Articles
DEVELOPMENT OF PHOTOSYNTHETIC AUTONOMY OF MICROPROPAGATED RHODODENDRON L. INOCULATED WITH MYCORRHIZAL FUNGI DURING EX VITRO ESTABLISHMENT
Article number
748_16
Pages
139 – 146
Language
English
Abstract
Influence of timing of ericoid mycorrhizal fungi (EMF) inoculation and two levels of photosynthetic photon flux density PPFD (75 and 150 µmol m-2 s-1) on the growth and development of photosynthetic potential of micropropagated Rhododendron Brigitte during acclimatisation and ex vitro establishment were evaluated.
Microcuttings were inoculated with EMF at the beginning of weaning stage (T 0) or after 6 weeks of ex vitro growth (T 1). Dry matter production was stimulated by high PPFD level (42%) as well as EMF at T 1 (31%). Mycorrhizal inoculation at the beginning of weaning stage (T 0) affected neither dry matter production nor photosynthetic potential of plants, irrespective of PPFD level.
Development of photosynthetic potential was monitored by chlorophyll a fluorescence every 4 weeks during 20 weeks of ex vitro establishment.
The Fv/Fm (variable to maximum fluorescence) ratio of in vitro formed leaves just after taking out of culture was 0.72 and then decreased progressively for the first 8 weeks to 0.62 at low and 0.48 at high PPFD. For the next 12 weeks, Fv/Fm increased gradually to the value 0.78 at both PPFD levels.
Fv/Fm of ex vitro formed leaves was higher that in vitro formed leaves.
EMF inoculation at T1 slightly increased the Fv/Fm of ex vitro formed leaves of plants grown under high PPFD. Rfd (the ratio of maximal fluorescence decrease to the steady state value) of in vitro formed leaves at the beginning of weaning stage was very low (0.8) and than progressively increased to 1.7 at low and 2.1 at high PPFD. Rfd of ex vitro formed leaves was always higher than in vitro formed ones.
After 20 weeks of ex vitro establishment, Rfd of ex vitro formed leaves was 2.5 at low and 2.8 at high PPFD. EMF inoculation at T 1 increased Rfd for ex vitro formed leaves of plants grown at high PFD. Increasing Rfd as a result of mycorrhizal inoculation indicates improved balance between the light and dark phases of photosynthesis and higher photosynthetic potential of micropropagated rhododendrons grown at good light conditions.
Microcuttings were inoculated with EMF at the beginning of weaning stage (T 0) or after 6 weeks of ex vitro growth (T 1). Dry matter production was stimulated by high PPFD level (42%) as well as EMF at T 1 (31%). Mycorrhizal inoculation at the beginning of weaning stage (T 0) affected neither dry matter production nor photosynthetic potential of plants, irrespective of PPFD level.
Development of photosynthetic potential was monitored by chlorophyll a fluorescence every 4 weeks during 20 weeks of ex vitro establishment.
The Fv/Fm (variable to maximum fluorescence) ratio of in vitro formed leaves just after taking out of culture was 0.72 and then decreased progressively for the first 8 weeks to 0.62 at low and 0.48 at high PPFD. For the next 12 weeks, Fv/Fm increased gradually to the value 0.78 at both PPFD levels.
Fv/Fm of ex vitro formed leaves was higher that in vitro formed leaves.
EMF inoculation at T1 slightly increased the Fv/Fm of ex vitro formed leaves of plants grown under high PPFD. Rfd (the ratio of maximal fluorescence decrease to the steady state value) of in vitro formed leaves at the beginning of weaning stage was very low (0.8) and than progressively increased to 1.7 at low and 2.1 at high PPFD. Rfd of ex vitro formed leaves was always higher than in vitro formed ones.
After 20 weeks of ex vitro establishment, Rfd of ex vitro formed leaves was 2.5 at low and 2.8 at high PPFD. EMF inoculation at T 1 increased Rfd for ex vitro formed leaves of plants grown at high PFD. Increasing Rfd as a result of mycorrhizal inoculation indicates improved balance between the light and dark phases of photosynthesis and higher photosynthetic potential of micropropagated rhododendrons grown at good light conditions.
Publication
Authors
B. Matysiak
Keywords
acclimatization, chlorophyll a fluorescence, ericoid mycorrhizal fungi, micropropagation, Rhododendron, photosynthesis
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