Planta
Planta (Berl.) 128, 241-245 (1976)
9 by Springer-Verlag 1976
Regulation der Entwicklung und des Stoffweehsels der Griinalge Urospora dutch die Temperatur* P. Bachmann, P. Kornmann** und K. Zetsche Botanisches Institut der Justus-Liebig-Universit/it, Senckenbergstral3e 17-21, D-6300 Giel3en, Federal Republic of Germany
Regulation of Development and Metabolism of the Green Algae Urospora by Temperature Summary. In the life cycle of Urospora wormskioldii (Mert. in Hornem) Rosenv. and U. vancouveriana (Tilden) Setschell and Gardner unbranched monosiphonous filaments (exceeding 15 cm in length) alternate with microscopic dwarf plants and a unicellular Codiolum stage. The interrelationship between these very different forms and the regulating effect of temperature on this life cycle are shown in Fig. 1. Beyond the morphological differences between the three forms there are large differences in the composition of the cell wall (Fig. 2). While the cell wall of the Codiolum stage is mainly built up of mannans, glucose-containing polysaccharides predominate in the cell wall of the dwarf plants and xylose-containing polysaccharides are abundant in the cell wall of the filamentous plants. Differences in metabolism between dwarf plants and filamentous plants were detected by 14CO2-incorporating experiments. On the basis of chlorophyll content dwarf plants have a higher total 14CO2-fixation rate than filamentous plants cultured at either 2~ C or 14~ C (Fig. 3). Furthermore, a higher rate of synthesis for Calvin-cycle intermediates and other metabolites was generally demonstrated in dwarf plants with one important exception: Uridine diphosphate glucose was synthesized faster in filamentous plants cultured at 2~ C (Fig. 4). Studies of 14CO2_incorporatio n in filamentous plants cultivated at 2 ~ C or 14~ C (at the higher temperature filamentous plants survive only for a limited time) revealed that the latter show a much higher incorporation * A b k i i r z u n g e n : F-6-P=Fructose-6-phosphat, F-1,6-P=Fructose-l,6-diphosphat, GaI=Galactose, Glc=Glucose, G-6-P= Glucose-6-phosphat, Man = Mannose, PEP - Phosphoenolpyruvat; 3 PGS=3-PhosphoglycerinsS, ure, Rham=Rhamnose, U D P G = Uridindiphosphat-glucose, Xyl=Xylose. ** Biologische Anstalt, D-2192 Helgoland.
of 14C into insoluble substances than the former. On the other hand, pools of soluble substances - especially Calvin-cycle intermediates-are much smaller in 14~ C-plants than in 2~ C-plants with the exception of that of sucrose, which is accumulated in 14~ Cplants in high amounts (more than 70% of the total radioactivity in soluble compounds, Fig. 5). These facts may be explained by temperature-sensitive differential gene expression and/or steps in metabolism (see discussion).
Einleitung Der Entwicklungscyclus der Grfinalge Urospora wormskioldii umfagt drei heteromorphe, sich ungeschlechtlich vermehrende Generationen (Kornmann, 1961 ; Abb. 1). Bei Temperaturen unter 5~ liegt die Alge in Form langer monosiphoner F/iden vor. Diese bilden viergeil31ige Zoosporen, aus denen bei Temperaturen unter 5~ C wiederum monosiphone Ffiden entstehen, w/ihrend sie sich bei Temperaturen fiber 10~ zu sogenannten Zwergpflanzen entwickeln. Die Zwergpflanzen vermehren sich ebenfalls durch viergeiBlige Zoosporen, aus denen bei Temperaturen fiber 10~ C Zwergpflanzen, bei Temperaturen unter 5~ C Fadenpflanzen hervorgehen. Aul3erdem k6nnen die Zwergpflanzen bei Temperaturen um 15~ C auch zweigeil3lige Zoosporen bilden, aus denen das einzellige keulenf6rmige Codiolumstadium hervorgeht. Die viergeil31igen Zoosporen des Codiolumstadiums entwikkeln sich entsprechend der Wassertemperatur zu Faden- oder Zwergpflanzen. Die Entwicklung von U. vancouveriana verlfiuft in ganz/ihnlicher Weise (Hanic, 1965). Dieser Entwicklungscyclus tritt nicht nut unter Kulturbedingungen auf, sondern ist offensichtlich
242
P. Bachmann et al. : Regulation der Entwicklung yon Urospora
Codiotum mOF:~P2one/ #,
// /i/,
~Zwergpf[anze
Zwergpflanze
