The Effects of Nutrient Solution Acic{ity (l'il}, Aluminium Content Taproot Elongation, Formation on Field Rosecoco f)iscovery and Innovatior Vol. 5 no. 1 March 1993 Rcrct Crowth in Irhosroils r,l.tlgatis L. cv Roser-trco 35 and Rhizobium Inoculati*n rrn Root Growth arxl Noelule Beans (Phasealus uulgr:rtr'rs [,.) cv

Abstract

'The effects of nutrient solution pH.aluminium concentration and Rhizobium irr6ttrrlalis.,i i,i1 !-rl\rir::f r,16;11g6{i111r, rgi1t p:rt-,wth and nqltrle ftrrmatittn on field beans (Plrascolrts ttulgaris L). cv Rosecoco, Ct.l, 2lyyc ., .., ,.ii;, li",! i;r i'r grr,fitlrr;rrsr' Ilrere was a highly significant reduction (p < 0.001) of the mean taproot length. lVith res1..,,,,'l t'i nutrient solution afli(ri,t, the highest mean taprrxtt length was observed at pH 4.0. These differences were attlitruil .r !,r i|16, exis{:ence of forrns of Al having varying degrees of toxicity, controlled by the ptl of the nutrient solutirxr. 'l'he c*o,.r,nlration of Al in ttrr: nrrtriept solution did not affect the mean root dry matter weight significantly but affected thc nlr.li,lo lrumbers wltirh dpcr+,ased as the concentration of this eleme,nt increased in the nutrient solution. The highest ntean trrurl!q,r,r.rf rro,;lrrles li:rrtred was 13.12 at pH 5.8 and 0 ppm Al. Field beans cultivar "Rosecoco", CLP 2, showed a poor teslxlrrse trr irirN:ui;rtiorr corlparxl tg pthers. Nutrient solution acidity inhibited nodulation of the beans. It is suggested that tlre inhibitliy efft,::t *f Al nray d;:pend on the sPecific ionic form of this element apart from its concentration and pH of the nutrient sr,iiir,ir;i;.