Root Xylem Influence on the Water Relations and Drought Resistance of Rice

• Published in: Journal of experimental botany 1992-07, Vol.43 (7), p.925-932
• Main Authors: YAMBAO, ELIZABETH B., INGRAM, KEITH T., REAL, JOSELITO G.
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; Biological and medical sciences; Drought; Drought resistance; Economic plant physiology; Fundamental and applied biological sciences. Psychology; Plant roots; Plant water relations; Plants; Rice; Rice (Oryza sativa); roots; Soil water; Tillers; Transpiration; Water relations, transpiration, stomata; Xylem; xylem characteristics
• ISSN: 0022-0957; 1460-2431
• DOI: 10.1093/jxb/43.7.925

In order to determine the importance of root axial resistance to water flow for drought resistance of rice (Oryza sativa L.) aseries of glasshouse and growth chamber studies was conducted from 1985 to 1986. A preliminary study surveyed root distribution and histological characteristics of six cultivars grown in aerobic soil (20×20×90cm boxes) under well–watered ormoisture deficit conditions. Subsequently, four experiments were conducted with plants grown in culture solution. Our results demonstrate that plant breeders can use root thickness as a selection index for xylem size for root diameters up to about 1–2 mm.Using the Poiseuille–Hagen Law for water movement in capillaries, rice root axial resistance explained differences in leaf water potential and transpiration when only one cultivar was used, but did not explain differences among cultivars. Thus, increasing root xylem vessel radii probably will not directly increase drought resistance.