Title

Gravitropic Moss Cells Default To Spiral Growth On The Clinostat And In Microgravity During Spaceflight

Keywords

Gravitropism; Microgravity; Moss; Spiral growth; Tip growth

Abstract

In addition to shoots and roots, the gravity (g)-vector orients the growth of specialized cells such as the apical cell of dark-grown moss protonemata. Each apical cell of the moss Ceratodon purpureus senses the g-vector and adjusts polar growth accordingly producing entire cultures of upright protonemata (negative gravitropism). The effect of withdrawing a constant gravity stimulus on moss growth was studied on two NASA Space Shuttle (STS) missions as well as during clinostat rotation on earth. Cultures grown in microgravity (spaceflight) on the STS-87 mission exhibited two successive phases of non-random growth and patterning, a radial outgrowth followed by the formation of net clockwise spiral growth. Also, cultures pre-aligned by unilateral light developed clockwise hooks during the subsequent dark period. The second spaceflight experiment flew on STS-107 which disintegrated during its descent on 1 February 2003. However, most of the moss experimental hardware was recovered on the ground, and most cultures, which had been chemically fixed during spaceflight, were retrieved. Almost all intact STS-107 cultures displayed strong spiral growth. Non-random culture growth including clockwise spiral growth was also observed after clinostat rotation. Together these data demonstrate the existence of default non-random growth patterns that develop at a population level in microgravity, a response that must normally be overridden and masked by a constant g-vector on earth. © Springer-Verlag 2005.

Publication Date

4-1-2005

Publication Title

Planta

Volume

221

Issue

1

Number of Pages

149-157

Document Type

Article

Personal Identifier

scopus

DOI Link

https://doi.org/10.1007/s00425-004-1467-3

Socpus ID

18044376474 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/18044376474

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