Does altered nitrogen metabolism and H2O2accumulation explain the vitrified status of the fully habituated callus ofBeta vulgaris(L.)?

✍ Scribed by Frédérik Dily; Claude Huault; Thomas Gaspar; Jean-Pierre Billard

• Book ID: 104620818
• Publisher: Springer
• Year: 1993
• Tongue: English
• Weight: 492 KB
• Volume: 35
• Category: Article
• ISSN: 0167-6857
• DOI: 10.1007/bf00043941

✦ Synopsis

The habituated callus is a vitrified tissue which has two main biochemical characteristics both leading to production of toxic forms of oxygen: first the blockage of the porphyrin pathway and a lack of H20 2 detoxifying enzymes (catalase and peroxidases); secondly a deviation of the nitrogen metabolism induced by NH 3 accumulation. Ammonia detoxification is ensured by increased glutamate dehydrogenase activity and accumulation of both proline and polyamines. A putative linkage between proline synthesis and the HMP pathway, as proposed for animal proliferating tissues (Phang 1985), might explain a high purine biosynthesis and cytokinin autonomy.