[Leaf photosynthetic pigment seasonal dynamic of Quercus aliena var. acuteserrata and its spectral reflectance response under throughfall elimination]. / ç©¿é€é›¨å‡å°‘ä¸‹é”é½¿æ Žå¶ç‰‡å ‰åˆè‰²ç´ å­£èŠ‚åŠ¨æ€åŠå ¶åå°„å ‰è°±å“åº”.

Our objective was to explore the mechanism of spectral reflectance response to leaf photosynthetic pigment seasonal dynamic of Quercus aliena var. acuteserrata under throughfall elimination. We simulated rainfall decline through throughfall elimination (TFE) treatment in the experiment plots of Baotianman Natural Reserve in Henan, measured leaf pigment content and its spectral reflectance during growing season in both TFE and control plots. We analyzed seasonal changes of photosynthetic pigments and changes of pigments induced by TFE and their spectral reflectance responses. The results showed that all photosynthetic pigments content and pigment-ratios exhibited clear seasonal patterns. Leaf photosynthetic pigments content and ratio had differences between TFE plot and control plot during the whole growing season, and significant difference was found in chlorophyll b (Chl b) indicating that Chl b had higher sensitivity than other pigments. Carotenoids (Car) content showed minor difference compared with other pigments, indicating that Car had less sensitivity to TFE. The spectral reflectance of 550 nm was found to be the waveband most sensitive to seasonal changes of pigments, so we formulated the sample ratio index (SR750,550) based on it. The strong positive relationships between SR750,550 and Chl a, Chl b, Chl and Car contents were found with high significant level. Similarly, significant negative relationships were also been found between photochemical reflectance index (PRI) and Car/Chl. The spectral reflectance of 550 nm was most sensitive to changes of pigments induced by TFE. SR750,550 was sensitive to changes of leaf Chl a, Chl b and Chl content induced by TFE (P＜0.01), but not to change of Chl a/b. PRI was sensitive to change of leaf Car/Chl induced by TFE (P＜0.01).

[Research advances in simulating land water-carbon coupling].

The increasing demand of adaptive management of land, forest, and water resources under the background of global change and water resources crisis has promoted the comprehensive study of coupling ecosystem water and carbon cycles and their restrictive relations. To construct the water-carbon coupling model and to approach the ecosystem water-carbon balance and its interactive response mechanisms under climate change at multiple spatiotemporal scales is nowadays a major concern. After reviewing the coupling relationships of water and carbon at various scales, this paper explored the implications and estimation methods of the key processes and related parameters of water-carbon coupling, the construction of evapotranspiration model at large scale based on RS, and the importance of this model in water-carbon coupling researches. The applications of assimilative multivariate data in water-carbon coupling researches under future climate change scenarios were also prospected.

[The variability of vegetation beginning date of greenness period in spring in the north-south transect of eastern China based on NOAA NDVI].

NDVI based on NOAA/AVHRR from 1982 to 2003 are used to monitor variable rules for the growing season in spring of vegetation in the north-south transect of eastern China (NSTEC). The following, mainly, are included: (1) The changing speed of greenness period in spring of most regions in NSTEC is slow and correlation with the year is not distinct; (2) The regions in which greenness period in spring distinctly change mainly presented an advance; (3) The regions in which inter-annual fluctuation of greenness period in spring is over 10 days were found in 3 kinds of areas: the area covered with agricultural vegetation types; the areas covered with evergreen vegetation types; the areas covered with steppe vegetation types; (4) changes of vegetation greenness period in spring have spatio-temporal patterns.

[Canopy interception of sub-alpine dark coniferous communities in western Sichuan, China].

Based on field measurements of throughfall and stemflow in combination with climatic data collected from the meteorological station adjacent to the studied sub-alpine dark coniferous forest in Wolong, Sichuan Province, canopy interception of sub-alpine dark coniferous forests was analyzed and modeled at both stand scale and catchment scale. The results showed that monthly interception rate of Fargesia nitida, Bashania fangiana--Abies faxoniana old-growth ranged from 33% Grass to 72%, with the average of 48%. In growing season, there was a linear or powerful or exponential relationship between rainfall and interception an. a negative exponential relationship between rainfall and interception rate. The mean maximum canopy interception by the vegetation in the catchment of in.44 km was 1.74 ment and the significant differences among the five communities occurred in the following sequence: Moss-Fargesia nitida, Bashan afanglana-A. faxoniana stand > Grass-F. nitida, B. fangiana-A. faxoniana stand > Moss-Rhododendron spp.-A. faxoniana stand > Grass-Rh. spp.-A. faxoniana stand > Rh. spp. shrub. In addition, a close linear relationship existed between leaf area index (LAI) and maximum canopy interception. The simulated value of canopy interception rate, maximum canopy interception rate and addition interception rate of the vegetation in the catchment were 39%, 25% and 14%, respectively. Simulation of the canopy interception model was better at the overall growing season scale, that the mean relative error was 9%-14%.