Pollen 2021 Download
Pollen grains that accumulate in sediments can provide a record of the vegetation that grew on or adjacent to the shore in different time periods. Researchers can reference this record to infer climate conditions for time periods with no direct observational data by determining what conditions were favorable to pollen types found in the sediment.
HollisterStier offers a wide-range of tree, grass and weed pollen antigens, so you can tailor your testing and treatment panels to the pollens prevalent in your region. All of our pollen antigens are offered in a phenol free presentation and can be purchased in either 5mL scratch or larger bulk vials.
An in-depth knowledge of allergen cross-reactivity is imperative when selecting allergens for immunotherapy. Because limiting the number of allergens in a vaccine preparation may be necessary to achieve the optimal therapeutic dose for each allergen, the cross-reactivity of clinically relevant allergens should be taken into account when making allergen selections. When cross-reactivity between pollens is substantial, selection of a single pollen within the cross-reactive genus or subfamily may suffice. View our interactive cross reactivity guide, or download the PDF.
To help educate pollen-sensitive patients be aware of the seasonality of pollens, we have developed regional pollen activity calendars which can easily be downloaded and printed. The interactive regional pollen activity information below provides a quick peek at the helpful information found in the downloadable files. Poster-size calendars suitable for your office can be ordered from your sales representative.
Make it easier for your patients with food allergies or food intolerances to stick to a diet by offering these comprehensive handouts. Each downloadable handout includes useful information, featuring how to read food labels, a thorough list of acceptable choices, nutritionally equal substitutions, foods to avoid, types of products that may contain the allergen and more.
This figure shows how the length of ragweed pollen season changed at 11 locations in the central United States and Canada between 1995 and 2015. Red circles represent a longer pollen season; the blue circle represents a shorter season. Larger circles indicate larger changes.
Ragweed plants mature in mid-summer and produce small flowers that generate pollen. Ragweed pollen season usually peaks in late summer and early fall, but these plants often continue to produce pollen until the first frost. A single ragweed plant can produce up to a billion pollen grains in one season, and these grains can be carried long distances by the wind.7
Climate change can affect pollen allergies in several ways. Warmer spring temperatures cause some plants to start producing pollen earlier (see the Leaf and Bloom Dates indicator), while warmer fall temperatures extend the growing season for other plants, such as ragweed (see the Length of Growing Season indicator). Warmer temperatures and increased carbon dioxide concentrations also enable ragweed and other plants to produce more allergenic pollen, in larger quantities. This means that many locations could experience longer allergy seasons and higher pollen counts as a result of climate change.8
This indicator shows changes in the length of the ragweed pollen season in 11 cities in the central United States and Canada. These locations were selected as part of a study that looked at trends in pollen season at sites similar in elevation, but across a range of latitudes from south to north. At each location, air samples have been collected and examined since at least the 1990s as part of a national allergy monitoring network. Pollen spores are counted and identified using microscopes.
This indicator is based on data from a limited number of cities in the central states and provinces. These cities cover a broad range from north to south, however, which allows researchers to establish a clear connection between pollen season changes and latitude.
Many factors can influence year-to-year changes in pollen season, including typical local and regional variations in temperature and precipitation, extreme events such as floods and droughts, and changes in plant diversity. In addition, seasonal pollen production may differ between stations located in densely urbanized areas and stations in outlying areas. Adding more years of data would provide a better picture of long-term trends, but widespread data were not available prior to 1995.
Ornamental peppers (Capsicum annuum L.) are widely used as potted flowering or bedding plants for their morphologically diverse characteristics. Ideal cultivation conditions for ornamental peppers are similar to typical vegetable pepper production with the crop requiring high radiation and minimum daytime temperatures between 18 and 21 C for maximum fruit set. Pepper, being a warm-season crop, requires night and soil temperatures of 14.5 C or higher to promote growth. Lower temperatures are tolerated by ornamental pepper plants as they mature (Stummel and Bosland, 2007). Yellowing and leaf drop are caused by low temperatures and light and insufficient moisture or nutrients (Stummel and Bosland, 2007). In addition, pollen vitality and fruit quality are also affected by low night temperature (Polowick and Sawhney, 1986). As described by Young et al. (2004), high temperature during flowering or during pollen release affects male reproductive processes (microsporogenesis) resulting in lower fruit set and smaller fruit. Both low and high temperature extremes are detrimental, especially for reproductive development of pepper plants (Polowick and Sawhney, 1986).
