Wu Lingyi, Li Ruohan, Liu Juncheng, Cui Wenzhong, Qi Zhiyong, Zhou Wanlai
Institute of Urban Agriculture, Chinese Academy of Agricultural Sciences, Chengdu 610213, China.
School of Mechanical Engineering, Chengdu University, Chengdu 610100, China.
Plants (Basel). 2025 May 19;14(10):1518. doi: 10.3390/plants14101518.
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). 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 amplitude). The findings provide an important theoretical basis for optimising nitrogen management strategies for wood fibre substrates.
木纤维基质在园艺中被广泛用作泥炭替代品，但其高碳氮比 对氮固定和作物光合性能的影响仍不清楚。本研究通过盆栽试验系统地研究了木纤维基质对生菜光合性能及潜在生理机制的影响。两种基质处理——泥炭（对照）和木纤维——与三种氮水平相结合：低、中、高（63、127 和 210 mg N·L）。结果表明，木纤维基质显著降低了速效氮的有效性，导致生菜生物量（39.0 - 56.8%）、总氮含量（7.2 - 39.9%）和叶绿素含量（13.7 - 36.2%）大幅下降。叶绿素荧光动力学分析表明，木纤维基质通过多种途径损害光合系统功能。在早期阶段（15 天），关键影响包括 PSII（光系统 II）供体侧的结构损伤，由 L 和 K 峰表示，以及 PSI（光系统 I）受体侧的电子传递受到抑制（δRo 下降 15.08 - 27.90%，同时 W 振幅降低）。这些发现为优化木纤维基质的氮管理策略提供了重要的理论依据。
