Silicon Addition Alleviates Light Stress on Seedlings: Evidence from Plantation of Liquidambar formosana

TL;DR

Adding silicon helps Liquidambar formosana seedlings cope with high light stress by improving photosynthesis and reducing damage.

Contribution

The study reveals that moderate silicon application combined with partial shading optimizes seedling resilience under intense light.

Findings

Full sunlight reduced seedling growth and chlorophyll content while increasing oxidative stress markers.

Moderate silicon application (1000–2000 mg·kg−1) improved photosynthesis and reduced stress under high light.

Excessive silicon (3000 mg·kg−1) decreased catalase activity and leaf area under intense light.

Abstract

Excessive light intensity, often resulting from anthropogenic disturbances, poses a threat to light-sensitive Liquidambar formosana seedlings. This study examined the effects of five light intensity levels and three silicon (Si) application rates on photosynthetic performance, oxidative stress responses, and seedling growth. Results indicated that full sunlight significantly reduced ground diameter, chlorophyll content, specific leaf area, and stomatal conductance. Meanwhile, it increased the activities of superoxide dismutase and peroxidase, and led to higher accumulation of malondialdehyde (MDA). Application of Si enhanced seedling height, biomass accumulation, and antioxidant enzyme activity under high-light conditions, while reducing MDA content, stomatal CO2 conductance, and transpiration rate, and maintaining a stable net photosynthetic rate. However, excessive Si (3000 mg·kg−1) led to decreased catalase activity, chlorophyll content, and leaf area under intense light. These findings suggest that L. formosana seedlings perform best under moderate shade (11,000–46,000 lx) and moderate Si application (1000–2000 mg·kg−1), which together mitigate photoinhibition damage. Optimal physiological responses thus require balanced Si concentrations. Further investigation is warranted to elucidate the mechanisms underlying the interactive effects of shading and Si application for improved seedling resilience.

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