Sokoine University of Agriculture

Root-shoot growth interactions of sorghum (sorghum bicolor l moench) in response to mechanical impedance

Show simple item record Rwehumbiza, F.B.R. Mullins, C.E. 2017-12-15T06:00:59Z 2017-12-15T06:00:59Z 2000
dc.description Tanzania Journal of Agricultural Sciences 2000, VoI.3(1) :11-20 en_US
dc.description.abstract Soil mechanical impedance has a widespread influence on plant organ expansion, penetration, and growth. Studies on root-shoot intera'ctions in relation to mechanical impedance have only investigated the effect on shoots of mechanical impedance imposed on roots. The aim of the reported study was therefore to fill the identified iap in knowledge, including an investigation into all root-shoot interations in response to mechanical impedance. Individual pregerminated sorghum (Sorghum bicolor L. Moench) seeds cultivar ICSV-I12 were grown for 8 days in a growth room in seven replicate cylinders per treatment. Treatments were: (a) impeded root and impeded shoot (II), (b) impeded root and unimpeded shoot (lU), (c) unimpeded root and impeded shoot (VI), and (d) the control, in which both the root and shoot systems were unimpeded (UU). The impeding growth medium was a mixture of sand and vermiculite packed to give a penetration resistance (PR) of 1.18 MPa below the seed and 0.32 MPa above the seed. Control cylinders were completely packed with expanded vermiculite to a bulk density of 0.2 Mg m-3 giving aPR ofO. 025 MPa. Matnc suction was 5.kPa in both media. Results were that: (i) Impedance tg the shoot significantly (P < 0.05) delayed emergence, more so when the root was, also impeded. (ii) Shoots emerging through a mechanically impeding layer, had significantly greater extension rates after emergence than unimpeded ones. (iii) Mesocotyls became significantly thicker only when (he root systems were impeded. (iv) Impeding the shoot system, significantly increased root extension rate. (v) The length of the first internode, the number of leaves and the spacing of lateral roots were not changed by any of the treatments. Root-shoot signalling is suggested as one ofthefactors responsiblefor these interactions. Generally, our findings indicate that mechanical impedance which may be caused by sUrface crusting and hardsetting soils and shallow tilth achieved with a hand hoe results in poor crop establishment and probably total. crop failure. en_US
dc.language.iso en en_US
dc.subject Root-shoot interactions en_US
dc.subject Mechanical impedance en_US
dc.subject Crop establishment en_US
dc.subject Sorghum en_US
dc.title Root-shoot growth interactions of sorghum (sorghum bicolor l moench) in response to mechanical impedance en_US
dc.type Article en_US

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