Page 32 - Volume 1, Issue 2, July 2008

Troyanos & Hipps 84
the [K] at each harvest are presented
in figure. The [K] in leaves and roots in-
creased with time, whereas, there was
a continuous decrease in new shoots.
The [K] in stems increased from trans-
planting until 50 DAP and decreased
thereafter.
The [Ca] in leaves, stems and new shoots
were not affected by the external supply of
Mg (Figure 5) and therefore, only the mean
[Ca] at each harvest are presented. The [Ca]
in stems and new shoots increased with
time, whereas, there was an initial increase
in leaves and roots until 50 DAP and a con-
tinuous decrease thereafter. In the roots,
there was a significant (P<0.001) decrease in
[Ca] with increasing external supply of Mg.
The [N] in leaves, stems and new shoots
were unaffected by the external supply of
Mg (Figure 6). The [N] in leaves was with-
in the range 31-33 mg g-1 DW and the [N]
in new shoots and roots decreased with in-
creasing external supply of Mg. The [P] in
leaves, stem, roots and new shoots were
not affected by the increased external sup-
ply of Mg (Figure 7) and generally increased
during the course of the experiment.
Total contents of mineral nutrients
Based on regression analyses, quadrat-
ic equations were found to be the most ap-
propriate (Table 3) to explain the increase
over time in Mg, K, Ca, N, and P content of
the plants. There was a significant increase
(P<0.001) in the RUR with increasing external
supply of Mg. This resulted in a greater con-
Figure 5. The effect of Mg external supply on the [Ca] in leaves, stems, new shoots and roots of “Colt”. - 0, -
150 and - 1500 μmol Mg l-1. The vertical bars are the SEDs.