Nitrogen (N) availability influences the productivity and distribution of plants in tropical montane forests. Strategies to acquire soil N, such as direct uptake of organic compounds or associations with root symbionts to enhance N acquisition in exchange for carbon (C), may facilitate plant species coexistence and ecosystem N retention. Alternatively, rapid microbial turnover of soil N forms i...

Studies of wintertime air quality in the North China Plain (NCP) show that particulate-nitrate pollution persists despite rapid reduction NOx emissions. This intriguing NOx-nitrate relationship may originate from non-linear nitrate-formation chemistry, but it is unclear which feedback mechanisms dominate NCP. In this study, we re-interpret observations 17O excess nitrate (∆17O(NO3−)) Beijing us...

OBJECTIVE Perchlorate is a known competitive inhibitor of the sodium/iodide symporter (NIS). Possible thyroid-related effects of environmental perchlorate have created great health concerns, especially in the US, resulting in a debated reference dose (RfD) of 0.0007 mg/kg per day in drinking water recommended by the National Academy of Sciences (NAS). However, the impact of other environmental ...

Coordination of shoot photosynthetic carbon fixation with root inorganic nitrogen uptake optimizes plant performance in a fluctuating environment [1]. However, the molecular basis of this long-distance shoot-root coordination is little understood. Here we show that Arabidopsis ELONGATED HYPOCOTYL5 (HY5), a bZIP transcription factor that regulates growth in response to light [2, 3], is a shoot-t...

The impact of light and nutrients (such as silicate and iron) availability on nitrogen uptake and primary production vary seasonally and regionally in the Southern Ocean. The seasonal cycle of nitrogen uptake by phytoplankton in the Southern Ocean is not fully resolved over an annual scale due to the lack of winter in situ measurements. In this study, nitrate and ammonium uptake rates were meas...

Recent research shows that signals derived from nitrate are involved in triggering widespread changes in gene expression, resulting in a reprogramming of nitrogen and carbon metabolism to facilitate the uptake and assimilation of nitrate, and to initiate accompanying changes in carbon metabolism. These nitrate-derived signals interact with signals generated further downstream in nitrogen metabo...

A 4.0-kb DNA fragment of Trichodesmium sp. strain WH9601 contained gene sequences encoding the nitrate reduction enzymes, nirA and narB. A third gene positioned between nirA and narB encodes a putative membrane protein with similarity to the nitrate permeases of Bacillus subtilis (NasA) and Emericella nidulans (CrnA). The gene was shown to functionally complement a DeltanasA mutant of B. subtil...

Chlorella vulgaris was grown using mixed sources of nitrogen (nitrate and nitrite). Starting from B3N as basal medium, nitrate substituted by nitrite keeping total constant over 7 conditions: 0, 20, 40, 50, 60, 80 100% NO2–. Growth rate, uptake, photosynthetic apparatus status pigment contents were monitored. Nitrite addition triggered a growth rate inhibition early introduction (20% NO2–, 81 m...

in the present study, the root vigor and kinetic characteristics of nitrogen absorption in potato cultivars was investigated through sand cultivation and pot tests with nutrient solution. four cultivars of potatoes, namely, feiwuruita, yunshu301, liangshu97, and chuanyu56 were grown in nutrient solution matrix cultures. the result showed that: (1) nitrogen uptake rates differed significantly am...