1
|
Gao B, Hu S, Jing L, Wang Y, Zhu J, Wang K, Li H, Sun X, Wang Y, Yang L. Impact of Elevated CO 2 and Reducing the Source-Sink Ratio by Partial Defoliation on Rice Grain Quality - A 3-Year Free-Air CO 2 Enrichment Study. FRONTIERS IN PLANT SCIENCE 2021; 12:788104. [PMID: 35003176 PMCID: PMC8733338 DOI: 10.3389/fpls.2021.788104] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 12/06/2021] [Indexed: 05/26/2023]
Abstract
Evaluating the impact of increasing CO2 on rice quality is becoming a global concern. However, whether adjusting the source-sink ratio will affect the response of rice grain quality to elevated CO2 concentrations remains unknown. In 2016-2018, we conducted a free-air CO2 enrichment experiment using a popular japonica cultivar grown at ambient and elevated CO2 levels (eCO2, increased by 200 ppm), reducing the source-sink ratio via cutting leaves (LC) at the heading stage, to investigate the effects of eCO2 and LC and their interactions on rice processing, appearance, nutrition, and eating quality. Averaged across 3 years, eCO2 significantly decreased brown rice percentage (-0.5%), milled rice percentage (-2.1%), and head rice percentage (-4.2%) but increased chalky grain percentage (+ 22.3%) and chalkiness degree (+ 26.3%). Markedly, eCO2 increased peak viscosity (+ 2.9%) and minimum viscosity (+ 3.8%) but decreased setback (-96.1%) of powder rice and increased the appearance (+ 4.5%), stickiness (+ 3.5%) and balance degree (+ 4.8%) of cooked rice, while decreasing the hardness (-6.7%), resulting in better palatability (+ 4.0%). Further, eCO2 significantly decreased the concentrations of protein, Ca, S, and Cu by 5.3, 4.7, 2.2, and 9.6%, respectively, but increased K concentration by 3.9%. Responses of nutritional quality in different grain positions (brown and milled rice) to eCO2 showed the same trend. Compared with control treatment, LC significantly increased chalky grain percentage, chalkiness degree, protein concentration, mineral element levels (except for B and Mn), and phytic acid concentration. Our results indicate that eCO2 reduced rice processing suitability, appearance, and nutritional quality but improved the eating quality. Rice quality varied significantly among years; however, few CO2 by year, CO2 by LC, or CO2 by grain position interactions were detected, indicating that the effects of eCO2 on rice quality varied little with the growing seasons, the decrease in the source-sink ratios or the different grain positions.
Collapse
Affiliation(s)
- Bo Gao
- Key Laboratory of Crop Genetics and Physiology of Jiangsu Province, Co-Innovation Center for Modern Production Technology of Grain Crops of Jiangsu Province, Yangzhou University, Yangzhou, China
- Jiangsu Coastal Area Institute of Agricultural Sciences, Yancheng, China
| | - Shaowu Hu
- Key Laboratory of Crop Genetics and Physiology of Jiangsu Province, Co-Innovation Center for Modern Production Technology of Grain Crops of Jiangsu Province, Yangzhou University, Yangzhou, China
| | - Liquan Jing
- Key Laboratory of Crop Genetics and Physiology of Jiangsu Province, Co-Innovation Center for Modern Production Technology of Grain Crops of Jiangsu Province, Yangzhou University, Yangzhou, China
| | - Yunxia Wang
- College of Environmental Science and Engineering, Yangzhou University, Yangzhou, China
| | - Jianguo Zhu
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, China
| | - Kai Wang
- Jiangsu Coastal Area Institute of Agricultural Sciences, Yancheng, China
| | - Hongyang Li
- Jiangsu Coastal Area Institute of Agricultural Sciences, Yancheng, China
| | - Xingxing Sun
- Jiangsu Coastal Area Institute of Agricultural Sciences, Yancheng, China
| | - Yulong Wang
- Key Laboratory of Crop Genetics and Physiology of Jiangsu Province, Co-Innovation Center for Modern Production Technology of Grain Crops of Jiangsu Province, Yangzhou University, Yangzhou, China
| | - Lianxin Yang
- Key Laboratory of Crop Genetics and Physiology of Jiangsu Province, Co-Innovation Center for Modern Production Technology of Grain Crops of Jiangsu Province, Yangzhou University, Yangzhou, China
