Pollen number

Brownian movement The rapid and random movement of particles of a colloidal sol, observed brightly lit against a dark ground. First observed with a pollen suspension. The Brownian movement is due to the impact on the dispersed particles of the molecules of the dispersion medium. As the particles increase in size, the probability of unequal bombardment from different sides decreases, and eventually collisions from all sides cancel out and the Brownian movement becomes imperceptible at a particle size of about 3-4/z. From the characteristics of the movement, Perrin calculated Avogadro s number L. 

The problem of allergies has increased during the last few years. The tendency to develop allergies and asthma is not well understood, but a number of pollutants can trigger the reaction, for instance, airborne allergens such as pollen,... 

By number count the great majority of particles in the outside air are likely to be less than 1 pm. By weight, these small particles will account for a very small proportion of the sample. A filter with a high efficiency measured by weight of particles trapped may be almost transparent to the small ones. Very high counts can be found in rural areas from pollen or agricultural activities. 

Larva Decreases worker response proboscis threshold to sucrose in a extension response increases number of pollen foragers Ten component blend of brood pheromone [123]... 

Procedure Pollen develops on the nutrition medium, forming pollen tube (Fig. 3). The nutrient medium for pollen was 10% sucrose solution and tested compounds were also dissolved in 10% sucrose. The pollen develops till the formation of pollen tube that lasts from 2-3 h (fresh collected and one week stored pollen) to 24 h (stored > 1 week, but < 1.5-2 months). All experiments were done at room temperature 20-22 °C. The growth occurred in the solution studied (0.05 ml = 1 drop) on the slides (object glasses) put on wet paper in Petri dishes. Five ml of water was added to the bottom of every dish and 4-5 dishes with the slides were used per treatment. Using light microscope, we determined the microspores germination (%) 2-24 h after moistening. The number of developed pollen tubes was counted. 

Statistical analysis One hundred pollen grains were examined on each slide and 100 microspores were analysed per slide. Counting was done in four or five replicates (the number of Petri dishes per treatment). Results were expressed as mean SEM. The relative standard deviation (RSD) was 5-6% (n = 400-500 microspores per one variant P =0.95). 

While more commonly used to count or otherwise characterize cells for medical applications, Coulter Counters and flow cytometry technique can also be applied to the analysis of pollen grains in allelopathic studies. They are quite useful in determining the size and number of pollen grains. The technique is often used for assessing the production and size of pollen from the originating individual rather than how much was transferred to heterospecific stigma, as would be needed in a basic assessment of potential allelopathic interactions. 

Sample number Depth (m) Abundance of pollen (grain g 1) Total abundance of sporopollen (grain g )... 

Another problem is the direction of pollen tube growth, which should be considered as tropism, related to attraction by the fertile ovules. Many observations of pollen tubes in the fluorescence microscope supported this suggestion—pollen tubes pass by the sterile ovules and grow in the direction of the fertile ones. The number of ovules penetrated by a pollen tube is correlated with the number of developing seeds, which supports the hypothesis about interaction (attraction) between the ovule and pollen tube (1,2,5). 

Chronic inflammatory response is one of the hallmarks of allergic diseases. Over the course of pollen season, there might be even a tenfold increase in numbers of nasal epithelial submucosal mast cells. Histamine released from these cells might not only induce acute allergic symptoms but also be crucial for sustaining this response into a chronic phase, as increasing evidence suggests that it influences several immune/inftammatory and effector functions (table 2) [2]. 

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