Showing papers by "Wuhan University published in 1982"

In vitro induction of haploid plants from unpollinated ovaries and ovules.

Abstract: A recent advance in plant tissue culture and experimental embryology is the successful induction of haploid plants by the culture of unpollinated ovaries or ovules. It means that not only the microspore but also the megaspore or female gametophyte of angiosperms can be triggered in vitro to sporophytic development, thus opening a new way to genetical research and haploid breeding. Since data so far accumulated are attractive, though not so rich, this paper tends to offer a preliminary review on this problem, covering the historical description, culture experiments, embryological observations, cytological and genetical studies and a brief discussion on its perspectives.

Spectrophotometric Determination of Trace Amounts of Copper in High-Purity Rare Earth with α,ß,γ,δ-Tetra-(4-Trimethylammonium-Phenyl) Porphine

Abstract: High-purity rare earth such as Y2O3 is a common material for the preparation of various solid-state luminescent materials. Since the luminescence is affected by the presence of trace copper impurities, attention has recently been given to the spectrophotometric determination of trace amounts of copper with porphyrin as spectrophotometric reagents, because of their high sensitivity and stability (1–3). In this paper, the complex reaction of water-soluble α,s,γ,δ-tetra-(4-trimethylammoniumphenyl)porphine T(4-TAP)P with copper(II) has been studied. This compound was synthesized according to the method proposed by Krishnamuthy (4). It was found to be a highly sensitive and selective reagent for the direct spectrophotometric determination of copper at ppb level. The soret band of the reagent was laid at 431 nm, which was well separated from that of the complex (411 nm). Apparent molar absorption coefficient of the reagent and sensitivity for 0.001 absorbance were 4.7×105 1 mol−l cm−l and 0.13 ng Cu cm−2, respectively, and that of the complex were 4.0×105 1 mol−l cm−l and 0.16 ng Cu cm−2, respectively (Fig. 1). The interference of many ions and salts has been examined and found to be minimal. Large amounts of rare earths do not interfere with the determination.

Separation of the Rare Earths and Some Polyvalent Cations on Inorganic Ion Exchangers

Abstract: Inorganic ion exchangers have been found to have excellent selectivity for the alkali metals and alkaline earths (1). We have investigated inorganic ion exchangers for the separation of the rare earths and other elements. Thallium tungstophosphate, ammonium molybdophosphate and zirconium tungstate have been studied for the absorption and separation of the rare earths and some polyvalent cations.

Spectrophotometric Determination of Rare Earths in Ligand Buffer Masking Systems

Abstract: Metal ions such as Fe(III), Al(III), Cr(III), Ti(IV) and Zr(IV) interfere strongly with the spectrophotometric determination of rare earths with organic reagents. We have utilized “ligand buffers” (1) for the spectrophotometric determination of rare earths with arsenazo III, dicarboxyarsenazo III, chlorophosphonazo III, carboxynitrazo and semixylenolorange cetylpyridiniumbromide (CPB)