In the Brassicaceae, compatible pollen-pistil interactions result in pollen adhesion to the stigma, while pollen grains from unrelated plant species are largely ignored. There can also be an additional layer of recognition to prevent self-fertilization, the self-incompatibility response, whereby self pollen grains are distinguished from nonself pollen grains and rejected. This pathway is activa...

Low temperature during reproductive stage of spring wheat causes sterility of pollen grains and reduced yield. Field experiment was conducted during the winter season in the farm of Indian Agricultural Research Institute with wheat crop to study the effect of temperature on phenology and pollen sterility of spring wheat crop. Lower mean temperature during the crop growth period led to enhanced ...

BACKGROUND The male gametophyte developmental programme can be divided into five phases which differ in relation to the environment and pollen hydration state: (1) pollen develops inside the anther immersed in locular fluid, which conveys substances from the mother plant--the microsporogenesis phase; (2) locular fluid disappears by reabsorption and/or evaporation before the anther opens and the...

BACKGROUND Analysis of pollen grains reveals valuable information on biology, ecology, forensics, climate change, insect migration, food sources and aeroallergens. Vibrational (infrared and Raman) spectroscopies offer chemical characterization of pollen via identifiable spectral features without any sample pretreatment. We have compared the level of chemical information that can be obtained by ...

1. Most animal-pollinated flowering plants offer nectar as a reward for their pollinators. Some 20 000 species, however, offer only pollen and rely on pollen-foraging bees for pollination. This creates a dilemma since pollen grains contain the male gametes and should be protected from becoming bee food. Darwin was the first to hypothesize that a ‘division-of-labour’ among stamens could solve th...

Little is known about the paleoecological histories of the three spruce species (white spruce, Picea glauca; black spruce, P. mariana; and red spruce P. rubens) in eastern North America, largely because of the difficulty of separating the three species in the pollen record. We describe a novel and effective classification method of distinguishing pollen grains on the basis of quantitative analy...

Gypsophila with approximately 150 speciesrepresents the fourth largest genus of Caryophyllaceae and the second genus of tribe Caryophylleae. Iran is the second main center of Gypsophila diversity with 38 species in the world. Considering Gypsophila as one of the most polymorphic genus of the family andalmost half of its taxa distributed in Iran as endemic, thus makes it as a significant genus f...

T H E waxy (wx) locus in maize conditions the type of starch which is synthesized in the triploid endosperm and in the haploid pollen grain. Further, the phenotype of a pollen grain is determined by its own genotype and not by that of the plant which produces the pollen grain (BRINK and MACGILLIVRAY 1924) and (DEMEREC 1924). This makes it possible to use the pollen grain as the unit of observat...

Cytoplasmic male sterility has been found independently in soybean three times since 1995, but no microscopic investigation has been published. The purpose of this microscopic study was to establish the developmental sequence leading to sterility in a cytoplasmic male-sterile soybean line that has been found to be stable under all environmental conditions tested and to demarcate the temporal an...

BACKGROUND In plants, reproductive success is largely determined by the composition of pollen (i.e., self-pollen and outcross-pollen from near and distant pollen-donors) transported as a result of pollinator foraging behavior (e.g., pollen carryover). However, little evidence is available on how and to what extent the pollen carryover affects the pollen-donor composition and on which insect tax...