Maximum axial and radial growth pressures of plant roots
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The axial root growth force exerted by seedlings of pea (Pisum sativum cv. Greenfeast), cotton (Gossypium hirsutum cv. Sicot 3) and sunflower (Helianthus annuus cv. Hysun) was measured. Effects of different seedling age and different batches of seeds on axial root growth pressure were investigated.
Mean values of the maximum axial root growth pressure (Pa) estimated from the maximum axial root growth force (Fmax) and root diameter were 497, 289, and 238 kPa respectively for pea, cotton and sunflower seedlings of same size. Pa and Fmax were significantly influenced by seedling age and for pea seedlings of same age they varied with the seed batch.
A new technique was developed for estimating radial root growth pressure and was tested on pea seedlings. Each pea root was confined both in the axial and radial directions in a cylindrical chalk sample at a constant water potential. The roots exerted radial stress which caused tensile failure in a proportion of the chalks. The measurement of tensile strength of duplicate chalks enabled estimation of the maximum radial pressures exerted by the roots. The maximum axial and radial root growth pressures were of comparable magnitude.
Key wordsAxial growth pressure Gossypium hirsutum Helianthus annuus Pisum sativum Radial growth pressure Root diameter
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- 3.Eavis B W, Ratliff L F and Taylor H M 1969 Use of a dead load technique to determine axial root growth pressure. Agron. J. 61, 640–643.Google Scholar
- 4.Gill W R and Bolt G H 1955 Pfeffer's, studies of the root growth pressures exerted by plants. Agron. J. 47, 166–168.Google Scholar
- 5.Goyal M R, Drew L O, Nelson G L and Logan T J 1980 Critical time for soybean seedling emergence force. Trans. ASAE 23, 831–835, 839.Google Scholar
- 8.Misra R K, Dexter A R and Alson A M 1986 Penetration of soil aggregates of finite size. II. Plant roots. Plant and Soil 94, 59–85.Google Scholar
- 9.Pfeffer W 1893 Druck und Arbeitsleistung durch wachsende Pflanzen. Abh. Sächs. Akad. Wiss. 33, 235–474.Google Scholar
- 10.Somapala H and Willatt S T 1979 Effect of plant age on root penetration.In SOil Physical Properties and Crop Production in the Tropics. Ed. R Lal and D J Greenland, John Wiley and Sons, Great Britain, pp. 349–361.Google Scholar
- 11.Stolzy L H and Barley K P 1968 Mechanical resistance encountered by roots entering compact soils. Soil Sci. 105, 297–301.Google Scholar
- 12.Taylor H M and Ratliff L F 1969 Root growth pressures of cotton, peas and peanuts. Agron. J. 61, 398–402.Google Scholar