In order to reveal the effects of nitrogen (N) deposition on forest ecosystems, we investigated the soil N dynamics across a chronosequence of subtropical evergreen broad-leaved forest stands in eastern China for two years. Current atmospheric N deposition was 18 kg ha -1 year -1 . Nitrogen fluxes in throughfall varied from 17 to 23 kg hawith an increasing trend with stand age. The total N fluxes ranged from 7.3 to 9.3 kg ha -1 year -1 under the forest floor and from 1.2 to 2.5 kg ha -1 year -1 at 30-cm soil depth with the high values in the older stand. The net mineralization potentials in the old stands ranged from 19 to 24 mg kg -1 month -1 , and were 30-55% higher than those in the young stands. The inorganic N concentration and flux at 30-cm soil depth were significantly (p < 0.05) correlated with net mineralization potential. The potential N transformation rates were significantly (p < 0.05) correlated with soil C/N ratio and DON while not with forest floor C/N ratio. Input-output budget suggests that the forest at our site is a finer buffering system to N deposition and is far from N saturation.

We report a versatile cyclometalated Iridium (III) complex probe that achieves synchronous fluorescence-electron microscopy correlation to reveal microtubule ultrastructure in cells. The selective insertion of probe between repeated and units of microtubule triggers remarkable fluorescent enhancement, and high TEM contrast due to the presence of heavy Ir ions. The highly photostable probe allows live cell imaging of tubulin localization and motion during cell division with an resolution of 20 nm, and under TEM imaging reveals the unit interspace of 45Å of microtubule in cells.