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Results and Discussion
Polyphenol oxidase showed an increase in its activity from 0
hr to 48 hr stage of germination followed by a decline at 72
hr stage (Table 1). The activity
was almost same at 96 hr stage but then again an increase in
the activity was recorded in one week old seedlings but
lower than 48 hr stage of germination. Maximum activity was
observed at 48 hr stage which was 4 to 9 fold more over the
O hr stage. Kruger (1976) reported similar changes in
activity of polyphenol oxidase in germinating wheat seeds.
All the isolines with Lr genes showed greater
activities than the susceptible entries, at one week old
stage, but significant differences between these two
susceptible entries and resistant isolines could not be
established in the early stages of germination.
A total of 7 isozyme forms of PPO were observed with maximum
of four bands could be seen at appeared. Similar changes
were observed in the case of peroxidase (Narasimham and
Chawla 1984) and were reported in case of 0-diphenolase
during various stages of germination (Taneja and Sachar
1974). These changes are the basis of possible differential
gene activities during the development of a sporophyte.
Two slow moving isozymes viz. band nos 5 and 6 whenever
observed were always present together and with almost
similar intensity which made us to speculate that perhaps
these are coded by a single locus.
Isolines with Lr genes could not be differentiated
from susceptible cultivars with a characteristic isozymic
pattern. All the lines showed the same isozymic pattern
especially at one week stage.
Fig.1. Zymogram
showing polyphenol oxidase isozymers at defferent stages of
seed germination.
Acknowledgment
Financial assistance received from the university is
gatefully acknowledged.
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