The Ebinur Lake region was described as a "Green Labyrinth" in "Xinjiang Map Records: Records of Rivers" published in 1910, however, the ecology and environment in the region have been seriously degenerated due to the impacts of human activities during the recent 40 years. A dried-up lake basin with an area of 107.4 km^2 forms in its northwestern part, is covered by unconsolidated silt deposit without vegetation, and has become one of the main dust sources of dust weathers in north Xinjiang, and the dust with an annual amount of 4.8×10^6 t is blown out of the region by strong winds from the Alataw mountain-gap where there are 164 days occurring strong winds in a year. The rational water area and inflow of the Ebinur Lake for improving the ecology in the lake region and effectively controlling wind erosion in the dried-up lake basin are estimated using the water balance equation after analyzing the current ecological problems and the relationship between the granular composition of deposit in the dried-up lake basin and the dust weathers, and the ecological effects in recent years are monitored. It is considered that the water area of the Ebinur Lake for improving the ecology in the lake region and effectively controlling wind erosion in the dried-up lake basin should be 800 km^2at least, and the annual volume of surface runoff and groundwater recharging the lake should be over 7.92×10^8 m^3. 相似文献
In this study, an ASD spectrometer made in USA is used to derive the hyperspectral data of cotton leaves in canopy in north Xinjiang. The integral area variables of red edge are used to estimate the total nitrogen (TN) content in cotton leaves in canopy. The first order differential of reflective spectra is carried out. The analysis methods based on the spectral position variables are derived from the first order differential spectral data. The analysis on the correlation between the integral area of red edge (SDr, regarded as the independent variable) and the TN content (regarded as the function) is carried out, and the correlation mathematical model between the integral area of red edge and the TN content in canopy leaves of cotton varieties named as Xinluzao No.6 is developed. The analysis on the correlation between the chlorophyll content and the TN content in single cotton leaves in canopy growing under the irrigation with different water volumes is carried out. The results show that there is a significant positive correlation between the chlorophyll content and the TN content (R = 0.8723, n = 39), and the data of chlorophyll content can be used to estimate the TN content in single cotton leaves; the correlation between the integral area variable of red edge and the TN content in cotton leaves in canopy is significant, their correlation coefficient is 0.7394 (n = 40), the TN contents in canopy leaves of cotton varieties named as Xinluzao No. 6 and No. 8 can be accurately estimated by using the developed model, and their RMSE values are 0.3859 and 0.4272 respectively. After researching, it is considered that there is an applying potential to use the integral area variables of red edge for estimating the TN content in cotton leaves in canopy, and the mathematical model developed with the third-side area variables has a high applying value in deriving the TN content in crop canopy. It is also considered that it is feasible to recognize the moisture stress suffered by cotton plants by researching the shift and change extent of red edge, and the key is to develop the corresponding rational recognition index system.
Retinoic acid (RA) plays an important role in development of vertebrate embryos. We demonstrate impacts of exogenous RA on
the formation of neural crest cells in zebrafish using specific neural crest markers sox9b and crestin. Treatment with all -trans RA at 10−7 mmol/L at 50% epiboly induces sox9b expression in the forebrain and crestin expression in the forebrain and midbrain, resulting in significant increase of pigment cells in the head derived from the
cranial neural crest. In addition, RA treatment induces expression of sox9b and crestin in the caudal marginal cells of the neuroectoderm during early segmentation. Earlier commitment of these cells to the neural
crest fate in the posterior margins leads to abnormal development of the posterior body, probably by preventing mingling of
ventral derived and dorsal-derived cells during the formation of the tailbud. 相似文献
Fibronectins (FNs) are major extracellular proteins in blood plasma and many tissues of vertebrates, and play important roles in adhesion, migration and differentiation of cells. We have identified a novel variant (FN3) of fibronectin in zebrafish. FN3 mRNA is abundant, as detected by whole-mount in situ hybridization, in the presomitic mesoderm and the newly formed somites, but less abundant in mature somites. Ectopic expression of Sonic Hedgehog (SHH) results in a decrease of FN3 expression, whereas the expression level of FN3 increases in the flh mutants that lack the notochord. Our results suggest that FN3 may be involved in the formation of somites, but during somite differentiation its expression needs to be downregulated by signals derived from the axial tissues. 相似文献
The Ebinur Lake region was described as a “Green Labyrinth” in “Xinjiang Map Records: Records of Rivers” published in 1910, however, the ecology and environment in the region have been seriously degenerated due to the impacts of human activities during the recent 40 years. A dried-up lake basin with an area of 107.4 km2 forms in its northwestern part, is covered by unconsolidated silt deposit without vegetation, and has become one of the main dust sources of dust weathers in north Xinjiang, and the dust with an annual amount of 4.8×106 t is blown out of the region by strong winds from the Alataw mountain-gap where there are 164 days occurring strong winds in a year. The rational water area and inflow of the Ebinur Lake for improving the ecology in the lake region and effectively controlling wind erosion in the dried-up lake basin are estimated using the water balance equation after analyzing the current ecological problems and the relationship be-tween the granular composition of deposit in the dried-up lake basin and the dust weathers, and the ecological effects in recent years are monitored. It is considered that the water area of the Ebinur Lake for improving the ecology in the lake region and effec-tively controlling wind erosion in the dried-up lake basin should be 800 km2 at least, and the annual volume of surface runoff and groundwater recharging the lake should be over 7.92×108 m3. 相似文献