Open Access. Powered by Scholars. Published by Universities.®
- Keyword
-
- Carbon partitioning (3)
- Carbon accumulation (2)
- Steady-state labelling (2)
- 14C-import (1)
- 3-phophoglyceric acid (1)
-
- Bean (1)
- Bean seed (1)
- Bush bean (1)
- Climate change (1)
- Development (1)
- Fabaceae (1)
- First flowering (1)
- Gene expression (1)
- Global warming (1)
- Glucose translocator (1)
- Growth rate coefficient (1)
- Invertase (1)
- Maltose translocator (1)
- Minimum temperature (1)
- Nutrition (1)
- Phaseolus Vulgaris L. (1)
- Phaseolus vulgaris (1)
- Phloem loading (1)
- Photosynthesis (1)
- Regulation (1)
- Self-regulation (1)
- Sink metabolism (1)
- Sink strength (1)
- Starch mobilization (1)
- Stress (1)
- File Type
Articles 61 - 76 of 76
Full-Text Articles in Biology
Glyphosate Effects On Carbon Assimilation And Gas Exchange In Sugar Beet Leaves, Donald Geiger, Michelle Tucci, Jerome Servaites
Glyphosate Effects On Carbon Assimilation And Gas Exchange In Sugar Beet Leaves, Donald Geiger, Michelle Tucci, Jerome Servaites
Donald R. Geiger
The mechanism responsible for the inhibition of net carbon exchange (NCE) which was reported previously (DR Geiger et al. 1986 Plant Physiol 82: 468-472) was investigated by applying glyphosate [N-(phosphonomethyl)glycine] to exporting leaves of sugar beet (Beta vulgaris L.). Leaf internal CO2 concentration (Ci) remained constant despite Dec.reases in stomatal conductance and NCE following glyphosate treatment, indicating that the cause of the inhibition was a slowing of carbon assimilation rather than Dec.reased conductance of CO2. Throughout a range of CO2 concentrations, NCE rate at a given Ci Dec.lined gradually, with the time-series of response curves remaining parallel. Gas exchange measurements …
Sources Of Carbon For Export From Spinach Leaves Throughout The Day, Jerome Servaites, Bernadette Fondy, Bin Li, Donald Geiger
Sources Of Carbon For Export From Spinach Leaves Throughout The Day, Jerome Servaites, Bernadette Fondy, Bin Li, Donald Geiger
Donald R. Geiger
Rates of net carbon exchange, export, starch, and sucrose synthesis were measured in leaves of spinach (Spinacia oleracea L.) throughout a 14-hour period of sinusoidal light to determine the sources of carbon contributing to export. Net carbon exchange rate closely followed light level, but export remained relatively constant throughout the day. In the morning when photosynthesis was low, starch degradation provided most of the carbon for export, while accumulated sucrose was exported during the evening. At high photosynthesis rate, the regulatory metabolite fructose 2,6-bisphosphate was low, allowing more of the newly fixed carbon to flow to sucrose through cytosolic fructose …
Role Of Starch In Carbon Translocation And Partitioning At The Plant Level, Donald Geiger, Jerome Servaites, Mark Fuchs
Role Of Starch In Carbon Translocation And Partitioning At The Plant Level, Donald Geiger, Jerome Servaites, Mark Fuchs
Donald R. Geiger
Endogenous regulation of translocation and of carbon partitioning, major factors for integrating plant function, depend on diurnal regulation of starch synthesis and mobilization. Regulated diurnal cycling of transitory starch provides a steady carbon supply to sink growth and avoids potentially adverse high sugar levels. Carbon availability from starch affects development and alters carbon availability with respect to nitrogen. Along with sugar sensing, the level and turnover of starch are involved in endogenous regulation in response to carbohydrate status. Despite their key roles in plant metabolism, mechanisms for endogenous regulation of starch synthesis and degradation are not well characterized. Time course …
Carbon Allocation And Response To Stress, Donald Geiger, Jerome Servaites
Carbon Allocation And Response To Stress, Donald Geiger, Jerome Servaites
Donald R. Geiger
This book presents a whole-plant perspective on plant integrated responses to multiple stresses, including an analysis of how plants have evolved growth forms and phenological responses to cope with changing stress patterns in natural environments.
