Members of the glucan synthase-like (GSL) family are believed to be involved in synthesis of the cell-wall component callose in specialized locations throughout the plant. We identified two members of the Arabidopsis GSL gene family, GSL8 and GSL10, that are independently required for male gametophyte development and plant growth. Analysis of gsl8 and gsl10 mutant pollen during development reve...

B chromosomes (Bs) are supernumerary components of the genome and do not confer any advantages on the organisms that harbor them. The maintenance of Bs in natural populations is possible by their transmission at higher than Mendelian frequencies. Although drive is the key for understanding B chromosomes, the mechanism is largely unknown. We provide direct insights into the cellular mechanism of...

The dominant allergenic components of grass pollen are known by immunologists as group 1 allergens. These constitute a set of closely related proteins from the beta-expansin family and have been shown to have cell wall-loosening activity. Group 1 allergens may facilitate the penetration of pollen tubes through the grass stigma and style. In maize (Zea mays), group 1 allergens are divided into t...

The walls deposited by growing pollen tubes contain two types of beta-glucan, the (1,3)-beta-glucan callose and the (1,4)-beta-glucan cellulose, as well as various alpha-linked pectic polysaccharides. Pollen tubes of Nicotiana alata Link et Otto, an ornamental tobacco, were therefore used to identify genes potentially encoding catalytic subunits of the callose synthase and cellulose synthase en...

Adult female western Xower thrips, Frankliniella occidentalis, were exposed for 24 h to impatiens leaf disks treated with Beauveria bassiana at low and high application rates (ca. 100 and 1000 viable conidia/mm2) and subsequently maintained on impatiens leaf disks supplemented or not supplemented with impatiens pollen. OVspring production and mortality of insects were monitored daily. Exposure ...

It was independently discovered and coincidentally reported by DEMEREC (1924) and by BRINK and MACGILLIVRAY (1924) that maize pollen grains carrying the waxy gene give a unique reaction with the iodine-potassium-iodide solution commonly employed in detecting starch. LONGLEY (1924) has also reported this phenomenon. In a recent paper, KIESSELBACH and PETERSEN (1925) question the validity of our...

Cytoplasmic male sterile line RC(7) of Chinese cabbage produces mature anthers without pollen. To understand the mechanisms involved, we examined the ultrastructural changes during development of the microspores. Development of microspores was not affected at the early tetrad stage. During the ring-vacuolated period, some large vacuoles appeared in the tapetum cells, making them larger, ext...

The centromeric histone H3 variant cenH3 is an essential centromeric protein required for assembly, maintenance, and proper function of kinetochores during mitosis and meiosis. We identified a kinetochore null2 (KNL2) homolog in Arabidopsis thaliana and uncovered features of its role in cenH3 loading at centromeres. We show that Arabidopsis KNL2 colocalizes with cenH3 and is associated with cen...