BACKGROUND AND AIMS Hydration, rupture and exine opening due to the sudden and large expansion of intine are typical of taxoid-type pollen grains. A hemispheric outgrowth external to the exine was observed on Cupressus and Juniperus pollen grains before the intine swelling and exine release. However, the actual existence of this permanent or temporary structure and its precise role in pollen hy...

The objective of the study was to determine the chemical composition and nutritional value of palm pollen grains. The proximate chemical composition, vitamin, mineral, amino acid and fatty acid contents of palm pollen grains were analyzed. The results obtained showed that the values of the proximate chemical composition of palm pollen grains were moisture (28.80%), ash (4.57%), crude fiber (1.3...

air pollutants are reported to increase the specific ige response to allergens. clinical tests and immonoblotting were performed with pollen grains of spartium junceum. to identify allergens and to determine the effect of air pollutants on the allergenicity of the pollen extracts, the pollen extracts were injected intraperitoneally and intracutaneously to guinea pigs. injection of the pollen ex...

Germination of pollen grains is a crucial step in plant reproduction. However, the molecular mechanisms involved remain unclear. We investigated the role of PECTIN METHYLESTERASE48 (PME48), an enzyme implicated in the remodeling of pectins in Arabidopsis (Arabidopsis thaliana) pollen. A combination of functional genomics, gene expression, in vivo and in vitro pollen germination, immunolabeling,...

nonea medik. is a genus of the boraginaceae tribe boragineae, with approximately 35 species worldwide. examination of their palynological characters supported the separation of taxa, which is usually based on morphological and micromorphological reproductive features. pollen grains of 10 taxa representing three groups of taxa in iran, the n. caspica group, the n. persica group and the n. lutea ...

Allergenic ragweed (Ambrosia spp.) pollen grains, after being released from anthers, can be dispersed by air masses far from their source. However, the action of air temperature, humidity and solar radiation on pollen grains in the atmosphere could impact on the ability of long distance transported (LDT) pollen to maintain allergenic potency. Here, we report that the major allergen of Ambrosia ...

The distribution of poly(A)-containing RNA [poly(A)+RNA] in pollen grains of Hyoscyamus niger during normal gametophytic development and embryogenic development induced by culture of anther segments was followed by in situ hybridization with [3H]-polyuridylic acid as a probe. No binding of the isotope occurred in pollen grains during the uninucleate phase of their development. Although [3H]poly...

This review summarizes the available data related to the effects of air pollution on pollen grains from different plant species. Several studies carried out either on in situ harvested pollen or on pollen exposed in different places more or less polluted are presented and discussed. The different experimental procedures used to monitor the impact of pollution on pollen grains and on various pro...