The cellular sites of the glycoproteins Group 1 allergen (glycoprotein 1) and Antigen A (glycoprotein 2) in mature ryegrass pollen have been investigated by immunoelectron microscopy. Radioimmunoassays confirm previous findings of cross-reactivity between the purified glycoprotein antigens at the high immunoglobulin G (IgG) concentrations used for localization. Freeze-drying of anthers followed by anhydrous processing has been employed because of the water solubility and mobility of the glycoproteins. A double-embedding technique has been developed. This involves, first, embedding anthers in the water-soluble plastic resin JB-4, sectioning and incubating in ferritin-labelled antisera by the indirect method. The sections are then embedded in Spurr's resin for ultra-thin sectioning. Both glycoproteins are found in the following sites: (1) exine and intine wall layers; (2) pollen cytoplasm; (3) the orbicules and anther loculus; and (4) the anther cuticle. In the exine arcades and surface and in the anther loculus, the ferritin label is bound to pollenkitt. The finding that the glycoproteins are in similar sites is predictable in view of the cross-specificity of the antisera. The extent of antibody penetration of the plastic sections has been examined; labelling is confined to cut grains and absent from intact grains.

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The response to incompatible (self) pollination in rye (Secale cereale L.) includes the rapid deposition in the germinating pollen grain and pollen tube of a substance that stains with aniline blue, resorcin blue and calcofluor, and in these respects resembles callose. This substance has been isolated and analysed by acid hydrolysis and methylation as well as specific enzyme hydrolysis. It contains a glucan component with 1,4-β-glucosidic and 1,3-β-glucosidic linkages within the same linear chains. The proportion of 1,4-to 1,3-glucosidic linkages in the preparation is 77∶9.