Potassium chloride, Na-pyrophosphate, CuCl2, NH4-oxalate, dithionite-citrate-bicarbonate (DCB) and Na-citrate solutions were employed to extract aluminum (Al) and iron (Fe) sequentially and separately from 15 acidic s...Potassium chloride, Na-pyrophosphate, CuCl2, NH4-oxalate, dithionite-citrate-bicarbonate (DCB) and Na-citrate solutions were employed to extract aluminum (Al) and iron (Fe) sequentially and separately from 15 acidic soils located at the Mangshan Mountains, Hunan Province, China. Many evidences showed that separate pyrophosphate extracted mainly KCI-extractable Al, organo-Al complexes and some inorganic Al compounds, whereas separate CuCl2 extracted KCl-extractable Al and some organo-Al complexes. CuCl2 extracted much less amounts of Al than pyrophosphate did from the soils. Separate oxalate did not extract all KCl-Pyrophosphate- CuCl2 -oxalate sequentially extractable Al and Fe. Also, separate DCB did not extract all KCl- pyrophosphate- CuCl2 -oxalate- DCB sequentially extractable Al. The forms of Al extracted by oxalate and DCB from the soils were majorly noncrystalline. The interlayered materials of 1.4-nm intergrade minerals of the soils were attributed mainly to hydroxy Al polymers.展开更多
We conducted sexual selection experiments to produce strains with high and low mating discrimination in females of laboratory strains of Hawaiian Drosophila, D.silvestris, then examined secondary sexual traits of thes...We conducted sexual selection experiments to produce strains with high and low mating discrimination in females of laboratory strains of Hawaiian Drosophila, D.silvestris, then examined secondary sexual traits of these two lines, and compared them with that of standard line. In order to do this, we screened out super-males which mated successfully with females and with high mating records;and poor males which usually could not mate successfully with females and had low mating records. In the meantime,choosy females were also screened out, which almost never responded to males' nuptial dance and were difficult to be mated; but indiscriminate females were on the contrary,which were very ready to accept male's nuptial dance and were very easy to be mated. As a result, by mating supermales with choosy females, we were able to produce the high-line strain; similarly, for the low line, we mated poor males with indiscriminate females and we had a strain that was significantly different from our standard strain within just two generations of selection, i.e., morphological trait differences were measured between the standard strain and the two selected lines, which indicated that mating discrimination has affected secondary sexual traits of the lowline strain significantly: Cilia number on the foretibia of low-line males is significantly different from that of the standard line, which perhaps was the indication of incipient speciation in Hawaiian Drosophila.展开更多
文摘Potassium chloride, Na-pyrophosphate, CuCl2, NH4-oxalate, dithionite-citrate-bicarbonate (DCB) and Na-citrate solutions were employed to extract aluminum (Al) and iron (Fe) sequentially and separately from 15 acidic soils located at the Mangshan Mountains, Hunan Province, China. Many evidences showed that separate pyrophosphate extracted mainly KCI-extractable Al, organo-Al complexes and some inorganic Al compounds, whereas separate CuCl2 extracted KCl-extractable Al and some organo-Al complexes. CuCl2 extracted much less amounts of Al than pyrophosphate did from the soils. Separate oxalate did not extract all KCl-Pyrophosphate- CuCl2 -oxalate sequentially extractable Al and Fe. Also, separate DCB did not extract all KCl- pyrophosphate- CuCl2 -oxalate- DCB sequentially extractable Al. The forms of Al extracted by oxalate and DCB from the soils were majorly noncrystalline. The interlayered materials of 1.4-nm intergrade minerals of the soils were attributed mainly to hydroxy Al polymers.
基金supported by the China Scholarship Council(CSC)(2010843314)
文摘We conducted sexual selection experiments to produce strains with high and low mating discrimination in females of laboratory strains of Hawaiian Drosophila, D.silvestris, then examined secondary sexual traits of these two lines, and compared them with that of standard line. In order to do this, we screened out super-males which mated successfully with females and with high mating records;and poor males which usually could not mate successfully with females and had low mating records. In the meantime,choosy females were also screened out, which almost never responded to males' nuptial dance and were difficult to be mated; but indiscriminate females were on the contrary,which were very ready to accept male's nuptial dance and were very easy to be mated. As a result, by mating supermales with choosy females, we were able to produce the high-line strain; similarly, for the low line, we mated poor males with indiscriminate females and we had a strain that was significantly different from our standard strain within just two generations of selection, i.e., morphological trait differences were measured between the standard strain and the two selected lines, which indicated that mating discrimination has affected secondary sexual traits of the lowline strain significantly: Cilia number on the foretibia of low-line males is significantly different from that of the standard line, which perhaps was the indication of incipient speciation in Hawaiian Drosophila.
