Page 438 - Biosystems Engineering

Exogenous Bior egulators–Fruit Composition & Storability 415

of limited seed volume from the replicates, chemical analyzes were
executed on mean sample from all replicates, leaves from the middle
of terminal shoots longer than 10 cm were sampled in the middle of
August. Each sample consisted of about 100 leaves taken from the
same branch (five samples per treatment).
The content of minerals Ca, K, Mg, and N (in percent of dry
weight) was assessed in fruit, seeds, and leaves. The collected sam-
ples (five per treatment) were air dried at 60°C and ground down.
Nitrogen content was assessed using the Kjeldahl method. Before
analysis, other elements were mineralized in a mixture of HNO ,
3
H SO , and HClO . Calcium, potassium, and magnesium were assessed
3 4 4
using the atomic absorption method with a Pye Unicam SP 09 spec-
trophotometer (Thermo Scientific, Cambridge, UK).
The following measurements were also taken: mean fruit weight,
number of seeds per fruit, mean length of 1-year terminal shoots and
mineral composition of the soil. Soil was sampled according to gener-
ally accepted rules (data are not shown here).
The results concerning fruit and leaf content were analyzed sta-
tistically with analyzes of variance. The significance of means differ-
ences was assessed with Duncan’s t test at a 95 percent probability
level. The results of the mineral content of the seeds were not ana-
lyzed statistically because chemical analyzes was made on a mixed
sample of five replicates.
From changes in calcium content (Fig. 15.1), the soil in the orchard
showed pH from 4.8 to 5.3, which indicates relatively low calcium
content. The Ca supply of leaves and fruits differed in years. Also, the
influence of bioregulators on Ca content was inconsistent in separate
experiments.

Ca in Fruits In experiment 2, apples from control trees, untreated
with growth BRs, contained almost double the amount of calcium as
compared to the calcium in experiments 1 and 3. Retardants did not
affect the Ca volume in experiment 2 when fruits were rich in this
element. In the remaining experiments, however, retardants had
slightly increased its contents of Ca. However, the significance of the
differences was proven only in the case of fruits and shoots after
treatment with daminozide in experiment 1 and paclobutrazol in
experiment 3. Auxin did not affect calcium content in fruits as com-
pared to plants treated with retardant only.

Ca in Seeds The seeds contained over 2 to 3 times more calcium than
did fruit flesh. Retardants caused a slight increase of this element in
seeds. Auxin influenced a further increase of Ca in seeds from plants
treated with daminozide to shoots only in experiment 1 and from
plants treated with paclobutrazol applied to shoots and fruits in
experiment 3. In experiment 2, however, seeds from trees from which
shoots and fruits were treated with daminozide, after application