Water stress, CO2 and photoperiod influence hormone levels in wheat

• Published in: Journal of plant physiology Vol. 159; no. 3; pp. 307 - 312
• Main Authors: Nan, Rubin, Carman, John G., Salisbury, Frank B., Campbell, W. F.
• Format: Journal Article
• Language: English
• Published: Ames Research Center Elsevier 01-03-2002
• Subjects: Abscisic Acid - metabolism; Agronomy. Soil science and plant productions; Biological and medical sciences; Carbon Dioxide - pharmacology; Economic plant physiology; Fundamental and applied biological sciences. Psychology; Growth and development; Growth regulators; Indoleacetic Acids - metabolism; Isopentenyladenosine - metabolism; Life Sciences (General); Light; Metabolism; Photoperiod; Plant Growth Regulators - metabolism; Plant Leaves - drug effects; Plant Leaves - metabolism; Plant Leaves - radiation effects; Plant physiology and development; Plant Roots - drug effects; Plant Roots - metabolism; Plant Roots - radiation effects; Space life sciences; Triticum - drug effects; Triticum - metabolism; Triticum - radiation effects; Water - pharmacology; Nasa Discipline Plant Biology; Non-Nasa Center; Monocotyledones; Auxin; Root; Growth; Seed production; Water deficit; Carbon dioxide; Submersion; Space flight; Cytokinin; Cereal crop; Luminous intensity; Gramineae; Indoleacetic acid; Angiospermae; Abscisic acid; Plant growth substance; Spermatophyta; Biological accumulation; Microgravity; Triticum aestivum; Gravity; NASA Discipline Plant Biology; Non-NASA Center
• ISSN: 0176-1617; 1618-1328
• DOI: 10.1078/0176-1617-00703

'Super Dwarf' wheat (Triticum aestivum L.) plants have been grown from seed to maturity in the Mir space station where they were periodically exposed, because of microgravity and other constraints, to water deficit, waterlogging, high CO2 levels, and low light intensities. The plants produced many tillers, but none of them produced viable seed. Studies have been initiated to determine why the plants responded in these ways. In the present study, effects of the listed stresses on abscisic acid (ABA), indole-3-acetic acid (IAA) and isopentenyl adenosine ([9R]iP) levels in roots and leaves of plants grown under otherwise near optimal conditions on earth were measured. Hormones were extracted, purified by HPLC, and quantified by noncompetitive indirect ELISA. In response to water deficit, ABA levels increased in roots and leaves, IAA levels decreased in roots and leaves, and [9R]iP levels increased in leaves but decreased in roots. In response to waterlogging, ABA, IAA and [9R]iP levels briefly increased in roots and leaves and then decreased. When portions of the root system were exposed to waterlogging and/or water deficit, ABA levels in leaves increased while [9R]iP and IAA levels decreased. These responses were correlated with the percentage of the root system stressed. At a low photosynthetic photon flux (100 micromoles m-2 s-1), plants grown in continuous light had higher leaf ABA levels than plants grown using an 18 or 21 h photoperiod.