Reponses of morphological and biochemical traits of bamboo trees under elevated atmospheric O3 enrichment

Li Li; Jinling Li; Xiaoke Wang; Sami Ullah; Shuyan Lin

doi:10.1016/j.envres.2024.119069

Reponses of morphological and biochemical traits of bamboo trees under elevated atmospheric O₃ enrichment

Environ Res. 2024 May 10;252(Pt 4):119069. doi: 10.1016/j.envres.2024.119069. Online ahead of print.

Authors

Li Li¹, Jinling Li², Xiaoke Wang³, Sami Ullah⁴, Shuyan Lin⁵

Affiliations

¹ Co-Innovation Center for Sustainable Forestry in Southern China, Bamboo Research Institute, Nanjing Forestry University, Nanjing, Jiangsu 210037, China. Electronic address: lili028@njfu.edu.cn.
² Co-Innovation Center for Sustainable Forestry in Southern China, Bamboo Research Institute, Nanjing Forestry University, Nanjing, Jiangsu 210037, China; Guangxi Eco-engineering Vocational and Technical College, Liuzhou, Guangxi, China.
³ State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
⁴ School of Geography, Earth and Environmental Sciences & Birmingham Institute of Forest Research, University of Birmingham, UK. Electronic address: S.Ullah@bham.ac.uk.
⁵ Co-Innovation Center for Sustainable Forestry in Southern China, Bamboo Research Institute, Nanjing Forestry University, Nanjing, Jiangsu 210037, China.

PMID: 38735376
DOI: 10.1016/j.envres.2024.119069

Abstract

Dwarf bamboo (Indocalamus decorus) is an O₃-tolerant plant species. To identify the possible mechanism and response of leaf morphological, antioxidant, and anatomical characteristics to elevated atmospheric O₃ (EO₃) concentrations, we exposed three-year-old I. decorus seedlings to three O₃ levels (low O₃-LO: ambient air; medium O₃-MO: Ambient air+70 ppb high O₃-HO: Ambient air+140 ppb O₃) over a growing season using open-top chambers. Leaf shape and stomatal characteristics, and leaf microscopic structure of I. decorus were examined. The results indicated that 1) the stomata O₃ flux (F_st) of HO decreased more rapidly under EO₃ as the exposure time increased. The foliar O₃ injury of HO and MO occurred when AOT40 was 26.62 ppm h and 33.20 ppm h, respectively, 2) under EO₃, leaf number, leaf mass per area, leaf area, and stomata length/width all decreased, while leaf thickness, stomatal density, width, and area increased compared to the control, 3) MDA and total soluble protein contents all showed significantly increase under HO (36.57% and 32.77%) and MO(31.91% and 19.52%) while proline contents only increased under HO(33.27%). 4) MO and HO increased bulliform cells numbers in the leaves by 6.28% and 23.01%, respectively. HO reduced the transverse area of bulliform cells by 13.73%, while MO treatments had no effect, and 5) the number of fusoid cells interspace, the transverse area of fusoid cells interspace, and mesophyll thickness of HO significantly increased by 11.16%, 28.58%, and 13.42%, respectively. In conclusion, I. decorus exhibits strong O₃ tolerance characteristics, which stem from adaptions in the leaf's morphological, structural, antioxidant, and anatomical features. One critical attribute was the enlargement of the bulliform cell transverse area and the transverse area of fusoid cells interspace that drove this resistance to O₃. Local bamboo species with high resistance to O₃ pollution thus need to be promoted for sustained productivity and ecosystem services in areas with high O₃ pollution.

Keywords: Anatomical features; Elevated O(3) concentration; Indocalamus decorus; Leaf tissue structure; Stomata.