Asthma and allergic diseases cases have risen in recent decades. Plant pollen is considered as the main aeroallergen causing allergic reactions. According to available data, urban residents experience more respiratory allergies than rural residents mainly due to the interaction between chemical air pollutants and pollen grains. This interaction can occur through several mechanisms; chemical pol...

pollen grain morphology of 15 taxa of the hedysareae tribe distributed throughout iran was studied using light and electron microscopy to identify major taxonomical characteristics of pollen grains. the pollen grains were tricolpate and tricolporate, prolate and perprolate. the ectocolpi were elongated, shallow or deep, narrowing at the poles. the colpus membrane was covered by large granules. ...

Flowers of cultivated buckwheat (Fagopyrum esculentum Moench) often receive natural pollen loads of fewer than 10 pollen grains. The cultivated varieties also have high genetic variability. These observations raise the question of whether seed production in buckwheat is often limited by pollen delivery, and whether small increases in pollen load could result in gametophytic selection through po...

weed pollen grains belonging to  the  asteraceae  family contain  a variety of  allergens inducing type i  and iv allergies in susceptible people. the  aim of this research was to compare  the  allergenic properties  of  immature  and  mature  shasta  daisy pollen  grains (chrysanthemum maximum ramond) to define the potential role of the maturation process on the allergenicity of asteraceae pol...

In this study, pollen grains were sampled by using a Lanzoni trap (Lanzoni VPPS 2000) in atmosphere of Bursa in 1999 and 2000. During two years. a total of 13,991 pollen grains/m3 which belonged to 59 taxa and unidentified pollen grains were recorded. A total of 7.768 pollen grains were identified in 1999 and a total of 6.223 in 2000. From these taxa, 36 belong to arboreal and 23 taxa to non-ar...

PREMISE OF THE STUDY Pollen grains are subject to intense dehydration before dispersal. They rehydrate after landing on a stigma or when placed in humid environment by absorbing water from the stigma or surroundings. Resulting fluctuations in water content cause pollen grains to undergo significant changes in volume. Thus, morphological or structural adaptations might exist to help pollen adjus...

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 ...

BACKGROUND AND AIMS Exposure to higher-than-optimal temperatures reduces crop yield and quality, mainly due to sensitivity of developing pollen grains. The mechanisms maintaining high pollen quality under heat-stress conditions are poorly understood. Our recently published data indicate high heat-stress-induced expression of ethylene-responsive genes in tomato pollen, indicating ethylene involv...