Do dicotyledons generate greater maximum axial root growth pressures than monocotyledons?

Abstract

While plants exert growth pressures in both axial and radial directions, this paper is only concerned with axial Roots of dicotyledons (dicots) have often been growth pressures (i.e. the axial growth force per unit observed to grow better in strong soil than monocoty- cross-sectional area of root). There is evidence that roots ledons (monocots), and it has been suggested that this of dicotyledons (dicots) are better than monocotyledons could be due to the dicots generating greater root (monocots) at penetrating strong soil (Materechera et al., growth pressures. Experiments were therefore carried 1991, 1992) and it was suggested that diVerences in the out to measure the maximum axial root growth pres- maximum axial root growth pressures (s max ) generated sure (s max ) in seedlings of monocots and dicots. Dicots may be responsible (Materechera et al., 1991, 1992). In did not generate greater s max than monocots: the mean this paper, direct measurements of s max in seedling semfor dicots was 0.41 MPa; the mean for monocots was inal root axes of various crop species are reported, using 0.44 MPa. the shear beam force transducer method (Clark et al., 1996).