Leaf reflectance and functional traits as environmental indicators of urban dust deposition

Jiyou Zhu; Jingliang Xu; Yujuan Cao; Jing Fu; Benling Li; Guangpeng Sun; Xinna Zhang; Chengyang Xu

doi:10.1186/s12870-021-03308-8

Leaf reflectance and functional traits as environmental indicators of urban dust deposition

BMC Plant Biol. 2021 Nov 13;21(1):533. doi: 10.1186/s12870-021-03308-8.

Authors

Jiyou Zhu¹, Jingliang Xu¹, Yujuan Cao¹, Jing Fu¹, Benling Li², Guangpeng Sun¹, Xinna Zhang¹, Chengyang Xu³

Affiliations

¹ Research Center for Urban Forestry, The Key Laboratory for Silviculture and Conservation of Ministry of Education, Beijing Forestry University, Key Laboratory for Silviculture and Forest Ecosystem of State Forestry and Grassland Administration , Beijing Forestry University, Beijing, 100083, China.
² Production and Operation Management Department, China Communications Construction Company, Beijing, 100088, China.
³ Research Center for Urban Forestry, The Key Laboratory for Silviculture and Conservation of Ministry of Education, Beijing Forestry University, Key Laboratory for Silviculture and Forest Ecosystem of State Forestry and Grassland Administration , Beijing Forestry University, Beijing, 100083, China. cyxu@bjfu.edu.cn.

Abstract

Background: How to quickly predict and evaluate urban dust deposition is the key to the control of urban atmospheric environment. Here, we focus on changes of plant reflectance and plant functional traits due to dust deposition, and develop a prediction model of dust deposition based on these traits.

Results: The results showed that (1) The average dust deposition per unit area of Ligustrum quihoui leaves was significantly different among urban environments (street (18.1001 g/m²), community (14.5597 g/m²) and park (9.7661 g/m²)). Among different urban environments, leaf reflectance curves tends to be consistent, but there were significant differences in leaf reflectance values (park (0.052-0.585) > community (0.028-0.477) > street (0.025-0.203)). (2) There were five major reflection peaks and five major absorption valleys. (3) The spectral reflectances before and after dust removal were significantly different (clean leaves > dust-stagnant leaves). 695 ~ 1400 nm was the sensitive range of spectral response. (4) Dust deposition has significant influence on slope and position of red edge. Red edge slope was park > community > street. After dust deposition, the red edge position has obviously "blue shift". The moving distance of the red edge position increases with the increase of dust deposition. The forecast model of dust deposition amount established by simple ratio index (y = 2.517x + 0.381, R² = 0.787, RMSE (root-mean-square error) = 0.187. In the model, y refers to dust retention, x refers to simple ratio index.) has an average accuracy of 99.98%. (5) With the increase of dust deposition, the specific leaf area and chlorophyll content index decreased gradually. The leaf dry matter content, leaf tissue density and leaf thickness increased gradually.

Conclusion: In the dust-polluted environment, L. quihoui generally presents a combination of characters with lower specific leaf area, chlorophyll content index, and higher leaf dry matter content, leaf tissue density and leaf thickness. Leaf reflectance spectroscopy and functional traits have been proved to be effective in evaluating the changes of urban dust deposition.

Keywords: Dust deposition; Forecast model; Leaf functional traits; Leaf reflectance.

MeSH terms

Chlorophyll / metabolism*
Environmental Indicators
Plant Leaves / metabolism*

Substances

Chlorophyll