WATER RELATIONS OF PINUS PUMILA IN THE SNOW MELTING SEASON AT THE ALPINE REGION OF MT. TATEYAMA (17th Symposium on Polar Biology)

• Main Authors: マルタ エミコ, ナカノ タカシ, イシダ アツシ, イイダ ハジメ, マスザワ タケヒロ, Emiko MARUTA, Takashi NAKANO, Atsushi ISHIDA, Hajime IIDA, Takehiro MASUZAWA
• Format: Report
• Language: English
• Published: Proceeding 1996
• Subjects: The Needles; Polar Biology; Proceedings of the NIPR Symposium on Polar Biology
• Online Access: https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=5327; http://id.nii.ac.jp/1291/00005327/; https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=5327&item_no=1&attribute_id=18&file_no=1

During the snow melting season of 1994, some exposed needles of Pinus pumila turned yellow in the alpine zone (2450 m) on Mt. Tateyama. However, relative water content (RWC) of the needles was far over the lethal RWC. Temperatures of soil and stems below snowpack remained near 0℃ during midday on 7 May, whereas those of needles and shoots over snowpack increased to 15℃ under high solar radiation. This result shows that transpired water from needles may be sufficiently replenished with water stored in sapwood of stems in the spring. It is concluded that desiccation is an unlikely cause of needle die-back. The most likely alternative explanation appears to be freezing damage, because freezing tolerance of most plants rapidly decreases in spring when minimum air temperature is often below zero in night at high altitude.