Pathway Of Phloem Unloading In Developing Leaves Of Sugar Beet., J. Schmalstig, Donald Geiger, William Hitz
Pathway Of Phloem Unloading In Developing Leaves Of Sugar Beet., J. Schmalstig, Donald Geiger, William Hitz
Donald R. Geiger
No abstract provided.
Diurnal Changes In Allocation Of Newly Fixed Carbon In Exporting Sugar Beet Leaves, Bernadette Fondy, Donald Geiger
Diurnal Changes In Allocation Of Newly Fixed Carbon In Exporting Sugar Beet Leaves, Bernadette Fondy, Donald Geiger
Donald R. Geiger
Storage of newly fixed carbon as starch and sucrose follows a regular daily pattern in exporting sugar beet leaves under constant day length and level of illumination. Up to the final two hours of the light period, when starch storage Dec.lines, a nearly constant proportion of newly fixed carbon was allocated to carbohydrate storage, principally starch. Sucrose is stored only early in the light period, when there is little accumulation of starch. Pulse labeling with 14CO2revealed that considerable starch synthesis was taking place at this time. Starch made the previous day was not mobilized during this period but breakdown of …
A Method For Continuous Measurement Of Export From A Leaf, Donald Geiger, Bernadette Fondy
A Method For Continuous Measurement Of Export From A Leaf, Donald Geiger, Bernadette Fondy
Donald R. Geiger
Export of labeled material derived by continuous photosynthesis in 14CO2 was monitored with a Geiger-Müller detector positioned next to an exporting leaf blade. Rate of export of labeled material was calculated from the difference between rates of retention and net photosynthesis of labeled carbon for the observed leaf. Given certain conditions, including nearly constant distribution of labeled material among minor veins and various types of cells, count rate data for the source leaf can be converted to rate of export of carbon. Changes in counting efficiency resulting from changes in leaf water status can be corrected for with data from …
Processess Affecting Carbon Allocation And Partitioning Among Sinks, Donald Geiger
Processess Affecting Carbon Allocation And Partitioning Among Sinks, Donald Geiger
Donald R. Geiger
No abstract provided.
Sink Strength: Learning To Measure, Measuring To Learn, Donald Geiger, Wen-Jang Shieh
Sink Strength: Learning To Measure, Measuring To Learn, Donald Geiger, Wen-Jang Shieh
Donald R. Geiger
No abstract provided.
Photosynthesis, Translocation, And Crop Yield, Donald Geiger, Robert Giaquinta
Photosynthesis, Translocation, And Crop Yield, Donald Geiger, Robert Giaquinta
Donald R. Geiger
No abstract provided.
