in this study the effect of nitrogen form and different oxygen levels on growth and development and macronutrients concentrations in lettuce plants was investigated. this investigation showed that sole ammonium application caused fresh and dry weight reduction of shoot and root in lettuce plant. but different oxygen levels had no effect on them. nitrogen concentration of shoot was higher in amm...

Nitrogen exists in soils in many forms and constantly changes from one form to another. The paths that the different forms of nitrogen follow through the ecosystem are collectively called the nitrogen cycle (Figure 1). Understanding how the different pools of nitrogen interact and the processes by which these forms enter and leave the cycle is the subject of continuing study. Nitrogen is found ...

This review provides a good overview of biological nitrogen fixation in the growth of leguminous plants, particularly relating to fertilizer needs for crops. In addition to plants that form nodules that host nitrogen-fixing bacteria, other bacteria form different associations with plants, and this is currently under intense study to determine if there is significant nitrogen transfer to the pla...

The complex symbiotic relationship between corals and their dinoflagellate partner Symbiodinium is believed to be sustained through close associations with mutualistic bacterial communities, though little is known about coral associations with bacterial groups able to fix nitrogen (diazotrophs). In this study, we investigated the diversity of diazotrophic bacterial communities associated with t...

The experiment sets out to investigate the effect of oxidation-reduction on nitrogen formsin soil. trial was a 3 x 2 factorial laid in Randomized Complete Block Design (RCBD) and replicated three times. Treatment consisted two variables which are poultry manure at levels (0t/ha, 6t/ha 8t/ha) water regime (field capacity waterlogged).The combinations resulted into six (6) treatments resulting po...

Legumes form root nodules to gain fixed nitrogen from rhizobia and can also access in soil. Data suggest that plants might discriminate among these sources optimize growth, but recognition of symbiotically its regulation remain poorly understood. A greenhouse inoculation study manipulated the molecular concentration available using two Lotus japonicus genotypes nitrogen-fixing symbiont, Mesorhi...

Dinoflagellates are important contributors to the marine phytoplankton and global carbon fixation, but are also infamous for their ability to form the spectacular harmful algal blooms called red tides. While blooms are often associated with high available nitrogen, there are instances where they are observed in oligotrophic environments. In order to maintain their massive population in conditio...

In previous work with the chlorate method (1, 2) for determining nitrogen in plant tissues, materials were used in which the amounts of ammonia and amide nitrogen were either absent or negligible in relation to the total nitrogen present. In working with samples containling significant amounts of ammonia compounds or amide nitrogen, it is necessary to accomiipany the determination with a Nessle...