EFFECTS OF WATER SUPPLY ON PARTITIONING OF DRY MATTER BETWEEN ROOTS AND SHOOTS IN LOLIUM PERENNE

(1) When plants of Lolium perenne were subjected to one cycle of soil drying, to repeated cycles of drying, or when they were grown in dry soils, the relative growth rate of the root system was reduced more than that of the shoot system. This brought about a decrease in the root : shoot ratio. (2) Drought initially resulted in lower availability of water near to the soil surface than at greater depths. Consequently, growth of that part of the root system near the soil surface was restricted, and newly initiated main roots at the base of the shoot were unable to elongate. (3) When plants were grown in solutions of low osmotic potential, there was no effect on distribution of dry matter between roots and shoots, except at the lowest potential (-9.5 bars) which reduced root growth rather more than shoot growth. (4) The effect of drought on root : shoot ratio in these experiments is compared with that reported by others. It is suggested that, in some circumstances, the availability of phosphate in the soil may influence the effect of drought on root: shoot ratios.

[1]  A. Troughton.  The Effect of the Prevention of the Production of Additional Root Axes upon the Growth of Plants of Lolium perenne , 1978 .

[2]  W. Williams,et al.  Growth, water relations and nutrition of three grassland annuals as affected by drought. , 1975 .

[3]  D. Lawlor.  GROWTH AND WATER ABSORPTION OF WHEAT WITH PARTS OF THE ROOTS AT DIFFERENT WATER POTENTIALS , 1973 .

[4]  P. Kramer,et al.  Responses of Plants to Environmental Stresses , 1973 .

[5]  J. Ketcheson,et al.  INFLUENCE OF SOIL BULK DENSITY AND MATRIC PRESSURE ON SOIL RESISTANCE TO PENETRATION , 1972 .

[6]  J. Williams,et al.  The Influence of Soil Water Matric Potential on the Strength Properties of Unsaturated Soil1 , 1970 .

[7]  D. Lawlor.  Absorption of polyethylene glycols by plants and their effects on plant growth , 1970 .

[8]  D. Lawlor.  Plant Growth in Polyethylene Glycol Solutions in Relation to the Osmotic Potential of the Root Medium and the Leaf Water Balance , 1969 .

[9]  R. L. Davidson.  Effects of Soil Nutrients and Moisture on Root/Shoot Ratios in Lolium perenne L. and Trifolium repens L , 1969 .

[10]  G. Sagar,et al.  Crop Responses to Water at Different Stages of Growth. , 1968 .

[11]  R. Hiller,et al.  Respiratory Inhibition in Chlorella Produced by "Purified" Polyethylene Glycol 1540 , 1968, Science.

[12]  C. J. Asher,et al.  RESPONSE OF PLANTS TO PHOSPHATE CONCENTRATION IN SOLUTION CULTURE: II. RATE OF PHOSPHATE ABSORPTION AND ITS RELATION TO GROWTH , 1967 .

[13]  Howard M. Taylor,et al.  SOIL STRENGTH‐ROOT PENETRATION RELATIONS FOR MEDIUM- TO COARSE‐TEXTURED SOIL MATERIALS , 1966 .

[14]  E. Newman.  RELATIONSHIP BETWEEN ROOT GROWTH OF FLAX (LINUM USITATISSIMUM) AND SOIL WATER POTENTIAL , 1966 .

[15]  P. F. Scholander,et al.  Sap Pressure in Vascular Plants , 1965, Science.

[16]  S. R. Olsen,et al.  Diffusion of Phosphorus as Related to Soil Texture and Plant Uptake1 , 1963 .

[17]  W. D. Kemper,et al.  Phosphate Diffusion to Plant Roots1 , 1962 .

[18]  S. R. Olsen,et al.  Phosphorus Absorption by Corn Roots as Affected by Moisture and Phosphorus Concentration1 , 1961 .

[19]  J. V. Lagerwerff,et al.  Control of Osmotic Pressure of Culture Solutions with Polyethylene Glycol , 1961, Science.

[20]  A. Troughton.  Further studies on the relationship between shoot and root systems of grasses. , 1960 .

[21]  C. A. Black.  Soil-Plant Relationships , 1958 .

[22]  A. Troughton.  The underground organs of herbage grasses. , 1958 .

[23]  A. Troughton.  STUDIES ON THE GROWTH OF YOUNG GRASS PLANTS WITH SPECIAL REFERENCE TO THE RELATIONSHIP BETWEEN THE SHOOT AND ROOT SYSTEMS , 1956 .

[24]  C. Olmsted.  Growth and Development in Range Grasses. I. Early Development of Bouteloua curtipendula in Relation to Water Supply , 1941, Botanical Gazette.

[25]  K. Gales.  Study of the effect of drought on root growth and root-shoot relationships in Lolium perenne L. , 1977 .

[26]  D. Atkinson.  SOME GENERAL EFFECTS OF PHOSPHORUS DEFICIENCY ON GROWTH AND DEVELOPMENT , 1973 .

[27]  D. Jackson.  The effects of drought on the growth and water balance of Dactylis glomerata and Lolium perenne , 1972 .

[28]  J. Passioura.  The effect of root geometry on the yield of wheat growing on stored water , 1972 .

[29]  C. R. Camp,et al.  Effect of Mechanical Impedance on Cotton Root Growth , 1968 .

[30]  D. B. Peters,et al.  Shoot and Root Growth as Affected by Water Availability , 1967 .

[31]  E. Hewitt.  Sand and Water Culture Methods Used in the Study of Plant Nutrition , 1966 .

[32]  J. Quirk,et al.  The effect of soil-water stress on the absorption of soil phosphorus by wheat plants , 1962 .

[33]  E. Wangermann.  The effect of water supply and humidity on growth and development , 1961 .