| |
Collapse
|
2
|
Gao B, Hu S, Jing L, Niu X, Wang Y, Zhu J, Wang Y, Yang L. Alterations in Source-Sink Relations Affect Rice Yield Response to Elevated CO 2: A Free-Air CO 2 Enrichment Study. FRONTIERS IN PLANT SCIENCE 2021; 12:700159. [PMID: 34276751 PMCID: PMC8283783 DOI: 10.3389/fpls.2021.700159] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2021] [Accepted: 06/08/2021] [Indexed: 05/29/2023]
Abstract
To understand the effects of source-sink relationships on rice yield response to elevated CO2 levels (eCO2), we conducted a field study using a popular japonica cultivar grown in a free-air CO2 enrichment environment in 2017-2018. The source-sink ratio of rice was set artificially via source-sink treatments (SSTs) at the heading stage. Five SSTs were performed in 2017 (EXP1): cutting off the flag leaf (LC1) and the top three functional leaves (LC3), removing one branch in every three branches of a panicle (SR1/3) and one branch in every two branches of a panicle (SR1/2), and the control (CK) without any leaf cutting or spikelet removal. The eCO2 significantly increased grain yield by 15.7% on average over all treatments; it significantly increased grain yield of CK, LC1, LC3, SR1/3, and SR1/2 crops by 13.9, 18.1, 25.3, 12.0, and 10.9%, respectively. The yield response to eCO2 was associated with a significant increase of panicle number and fully-filled grain percentage (FGP), and the response of crops under different SSTs was significantly positively correlated with FGP and the average grain weight of the seeds. Two SSTs (CK and LC3) were performed in 2018 (EXP2), which confirmed that the yield response of LC3 crops (25.1%) to eCO2 was significantly higher than that of CK (15.9%). Among the different grain positions, yield response to eCO2 of grains attached to the lower secondary rachis was greater than that of grains attached to the upper primary rachis. Reducing the source-sink ratio via leaf-cutting enhanced the net photosynthetic rate response of the remaining leaves to eCO2 and increased the grain filling ability. Conversely, spikelet removal increased the non-structural carbohydrate (NSC) content of the stem, causing feedback inhibition and photosynthetic down-regulation. This study suggests that reducing the source-sink ratio by adopting appropriate management measures can increase the response of rice to eCO2.
Collapse
Affiliation(s)
- Bo Gao
- Key Laboratory of Crop Genetics and Physiology of Jiangsu Province, Yangzhou University, Yangzhou, China
- Jiangsu Co-Innovation Center for Modern Production Technology of Grain Crops of Jiangsu Province, Yangzhou University, Yangzhou, China
- Jiangsu Coastal Area Institute of Agricultural Sciences, Yancheng, China
| | - Shaowu Hu
- Key Laboratory of Crop Genetics and Physiology of Jiangsu Province, Yangzhou University, Yangzhou, China
- Jiangsu Co-Innovation Center for Modern Production Technology of Grain Crops of Jiangsu Province, Yangzhou University, Yangzhou, China
| | - Liquan Jing
- Key Laboratory of Crop Genetics and Physiology of Jiangsu Province, Yangzhou University, Yangzhou, China
- Jiangsu Co-Innovation Center for Modern Production Technology of Grain Crops of Jiangsu Province, Yangzhou University, Yangzhou, China
| | - Xichao Niu
- College of Environmental Science and Engineering, Yangzhou University, Yangzhou, China
| | - Yunxia Wang
- College of Environmental Science and Engineering, Yangzhou University, Yangzhou, China
| | - Jianguo Zhu
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, China
| | - Yulong Wang
- Key Laboratory of Crop Genetics and Physiology of Jiangsu Province, Yangzhou University, Yangzhou, China
- Jiangsu Co-Innovation Center for Modern Production Technology of Grain Crops of Jiangsu Province, Yangzhou University, Yangzhou, China
| | - Lianxin Yang
- Key Laboratory of Crop Genetics and Physiology of Jiangsu Province, Yangzhou University, Yangzhou, China
- Jiangsu Co-Innovation Center for Modern Production Technology of Grain Crops of Jiangsu Province, Yangzhou University, Yangzhou, China
| |
Collapse
|