Light Energy Partitioning and Photoprotection in an Exotic Species (Salix Psammophila) Grown in a Semi-Arid Area of Northwestern China
1
Key Laboratory of Soil and Water Conservation and Desertification Combating, Ministry of Education, Beijing Forestry University, Beijing 100083, China
2
Beijing Research & Development Center for Grass and Environment, Beijing Academy of Agriculture and Forestry Sciences, Beijing 100097, China
3
Yanchi Research Station, School of Soil and Water conservation, Beijing Forestry University, Beijing 100083, China
4
Faculty of Forestry and Environmental Management, 28 Dineen Drive, University of New Brunswick, Fredericton, NB E3B 6C2, Canada
*
Author to whom correspondence should be addressed.
Forests 2018, 9(6), 341; https://doi.org/10.3390/f9060341
Received: 3 April 2018 / Revised: 26 May 2018 / Accepted: 4 June 2018 / Published: 9 June 2018
(This article belongs to the Section Forest Ecophysiology and Biology)
Thermal dissipation of excess excitation energy is an important photoprotective mechanism that plants have evolved to cope with surplus illumination. However, light-energy-partitioning dynamics in an exotic sand-dune willow (Salix psammophila) commonly used in restoring and/or stabilizing sand lands in northwestern China is largely unknown. In this study, chlorophyll fluorescence (ChlF) of photosystem II (PSII) was continuously monitored in situ in Salix psammophila to investigate plant acclimation processes driven by excessive solar radiation and extreme air temperatures (Ta). As part of a heat-regulation mechanism, energy partitioning is shown to vary with prevailing environmental conditions. In this investigation, energy absorbed during periods of moderate photosynthetically active radiation (PAR < 1200 μmoL·m−2·s−1) was largely allocated towards photochemistry (ΦPSII) with nominal amounts to thermal dissipation through reversible thermal dissipation (ΦNPQr). In extremely high solar radiation (PAR > 1500 μmoL·m−2·s−1) or in a cold temperature (Ta < 0 °C), more energy was dissipated by way of non-regulated thermal energy (Φf,D) and sustained thermal dissipation (ΦNPQs), leading to non-reversible photoinhibition or photodamage. This was mainly as a result of the low utilization and high absorption of light energy by PSII under cold conditions and physiologically-induced vulnerability. It was concluded that Salix psammophila had a clear tolerance to high temperatures and moderate solar radiation, but tended to be more vulnerable to high solar radiation and cold temperature. Based on species sensitivity to extreme environmental conditions, practical application and extension of Salix psammophila for land-restoration purposes should be approached cautiously, especially in high-latitude or high-altitude desert ecosystems commonly affected by events of high solar radiation and cold temperature.
View Full-Text
Keywords:
Chlorophyll fluorescence; environmental stress; semi-arid; energy partitioning; Salix psammophila
▼
Show Figures
Figure 1
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited
MDPI and ACS Style
Han, Y.; Wu, J.; Tian, Y.; Zha, T.; Jia, X.; Bourque, C.P.-A.; Wu, Y.; Bai, Y.; Ma, J.; Zhang, M. Light Energy Partitioning and Photoprotection in an Exotic Species (Salix Psammophila) Grown in a Semi-Arid Area of Northwestern China. Forests 2018, 9, 341.
Show more citation formats
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.
