Responses of photosynthesis and chlorophyll fluorescence during light induction in different seedling ages of Mahonia oiwakensis

Abstract

Abstract Background The aim of this study was to determine the actual state of the photosynthetic apparatus and exhibit distinguishable differences in the chlorophyll fluorescence (ChlF) components in different seedling ages of M. oiwakensis plants subjected to different light intensity (LI), that reflected their adaptability to their habitats and how they responded to LI changes. Potted 6-month-old greenhouse seedlings and field collected 2.4-year-old seedlings with 5 cm heights were selected and randomly separated into seven groups for photosynthesis measurements illuminated with 50, 100 (assigned as low LI), 300, 500, 1,000 (as moderate LI), 1,500 and 2,000 (as high LI) µmol m–2 s–1 photosynthetic photon flux density (PPFD) treatments. Results In 6-month-seedlings, as LI increased from 50 to 2,000 PPFD, the values of non-photochemical quenching and photoinhibitory quecnhing (qI) increased but potential quantum efficiency of PSII (Fv/Fm) and ΦPSII values decreased, indicating adaptation to low LI conditions. High electron transport rate, actual PSII efficiency %, and Fv/Fm% values were observed in 2.4-year-old seedlings at high LI conditions, suggesting that these seedlings can have higher photoprotective ability under high LI treatments to maintain higher photosynthetic system performance. Furthermore, higher ΦPSII was detected under low LI conditions, with lower energy-dependent quenching (qE) and qI values and photo-inhibition % decreased as well. However, qE and qI increased as ΦPSII decreased and photo-inhibition% increased under high LI treatments. Conclusions These results could be useful for predicting the changes in growth and distribution of Mahonia species grown in controlled environments and open fields with various combinations of varying light illuminations, and ecological monitoring of their restoration and habitat creation is important for provenance conservation and helps to formulate better conservation strategies.