Sugarcane Nl had a higher specific activity than SAI (apoplastic and vacuolar) in the sucrose-accumulating region of the sugarcane culm. Where use has been made of the work of others, this is duly acknowledged in the text. Flux model simulation of the changes in the specific activity of individual pools in internode six tissues after feeding labeled glucose.
Flux model simulation of the changes in the specific activity of individual pools in internode six tissues after feeding labeled fructose. The outer space invertase was recognized as part of the total acid invertase, which is also found in the vacuole. Co2+ is a potent inhibitor of Chichorium intybus Nl (Van den Ende and Van Laere, 1995).
Due to the complexity of metabolic pathways, the use of theoretical models will be helpful in the interpretation of experimental results. In the case of sucrose synthesis (one-way), the specific activity of hexose was predicted as the activity of the bathing medium. The gradual increase in sucrose content in younger internodes coincides with an increase in glucose and fructose content.
After feeding labeled fructose, most of the radiolabel was recovered in the sugar pool in sucrose (Table 3.2).
A) a lower activity was not observed in internode three. Invertase activities therefore remained constant on a volume basis as shown by the activity
Based on the sucrose present in the sugarcane pulp (Table 3.1) and the activities of neutral and SAI (Fig. 3.1), the time required for hydrolysis of the sucrose pool by combined sucrolytic activities of Nl and SAI was calculated (Table 3.3 ). . Method 1 assumes that the hexose label is uniformly distributed in the cell and the sugar phosphate pool is the specific activity of the external medium. Method three assumes that the hexose label is exclusively in the cytosol and the sugar phosphate pool is the average specific activity of the hexoses between 60 and 120 min.
Method one assumes that the label is uniformly distributed within the cell and the specific activity of the sucrose pool is the average of 60 and 120 min. Method two assumes that the label is exclusively in the cytosol and the specific activity of the sucrose pool is the average of 60 and 120 min. The decrease in the specific activity of the hexose pool (Fig. 5.1) was not consistent with the rapid decrease in 14CO2 release to the pulse (Fig. 5.2).
14CO2 emissions for internodes three and six until time zero of the chase. The specific activity of the bronhexose is consistently greater than the specific activity of the non-. It resulted in the calculated synthesis rate being one low due to the high estimated specific activity of the.
The ratio of 14CO2 to the To of the chase (Fig. 5.4) indicates that the internode is six. The specific activity of the bronhexose is greater than that of the non-bronhexose (Table 5.1). If all sugars were in one compartment, the specific activity of the non-source hexose would approximate the specific activity of sucrose.
A similar trend, mirroring that of the water/alcohol fraction, is observable in the insoluble fraction (Fig. 5.5C). The majority of the label was initially in the neutral fraction as would be expected due to the tissue being fed 14C-Glucose. An observation of particular interest is the difference in specific activity of the source and non-source hexoses.
This will also help in assessing the importance of sucrose turnover in sugarcane stem tissue. The change in activity of individual basins has been plotted to aid in interpretation.
If 14C-Fructose were fed to sugarcane tissue, 14C-Glucose would result from
It was recognized that it was not possible to reach isotopic steady state within a realistic experimental time period due to the sizes of the metabolic pools
A relatively short experimental time period was adopted to minimize any time dependent effects on sliced internodal tissue
Optimization of the model for the experimental data (Table 6.4) led to the selected best performing data sets for each internode (Table 6.5). Flux model simulation of changes in the specific activity of individual pools in intermode three tissue after feeding with labeled glucose. Flux model simulation of changes in the specific activity of individual pools in intermode three tissue after feeding with labeled fructose.
The flow of etiquette through the system can be seen in the specific activities of the individual pools (Fig. 6.4, 6.6). Because of the relatively small pool size (Table 6.3), the sugar phosphate pool will turn over rapidly and follow the specific activity of the source-labeled hexose. The important feature of the plots is the change in the slope of the curve with time.
This apparent plateau of specific activity leads to the apparently constant slope of the output pool. A significant feature of the internode three labeling is that the source hexose-specific activity is less than the sucrose-specific activity (Fig. 6.3, 6.5). Flux model simulation of the changes in the specific activity of individual pools in intermode six tissues after feeding with labeled glucose.
The specific activities of the source and non-source hexoses are similar in the three internode experiments (Figs. 6.3, 6.5). In the glucose source labeling experiments, the specific activity of the glucose moiety of sucrose in the cytosol (Fig. The implementation of the labeling ratio between the hexose moieties of sucrose as a constraint refines the model.
The manipulation of the sucrose-substrate cycle is a possible way to increase the rate of sucrose accumulation in sugarcane. Developmental changes in sugarcane stem anatomy in relation to phloem unloading and sucrose storage.
![Table 3.2. The distribution of 14C in sucrose, glucose and fructose after labelling of internodal discs of NCo376 with [U-14C]Fructose for 5.5 h at 28 °C.](https://thumb-ap.123doks.com/thumbv2/pubpdfnet/10629053.0/49.828.151.684.277.449/distribution-sucrose-glucose-fructose-labelling-internodal-nco376-fructose.webp)
