<abstract xmlns="http://www.w3.org/1999/xhtml">

<p><italic>Alnus nepalensis</italic> is a medium-sized, deciduous tree that occurs in the Indian sub-continent, South America, Hawaii, and China. It is a prolific pioneer species in freshly exposed soil in landslide areas of the western Himalayas and has the potential of fixing nitrogen. A study was conducted to assess the reproductive phenology, pollen production, pollen release, and pollen-mediated gene flow of <italic>Alnus nepalensis</italic> by considering a patch of trees as a pollen source in the temperate forest of Garhwal Himalaya to develop sustainable management strategies relating to the plantation geometry in seed orchards. Staminate flowers of <italic>A. nepalensis</italic> are composed of “cymules”. The presence of bifid stigma and protandry condition were the unique features of the species. Flowering in the male phase was initiated in the last week of September and continued till November. Peak shedding of pollen generally proceeds peak receptivity by 1–2 weeks. The time between onset and peak flowering was 2 weeks 4 days and the total average duration of the flowering period was about 24.8 days. Temperature and relative humidity played a major role in pollen release and the maximum pollen release occurred at 29.2 °C at 13.00 hrs of the day. Pollen production per catkin varied significantly among trees. The average pollen grains per tree were 2.20 × 10<sup>10</sup>. The pollen-ovule ratio suggests that the breeding system of <italic>A. nepalensis</italic> falls under the class xenogamy. Pollen mediated gene flow revealed that the significant pollen which can cause pollination of <italic>A. nepalensis</italic> can travel up to 40 m uphill and 80 m in downhill directions. Thus, an isolation strip of 80 m is sufficient to manage the seed orchard of <italic>A. nepalensis</italic> in the western Himalayan region.</p>
</abstract>

Alnus nepalensis is a medium-sized, deciduous tree that occurs in the Indian sub-continent, South America, Hawaii, and China. It is a prolific pioneer species in freshly exposed soil in landslide areas of the western Himalayas and has the potential of fixing nitrogen. A study was conducted to assess the reproductive phenology, pollen production, pollen release, and pollen-mediated gene flow of Alnus nepalensis by considering a patch of trees as a pollen source in the temperate forest of Garhwal Himalaya to develop sustainable management strategies relating to the plantation geometry in seed orchards. Staminate flowers of A. nepalensis are composed of “cymules”. The presence of bifid stigma and protandry condition were the unique features of the species. Flowering in the male phase was initiated in the last week of September and continued till November. Peak shedding of pollen generally proceeds peak receptivity by 1–2 weeks. The time between onset and peak flowering was 2 weeks 4 days and the total average duration of the flowering period was about 24.8 days. Temperature and relative humidity played a major role in pollen release and the maximum pollen release occurred at 29.2 °C at 13.00 hrs of the day. Pollen production per catkin varied significantly among trees. The average pollen grains per tree were 2.20 × 1010. The pollen-ovule ratio suggests that the breeding system of A. nepalensis falls under the class xenogamy. Pollen mediated gene flow revealed that the significant pollen which can cause pollination of A. nepalensis can travel up to 40 m uphill and 80 m in downhill directions. Thus, an isolation strip of 80 m is sufficient to manage the seed orchard of A. nepalensis in the western Himalayan region.

Pollen production, release and dispersion in Himalayan alder (<italic>Alnus nepalensis</italic> D. Don.): a major aeroallergens taxa

Department of Forestry, College of Forestry

VCSG Uttarakhand University of Horticulture and Forestry

Folia Oecologica

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Pollen production, release and dispersion in Himalayan alder ( D. Don.): a major aeroallergens taxa

Alnus nepalensis is a medium-sized, deciduous tree that occurs in the Indian sub-continent, South America, Hawaii, and China. It is a prolific pioneer species...

Pollen production, release and dispersion in Himalayan alder (Alnus nepalensis D. Don.): a major aeroallergens taxa

Published Online: Jul 26, 2023

Page range: 147 - 158

Received: Dec 05, 2022

Accepted: May 06, 2023

DOI: https://doi.org/10.2478/foecol-2023-0013

Keywords
anther dehiscence, atmospheric pollen, pollen allergy, pollen yield, pollen gene flow

© 2023 Anchal Bisht et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Pollen production, release and dispersion in Himalayan alder (Alnus nepalensis D. Don.): a major aeroallergens taxa

Published Online: Jul 26, 2023

Page range: 147 - 158

Received: Dec 05, 2022

Accepted: May 06, 2023

DOI: https://doi.org/10.2478/foecol-2023-0013

Keywordsanther dehiscence, atmospheric pollen, pollen allergy, pollen yield, pollen gene flow

© 2023 Anchal Bisht et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Keywords
anther dehiscence, atmospheric pollen, pollen allergy, pollen yield, pollen gene flow