Seed germination ecophysiology of the Asian species Osmorhiza aristata (Apiaceae): comparison with its North American congeners and implications for evolution of types of dormancy

Osmorhiza aristata is an herbaceous perennial that grows primarily in Japan, through southern China, to the Himalayas. It closely resembles the eastern North American species O. claytonii and O. longistylis, and, together, the three species are an example of the well-known North American-Asian patte...

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Bibliographic Details
Published in:	American journal of botany Vol. 89; no. 5; pp. 829 - 835
Main Authors:	Walck, Jeffrey L., Hidayati, Siti N., Okagami, Nobuo
Format:	Journal Article
Language:	English
Published:	United States Botanical Soc America 01-05-2002 Botanical Society of America Botanical Society of America, Inc
Subjects:	Apiaceae Asia Botany Congeners disjunct taxa Dormancy Ecology Ecophysiology Embryos Evolution Flowers & plants Germination morphological stasis morphophysiological dormancy North America Osmorhiza Plant growth Plants Prefectures Seed dormancy Seeds
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Summary:	Osmorhiza aristata is an herbaceous perennial that grows primarily in Japan, through southern China, to the Himalayas. It closely resembles the eastern North American species O. claytonii and O. longistylis, and, together, the three species are an example of the well-known North American-Asian pattern of disjunction. Requirements for dormancy break and embryo growth were determined for seeds of O. aristata collected in Japan during the summers of 1998-2000. Embryos in fresh seeds were ca. 0.5 mm long, and they had to grow to 9 mm before the radicle emerged from the mericarp. Embryo growth and germination occurred during cold stratification at 5°C, the optimum temperature for germination. Gibberellic acid did not substitute for cold stratification. Thus, O. aristata seeds have deep complex morphophysiological dormancy (MPD). The type of MPD in O. aristata is similar to that in two western North American congeners but different from that in eastern North American congeners (nondeep complex MPD). Mapping the types of MPD onto a phylogeny of the genus suggests that nondeep complex MPD is derived from deep complex MPD. Although eastern North American-Asian disjuncts often exhibit morphological stasis, the taxa may differ greatly in physiological traits, such as seed dormancy.
Bibliography:	jwalck@mtsu.edu Osmorhiza ) Author for reprint requests (phone: 615‐904‐8390; fax: 615‐898‐5093 The authors thank Daniel Crawford, Michiko Masuda‐Maki, Ken‐ichi Satoh, and Kouzi Yonekura for help in collecting seeds. We are grateful to Carol and Jerry Baskin for the use of laboratory facilities at the University of Kentucky and for conversations on the evolution of seed dormancy and to Jun Wen for discussions on the phylogeny of Portions of the research were done while the senior author held a postdoctoral fellowship at Ohio State University under the guidance of Daniel Crawford and Andrea Wolfe. ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 23 ObjectType-Article-1 ObjectType-Feature-2
ISSN:	0002-9122 1537-2197
DOI:	10.3732/ajb.89.5.829