Alpine revegetated dunes have been barely researched in terms of morphological change and migration within its regional aeolian environments. To reveal the sand-fixing and land-reforming mechanisms of artificial veget...Alpine revegetated dunes have been barely researched in terms of morphological change and migration within its regional aeolian environments. To reveal the sand-fixing and land-reforming mechanisms of artificial vegetation, we observed the morphology and migration of four dunes with four revegetated types(Hippophae rhamnoides Linn., Salix cheilophila Schneid., Populus simonii Carr., and Artemisia desertorum Spreng.) using unpiloted aerial vehicle images and GPS(global positioning system) mapping in 2009 and 2018. Spatial analysis of GIS(geographic information system) revealed that the revegetated dunes exhibited a steady progression from barchan dune shapes to dome or ribbons shapes mainly through knap planation, wing amplification, and slope symmetrization. Generally, conditions of northern aspects, smaller slope degree, and larger altitude of unvegetated dunes would suffer more serious wind erosion. The southward movement of dune wings with a migration speed of 2.0–5.0 m/a and the alternating motion of sand ridges in eastwestern directions led greater stability in revegetated dunes. The moving distances of revegetated dunes remarkably changed in patterns of quadratic or linear function with depositional depth. Compared with unvegetated dunes, the near-surface wind velocity of revegetated dunes decreased by 20%–30%, which led to heavy accumulation in low-flat dunes and erosion in high-steep dunes, but all vegetation species produced obvious sand-fixing benefits(100%–450% and 3%–140% in the lower and higher dune scales of revegetated dunes, respectively) with decreasing sand transport rates and increasing coverages. In practice, the four vegetation species effectively anchored mobile dunes by adapting to regional aeolian environment. However, future revegetation efforts should consider optimizing dune morphology by utilizing H. rhamnoides as a pioneer plant, S. cheilophila and P.microphylla in windward and northward dune positions, and A. desertorum in a sand accumulative southward position. Also, we should adjust afforestation structure and replant some shrub or herbs in the higher revegetated dunes to prevent fixed dune activation and southward expansion.展开更多
在中枢神经系统中，髓鞘是由少突胶质细胞的突起缠绕神经元轴突所形成的管状节段性结构，其主要成分是70％脂类和30％蛋白质构成的鞘磷脂结构，而有髓神经纤维是大脑白质的重要组成部分。目前，检测髓鞘脂类表达的方法有多种，其中劳克...在中枢神经系统中，髓鞘是由少突胶质细胞的突起缠绕神经元轴突所形成的管状节段性结构，其主要成分是70％脂类和30％蛋白质构成的鞘磷脂结构，而有髓神经纤维是大脑白质的重要组成部分。目前，检测髓鞘脂类表达的方法有多种，其中劳克坚牢蓝（1uxol fast blue，LFB）染色是一种较为常用的髓鞘染色方法.但LFB染色也有不同的复染方法，其染色效果亦有差异。本研究通过对成年鼠和幼鼠2种不同鼠龄阶段的大脑髓鞘LFB染色，比较焦油紫和伊红2种不同复染方法的优缺点，为相关研究提供合适的染色方法。展开更多
基金funded by the Jiangxi Provincial Natural Science Foundation (20202BABL213028)the Open Project of the State Key Laboratory of Plateau Ecology and Agriculture, Qinghai University, China (2022-KF-07)the Doctoral Scientific Research Foundation of East China University of Technology (2019052, 2019045)。
文摘Alpine revegetated dunes have been barely researched in terms of morphological change and migration within its regional aeolian environments. To reveal the sand-fixing and land-reforming mechanisms of artificial vegetation, we observed the morphology and migration of four dunes with four revegetated types(Hippophae rhamnoides Linn., Salix cheilophila Schneid., Populus simonii Carr., and Artemisia desertorum Spreng.) using unpiloted aerial vehicle images and GPS(global positioning system) mapping in 2009 and 2018. Spatial analysis of GIS(geographic information system) revealed that the revegetated dunes exhibited a steady progression from barchan dune shapes to dome or ribbons shapes mainly through knap planation, wing amplification, and slope symmetrization. Generally, conditions of northern aspects, smaller slope degree, and larger altitude of unvegetated dunes would suffer more serious wind erosion. The southward movement of dune wings with a migration speed of 2.0–5.0 m/a and the alternating motion of sand ridges in eastwestern directions led greater stability in revegetated dunes. The moving distances of revegetated dunes remarkably changed in patterns of quadratic or linear function with depositional depth. Compared with unvegetated dunes, the near-surface wind velocity of revegetated dunes decreased by 20%–30%, which led to heavy accumulation in low-flat dunes and erosion in high-steep dunes, but all vegetation species produced obvious sand-fixing benefits(100%–450% and 3%–140% in the lower and higher dune scales of revegetated dunes, respectively) with decreasing sand transport rates and increasing coverages. In practice, the four vegetation species effectively anchored mobile dunes by adapting to regional aeolian environment. However, future revegetation efforts should consider optimizing dune morphology by utilizing H. rhamnoides as a pioneer plant, S. cheilophila and P.microphylla in windward and northward dune positions, and A. desertorum in a sand accumulative southward position. Also, we should adjust afforestation structure and replant some shrub or herbs in the higher revegetated dunes to prevent fixed dune activation and southward expansion.
文摘在中枢神经系统中，髓鞘是由少突胶质细胞的突起缠绕神经元轴突所形成的管状节段性结构，其主要成分是70％脂类和30％蛋白质构成的鞘磷脂结构，而有髓神经纤维是大脑白质的重要组成部分。目前，检测髓鞘脂类表达的方法有多种，其中劳克坚牢蓝（1uxol fast blue，LFB）染色是一种较为常用的髓鞘染色方法.但LFB染色也有不同的复染方法，其染色效果亦有差异。本研究通过对成年鼠和幼鼠2种不同鼠龄阶段的大脑髓鞘LFB染色，比较焦油紫和伊红2种不同复染方法的优缺点，为相关研究提供合适的染色方法。