Time Course Of Low Temperature Inhibition Of Sucrose Translocation In Sugar Beets, Donald Geiger, C. Swanson
Time Course Of Low Temperature Inhibition Of Sucrose Translocation In Sugar Beets, Donald Geiger, C. Swanson
Donald R. Geiger
Further studies are presented characterizing the time-course response of sucrose translocation in sugar beet (Beta vulgaris L. cv Klein Wanzleben) to low temperature inhibition. Only the temperature of a 2 cm zone of the source-leaf petiole was varied (1° vs 25°, approximately). The half-time of inhibition, defined as the time required for 50% inhibition of the control or pre-cooling rate, varied from 4 to 15 minutes, and the half-time of recovery from 30 to 100 minutes. Maximum inhibition varied from 68 to 92%. Possible uncertainties in evaluating these parameters are discussed. When the duration of the low temperature period was …
Growth, Sucrose Synthase, And Invertase Activities Of Developing Phaseolus Vulgaris L. Fruits, S. Sung, Wen-Jang Shieh, Donald Geiger, Clanton Black
Growth, Sucrose Synthase, And Invertase Activities Of Developing Phaseolus Vulgaris L. Fruits, S. Sung, Wen-Jang Shieh, Donald Geiger, Clanton Black
Donald R. Geiger
Activities of the sucrose-cleaving enzymes, acid and neutral invertase and sucrose synthase, were measured in pods and seeds of developing snap bean (Phaseolus vulgaris L.) fruits, and compared with 14C-import, elongation and dry weight accumulation. During the first 10 d post-anthesis, pods elongated rapidly with pod dry weight increase lagging behind by several days. The temporal patterns of acid invertase activity and import coincided closely during the first part of pod development, consonant with a central role for this enzyme in converting imported sucrose during pod elongation and early dry weight accumulation. Later, sucrose synthase became the predominant enzyme of …
Regulation Of Photosynthetic Carbon Reduction Cycle By Ribulose Bisphosphate And Phosphoglyceric Acid, Jerome Servaites, Wen-Jang Shieh, Donald Geiger
Regulation Of Photosynthetic Carbon Reduction Cycle By Ribulose Bisphosphate And Phosphoglyceric Acid, Jerome Servaites, Wen-Jang Shieh, Donald Geiger
Donald R. Geiger
The activation states of a number of chloroplastic enzymes of the photosynthetic carbon reduction cycle and levels of related metabolites were measured in leaves of sugar beet (Beta vulgaris L., Klein E-type multigerm) under slowly changing irradiance during a day. The activation states of both phosphoribulokinase and NADP+-glyceraldehyde-3-phosphate dehydrogenase increased early in the light period and remained constant during the middle of the day. Initial ribulose 1,5-bisphosphate carboxylase activity was already about one third of the midday level, did not change for the first 2 hours, but then increased in parallel with the rate of carbon fixation. Because the activation …
Characterization And Subcellular Localization Of Debranching Enzyme And Endoamylase From Leaves Of Sugar Beet, Bin Li, Jerome Servaites, Donald Geiger
Characterization And Subcellular Localization Of Debranching Enzyme And Endoamylase From Leaves Of Sugar Beet, Bin Li, Jerome Servaites, Donald Geiger
Donald R. Geiger
Sugar beet leaves (Beta vulgaris L.) contained up to five endoamylases, two exoamylases, and a single debranching enzyme. Four of the endoamylases and the debranching enzyme were present in the chloroplast. The chloroplastic starch-debranching enzyme and an apoplastic endoamylase were copurified from mature leaves of sugar beet by 35 to 50% ammonium sulfate precipitation and chromatography on diethylaminoethyl-Sephacryl, β-cyclodextrin Sepharose 6B, and Sephadex G-150. The debranching enzyme, which was purified to homogeneity, had a molecular mass of 100 kilodaltons and a pH optimum of 5.5. It showed a high activity with pullulan as a substrate, low activity with soluble starch …
Evidence For Circadian Regulation Of Starch And Sucrose Synthesis In Sugar Beet Leaves, Bin Li, Donald Geiger, Wen-Jang Shieh
Evidence For Circadian Regulation Of Starch And Sucrose Synthesis In Sugar Beet Leaves, Bin Li, Donald Geiger, Wen-Jang Shieh
Donald R. Geiger
Starch accumulation and sucrose synthesis and export were measured in leaves of sugar beet (Beta vulgaris L.) during a period of prolonged irradiance in which illumination was extended beyond the usual 14-hour day period. During much of the 14-hour day period, approximately 50% of the newly fixed carbon was distributed to sucrose, about 40% to starch, and less than 10% to hexose. Beginning about 2 hours before the end of the usual light period, the portion of newly fixed carbon allocated to sucrose gradually increased, and correspondingly less carbon went to starch. By the time the transition ended, about 4 …
Evaluation Of Selected Parameters In A Sugar Beet Translocation System, Donald Geiger, C. Swanson
Evaluation Of Selected Parameters In A Sugar Beet Translocation System, Donald Geiger, C. Swanson
Donald R. Geiger
No abstract provided.