Articles
CORRELATION BETWEEN BROWNING, TOTAL PHENOLIC CONTENT, POLYPHENOL OXIDASE AND SEVERAL ANTIOXIDATION ENZYMES DURING PISTACHIO TISSUE CULTURE
Article number
829_17
Pages
127 – 132
Language
English
Abstract
A major obstacle to tissue culture of pistachio is the browning of explants, which is usually attributed to phenolic compounds being oxididied to highly toxic quinone compounds by polyphenol oxidase (PPO). Browning is regarded as an oxidation process involving phenols, PPO, and antioxidation enzymes.
This experiment was designed to investigate correlations between browning and total phenolic content, PPO, peroxidase (POD), and superoxide dismutase (SOD) in pistachio explants.
Young tissue and organs of pistachio contained less phenolic compounds, which were biosynthesized and accumulated more in older cells.
Browning index and total phenolic content of explants increased gradually throughout a proliferation cycle.
Explants browned heavily and started shrinking during later phases of subculture.
The activity of POD and SOD increased gradually during initial phases of subculture, but dropped rapidly after three weeks.
The activity of PPO, however, did not change markedly during 35 days after subculture.
The browning of pistachio explants showed a positive correlation with phenolic content, but this did not correlate with PPO enzymes.
It is suggested that explants be taken from young shoots of pistachio and that regular transfer of subcultures occur (once every three to four weeks) to control browning by reducing polymerized phenols in the media.
This experiment was designed to investigate correlations between browning and total phenolic content, PPO, peroxidase (POD), and superoxide dismutase (SOD) in pistachio explants.
Young tissue and organs of pistachio contained less phenolic compounds, which were biosynthesized and accumulated more in older cells.
Browning index and total phenolic content of explants increased gradually throughout a proliferation cycle.
Explants browned heavily and started shrinking during later phases of subculture.
The activity of POD and SOD increased gradually during initial phases of subculture, but dropped rapidly after three weeks.
The activity of PPO, however, did not change markedly during 35 days after subculture.
The browning of pistachio explants showed a positive correlation with phenolic content, but this did not correlate with PPO enzymes.
It is suggested that explants be taken from young shoots of pistachio and that regular transfer of subcultures occur (once every three to four weeks) to control browning by reducing polymerized phenols in the media.
Authors
Pingsheng Leng, Shuchai Su, Fang Wei, Fei Yu, Yunfeng Duan
Keywords
Pistacia vera L., tissue culture, phenolics , browning index, PPO, POD, SOD
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