gradient of endogenous calcium forms in mucilage of graviresponding roots of Zea mays

• Published in: Annals of botany Vol. 61; no. 1; pp. 113 - 116
• Main Authors: Moore, R, Fondren, W.M
• Format: Journal Article
• Language: English
• Published: Headquarters Oxford University Press 1988; Academic Press
• Subjects: Agronomy. Soil science and plant productions; Atomic absorption; Biological and medical sciences; Biological Transport; Calcium; Calcium - metabolism; Calcium - physiology; Corn; Curvature; Economic plant physiology; Epidermal cells; Fundamental and applied biological sciences. Psychology; graviperception; Gravitation; Gravitropism; gravitropism (root); Gravitropism - physiology; Life Sciences (General); mucilages; Mutation; Physical agents; Plant cells; Plant physiology and development; Plant roots; Plant Roots - genetics; Plant Roots - growth & development; Plant Roots - metabolism; Root cap; Root tips; roots; Seedlings; Space life sciences; Tropism and nastic movements; Vegetative apparatus, growth and morphogenesis. Senescence; Zea mays; Zea mays - genetics; Zea mays - growth & development; Zea mays - metabolism; Nasa Program Space Biology; Nasa Discipline Plant Biology; Non-Nasa Center; Nasa Discipline Number 40-10; Monocotyledones; Zea mays; Calcium; Root; Gramineae; Angiospermae; Atomic absorption; Spermatophyta; Mucilage; Cereal crop; Gravity; Geotropism; NASA Program Space Biology; NASA Discipline Number 40-10; NASA Discipline Plant Biology; Non-NASA Center
• ISSN: 0305-7364; 1095-8290
• DOI: 10.1093/oxfordjournals.aob.a087523

Agar blocks that contacted the upper sides of tips of horizontally-oriented roots of Zea mays contain significantly less calcium (Ca) than blocks that contacted the lower sides of such roots. This gravity-induced gradient of Ca forms prior to the onset of gravicurvature, and does not form across tips of vertically-oriented roots or roots of agravitropic mutants. These results indicate that (1) Ca can be collected from mucilage of graviresponding roots, (2) gravity induces a downward movement of endogenous Ca in mucilage overlying the root tip, (3) this gravity-induced gradient of Ca does not form across tips of agravitropic roots, and (4) formation of a Ca gradient is not a consequence of gravicurvature. These results are consistent with gravity-induced movement of Ca being a trigger for subsequent redistribution of growth effectors (e.g. auxin) that induce differential growth and gravicurvature.