Physiological responses and tolerance of Idesia polycarpa seedlings under simulated rhizosphere acidification
4 affiliations
- 1College of Forestry, Henan Agricultural University
- 2College of Urban Construction, Zhejiang Shuren University
- 3Henan Province Engineering Technology Research Center for Idesia
- 4Key Laboratory for Idesia polycarpa, National Forestry and Grassland Administration
Abstract
Introduction: Soil acidification poses a growing threat to forest seedling establishment, yet the physiological responses and tolerance limits of many multipurpose woody species under increasing acidity remain poorly understood. Idesia polycarpa Maxim. is an emerging woody oil tree with high ecological and economic value, but its physiological responses to root-zone acidification are largely unknown.
Methods: We subjected one-year-old I. polycarpa seedlings to 50 d of root-zone irrigation with acidified solutions at pH 5.5, 4.5, and 3.5, with deionized water as the control, and monitored visible injury, photosynthetic pigments, malondialdehyde (MDA), osmotic adjustment substances, and the activities of peroxidase (POD) and superoxide dismutase (SOD).
Results: Visible injury increased with both acidity and exposure duration, and the cumulative injury index reached 85.00% under pH 3.5, 40.00% under pH 4.5, and 16.67% under pH 5.5 after 50 d, while CK remained at 0%. Under pH 3.5, photosynthetic pigment contents showed pronounced temporal fluctuations, with marked reductions at 20 and 50 d and partial recovery during the intermediate stages. MDA content also exhibited a non-monotonic response, with significantly higher values under pH 3.5 at several middle and late sampling times. Soluble sugar, proline, and soluble protein showed stage- and treatment-dependent changes rather than continuous accumulation or decline. POD activity under pH 3.5 reached approximately 3.55-fold the CK value at 10 d and subsequently declined, whereas SOD activity fluctuated markedly among treatments and sampling times. Correlation analysis revealed coordinated variation among photosynthetic pigments, MDA, osmotic adjustment substances, and the two measured antioxidant enzymes, but these associations do not establish causal relationships.
Discussion: Overall, seedlings under pH 5.5 and pH 4.5 showed partial physiological adjustment, whereas pH 3.5 was associated with substantially greater visible injury and physiological disturbance. The contrasting responses between the pH 4.5 and pH 3.5 irrigation treatments suggest a potential physiological tolerance boundary within this tested acidity interval under the present controlled conditions, rather than a statistically defined biological breakpoint.
Related
- Waterlogging tolerance in pigeonpea: current understanding of physiological responses, genetic resources, and genomic prospects
- Enhancement of Drought Stress Tolerance in Lettuce by Pseudomonas fluorescens FSO7 Isolated from Artemisia ordosica Rhizosphere
- Differences in microbial composition and salt tolerance between rhizosphere and bulk soil of Kalidium foliatum
- Rhizosphere Fungal Community Responses to Nitrogen Addition Reflect Genotypic Versus Trait Variation in the Marsh Sedge Schoenoplectus americanus Over Time
- Integrating physiological and proteomics signatures for understanding drought, salinity and alkalinity stress tolerance mechanisms in lentil
BibTeX
@article{hu2026physiological,
title = {{Physiological responses and tolerance of Idesia polycarpa seedlings under simulated rhizosphere acidification}},
author = {Zuwei Hu and Wenwen Zhong and Yanan Ma and Can Cao and Yulan Bei and Jiajia Hou and Yaohui Liu and Yanmei Wang and Li Dai and Qifei Cai and Xiaodong Geng and Juan Wang and Yongyu Ren and Fangming Liu and Zhen Liu and Hongzhu Zou and Shaoyu Chen and Tailin Zhong and Zhi Li},
journal = {Frontiers in Plant Science},
year = {2026},
month = oct,
doi = {10.3389/fpls.2026.1967073},
url = {https://www.frontiersin.org/articles/10.3389/fpls.2026.1967073/full},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Physiological responses and tolerance of Idesia polycarpa seedlings under simulated rhizosphere acidification
AU - Zuwei Hu
AU - Wenwen Zhong
AU - Yanan Ma
AU - Can Cao
AU - Yulan Bei
AU - Jiajia Hou
AU - Yaohui Liu
AU - Yanmei Wang
AU - Li Dai
AU - Qifei Cai
AU - Xiaodong Geng
AU - Juan Wang
AU - Yongyu Ren
AU - Fangming Liu
AU - Zhen Liu
AU - Hongzhu Zou
AU - Shaoyu Chen
AU - Tailin Zhong
AU - Zhi Li
PY - 2026
DA - 2026/10/26
JO - Frontiers in Plant Science
DO - 10.3389/fpls.2026.1967073
UR - https://www.frontiersin.org/articles/10.3389/fpls.2026.1967073/full
AB - Introduction: Soil acidification poses a growing threat to forest seedling establishment, yet the physiological responses and tolerance limits of many multipurpose woody species under increasing acidity remain poorly understood. Idesia polycarpa Maxim. is an emerging woody oil tree with high ecological and economic value, but its physiological responses to root-zone acidification are largely unknown. Methods: We subjected one-year-old I. polycarpa seedlings to 50 d of root-zone irrigation with acidified solutions at pH 5.5, 4.5, and 3.5, with deionized water as the control, and monitored visible injury, photosynthetic pigments, malondialdehyde (MDA), osmotic adjustment substances, and the activities of peroxidase (POD) and superoxide dismutase (SOD). Results: Visible injury increased with both acidity and exposure duration, and the cumulative injury index reached 85.00% under pH 3.5, 40.00% under pH 4.5, and 16.67% under pH 5.5 after 50 d, while CK remained at 0%. Under pH 3.5, photosynthetic pigment contents showed pronounced temporal fluctuations, with marked reductions at 20 and 50 d and partial recovery during the intermediate stages. MDA content also exhibited a non-monotonic response, with significantly higher values under pH 3.5 at several middle and late sampling times. Soluble sugar, proline, and soluble protein showed stage- and treatment-dependent changes rather than continuous accumulation or decline. POD activity under pH 3.5 reached approximately 3.55-fold the CK value at 10 d and subsequently declined, whereas SOD activity fluctuated markedly among treatments and sampling times. Correlation analysis revealed coordinated variation among photosynthetic pigments, MDA, osmotic adjustment substances, and the two measured antioxidant enzymes, but these associations do not establish causal relationships. Discussion: Overall, seedlings under pH 5.5 and pH 4.5 showed partial physiological adjustment, whereas pH 3.5 was associated with substantially greater visible injury and physiological disturbance. The contrasting responses between the pH 4.5 and pH 3.5 irrigation treatments suggest a potential physiological tolerance boundary within this tested acidity interval under the present controlled conditions, rather than a statistically defined biological breakpoint.
SN - 1664-462X
ER -