Allocation of a hydroxamic acid and biomass during vegetative development in rye

The allocation of a hydroxamic acid (DIBOA) and biomass was evaluated in ve getative growth stages (GS) of rye. Allocation to the shoot, root/shoot rat io of allocation, and the effect of reduced pot volume on such patterns of allocation were evaluated. Higher allocation of biomass to the shoot relati ve to the root as the plant aged was observed. No significant differences i n allocation of DIBOA were found at different plant GS. Reducing pot volume decreased final shoot biomass. The effect at an early GS was marginally no n-significant, while it was highly significant at a late GS. The effect of reduced pot volume on DIBOA accumulation differed between the GS. At the ea rly stage the DIBOA content per unit of biomass in the shoot increased sign ificantly with reduced pot volume, whereas at the late stage it was not sig nificantly different. The effects of reduced pot volume on the shoot were n ot a consequence of a significant shift in the corresponding root/shoot rat ios. While the total content of DIBOA (nmol) and the total biomass (g) in t he shoot varied at similar rates in the first GS evaluated, a substantially greater relative increase in biomass occurred in the last two GS.