Inhibition of phytoplankton by allelochemicals released by submerged macrophytes is supposed to be one of the mechanisms that contribute to the stabilisation of clear-water states in shallow lakes. The relevance of this process at ecosystem level, however, is debated because in situ evidence is difficult to achieve. Our literature review indicates that allelopathically active species such as My...

this research was carried out to investigate allelopathic effect of peganum harmala on seed germination of bromus tectorum. aboveground and underground tissues of peganum harmala in addition to its seeds were collected from bijar rangelands. collected materials of root, leaves, stem, seeds and a complex of mentioned parts were dried and powder. the research was performed at the greenhouse condi...

Salinity is one of the main factors that explain the distribution of species in the Baltic Sea. Increased precipitation and consequent increase in freshwater inflow is predicted to decrease salinity in some areas of the Baltic Sea. Clearly such changes may have profound effects on the organisms living there. Here we investigate the response of the commonly occurring cyanobacterium Dolichospermu...

Although the impacts of exotic plant invasions on community structure and ecosystem processes are well appreciated, the pathways or mechanisms that underlie these impacts are poorly understood. Better exploration of these processes is essential to understanding why exotic plants impact only certain systems, and why only some invaders have large impacts. Here, we review over 150 studies to evalu...

Phytoplankton have been shown to compete for light and nutrients through different physiological and biochemical adaptations, such as, variation in surface area to volume ratio, production of specific enzymes, different nutrient requirements, luxury uptake, pigment composition, photosynthetic capacity, mixotrophy and vertical migration. Algal proliferations with respect to competition are part ...

Coral reefs are in dramatic global decline due to a host of local- and global-scale anthropogenic disturbances that suppress corals and enhance seaweeds. This decline is exacerbated, and recovery made less likely, due to over-fishing of herbivores that normally limit seaweed effects on corals. Seaweeds were known to suppress coral reproduction and recruitment, but in a recent study, we demonstr...

Tropical reefs are in global decline with seaweeds commonly replacing corals. Negative associations between macroalgae and corals are well documented, but the mechanisms involved, the dynamics of the interactions, and variance in effects of different macroalgal-coral pairings are poorly investigated. We assessed the frequency, magnitude, and dynamics of macroalgal-coral competition involving al...

Steffens and Robeson, 1987). The compound inhibited the onion seedling elongation by 4, 32, 40, 68, and 94% The seeds of some dicotyledons fail to germinate and grow well at concentrations of 1029, 1028, 1027, 1026, and 1025 M, when contaminated by Aspergillus japonicus Saito. One strain of A. japonicus isolated from the seeds of contaminated rape (Brassica respectively. Penicillium oxalicum, w...