Dataset Information

Anatomically induced changes in rice leaf mesophyll conductance explain the variation in photosynthetic nitrogen use efficiency under contrasting nitrogen supply.

ABSTRACT:

Background

The ratio of CO₂ mesophyll conductance (g_m) to Ribulose-1, 5-bisphosphate carboxylase/oxygenase (Rubisco) content has been suggested to positively affect photosynthetic nitrogen use efficiency (PNUE). The anatomical basis of g_m has been quantified, but information on the relationship between cell-level anatomies and PNUE is less advanced. Here, hydroponic experiments were conducted in rice plants supplied with ammonium (NH₄⁺) and nitrate (NO₃^-) under three N levels (low, 0.71?mM; intermediate, 2.86?mM; high, 7.14?mM) to investigate the gas exchange parameters, leaf anatomical structure and PNUE.

Results

The results showed a lower PNUE in plants supplied with high nitrogen and NH₄⁺, which was positively correlated with the g_m/Rubisco ratio. A one-dimensional within-leaf model revealed that the resistance to CO₂ diffusion in the liquid phase (r_liq) dominated the overall mesophyll resistance (r_m), in which CO₂ transfer resistance in the cell wall, cytoplasm and stroma were significantly affected by nitrogen supply. The chloroplast surface area exposed to intercellular space (S_c) per Rubisco rather than the g_m/S_c ratio was positively correlated with PNUE and was thus considered a key component influencing PNUE.

Conclusion

In conclusion, our study emphasized that S_c was the most important anatomical trait in coordinating g_m and PNUE with contrasting N supply.

SUBMITTER: Gao L

PROVIDER: S-EPMC7672947 | biostudies-literature | 2020 Nov

REPOSITORIES: biostudies-literature

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Publications

Anatomically induced changes in rice leaf mesophyll conductance explain the variation in photosynthetic nitrogen use efficiency under contrasting nitrogen supply.

Gao Limin L Lu Zhifeng Z Ding Lei L Xie Kailiu K Wang Min M Ling Ning N Guo Shiwei S

BMC plant biology 20201118 1

<h4>Background</h4>The ratio of CO<sub>2</sub> mesophyll conductance (g<sub>m</sub>) to Ribulose-1, 5-bisphosphate carboxylase/oxygenase (Rubisco) content has been suggested to positively affect photosynthetic nitrogen use efficiency (PNUE). The anatomical basis of g<sub>m</sub> has been quantified, but information on the relationship between cell-level anatomies and PNUE is less advanced. Here, hydroponic experiments were conducted in rice plants supplied with ammonium (NH<sub>4</sub><sup>+</su ...[more]

PMID: 33208102

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Project description:Sub-optimal nitrogen (N) conditions reduce maize yield due to a decrease in two sink components: kernel set and potential kernel weight. Both components are established during the lag phase, suggesting that they could compete for resources during this critical period. However, whether this competition occurs or whether different genotypic strategies exist to optimize photoassimilate use during the lag phase is not clear and requires further investigation. We have addressed this knowledge gap by conducting a nutrient solution culture experiment that allows abrupt changes in N level and light intensity during the lag phase. We investigated plant growth, dry matter partitioning, non-structural carbohydrate concentration, N concentration, and 15N distribution (applied 4 days before silking) in plant organs at the beginning and the end of the lag phase in two maize hybrids that differ in grain yield under N-limited conditions: one is a nitrogen-use-efficient (EFFI) genotype and the other is a control (GREEN) genotype that does not display high N use efficiency. We found that the two genotypes used different mechanisms to regulate kernel set. The GREEN genotype showed a reduction in kernel set associated with reduced dry matter allocation to the ear during the lag phase, indicating that the reduced kernel set under N-limited conditions was related to sink restrictions. This idea was supported by a negative correlation between kernel set and sucrose/total sugar ratios in the kernels, indicating that the capacity for sucrose cleavage might be a key factor defining kernel set in the GREEN genotype. By contrast, the kernel set of the EFFI genotype was not correlated with dry matter allocation to the ear or to a higher capacity for sucrose cleavage; rather, it showed a relationship with the different EFFI ear morphology with bigger kernels at the apex of the ear than in the GREEN genotype. The potential kernel weight was independent of carbohydrate availability but was related to the N flux per kernel in both genotypes. In conclusion, kernel set and potential kernel weight are regulated independently, suggesting the possibility of simultaneously increasing both sink components in maize.

Dataset Information

Anatomically induced changes in rice leaf mesophyll conductance explain the variation in photosynthetic nitrogen use efficiency under contrasting nitrogen supply.

Background

Results

Conclusion

Publications

Anatomically induced changes in rice leaf mesophyll conductance explain the variation in photosynthetic nitrogen use efficiency under contrasting nitrogen supply.

Similar Datasets

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