Original data for for intercropped maize experiments, root barrier experiments in intercropped maize, and unilateral shading experiments
Data files
Sep 20, 2023 version files 33.52 KB
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1._Photosynthetically_active_radiation.csv
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2._2020-2021_Gas_exchange_parameters.csv
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3._Starch_granule_number_and_size.csv
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4._2020-2021_Sucrose_and_starch_concentrations.csv
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5._Leaf_dry_matter_weight_and_13C_content.csv
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6._Expression_of_genes_related_to_sugar_and_starch_metabolism.csv
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7._Grain_weight_and_gas_exchange_parameters_after_ear_removal.csv
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8._2020-2021_Intercropped_maize_yield.csv
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README.md
Abstract
Intercropping improves resource utilization and yield; however, shading causes a decline in yield. Under wide-narrow-row maize-soybean intercropping, maize plants are subjected to weak unilateral illumination and exhibit high photosynthetic performance. However, the mechanism regulating photosynthesis under unilateral weak light remains unknown. Therefore, we conducted an experiment with different planting configurations and two controlled environments to investigate photosynthesis, sugar metabolism, and photosynthate allocation in unshaded and shaded leaves under weak light. All three experiments detected an increase in the net photosynthetic rate (Pn) of unshaded leaves on one side with an increase in the level of shade on the other side leaves. On the contrary, the concentration of sucrose and starch and the number of starch granules in the unshaded leaves decreased with increased shading due to the transfer of abundant 13C into the grains. However, sink loss with ear removal reduced the Pn of unshaded leaves, limiting their ability to transport sugar. Detailed analysis showed that intense unilateral shade (40% to 20% normal light) reduced grain yield (37.6% to 54.4%) but not mild unilateral shade (60% normal light). We further found that in unshaded leaves, Agpsl, Bmy, and Mexl-like significantly influenced sucrose and starch metabolism, while Sweet13a and Sut1 were crucial for sugar export. Sps1, Agpsl, and Sweet13c were crucial for sugar metabolism and export in shaded leaves. Thus, our study confirmed that under unilateral illumination, unshaded leaves, which transported photosynthates to the ear, contributed significantly to the grain filling and reduced sugar concentration, resulting in a higher photosynthetic performance, while the shaded leaves synthesized fewer photosynthates, primarily for their growth and development. We, therefore, propose a narrow-row spacing (40 cm) that provides appropriate unilateral shade (60% normal light) and limits yield reduction in a wide-narrow-row intercropping system.
README: Original data for for intercropped maize experiments, root barrier experiments in intercropped maize, and unilateral shading experiments
doi:10.5061/dryad.pg4f4qrw5
These datasets were collected between 2020 and 2021 and include data from experiments involving different row spacings in intercropped maize, root barrier experiments in intercropped maize, and unilateral shading experiments.
Description of the data and file structure
The dataset includes:
A) The photosynthetically active radiation (PAR) in the maize canopy during intercropping is measured in units of micromoles per square meter per second (µmol/m²/s). Please refer to the file "1. Photosynthetically active radiation" for specific data.
B) To view the gas exchange parameters for the intercropped maize experiments with different row spacings, root barrier experiments in intercropped maize, and unilateral shading experiments, please refer to the file "2. 2020-2021 Gas exchange parameters."
C) Unilateral shading experiment: Starch granule number and size. For detailed data, please refer to the file "3. Starch granule number and size."
D) Unilateral shading experiment: Sucrose and starch concentrations at different time intervals. Please refer to the file "4. 2020-2021 Sucrose and starch concentrations" for detailed data.
E) Leaf dry matter weight (in grams), leaf 13C content, and grain 13C content for the unilateral shading experiment. For detailed data, please consult "5. Leaf dry matter weight and 13C content."
F) Expression data for genes related to sugar and starch metabolism at different time intervals in the unilateral shading experiment. Please refer to the file "6. Expression of genes related to sugar and starch metabolism" for detailed information.
G) Grain weight (in grams) and gas exchange parameters after ear removal for the unilateral shading experiment. Please consult the file "7. Grain weight and gas exchange parameters after ear removal" for detailed data.
H) Yield data (in kilograms) for the intercropped maize experiments with different row spacings and root barrier experiments in intercropped maize for two years. Please refer to the file "8. 2020-2021 Intercropped maize yield" for detailed information.
Abbreviations
PAR: photosynthetically active radiation (µmol/m²/s)
Photo: net photosynthetic rates (µmolCO2/m²/s)
Ci: intercellular CO2 concentration (µmolCO2/mmol)
Cond: stomatal conductance (µmolH2O/m²/s)
BC: blank control, natural abundance isotope in organs
I20, I40, and I60 indicate intercropping maize, narrow (N) and wide (W) rows spacing of 20 + 200, 40 + 180, and 60 + 160 cm, respectively. M represents monoculture maize with a row spacing of 70 cm, and CK represents monoculture maize with row spacing of 160 cm and plant spacing of 160 cm. L indicates the left side of the plant and R indicates the right side of the plant.
SI20, SI40, and SI60 indicate intercropping maize with split-root, narrow (N) and wide (W) rows spacing of 20 + 200, 40 + 180, and 60 + 160 cm, respectively. SM: split-root, monoculture maize with a row spacing of 70 cm. SCK: split-root, monoculture maize with row spacing of 160 cm and plant spacing of 160 cm. L represents the left side of the plant, and R represents right side of the plant.
The leaves on the right side of the plants were exposed to normal light (non-shaded; NS) in all treatments, while the leaves on the left side of plants were shaded (S) and exposed to 20%, 40%, and 60% normal light (T20, T40, and T60, respectively). Leaves of the whole plants exposed to 50% normal light and normal light were used as control 1 (TCK1) and control 2 (TCK2), respectively. Capital letters (L and R) indicate the left and right side leaves of the plants, respectively.