| Autor: |
A. Quint, Th. B. van Vliet, Kees R. Libbenga, R.J. Bogers, Z. Kulescha |
| Rok vydání: |
1980 |
| Předmět: |
|
| Zdroj: |
Plant Science Letters. 19:311-317 |
| ISSN: |
0304-4211 |
| DOI: |
10.1016/0304-4211(80)90053-x |
| Popis: |
The presence of a receptor for 3-indoleacetic acid (IAA) in the cytosol of tobacco-pith explants was investigated. We never detected any receptor activity in unpurified extracts from explants immediately after excision. However, after 1 or 2 days of culture of the explants on MS medium with or without phytohormones a cytoplasmic receptor (Krma approx. 108 M−1) for IAA could be detected. If the extracts were purified on a Sepharose-6B column the presence of the receptor could also be demonstrated in explants immediately after excision. We suggest that the wound-reaction in the explants comprises an increase in receptor concentration and/or decrease in the concentration of a binding-inhibiting compound. If IAA was added to the medium at 10−6–10−4 M, only 10–20% of it was stored in the explants; 5–10% remained in the medium and the rest was degraded during a 3–10-day culture period. The bulk of the IAA in the explants was rapidly metabolized to indoleacetyl aspartate (IAAsp), which then seemed to be slowly converted to a compound (A) consisting of IAA, aspartate and glutamate (mol wt approx. 600). At last an equilibrium was reached between IAA (less than 2%), IAAsp (10–15%), and A (85–90%). We calculated that addition of 10−5 M IAA to the medium may have resulted in an internal IAA concentration of approx. 10−7 M, which is high enough to saturate the receptor (more than 90% occupied). |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
|
