Ecological features of the flowers of Aesculus hippocastanum L. and characteristics of Aesculus L. pollen seasons under the conditions of central-eastern Poland

Abstract

A b s t r a c tThe content of Aesculus pollen in aeroplankton of Lublin, located in central-eastern Poland, was studied during the period 2001-2012. The volumetric method was used for the study. The following parameters were determined: start, end, and duration of the pollen season, days of maximum concentration, and total annual pollen counts. Correlation coefficients were calculated between the start of the pollen season and meteorological parameters. The study showed that during the period 2007-2012 the onset of the Aesculus pollen season occurred on average 4 days earlier than in the years 2001-2006. The total annual pollen counts were in the range of 53-271, with an average number of 117. The average pollen counts did not differ significantly in the first and second year of a 6-year period of the study. The analysis of the correlation coefficients showed that there were significant positive correlations only between the season start date and minimum temperature of the first decade of May. The highest Aesculus pollen concentration occurred between 6 and 22 May. The flowers of A. hippocastanum demonstrate an ambophilous pollination strategy due to partial insect and wind pollination.

Biological Flora of the British Isles:Aesculus hippocastanum

“…In western Poland, mean first flowering date over 20 years was 6 May (Sparks et al., ). Pollen production (taken to indicate longevity of flowering) from five trees in Lublin, Poland, between 2002 and 2009 lasted for 18–42 days with a mean of 28 days (Weryszko‐Chmielewska et al., ). Anthesis is at a maximum between 13 and 18°C air temperature, compared to 10.2–18°C in Crataegus monogyna , and is much reduced during rain (Percival, ).…”

“…Anthesis is at a maximum between 13 and 18°C air temperature, compared to 10.2–18°C in Crataegus monogyna , and is much reduced during rain (Percival, ). Maximum pollen release was 6–22 May in Poland (Weryszko‐Chmielewska et al., ).…”

“…Both ends of the anthers have red appendages, and the upper part of the style and the stigma are similarly red‐coloured. These markings may also act of pollinator guides (Weryszko‐Chmielewska et al., ).…”

“…Pollination is primarily by insects, but due to the large number of pollen grains produced, wind pollination is considered a viable supplement. Certainly air‐borne pollen has been detected in many European countries, averaging 8–69 pollen grains/m 3 of air during the flowering season (Biçakci, Benlioglu, & Erdogan, ; Popp et al., ; Weryszko‐Chmielewska et al., ). Studies across Europe have shown that horse‐chestnut pollen in urban areas accounts for 0.13%–1.54% of total air‐borne pollen (Melgar et al., ; Peternel, Čulig, Mitić, Vukušić, & Šostar, ; Rizzi‐Longo, Pizzulin‐Sauli, Stravisi, & Ganis, ; Stefanic, Rasic, Merdic, & Colacovic, ), high enough densities to cause an allergic reaction in children in Vienna (Popp et al., ) and presumably high enough to supplement insect pollination.…”

“…1 cm, white with basal spots at first yellow then pink. In Poland, Weryszko‐Chmielewska, Tietze, and Michońska () found 56% 4‐petalled and 44% 5‐petalled flowers. Stamens 5–9 of variable length within the same flower, mostly longer than petals and arched downwards; pollen red.…”