Nitrogen Immobilization by Wood Fiber Substrates Strongly Affects the Photosynthetic Performance of Lettuce
Wood fiber substrates are widely used as peat substitutes in horticulture, but the impact of their high carbon-to-nitrogen ratio on nitrogen immobilization and crop photosynthetic performance remains unclear. This study systematically examined the effects of wood fiber substrates on lettuce photosyn...
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MDPI AG
2025-05-01
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| Series: | Plants |
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| Online Access: | https://www.mdpi.com/2223-7747/14/10/1518 |
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| author | Lingyi Wu Ruohan Li Juncheng Liu Wenzhong Cui Zhiyong Qi Wanlai Zhou |
| author_facet | Lingyi Wu Ruohan Li Juncheng Liu Wenzhong Cui Zhiyong Qi Wanlai Zhou |
| author_sort | Lingyi Wu |
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| description | Wood fiber substrates are widely used as peat substitutes in horticulture, but the impact of their high carbon-to-nitrogen ratio on nitrogen immobilization and crop photosynthetic performance remains unclear. This study systematically examined the effects of wood fiber substrates on lettuce photosynthetic performance and underlying physiological mechanisms using pot experiments. Two substrate treatments—peat (control) and wood fiber—were combined with three nitrogen levels: low, medium, and high (63, 127, and 210 mg N·L<sup>−1</sup>). Results indicated that wood fiber substrates significantly reduced the availability of fast-acting nitrogen, leading to a substantial decrease in lettuce biomass (39.0–56.8%), total nitrogen content (7.2–39.9%), and chlorophyll content (13.7–36.2%). Chlorophyll fluorescence kinetics analysis revealed that wood fiber substrates impair photosystem function through multiple pathways. At the early stage (15 days), key effects included structural damage to the donor side of PSII(Photosystem II), indicated by L and K peaks, and inhibited electron transfer on the PSI(Photosystem I) acceptor side (δRo decreased by 15.08–27.90%, along with a reduction in W<sub>OI</sub> amplitude). The findings provide an important theoretical basis for optimising nitrogen management strategies for wood fibre substrates. |
| format | Article |
| id | doaj-art-d71af2af534a45efaee9fbf9e9f8bf10 |
| institution | OA Journals |
| issn | 2223-7747 |
| language | English |
| publishDate | 2025-05-01 |
| publisher | MDPI AG |
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| series | Plants |
| spelling | doaj-art-d71af2af534a45efaee9fbf9e9f8bf102025-08-20T01:56:45ZengMDPI AGPlants2223-77472025-05-011410151810.3390/plants14101518Nitrogen Immobilization by Wood Fiber Substrates Strongly Affects the Photosynthetic Performance of LettuceLingyi Wu0Ruohan Li1Juncheng Liu2Wenzhong Cui3Zhiyong Qi4Wanlai Zhou5Institute of Urban Agriculture, Chinese Academy of Agricultural Sciences, Chengdu 610213, ChinaInstitute of Urban Agriculture, Chinese Academy of Agricultural Sciences, Chengdu 610213, ChinaSchool of Mechanical Engineering, Chengdu University, Chengdu 610100, ChinaSchool of Mechanical Engineering, Chengdu University, Chengdu 610100, ChinaInstitute of Urban Agriculture, Chinese Academy of Agricultural Sciences, Chengdu 610213, ChinaInstitute of Urban Agriculture, Chinese Academy of Agricultural Sciences, Chengdu 610213, ChinaWood fiber substrates are widely used as peat substitutes in horticulture, but the impact of their high carbon-to-nitrogen ratio on nitrogen immobilization and crop photosynthetic performance remains unclear. This study systematically examined the effects of wood fiber substrates on lettuce photosynthetic performance and underlying physiological mechanisms using pot experiments. Two substrate treatments—peat (control) and wood fiber—were combined with three nitrogen levels: low, medium, and high (63, 127, and 210 mg N·L<sup>−1</sup>). Results indicated that wood fiber substrates significantly reduced the availability of fast-acting nitrogen, leading to a substantial decrease in lettuce biomass (39.0–56.8%), total nitrogen content (7.2–39.9%), and chlorophyll content (13.7–36.2%). Chlorophyll fluorescence kinetics analysis revealed that wood fiber substrates impair photosystem function through multiple pathways. At the early stage (15 days), key effects included structural damage to the donor side of PSII(Photosystem II), indicated by L and K peaks, and inhibited electron transfer on the PSI(Photosystem I) acceptor side (δRo decreased by 15.08–27.90%, along with a reduction in W<sub>OI</sub> amplitude). The findings provide an important theoretical basis for optimising nitrogen management strategies for wood fibre substrates.https://www.mdpi.com/2223-7747/14/10/1518chlorophyll fluorescenceJIP testPSIPSII |
| spellingShingle | Lingyi Wu Ruohan Li Juncheng Liu Wenzhong Cui Zhiyong Qi Wanlai Zhou Nitrogen Immobilization by Wood Fiber Substrates Strongly Affects the Photosynthetic Performance of Lettuce Plants chlorophyll fluorescence JIP test PSI PSII |
| title | Nitrogen Immobilization by Wood Fiber Substrates Strongly Affects the Photosynthetic Performance of Lettuce |
| title_full | Nitrogen Immobilization by Wood Fiber Substrates Strongly Affects the Photosynthetic Performance of Lettuce |
| title_fullStr | Nitrogen Immobilization by Wood Fiber Substrates Strongly Affects the Photosynthetic Performance of Lettuce |
| title_full_unstemmed | Nitrogen Immobilization by Wood Fiber Substrates Strongly Affects the Photosynthetic Performance of Lettuce |
| title_short | Nitrogen Immobilization by Wood Fiber Substrates Strongly Affects the Photosynthetic Performance of Lettuce |
| title_sort | nitrogen immobilization by wood fiber substrates strongly affects the photosynthetic performance of lettuce |
| topic | chlorophyll fluorescence JIP test PSI PSII |
| url | https://www.mdpi.com/2223-7747/14/10/1518 |
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