Page 440 - Biosystems Engineering

Exogenous Bior egulators–Fruit Composition & Storability 417

of auxin, contained less calcium than trees treated with the retardant
only.
Ca in Leaves Both retardants, alone or with auxin, did not change Ca
content significantly during the entire experimentation period. How-
ever, in four cases (paclobutrazol applied to shoots and fruits in
experiments 1 and 2), there was a tendency to find a decreased
amount of calcium in leaves after application of auxin and treatment
with retardant.
From changes of potassium content (Fig. 15.2) in fruits, it was
observed that the control fruit contained the least amount of this
element in experiment 3 and the most in experiment 2. The greatest
changes in the content were caused by BRs in experiment 1. Paclobutrazol
evoked a significant decrease of potassium in fruits. But the effect of
daminozide on K fruit content varied. The auxin influenced the
increase of the element both in the control (unsprayed) fruits and in
fruits treated with daminozide (especially when given to leaves only).
The reverse effect (i.e., decreased potassium content) was caused by
auxin in experiments 1 and 3 after treating trees previously sprayed
with paclobutrazol and in experiment 2, after covering leaves only
with daminozide. Regarding the low potassium content in fruits
(experiment 3), both daminozide and auxin did not change the amount
of this element in fruit. In all experiments, the greatest accumulation
of this element in fruit was recorded after treatment with GA and the
3
lowest accumulation was in fruits with shoots tipped off earlier.
K in Seeds The results presented here do not unanimously describe
the influence of retardants on the potassium content in seeds. But
auxin, in many cases, caused an increase of this element in seeds from
trees treated with a retardant, especially when used on shoots and
leaves.
K in Leaves According to the results presented here, the influence of
retardant and auxin on potassium content in leaves was inconsistent.
From changes in magnesium content (Fig. 15.3) in fruits in spite
of differences in magnesium content, no matter what the type and
method of treatment, the retardants did not affect its accumulation in
fruits. However, auxin caused a Mg decrease in apples after treatment
with daminozide, both in shoots and fruits in experiment 3.
Mg in Leaves It was observed that in case of low content of magne-
sium in plants not treated with retardants, both retardants and auxin
generally induced a small (insignificant) increase of Mg in leaves. The
reverse changes were observed after applying auxin following treat-
ment with a retardant.
With changes in the content of nitrogen, it can be explained that
simultaneous treatment with retardants and auxin decreased the
amount of nitrogen in apple leaves. This treatment did not influence