Dataset Information

Interspecific differences in how sink-source imbalance causes photosynthetic downregulation among three legume species.

ABSTRACT:

Background and aims

Sink-source imbalance could cause an accumulation of total non-structural carbohydrates (TNC; soluble sugar and starch) in source leaves. We aimed to clarify interspecific differences in how sink-source imbalance and TNC causes the downregulation of photosynthesis among three legume plants. The TNC in source leaves was altered by short-term manipulative treatments, and its effects on photosynthetic characteristics were evaluated.

Methods

Soybean, French bean and azuki bean were grown under high nitrogen availability. After primary leaves were fully expanded, they were subjected to additional treatments: defoliation except for two primary leaves; transfer to low nitrogen conditions; transfer to low nitrogen conditions and defoliation; or irradiation by light-emitting diodes. Physiological and anatomical traits such as TNC content, maximum photosynthetic rate, cell wall content and ?13C values of primary leaves and whole-plant growth were examined.

Key results

Among the three legume plants, the downregulation of maximum photosynthesis and ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) content was co-ordinated with an increase in TNC only in French bean. Rubisco did not decrease with an increase in TNC in soybean and azuki bean. The defoliation treatment caused an increase in cell wall content especially in soybean, and maximum photosynthesis decreased despite resulting in a higher Rubisco content. This indicates that a decrease in mesophyll conductance could cause photosynthetic downregulation, which was confirmed by an increase in ?13C.

Conclusion

The present results suggest that a downregulation of photosynthesis in response to increased levels of TNC in source leaves can result not only from decreases in Rubisco content, but also from anatomical factors, such as an increase in cell wall thickness leading to reduced chloroplast CO2 concentrations.

SUBMITTER: Sugiura D

PROVIDER: S-EPMC6417475 | biostudies-literature | 2019 Mar

REPOSITORIES: biostudies-literature

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Publications

Interspecific differences in how sink-source imbalance causes photosynthetic downregulation among three legume species.

Sugiura Daisuke D Betsuyaku Eriko E Terashima Ichiro I

Annals of botany 20190301 4

<h4>Background and aims</h4>Sink-source imbalance could cause an accumulation of total non-structural carbohydrates (TNC; soluble sugar and starch) in source leaves. We aimed to clarify interspecific differences in how sink-source imbalance and TNC causes the downregulation of photosynthesis among three legume plants. The TNC in source leaves was altered by short-term manipulative treatments, and its effects on photosynthetic characteristics were evaluated.<h4>Methods</h4>Soybean, French bean an ...[more]

PMID: 30517608

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Dataset Information

Interspecific differences in how sink-source imbalance causes photosynthetic downregulation among three legume species.

Background and aims

Methods

Key results

Conclusion

Publications

Interspecific differences in how sink-source imbalance causes photosynthetic downregulation among three legume species.

Similar Datasets

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