... REVIEW Regeneration of roots, shoots and embryos: physiological, biochemical and molecular as... more ... REVIEW Regeneration of roots, shoots and embryos: physiological, biochemical and molecular aspects G.-J. DE KLERK, B. ARNHOLDT-SCHMITT ... of gene expression during the early stages of differentiation have been reported (foi review see Sterck and de Vries 1993). ...
The methylation and amplification pattern of genomic DNA of carrot root expiants (Daucus carota L... more The methylation and amplification pattern of genomic DNA of carrot root expiants (Daucus carota L.) undergoes transitory changes during the cultural cycle. A high degree of variation was observed as early as 36 h after the incubation of fresh expiants in the nutrient medium and, depending on the hormonal treatment significant modifications occurred during 14 days of culture. Proliferative tissue conditioned by kinetin showed an extensive reduction in DNA methylation. Changes in the DNA amplification pattern were not necessarily linked to methylation.
ABSTRACT In an attempt to improve chilling tolerance, the carrot gene encoding the antifreeze pro... more ABSTRACT In an attempt to improve chilling tolerance, the carrot gene encoding the antifreeze protein (AFP) was cloned under the control of constitutive CaMV35S promoter and genetically transformed the tomato var. PKM1 using Agrobacterium-mediated genetic transformation. Putative transgenic plants were confirmed by PCR using AFP-specific primers and grown to maturity. The integration of AFP transgene in the tomato genome was confirmed by Southern blot analysis. The AFP gene expression in transgenic plants was determined using semi-quantitative reverse transcription PCR. Upon exposure to chilling stress (4 �C), a significant decrease in membrane injury index was observed in AFP transgenic tomato lines without any phenotypic aberrations when compared with WT plants. Hence, this study clearly proves that the development of chilling tolerant tomato plants will soon become a reality.
Calorespirometric measurements of metabolic heat rates and CO2 emission rates of respiring tissue... more Calorespirometric measurements of metabolic heat rates and CO2 emission rates of respiring tissues as functions of temperature enable rapid determination of the temperatures that plants are adapted to without growing them in different environmental temperatures. However, the correct choice of target material for measurements that enable prediction of growth temperature responses is crucial, and needs to be identified in a species- and trait-specific manner. In this study, different carrot materials were tested: a primary culture system proposed as an in vitro test system for carrot yield potential, taproots of young plants, and the root meristem of actively growing plants during secondary root growth. The central root meristem is the most suitable for studying temperature response by calorespirometry for genotype comparison. Calorespirometric methods for predicting genotype-specific temperature responses of crop plant cultivars can be used to predict productivity in environments with differing temperature conditions.
... REVIEW Regeneration of roots, shoots and embryos: physiological, biochemical and molecular as... more ... REVIEW Regeneration of roots, shoots and embryos: physiological, biochemical and molecular aspects G.-J. DE KLERK, B. ARNHOLDT-SCHMITT ... of gene expression during the early stages of differentiation have been reported (foi review see Sterck and de Vries 1993). ...
The methylation and amplification pattern of genomic DNA of carrot root expiants (Daucus carota L... more The methylation and amplification pattern of genomic DNA of carrot root expiants (Daucus carota L.) undergoes transitory changes during the cultural cycle. A high degree of variation was observed as early as 36 h after the incubation of fresh expiants in the nutrient medium and, depending on the hormonal treatment significant modifications occurred during 14 days of culture. Proliferative tissue conditioned by kinetin showed an extensive reduction in DNA methylation. Changes in the DNA amplification pattern were not necessarily linked to methylation.
ABSTRACT In an attempt to improve chilling tolerance, the carrot gene encoding the antifreeze pro... more ABSTRACT In an attempt to improve chilling tolerance, the carrot gene encoding the antifreeze protein (AFP) was cloned under the control of constitutive CaMV35S promoter and genetically transformed the tomato var. PKM1 using Agrobacterium-mediated genetic transformation. Putative transgenic plants were confirmed by PCR using AFP-specific primers and grown to maturity. The integration of AFP transgene in the tomato genome was confirmed by Southern blot analysis. The AFP gene expression in transgenic plants was determined using semi-quantitative reverse transcription PCR. Upon exposure to chilling stress (4 �C), a significant decrease in membrane injury index was observed in AFP transgenic tomato lines without any phenotypic aberrations when compared with WT plants. Hence, this study clearly proves that the development of chilling tolerant tomato plants will soon become a reality.
Calorespirometric measurements of metabolic heat rates and CO2 emission rates of respiring tissue... more Calorespirometric measurements of metabolic heat rates and CO2 emission rates of respiring tissues as functions of temperature enable rapid determination of the temperatures that plants are adapted to without growing them in different environmental temperatures. However, the correct choice of target material for measurements that enable prediction of growth temperature responses is crucial, and needs to be identified in a species- and trait-specific manner. In this study, different carrot materials were tested: a primary culture system proposed as an in vitro test system for carrot yield potential, taproots of young plants, and the root meristem of actively growing plants during secondary root growth. The central root meristem is the most suitable for studying temperature response by calorespirometry for genotype comparison. Calorespirometric methods for predicting genotype-specific temperature responses of crop plant cultivars can be used to predict productivity in environments with differing temperature conditions.
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Papers by Birgit Arnholdt-schmitt