Photosynthetica 2018, 56(2):537-548 | DOI: 10.1007/s11099-017-0706-3

Morphological and physiological acclimation of Catalpa bungei plantlets to different light conditions

J. W. Wu¹, Y. Su¹, J. H. Wang^2,*, Q. He¹, Q. Qiu¹, J. W. Ma³, J. Y. Li^1,*

¹ Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, China

² State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, China

³ Xiaolongshan Forestry Science and Technology Research Institute, Tianshui, China

This study was performed to evaluate the ecophysiological acclimation of Catalpa bungei plantlets to different light conditions. We hypothesized that the acclimation of old and newly developed leaves to both increasing and decreasing irradiance should follow different patterns. The growth, photosynthesis, chlorophyll (Chl) content, and Chl fluorescence response were examined over a range of light treatments. The plants were grown under fixed light intensities of 80% (HH), 50% (MM), 30% (LL) of sun light and transferring irradiance of 80% to 50% (HM), 80% to 30% (HL), 30% to 50% (LM) and 30% to 80% (LH). For old leaves, light-saturation point, photosynthetic capacity, dark respiration rate of LH were lower than that of HH, while HL were higher than LL, indicating that light-response parameters were affected by the original growth light environment. Initial fluorescence increased and variable fluorescence decreased in LH and LM after transfer, and the PSII damage was more serious in LH than that in LM, and could not recover within 30 d. It suggested that the photoinhibition damage and recovery time in old leaves was related to the intensity of light after transfer. For the newly emerged leaves with leaf primordia formed under the same light environment, a significant difference was observed in leaf morphology and pigment contents, suggesting that previous light environment exhibited carry-over effect on the acclimation capacity to a new light environment. Our result showed that thinning and pruning intensity should be considered in plantation management, because great changes in light intensity may cause photoinhibition in shade-adapted leaves.

Additional key words: Catalpa bungei; chlorophyll fluorescence; light acclimation; newly developed leaves; photoinhibition

Received: May 8, 2016; Accepted: September 20, 2016; Published: June 1, 2018Show citation