photosynthetic pigments of the nitrogen-fixing cyanobacterium Anabaena flos-aquae grown exposed to 2000-, 3000-, and 4000-lux light intensity were studied. Exposed to three light intensities, the seven concentrations of monosulfuron tested can significantly inhibit algal growth in a dose-dependent manner. The cell numbers and growth rate were decreased with the increase in mono-sulfuron concentration, and A. flos-aquae had different degrees of sensitivity to monosulfuron with the most sensitive light intensity being 4000-lux followed by 3000-lux and 2000-lux. The herbicide monosulfuron appeared to have different effects on the synthesis of photosynthetic pigments. The chlorophyll appeared to tackle monosulfuron concentrations. The caroteniod content of algae treated with 0.008 and 0.08 mg/L monosulfuron exposed to 2000-lux had a different stimulatory effect from that of treatments exposed to 3000-lux and 4000-lux, but an inhibitory effect at concentration above 0.8 mg/L. The effect of monosulfuron on biliprotein in cells of A. flos-aquae exposed three light intensities displayed contrary dose dependence.
Highlights
Effects of herbicides on non-target organisms in the soil ecosystem such as microorganisms have recently been paid great attention
It can be seen that the herbicide monosulfuron applied stimulated the algal growth at initially 24h, but markedly inhibited the mixotrophic growth of the algal grown exposed to three light intensities in a dose-dependent manner; namely, the inhibitory effect increased with the increase in monosulfuron concentration
It is clear that A. flos-aquae had different degrees of sensitivity to monosulfuron with the most sensitive light intensity being 4000-lux followed by 3000-lux and 2000-lux
Summary
Effects of herbicides on non-target organisms in the soil ecosystem such as microorganisms have recently been paid great attention. Nitrogenfixing cyanobacteria, are important photosynthetic microoganisms because they contribute to soil fertility by fixing atmospheric nitrogen. They are sensitive to herbicides because they have many characteristics of higher plants [1]. Many effects of herbicides on non-target algae, such as algal growth, photosynthesis, nitrogen fixation, and metabolic activities have been reported [2]. In the fields, the algae grown in soil or inland waters is mixotrophic rather than autotrophic [3], and herbicide toxicity to algae is affected by many environmental factors such as nutrient level, temperature, and light. Little is known about the specific roles of these environmental factors, the effect of light on herbicide toxicity to algal growth
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
