Carbon allocation and translocation in chlorsulfuron-treated canola (Brassica napus)

Weed Science ◽  
1997 ◽  
Vol 45 (4) ◽  
pp. 466-469 ◽  
Author(s):  
Songmun Kim ◽  
William H. Vanden Born
Keyword(s):  
Brassica Napus ◽  
Carbon Fixation ◽  
No Reduction ◽  
Carbon Allocation ◽  
Starch Content ◽  
Carbon Exchange ◽  
Net Carbon Exchange

Our objective was to determine if the chlorsulfuron-induced reduction in assimilate export from leaves can be attributed to a shortage of carbohydrates. Treated canola leaves showed no reduction in carbon fixation or carbohydrate production during the first 24 h, but they exuded only 17 to 27% of the amount of sucrose exuded by corresponding control leaves. Exposure of the leaves to higher concentrations of CO2(500 vs. 350 μl L−1) resulted in greater net carbon exchange and higher starch content, but failed to overcome the reduction in sucrose export, presumably because of increased carbon allocation to starch.

scholarly journals Molecular mechanism underlying the effect of maleic hydrazide treatment on starch accumulation in S. polyrrhiza 7498 fronds

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Yerong Zhu ◽  
Xiaoxue Li ◽  
Xuan Gao ◽  
Jiqi Sun ◽  
Xiaoyuan Ji ◽  
...  
Keyword(s):  
Plant Growth ◽  
Carbon Fixation ◽  
Maleic Hydrazide ◽  
Starch Content ◽  
Vegetative Reproduction ◽  
Photosynthetic Pigment ◽  
Starch Accumulation ◽  
Chlorophyll Fluorescence Parameters ◽  
Significant Difference ◽  
Starch Production

Abstract Background Duckweed is considered a promising feedstock for bioethanol production due to its high biomass and starch production. The starch content can be promoted by plant growth regulators after the vegetative reproduction being inhibited. Maleic hydrazide (MH) has been reported to inhibit plant growth, meantime to increase biomass and starch content in some plants. However, the molecular explanation on the mechanism of MH action is still unclear. Results To know the effect and action mode of MH on the growth and starch accumulation in Spirodela polyrrhiza 7498, the plants were treated with different concentrations of MH. Our results showed a substantial inhibition of the growth in both fronds and roots, and increase in starch contents of plants after MH treatment. And with 75 µg/mL MH treatment and on the 8th day of the experiment, starch content was the highest, about 40 mg/g fresh weight, which is about 20-fold higher than the control. The I2-KI staining and TEM results confirmed that 75 µg/mL MH-treated fronds possessed more starch and big starch granules than that of the control. No significant difference for both in the photosynthetic pigment content and the chlorophyll fluorescence parameters of PII was found. Differentially expressed transcripts were analyzed in S. polyrrhiza 7498 after 75 µg/mL MH treatment. The results showed that the expression of some genes related to auxin response reaction was down-regulated; while, expression of some genes involved in carbon fixation, C4 pathway of photosynthesis, starch biosynthesis and ABA signal transduction pathway was up-regulated. Conclusion The results provide novel insights into the underlying mechanisms of growth inhibition and starch accumulation by MH treatment, and provide a selective way for the improvement of starch production in duckweed.

scholarly journals Axial changes in wood functional traits have limited net effects on stem biomass increment in European beech (Fagus sylvatica)

2020 ◽  
Vol 40 (4) ◽  
pp. 498-510
Author(s):  
Richard L Peters ◽  
Georg von Arx ◽  
Daniel Nievergelt ◽  
Andreas Ibrom ◽  
Jonas Stillhard ◽  
...  
Keyword(s):  
Fagus Sylvatica ◽  
Carbon Fixation ◽  
Carbon Allocation ◽  
Volume Growth ◽  
Ring Width ◽  
European Beech ◽  
Wood Formation ◽  
Tree Level ◽  
Mature Trees ◽  
Anatomical Basis

Abstract During the growing season, trees allocate photoassimilates to increase their aboveground woody biomass in the stem (ABIstem). This ‘carbon allocation’ to structural growth is a dynamic process influenced by internal and external (e.g., climatic) drivers. While radial variability in wood formation and its resulting structure have been intensively studied, their variability along tree stems and subsequent impacts on ABIstem remain poorly understood. We collected wood cores from mature trees within a fixed plot in a well-studied temperate Fagus sylvatica L. forest. For a subset of trees, we performed regular interval sampling along the stem to elucidate axial variability in ring width (RW) and wood density (ρ), and the resulting effects on tree- and plot-level ABIstem. Moreover, we measured wood anatomical traits to understand the anatomical basis of ρ and the coupling between changes in RW and ρ during drought. We found no significant axial variability in ρ because an increase in the vessel-to-fiber ratio with smaller RW compensated for vessel tapering towards the apex. By contrast, temporal variability in RW varied significantly along the stem axis, depending on the growing conditions. Drought caused a more severe growth decrease, and wetter summers caused a disproportionate growth increase at the stem base compared with the top. Discarding this axial variability resulted in a significant overestimation of tree-level ABIstem in wetter and cooler summers, but this bias was reduced to ~2% when scaling ABIstem to the plot level. These results suggest that F. sylvatica prioritizes structural carbon sinks close to the canopy when conditions are unfavorable. The different axial variability in RW and ρ thereby indicates some independence of the processes that drive volume growth and wood structure along the stem. This refines our knowledge of carbon allocation dynamics in temperate diffuse-porous species and contributes to reducing uncertainties in determining forest carbon fixation.

A mutant of rice lacking the leaf large subunit of ADP-glucose pyrophosphorylase has drastically reduced leaf starch content but grows normally

2007 ◽  
Vol 34 (6) ◽  
pp. 480 ◽  
Author(s):  
Sandrine Rösti ◽  
Brendan Fahy ◽  
Kay Denyer
Keyword(s):  
Environmental Conditions ◽  
No Reduction ◽  
Starch Content ◽  
Large Subunit ◽  
Starch Synthesis ◽  
Small Subunit ◽  
Wild Type ◽  
Gene Encoding ◽  
Subunit Protein ◽  
Adp Glucose Pyrophosphorylase

A mutant of rice was identified with a Tos17 insertion in OsAPL1, a gene encoding a large subunit (LSU) of ADP-glucose pyrophosphorylase (AGPase). The insertion prevents production of a normal transcript from OsAPL1. Characterisation of the mutant (apl1) showed that the LSU encoded by OsAPL1 is required for AGPase activity in rice leaf blades. In mutant leaf blades, the AGPase small subunit protein is not detectable and the AGPase activity and starch content are reduced to <1 and <5% of that in wild type blades, respectively. The mutation also leads to a reduction in starch content in the leaf sheaths but does not significantly affect AGPase activity or starch synthesis in other parts of the plant. The sucrose, glucose and fructose contents of the leaves are not affected by the mutation. Despite the near absence of starch in the leaf blades, apl1 mutant rice plants grow and develop normally under controlled environmental conditions and show no reduction in productivity.

Net carbon exchange and evapotranspiration in postfire and intact sagebrush communities in the Great Basin

Oecologia ◽  
2005 ◽  
Vol 146 (4) ◽  
pp. 595-607 ◽  
Author(s):  
Margaret R. Prater ◽  
Daniel Obrist ◽  
John A. Arnone ◽  
Evan H. DeLucia
Keyword(s):  
Great Basin ◽  
Carbon Exchange ◽  
Net Carbon Exchange
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