| Abstract: | I-naphthylacetic acid (NAA) enhances main axis extension andlateral initiation of excised tomato roots cultured in 0.5 percent sucrose medium. NAA has a qualitatively similar effectupon the growth of root tips cultured in glucose medium or transferredafter 2 days' previous growth in standard (1.5 per cent sucrose)medium to a glucose medium containing NAA.NAA does not raisethe growth-rate of roots cultured in glucose medium to thatoccurring in presence of sucrose as carbon source. The enhancedgrowth resulting from addition of NAA to glucose medium is notdependent upon enhanced glucose uptake.The unique role of sucrosein the growth of excised tomato roots is discussed in the lightof the above observations and of studies on the ability of glucoseto maintain the growth of excised roots previously establishedby a period of culture in sucrose medium. |
