Explaining the diversity of mating systems and floral forms in flowering plants is a long-standing concern of evolutionary biologists. One topic of interest is the conditions under which self-pollination can interfere with seed set for flowering plants with a self-incompatibility system. We investigated the effect of self-pollen interference for wild radish, Raphanus raphanistrum, which has spo...

BACKGROUND Privet pollen rarely accounts for more than 1% of the annual total of daily pollen concentrations measured in a city; however in areas where these trees are widely used as ornamentals the amounts collected may be high enough to cause allergy symptoms. METHODS Air samples taken with volumetric particle samplers Lanzoni VPPS 1000 (Lanzoni s.r.l., Bologna, Italy) show that there are d...

Pollen of acacias is transported by insects as polyads, composite pollen grains. The polyad has enough pollen grains to fertilize all ovules within a flower and hence all seed within a pod may be full sibs. Isozyme markers were used to test this hypothesis in two populations of Acacia melanoxylon R.Br. The proportions of fruit pods with multiple paternity detected in two populations were 0.08 a...

The mean volume of pollen grains and total pollen production varied both within and among plants of Erythronium grandiflorum. The second flowers of two-flowered plants tended to produce smaller and fewer grains than first flowers, but there was no overall relationship between mean pollen grain size and production per flower. I evaluated the effects of pollen size differences within and among pl...

specifically. The book is supported by over 200 references and half again as many personal communications. The high-quality scanning electron micrographs of pollen grains are especially appealing. Willow, mimosa, and dandelion pollen have an architecture as intricate and beautiful as the plant superstructure which supports them. The spiny spherical pollen grains of ambrosia (ragweed) make them ...

The pollen calendar of Agra was recorded with special reference to allergenic significance. Pollen grains of 35 species belonging to 23 angiosperm families have been identified out of a total catch of 24,220/m3 of air annually. High occurrence of pollen grains in air belonged to Asteraceae (5222/m3) and Parthenium hysterophorus contributed the maximum (17.91%) of the total airspora. Higher coun...

Plants of the Urticaceae family can develop into a pest on soils enriched with nitrogen. Urticaceae pollen is a biohazard because it elicits severe pollinosis. Pollen grains were sampled by using a Lanzoni seven-day-recording trap from February 1995-December 2000 in the atmosphere of the city of Ponferrada (Leon, North Western Spain). The Spearman test was used to analyse the statistical correl...