High temperatures including short episodes of extreme events during the plant reproductive period have been shown to cause extensive damage to grain and fruit yield in many crops (Ahmed and Hall, 1993; Erickson and Markhart, 2002; Ferris et al., 1998; Gross and Kigel, 1994; Herrero and Johnson, 1980; Peet et al., 1998; Porch and Jahn, 2001; Prasad et al., 1999, 2003; Reddy et al., 1997; Sato et al., 2002; Taylor and Hepler, 1997). Because pollen is short-lived after release and acts as an independent functional unit, in vitro responses of pollen germination and tube length response characteristics such as maximum pollen germination and pollen tube length and cardinal temperatures (minimum, optimum, and maximum) of these two processes have been used in many studies to assess genetic variability among crops (Kakani et al., 2002, 2005; Salem et al., 2007; Singh et al., 2008) including vegetable peppers (Aloni et al., 2001; Reddy and Kakani, 2007). Also, Salem et al. (2007) have demonstrated the relationship between in vitro pollen germination and tube length responses to temperature and classification of genotypes based on these parameters and whole plant thermotolerance when plants were subjected to high temperatures for a long period of time. Therefore, pollen parameters could be good indicators in determining reproductive tolerance to high and low temperatures.
To our knowledge, there are no reports on screening the responses of ornamental pepper cultivars under a wide range of temperatures, particularly using pollen and physiological parameters. The objectives of the current study were to 1) quantify the responses of in vitro PG and PTL of ornamental pepper cultivars to a range of temperatures; 2) determine cultivar-specific cardinal temperatures for both PG and PTL response parameters; 3) quantify the cultivar stability to heat treatments using three physiological parameters: CMT, CSI, and CTD; 4) classify cultivars based on their level of tolerance to high and low temperatures using pollen- and physiological-based (CMT, CSI, and CTD) parameters; and 5) determine whether the observed variation among cultivars in pollen germination responses to temperature are related to physiological traits.
Twenty to 30 flowers at anthesis were randomly collected from each cultivar between 0900 and 1000 hr during the flowering period, 50 to 70 d after sowing. Pollen grains were collected in a petri dish by gently tapping the flowers. Pollen grains were distributed uniformly onto the solidified and modified germination medium using a tiny, clean bristle paint brush. The pollen medium for the highest pollen germination was identified through slight modification of the medium previously used for vegetable pepper by Reddy and Kakani (2007) with pH adjusted to 7.5. To this liquid medium, 10 g of agar was added and slowly heated on a hot plate. After the agar was completely dissolved, 10 mL of germination medium was poured into three replicate petri dishes for each cultivar in each temperature treatment and allowed to cool for 15 min for agar solidification. Petri dishes with medium were kept in the incubator set at treatment temperatures for 30 min before pollen distribution. The petri dishes were then covered and incubated in an incubator (Precision Instruments, New York, NY) at respective temperature treatments from 10 to 45 C at 5 C increments. Each petri dish per cultivar and temperature treatment was considered as a replicate.
Pollen germination and PTL were tested after 24 h of incubation. Total pollen grains and number of pollen grains germinated were counted using a Nikon SMZ 800 microscope (Nikon Alphaphot YS microscope; Nikon Instrument, Kangava, Japan) with a magnification of 6.3. Ten fields per replication were counted for percent pollen germination. When counting the pollen grains, a pollen grain was considered germinated when its tube length equaled the diameter of the pollen grain (Luza et al., 1987). Percentage pollen germination was calculated by counting the total number of pollen grains germinated in the microscope field of view and divided by the total number of pollen grains per field of view. The pollen tube lengths of 30 pollen grains selected randomly from each petri dish were measured with an ocular micrometer fitted to the eye piece of the microscope after 24 h of incubation.