Effects of Light Quality on Leaf Structure and Light Utilization Characteristics of Populus yunnanensis

PurposeTo study the response of light quality on leaf spectral parameters, leaf tissue structure and light and CO₂ response curves, providing a research basis for further revealing the adaptability of Populus yunnanensis to high-altitude distribution areas, and also providing a theoretical basis for the selection of canopy film for the facility seedling cultivation of P. yunnanensis under different light intensities.

MethodAnnual cuttings of P. yunnanensis were potted under three different color films, namely blue film, green film and white film. The light transmittance of the films, the spectral parameters, leaf tissue structure parameters, photosynthesis-light response (P_n-PAR) and photosynthesis-CO₂ response (P_n-CO₂) of P. yunnanensis cuttings under different light qualities were observed and analyzed.

ResultsUnder different color film treatments, leaf spectral characteristic parameters were significantly negatively correlated with leaf thickness, thickness of spongy tissue, and thickness of vascular bundle. There was a significant positive correlation with the thickness of upper and lower epidermis, cell tense ratio and palisade tissue and spongy tissue ratio. It showed that strong adaptability to high CO₂ concentration under both blue and green film treatments. Blue film promoted the utilization of strong light by increasing thickness of palisade tissue, cell tense ratio and palisade tissue and spongy tissue ratio, and which was more conducive to stomatal opening for gas exchange. However, the green film promoted the utilization capacity of P. yunnanensis to weak light and suggested higher potential photosynthetic capacity.

ConclusionBlue film treatment significantly improved the adaptability of P. yunnanensis cutting seedlings to strong light, while green film treatment significantly improved the adaptability of P. yunnanensis cutting seedlings to weak light.