Reproductive phenology of subalpine moss, Polytrichum ohioense Ren. et Card.

• Main Authors: Eri Ayukawa, Satoshi Imura, Sakae Kudoh, Hiroshi Kanda
• Format: Report
• Language: English
• Published: Graduate University for Advanced studies, Department of Polar Science, National Institute of Polar Research/National Institute of Polar Research/National Institute of Polar Research/National Institute of Polar Research 2002
• Subjects: moss; phenology; sub-alpine zone; growing period; snow cover; Polar bioscience; ren
• Online Access: https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=6186; http://id.nii.ac.jp/1291/00006186/; https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=6186&item_no=1&attribute_id=18&file_no=1

The reproductive phenology of Polytrichum ohioense was investigated in a sub-alpine forest at the foot of Mt. Tyausu, in the Yatsugatake Mountains, Central Honshu, Japan. Shoots were collected every 2 weeks from May to October from the study site. Developmental stages of gametangia and sporophytes formed in the current and previous year were registered. The temperature above the turf occasionally dropped below 0℃ before June, while the temperature in the turf did not drop below 0℃. Juvenile antheridia formed about one month earlier than archegonia. Mature antheridia and archegonia are observed from late May to early August and from late June to mid-July, respectively. Fertilization seems to occur from late June to mid-July. Longer persistence of mature antheridia is supposed to contribute to higher efficiency of fertilization to supply its sperm for a relatively long period. And delayed formation of archegonia in the warm season may contribute to the adaptation to the temperature decrease at the beginning of the growing season. Sporophytes were found first at the end of June, then gradually grew and reached the ECI stage by October. The sporophytes seemed to spend the period of snow cover in the ECI stage, and started to grow again in the next growing season in May. Spore dispersal was observed from mid-July to mid-August. Sporophytes took 13 months to mature including a 6 month resting period. The phenological parameters observed in the present study provide a way to adapt to the the short growing season in the sub-alpine zone in Central Honshu, Japan.