With the forms of pistil stigma of " Guiti 2" Chinese water chestnut cultivar during the pollination as the object of observation,we reveal the pollination process of Chinese water chestnut from the microsco...With the forms of pistil stigma of " Guiti 2" Chinese water chestnut cultivar during the pollination as the object of observation,we reveal the pollination process of Chinese water chestnut from the microscopic point of view,to provide reference for Chinese water chestnut crossbreeding. The results show that the Chinese water chestnut pistil has 2- 4 stigmas which present white filament and vascular bundle forms,and the vessels on epidermis are thick with long translucent branched hairs; after pollination,pollen grains are tightly bound on branched hairs,and after identification,the pollen tube can penetrate branched hairs,continue to grow,and transfer the genetic material in pollen to vascular bundle.展开更多
Particles from ambient air and combustion sources including vehicle emission, coal combustion and biomass burning were collected and chemically pretreated with the purpose of obtaining isolated BC（black carbon） samp...Particles from ambient air and combustion sources including vehicle emission, coal combustion and biomass burning were collected and chemically pretreated with the purpose of obtaining isolated BC（black carbon） samples. TEM（transmission electron microscopy）results indicate that BC from combustion sources shows various patterns, and airborne BC appears spherical and about 50 nm in diameter with a homogeneous surface and turbostratic structure. The BET（Barrett-Emmett-Teller） results suggest that the surface areas of these BC particles fall in the range of 3-23 m2/g, with a total pore volume of 0.03-0.05 cm3/g and a mean pore diameter of 7-53 nm. The nitrogen adsorption-desorption isotherms are indicative of the accumulation mode and uniform pore size. O2-TPO（temperature programmed oxidation）profiles suggest that the airborne BC oxidation could be classified as the oxidation of amorphous carbon, which falls in the range of 406-490℃ with peaks at 418, 423 and 475℃,respectively. Generally, the BC characteristics and source analysis suggest that airborne BC most likely comes from diesel vehicle emission at this site.展开更多
文摘With the forms of pistil stigma of " Guiti 2" Chinese water chestnut cultivar during the pollination as the object of observation,we reveal the pollination process of Chinese water chestnut from the microscopic point of view,to provide reference for Chinese water chestnut crossbreeding. The results show that the Chinese water chestnut pistil has 2- 4 stigmas which present white filament and vascular bundle forms,and the vessels on epidermis are thick with long translucent branched hairs; after pollination,pollen grains are tightly bound on branched hairs,and after identification,the pollen tube can penetrate branched hairs,continue to grow,and transfer the genetic material in pollen to vascular bundle.
基金supported by the Key project for Beijing Municipal Science and Technology Plan (No. D131100003613002)the Open Project from Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control of Nanjing University of Information Science and Technology (KHK1108)the Jiangsu Province Innovation Platform for Superiority Subject of Environmental Science and Engineering
文摘Particles from ambient air and combustion sources including vehicle emission, coal combustion and biomass burning were collected and chemically pretreated with the purpose of obtaining isolated BC（black carbon） samples. TEM（transmission electron microscopy）results indicate that BC from combustion sources shows various patterns, and airborne BC appears spherical and about 50 nm in diameter with a homogeneous surface and turbostratic structure. The BET（Barrett-Emmett-Teller） results suggest that the surface areas of these BC particles fall in the range of 3-23 m2/g, with a total pore volume of 0.03-0.05 cm3/g and a mean pore diameter of 7-53 nm. The nitrogen adsorption-desorption isotherms are indicative of the accumulation mode and uniform pore size. O2-TPO（temperature programmed oxidation）profiles suggest that the airborne BC oxidation could be classified as the oxidation of amorphous carbon, which falls in the range of 406-490℃ with peaks at 418, 423 and 475℃,respectively. Generally, the BC characteristics and source analysis suggest that airborne BC most likely comes from diesel vehicle emission at this site.
