Intergeneric Hybridisation between Litchi (Litchi chinensis Sonn.) and Longan (Dimocarpus longan Lour.)

The breeding barriers between commercial litchi (Litchi chinensisSonn.) and longan (Dimocarpus longan Lour.) cultivars were investigatedby conducting reciprocal pollinations. This work has shown thatit is possible to generate intergeneric hybrids using litchias the female parent. Investigation of comparative in vivo pollentube growth demonstrated that there is discrimination againstcross- compared to self-pollen at all sites in the pistil. Pollentubes were frequently observed in the ovary after cross-pollinationin litchi but rarely in longan. Fruit production was reducedafter crossing in both longan and litchi. Isozyme analysis usingphosphoglucose isomerase revealed that hybrid progeny only developedwhen litchi was the maternal parent. Morphologically the hybridplants were similar to the maternal parent but leaves were smaller.Three types of seeds developed in litchi following pollinationwith longan pollen. These were (1) normal seeds with a developedtesta and embryo, (2) seeds with aborted embryos but normaltesta development, and (3) seedless fruit where the ovule remainedthe same size as at anthesis without further development ofembryo or testa. The potential germplasm available to improvethese crops within the Sapindaceae is discussed.Copyright 1994,1999 Academic Press Litchi, Litchi Longan, Dimocarpus, hybridisation, isozyme     

Characterization of Aqueous Pb(II) and Cd(II) Biosorption on Native and Chemically Modified Alstonia macrophylla Saw Dust

This study was conducted in order to understand the mechanism of Cd and Pb adsorption in aqueous solutions by raw and modified saw dust (SD) of Alstonia macrophylla. The biosorbent was characterized by Boehm titration, specific surface area, scanning electron microscopy (SEM), X-ray energy dispersion (EDAX), and Fourier transform infrared (FTIR) analyses. SD was treated using organic acids and bases. Batch studies were conducted for raw and modified SD to determine the effect of initial concentration, pH, ionic strength, and contact time on metal adsorption. The specific surface area and total basic and acidic groups of SD were 77 m²/g and 1521 and 2312 μmol/g, respectively. The adsorption of both metals onto SD was pH dependent. No ionic strength dependency was observed in adsorption of Cd and Pb at pH >6, indicating inner sphere surface complexation. Monolayer adsorption is dominant in both metal sorptions by SD. Furthermore, there is no competition between metals on adsorption and raw SD was found to be suitable for removal of Cd and Pb as compared to organic acid– or base-treated SD. Maximum adsorption capacity of SD for Cd and Pb were 30.6 and 204.2 mg/g, respectively. Results indicate that the A. macrophylla SD can be considered as a potential material for metal ion removal from wastewater.     

Immunofluorescent localization of two water-soluble glycoproteins including the major allergen from the pollen of ryegrass,Lolium perenne

Summary Two major glycoproteins have been localized in sectioned grains of ryegrass pollen by direct and indirect immunofluorescence methods using Fluorescein isothiocyanate (FITC)-labelled IgC fractions of antisera. These glycoproteins are the major allergen Group 1 allergen, and a principal antigen Antigen A. Four methods of fixation were employed: freeze-drying, methanol, 2.5% glutaraldehyde and 4% paraformaldehyde for 1 h at 4°C. The post-embedding staining technique of immunocytochemistry was used: anthers were embedded directly, or after dehydration, in JB-4 plastic resin and antibody reacted with sectioned pollen.The effects of these fixatives on the antibody combining sites of the antigens were quantified by a solid phase radioimmunoassay using [¹²⁵I]protein A to measure antibody binding. Glutaraldehyde was the only fixative to significantly depress antibody binding of both Antigen A and Group 1 allergen to their homologous antisera. This radioimmunoassay was modified to reyeal that FITC conjugation to either antibody did not impair antigen binding. In mature pollen, these antigens were located in the cytoplasm and in the complex wall. In developing grains early in the maturation period, specific fluorescence was concentrated at the periphery of the cytoplasm.