Effects of low water potential on cortical cell length in growing regions of maize roots.

Roots growing under low water potential commonly exhibit a marked decrease in growth rate and in diameter. Using median longitudinal sections of fixed maize (Zea mays L. cv WF9 x Mo 17) seedling roots, we investigated the cellular basis for these effects. Cortical cells in the shortened elongation zone of water stressed roots were longer than cortical cells in the comparable location of well-watered roots. Nearly twofold differences in cell length were seen in the region 2 to 4 millimeters behind the root apex. The shortened growth zone, however, leads to a final mean cortical cell length approximately 30% shorter in the stressed roots. These differences were present regardless of the age of the control roots. These data, and the slower growth rate seen in water-stressed roots, suggest that the water deficit causes a significant reduction in the rate of cell supply to the cortical cell files.

[1]  P. Green.  Growth and Cell Pattern Formation on an Axis: Critique of Concepts, Terminology, and Modes of Study , 1976, Botanical Gazette.

[2]  Michael J. Goss,et al.  Effects of Mechanical Impedance on Root Growth in Barley, Hordeum vulgare L.II. EFFECTS ON CELL DEVELOPMENT IN SEMINAL ROOTS , 1977 .

[3]  R. E. Sharp,et al.  Growth of the maize primary root at low water potentials : I. Spatial distribution of expansive growth. , 1988, Plant physiology.

[4]  P. Gandar,et al.  A Simulation Model for Cell Proliferation in Root Apices II. Patterns of Cell Proliferation , 1986 .

[5]  P. Gandar.  The Analysis of Growth and Cell Production in Root Apices , 1980, Botanical Gazette.

[6]  T. Hsiao.  Plant Responses to Water Stress , 1973 .

[7]  H. Burström.  Studies on Growth and Metabolism of Roots. IX. Cell Elongation and Water Absorption , 1953 .

[8]  R. H. Goodwin,et al.  GROWTH AND DIFFERENTIATION IN THE ROOT TIP OF PHLEUM PRATENSE , 1945 .

[9]  W. Silk,et al.  Growth Patterns Inferred from Anatomical Records : Empirical Tests Using Longisections of Roots of Zea mays L. , 1989, Plant physiology.

[10]  D. Paolillo.  Cell and Axis Elongation in Etiolated Soybean Seedlings are Altered by Moisture Stress , 1989, Botanical Gazette.

[11]  R. O. Erickson,et al.  A Simulation Model for Cell Growth and Proliferation in Root Apices I. Structure of Model and Comparisons with Observed Data , 1986 .

[12]  Gray Lh,et al.  The effect of ionizing radiations on the broad bean root. VIII. Growth rate studies and histological analyses. , 1951 .