In the next solution culture experiment, which was
conducted to study 70Zn uptake, the shoot and root dry
weights of 20-day-old wheat plants were affected by
only the P treatment (Table 7). The shoot dry weights
exhibited a tendency to increase with increasing P supply
whereas the root dry weights decreased slightly.
Consequently, the low-P plants had greater root-toshoot
ratios than the medium-P and high-P plants. As
shown in Fig. 4a, the cumulative 70Zn uptake per unit
root biomass values obtained for the low-Zn plants were
significantly higher than those obtained for the high-Zn
plants at all time points during the 7-h uptake experiment.
In the low-Zn group, the low-P plants absorbed