Researchers reveal the photosynthetic potential of the leaf underside: net photosynthesis increased by 32%, yield doubled to 2.8 times, and energy consumption reduced by 30%.

The Intelligent Horticulture Equipment Team at the Institute of Urban Agriculture, Chinese Academy of Agricultural Sciences, has published a research paper titled “Abaxial leaf illumination: A strategy to enhance photosynthesis and yield in strawberry (Fragaria × ananassa)” online in Environmental and Experimental Botany. The study reveals the photosynthetic potential that can be activated on the abaxial (underside) surface of leaves, proposing a new, highly efficient LED lighting strategy for enhancing crop light-use efficiency and production performance in controlled-environment settings. This work provides new theoretical foundations and technical pathways for optimizing supplemental lighting in facilities and precisely regulating the light environment in LED-based plant factories.

Research Background

In the field of facility agriculture, artificial-light–based plant factories primarily rely on LED artificial light sources to cultivate crops. Current common lighting strategies are designed only for the adaxial (upper) leaf surface, neglecting the photosynthetic potential of the abaxial side, which has long remained underutilized. Under the combined influence of high-density cultivation and canopy shading, lower-layer leaves and their undersides typically experience weak light conditions, severely limiting the population’s overall light-use efficiency—a key bottleneck hindering further yield improvements.

Thus, unlocking the photosynthetic potential of the leaf underside while simultaneously optimizing innovative LED lighting schemes has become a central research focus for improving light-use efficiency and boosting overall production outcomes in facility-grown crops.

To address this issue, the research team, driven by the need for energy‑saving, high‑efficiency LED lighting in facility cultivation, systematically compared the effects of varying light intensities on both the adaxial and abaxial leaf surfaces—examining how these differences impact leaf photosynthetic physiology, stomatal development, and plant yield. The study placed particular emphasis on assessing the photosynthetic capacity of the spongy mesophyll tissue on the leaf underside and its contribution to the overall photosynthetic productivity of the plant population.

Figure: Effects of different lighting directions and intensities on leaf photosynthetic performance and plant yield

Research Content

The team selected strawberries—a typical berry crop—as the experimental material and conducted supplemental lighting trials at varying intensities on both the adaxial and abaxial leaf surfaces under suboptimal light conditions. Employing a comprehensive suite of analytical techniques—including photosynthetic gas exchange, chlorophyll fluorescence, and mesophyll conductance measurements—the researchers thoroughly investigated the regulatory role of abaxial leaf illumination on strawberry photosynthetic capacity.

By observing stomatal morphology, chlorophyll pigment content, and biomass allocation patterns, the study elucidated the underlying physiological mechanisms through which different lighting regimes influence strawberry growth and development. Furthermore, integrating comprehensive assessments of fruit yield and quality, the team identified the optimal abaxial lighting intensity capable of effectively enhancing both yield and fruit quality.

In addition, using Pearson correlation analysis, the research established a predictive model linking strawberry yield with photosynthetic and phenotypic indicators, quantifying the mechanism by which enhanced photosynthetic efficiency from abaxial illumination contributes to yield accumulation.

Research Conclusions and Significance

The study confirmed that applying moderate-intensity LED supplemental lighting to the underside of plant leaves can significantly improve leaf photochemical efficiency, gas exchange functions, and stomatal structure, thereby strengthening carbon assimilation and promoting biomass accumulation. Data show that compared to the unilluminated control group, net photosynthetic rates increased by 32%, and strawberry yields rose approximately 2.8-fold; meanwhile, soluble sugar and soluble protein contents in the fruit also increased markedly, and fruit maturity was advanced by 5 to 7 days.

In contrast, achieving comparable yield gains requires higher energy input when employing high-intensity adaxial lighting, whereas abaxial illumination demands much lower light intensity, resulting in a 30% reduction in photon flux consumption, superior light-use efficiency, and pronounced energy-saving benefits.

Grounded in the dual-sided photosynthetic characteristics of leaves, this research innovatively reimagines LED lighting protocols for facility cultivation, breaking away from the traditional practice of illuminating only the adaxial leaf surface. It not only opens up new avenues for supplemental lighting in facility agriculture and LED lighting applications in plant factories but also holds significant practical value for enhancing light-use efficiency, reducing production energy consumption, and increasing per-unit-area output within artificial-light–based plant production systems.

This research was supported by the Science and Technology Innovation Project of the Chinese Academy of Agricultural Sciences and the Sichuan Provincial Natural Science Foundation.

Original article link:

https://doi.org/10.1016/j.envexpbot.2026.106345

Source: Institute of Urban Agriculture, Chinese Academy of Agricultural Sciences; Intelligent Horticulture Equipment Innovation Team