Respiratory capacity, nitrogenase activity and structural changes of Frankia, in symbiosis with Alnus incana, in response to prolonged darkness

Plants of Alnus incana (L.) Moench in symbiosis with a local source of Frankia were exposed to prolonged darkness under controlled climate conditions. Frankia vesicle clusters were prepared from the root nodules, and the condition of Frankia was measured as respiratory capacity by supplying the prep...

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Bibliographic Details
Published in:Planta 1990-01, Vol.182 (4), p.617-625
Main Authors: Vikman, P.-A. (Umea Univ. (Sweden). Dept. of Plant Physiology), Lundquist, P.-O, Huss-Danell, K
Format: Article
Language:English
Subjects:
ACTIVIDAD ENZIMATICA
ACTIVITE ENZYMATIQUE
Agronomy. Soil science and plant productions
Alnus
ALNUS INCANA
Atmung
Biological and medical sciences
CELL STRUCTURE
Cell walls
Cytoplasm
DARKNESS
Dunkelheit
ECHANGE GAZEUX
Enzymaktivitaet
ENZYMIC ACTIVITY
ESTRUCTURA CELULAR
FRANKIA
Fundamental and applied biological sciences. Psychology
GAS EXCHANGE
Hyphae
INTERCAMBIO DE GASES
Knoellchen
Nitrogen
NITROGENASA
NITROGENASE
NODOSITE RACINAIRE
Nodules
NUDOSIDADES RADICULARES
OBSCURIDAD
OBSCURITE
Parasitism and symbiosis
Plant physiology and development
Plants
Respiration
ROOT NODULES
Starches
STRUCTURE CELLULAIRE
Ultrastruktur
Wurzel
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Summary:Plants of Alnus incana (L.) Moench in symbiosis with a local source of Frankia were exposed to prolonged darkness under controlled climate conditions. Frankia vesicle clusters were prepared from the root nodules, and the condition of Frankia was measured as respiratory capacity by supplying the preparation with saturating amounts of four different substrates. During darkness, nitrogenase (EC 1.7.99.2) activity decreased in intact plants and in the vesicle-cluster preparations. The respiratory capacity of Frankia also decreased. After 4 d in darkness most respiration was lost, though all nitrogenase activity was already lost after 3 d. When the dark treatment was ended after 2 d and normal light/dark conditions restored, nitrogenase activity immediately started to recover. The respiratory capacity continued to decrease and no recovery was observed until the third day after the end of the dark treatment. Whole-plant nitrogenase activity slowly increased at a rate similar to the rate of increase observed in untreated plants. Transmission electron micrographs of the root nodules showed that the cytoplasm of infected host cells and the cells of Frankia were structurally degraded in response to dark treatment, while young vesicles were frequent during recovery. Growth and differentiation of Frankia cells were apparently important for recovery of the enzyme activities studied.
ISSN:0032-0935
1432-2048
DOI:10.1007/BF02341040