The Influence Of Priming Two Cucumber Cultivar Seeds

J. Duhok Univ. Vol.13, No.1, (Agri. And Vet. Sciences) Pp 139-147, 2010
A
B
C
D
Ln(AA)
Ln(AA)
Ln(AA)
Ln(AA)
4
4
3
3
2
2
1
1
0
4
3
2
1
0
4
3
2
1
0
4
3
2
1
0
0 1 2 3 4 5
time(month)
0 1 2 3 4 5
Time(month)
0 1 2 3 4 5
Time(month)
0 1 2 3 4 5
Time(month)
20 c
30 c
40 c
20 c
30 c
40 c
20 c
30 c
40 c
20 C
30 C
40 C
Fig. (3): The relation between Ln of ascorbic acid degradation and time:(A)glass in light.(B)glass in
dark.(C)plastic in light.(D)plastic in dark.
The rate constant(K)for ascorbic acid
degradation were different at low and high
temperatures for the same model system(table
2).The results indicated that the rate constant(K)
of ascorbic acid loss was higher at elevated
temperatures,because the rise in temperature,
increases the reaction rate of ascorbic acid
loss.Also the results in the same table indicated
that the rate constant different with different
packaging material(i.e 0.119 month -1 in glass
bottles stored in light at 20 ° C and 0.176 month -1
in plastic bottles stored in the light at same
temperature) because the plastic bottles has
oxygen permeability which increase the
degradation of ascorbic acid.Also we saw in the
same table the half time t1/2(the time requisite to
react half of initial concentration of substrate) of
ascorbic acid loss decrease with increasing the
temperature of storage,the results were
5.819,4.053 and 2.473 months for glass bottles
°
in the light stored at 20,30 and 40 C
respectively.The results in the same table
indicated that the half time of the samples
exposed to the light is lower than samples stored
in dark(5.819 months for glass in the light stored
at 20 ° C and 13.327 months for glass bottles in
the dark stored at the same temperature).This
results agree with other studies ( Zerdin et al.
2003) who found much better retention of
ascorbic acid in stored orange juice at 4 ° C
compared to those at 25 ° C.
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