Morphological, antioxidase, and photosynthetic responses in Liaodong elata (Aralia elata) under treatments of light intensity

Abstract Light intensity is important for the growth, development, and productivity of shade-tolerant plants. Liaodong elata (Aralia elata) is a highly nutrient natural organic food widely used in northern China. However, little is known about its cultivation under shading treatments. In this study, we conducted the morphological, physiology, and photosynthetic capacity of Liaodong elata under five treatments of 0% (CK), 20% (S1), 35% (S2), 50% (S3), and 60% (S4) shading levels. The results showed that the plant morphology in both S3 and S4 is better than CK, S1, and S2. Furthermore, the antioxidant enzyme activities of CK, S1 and S2 were higher than S3 and S4 at 30 d (T1) and 40 d (T2) shading time. We speculate that a certain light stress could destroy the antioxidant enzyme system. Photosynthetic results showed that the chlorophyll content, Fv/Fm, Yll, qP of S3 were higher and the NPQ was lower. It explained that S3 had a more efficient photosynthetic system. At the same time, we measured the physiological indices of leaves at different positions and analyzed the correlation of each index. We found that the Top leaves had more stable antioxidant enzymes, higher chlorophyll content, Fv/Fm, YII, qP, and lower NPQ. And antioxidant enzyme activity was negatively correlated with Fv/Fm, Yll, qP. This study proved the effectiveness of using a shading net for Liaodong elata cultivation. The 50% shading treatment is the optimal condition for the cultivation of Liaodong elata. These results are helpful to improve the reference for the introduction and cultivation of Liaodong elata.