|Authors: ||Z. El-Din, F.M. Amal, M. AbdEl-Rasoul, I.S. Ibrahim, A.S. Aly, H.A.M. Sharaf Eldeen|
|Keywords: ||Phoenix dactylifera L., shoot tip, Bartamuda, Gondila, Shamia, SDS-PAGE, isozymes, peroxidase, polyphenol oxidase, tissue culture|
The present investigation aimed to study growth gradation from explant to plantlet and the biochemical changes at different stages via tissue culture propagation.
Shoot tip explants from three dry date palm cultivars (Bartamuda, Gondila and Shamia) were used.
Samples were taken from different developmental stages in tissue culture for morphological observations (including callus formation and degree of browning) and biochemical studies (including indole and phenol contents, SDS-PAGE of water soluble protein fraction, isozymes of peroxidase and polyphenol oxidase). The morphological studies indicated that shoot tip explants of Bartamuda cv. produced a higher degree of callus and a lower degree of browning than the other cultivars.
The shoot tip explant of Bartamuda cv. had a significant and positive effect on indole and phenol contents compared to other developmental stages.
Generally, the increase in indole content was more than phenol content in different developmental stages except phenol content of plantlet.
The combination between Bartamuda cv. and shoot tip explant or plantlet stage was more effective on indole and phenol contents in most cases.
These combinations markedly increased the previous chemical components.
SDS-PAGE of water soluble protein fraction and isozymes of peroxidase and polyphenol oxidase were used to identify and characterize the effect of genotypes and their developmental stages via embryogenesis.
SDS-PAGE of water protein fraction was used to determine the molecular weights of protein subunits.
The electrophoregrams revealed about 17 protomer bands of different intensities, with molecular weight ranging from 14 to 102 kD. The results revealed that a number of polypeptides increased or decreased in intensity.
At the same time, some polypeptides disappeared, or new one synthesized.
Most of these modifications appear to be part of the metabolic changes in response to developmental stages.
Isozymes analyses by electrophoresis detected the differences, at gene levels, corresponding to genotypes and developmental stages.
The peroxidase patterns showed different peroxidase isozyme bands, with five different intensity bands.
Meanwhile polyphenol oxidase profiles showed three isozyme bands with different intensities.
The increment of isozymes (peroxidase and polyphenol oxidase) was observed in explant and plantlet stages.
This may be correlated with the ratio of phenol and phenol-indole (auxin).
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