Forest productivity declines with tree age. This decline may be due to changes in metabolic functions, resource availability and/or changes in resource allocation (between growth, reproduction and storage) with tree age. Carbon and nitrogen remobilization/storage processes are key to tree growth and survival. However, studies of the effects of tree age on these processes are scarce and have not...

[In the course of studies of the inicorporation of adenine-8-C14 into the nucleic acids of Chlorella vtilgaris we observed an unexpectedly large formation of C'402 by the cultures in the dark. \When the oxidation of adenine in this system wvas followed manometrically, it was found that Up to 10 or 20 times more oxygen was taken up by the cells than could be accounted for by assuming the conmple...

Although organic nitrogen (ON) has been found to be a ubiquitous and significant component in wet and dry deposition, almost nothing is known about its concentration or composition in fog waters. To address this gap, we have investigated the concentration and composition of ON in fog waters collected in Davis, in California’s Central Valley. Significant quantities of dissolved organic nitrogen ...

The influence of fixed nitrogen on Azotobacter both with respect to utilization and inhibition of nitrogen fixation has been studied by a number of investigators. The results have not always been conclusive because of the relatively poor growths of cultures obtained in culture media now known to have been deficient in one or more of the elements essential for nitrogen fixation or growth, partic...

Nitrogen is essential for plant survival and growth. Excessive application of nitrogenous fertilizer has generated serious environment pollution and increased production cost in agriculture. To deal with this problem, tremendous efforts have been invested worldwide to increase the nitrogen use ability of crops. However, only limited success has been achieved to date. Here we report that NLP7 (N...

Under nitrogen deprivation, filaments of the cyanobacterium Anabaena undergo a process of development, resulting in a one-dimensional pattern of nitrogen-fixing heterocysts separated by about ten photosynthetic vegetative cells. Many aspects of gene expression before nitrogen deprivation and during the developmental process remain to be elucidated. Furthermore, the coupling of gene expression f...

The nitrogen cycle (N-cycle) in the biosphere, mainly driven by prokaryotes, involves different reductive or oxidative reactions used either for assimilatory purposes or in respiratory processes for energy conservation. As the N-cycle has important agricultural and environmental implications, bacterial nitrogen metabolism has become a major research topic in recent years. Archaea are able to pe...

Intensive agricultural systems are largely responsible for the increase in global reactive nitrogen compounds, which are associated with significant environmental impacts. The nitrogen cycle in agricultural systems is complex and highly variable, which complicates characterization in environmental assessments. Appropriately representing nitrogen inputs into an ecosystem is essential to better u...