Planta (Berl.) 128, 241-245 (1976)
9 by Springer-Verlag 1976
Regulation der Entwicklung und des Stoffweehsels der Griinalge Urospora dutch die Temperatur* P. Bachmann, P. Kornmann** und K. Zetsche Botanisches Institut der Justus-Liebig-Universit/it, Senckenbergstral3e 17-21, D-6300 Giel3en, Federal Republic of Germany
Regulation of Development and Metabolism of the Green Algae Urospora by Temperature Summary. In the life cycle of Urospora wormskioldii (Mert. in Hornem) Rosenv. and U. vancouveriana (Tilden) Setschell and Gardner unbranched monosiphonous filaments (exceeding 15 cm in length) alternate with microscopic dwarf plants and a unicellular Codiolum stage. The interrelationship between these very different forms and the regulating effect of temperature on this life cycle are shown in Fig. 1. Beyond the morphological differences between the three forms there are large differences in the composition of the cell wall (Fig. 2). While the cell wall of the Codiolum stage is mainly built up of mannans, glucose-containing polysaccharides predominate in the cell wall of the dwarf plants and xylose-containing polysaccharides are abundant in the cell wall of the filamentous plants. Differences in metabolism between dwarf plants and filamentous plants were detected by 14CO2-incorporating experiments. On the basis of chlorophyll content dwarf plants have a higher total 14CO2-fixation rate than filamentous plants cultured at either 2~ C or 14~ C (Fig. 3). Furthermore, a higher rate of synthesis for Calvin-cycle intermediates and other metabolites was generally demonstrated in dwarf plants with one important exception: Uridine diphosphate glucose was synthesized faster in filamentous plants cultured at 2~ C (Fig. 4). Studies of 14CO2_incorporatio n in filamentous plants cultivated at 2 ~ C or 14~ C (at the higher temperature filamentous plants survive only for a limited time) revealed that the latter show a much higher incorporation * A b k i i r z u n g e n : F-6-P=Fructose-6-phosphat, F-1,6-P=Fructose-l,6-diphosphat, GaI=Galactose, Glc=Glucose, G-6-P= Glucose-6-phosphat, Man = Mannose, PEP - Phosphoenolpyruvat; 3 PGS=3-PhosphoglycerinsS, ure, Rham=Rhamnose, U D P G = Uridindiphosphat-glucose, Xyl=Xylose. ** Biologische Anstalt, D-2192 Helgoland.
of 14C into insoluble substances than the former. On the other hand, pools of soluble substances - especially Calvin-cycle intermediates-are much smaller in 14~ C-plants than in 2~ C-plants with the exception of that of sucrose, which is accumulated in 14~ Cplants in high amounts (more than 70% of the total radioactivity in soluble compounds, Fig. 5). These facts may be explained by temperature-sensitive differential gene expression and/or steps in metabolism (see discussion).
Einleitung Der Entwicklungscyclus der Grfinalge Urospora wormskioldii umfagt drei heteromorphe, sich ungeschlechtlich vermehrende Generationen (Kornmann, 1961 ; Abb. 1). Bei Temperaturen unter 5~ liegt die Alge in Form langer monosiphoner F/iden vor. Diese bilden viergeil31ige Zoosporen, aus denen bei Temperaturen unter 5~ C wiederum monosiphone Ffiden entstehen, w/ihrend sie sich bei Temperaturen fiber 10~ zu sogenannten Zwergpflanzen entwickeln. Die Zwergpflanzen vermehren sich ebenfalls durch viergeiBlige Zoosporen, aus denen bei Temperaturen fiber 10~ C Zwergpflanzen, bei Temperaturen unter 5~ C Fadenpflanzen hervorgehen. Aul3erdem k6nnen die Zwergpflanzen bei Temperaturen um 15~ C auch zweigeil3lige Zoosporen bilden, aus denen das einzellige keulenf6rmige Codiolumstadium hervorgeht. Die viergeil31igen Zoosporen des Codiolumstadiums entwikkeln sich entsprechend der Wassertemperatur zu Faden- oder Zwergpflanzen. Die Entwicklung von U. vancouveriana verlfiuft in ganz/ihnlicher Weise (Hanic, 1965). Dieser Entwicklungscyclus tritt nicht nut unter Kulturbedingungen auf, sondern ist offensichtlich
242
P. Bachmann et al. : Regulation der Entwicklung yon Urospora
Codiotum mOF:~P2one/ #,
// /i/,
~Zwergpf[anze
Zwergpflanze
