Photosynthetic responses of Eulophia dentata, Bletilla formosana, and Saccharum spontaneum under various photosynthetic photon flux density conditions

Y-H Lai; K-H Lin; C-P Liu; T-S Liao; M-Y Huang; C-W Wang; C-I Chen

doi:10.32615/ps.2022.050

Photosynthetic responses of Eulophia dentata, Bletilla formosana, and Saccharum spontaneum under various photosynthetic photon flux density conditions

Photosynthetica. 2022 Dec 16;60(4):539-548. doi: 10.32615/ps.2022.050. eCollection 2022.

Authors

Y-H Lai¹, K-H Lin², C-P Liu¹, T-S Liao¹, M-Y Huang³, C-W Wang⁴, C-I Chen⁵

Affiliations

¹ Department of Forestry, National Chung Hsing University, 40227 Taichung, Taiwan.
² Department of Horticulture and Biotechnology, Chinese Culture University, 11114 Taipei, Taiwan.
³ Department of Life Sciences and Innovation and Development Center of Sustainable Agriculture, National Chung Hsing University, 40227 Taichung, Taiwan.
⁴ Endemic Species Research Institute, 552203 Nantou, Taiwan.
⁵ Department of Forestry, National Pingtung University of Science and Technology, 91201 Pingtung, Taiwan.

Abstract

This study aimed to determine the photosynthetic performance and differences in chlorophyll fluorescence (ChlF) parameters between Eulophia dentata and its companion species Bletilla formosana and Saccharum spontaneum when subjected to different photosynthetic photon flux density (PPFDs). Leaf surfaces were then illuminated with 50, 100 (low PPFDs), 300, 500, 800 (moderate PPFDs); 1,000; 1,500; and 2,000 (high PPFDs) μmol m^-2·s^-1, and the ChlF parameters were measured during the whole process. Increasing nonphotochemical quenching of ChlF and decreasing potential quantum efficiency of PSII, actual quantum efficiency of PSII, and quantum efficiency ratio of PSII in dark recovery from 0-60 min were observed in all leaves. A significant and negative relationship was detected between energy-dependent quenching (q_E) and photoinhibition percent in three species under specific PPFD conditions, whereas a significant and positive relationship was detected between photoinhibitory quenching (q_I) and photoinhibition percent. The q_E and q_I can be easily measured in the field and provide useful ecological indexes for E. dentata species restoration, habitat creation, and monitoring.

Keywords: Bletilla; Eulophia; Saccharum; chlorophyll fluorescence; light intensity; photoinhibition.