Open Access

ARTICLE

Impacts of Defoliation on Morphological Characteristics and Non-Structural Carbohydrates of Populus talassica × Populus euphratica Seedlings

Mengxu Su¹, Zhanjiang Han^1,*, Zhen Zhao², Xiaofeng Wu¹, Jiaju Wu¹

1 College of Life Science and Technology, Tarim University, Xinjiang Production and Construction Corps Key Laboratory of Protection and Utilization of Biological Resources in Tarim Basin, Alar, 843300, China
2 Agricultural Science Research Institute of the First Division, Xinjiang Production and Construction Corps, Alar, 843300, China

* Corresponding Author: Zhanjiang Han. Email:

(This article belongs to the Special Issue: Enhancing the Carbon Sequestration Capacity of the Agricultural, Forestry, and Agroforestry Ecosystems)

Phyton-International Journal of Experimental Botany 2024, 93(7), 1689-1703. https://doi.org/10.32604/phyton.2024.052814

Received 16 April 2024; Accepted 11 June 2024; Issue published 30 July 2024

Abstract

Leaves are important ‘source’ organs that synthesize organic matter, providing carbon sources for plant growth. Here, we used Populus talassica × Populus euphratica, the dominant species in ecological and timber forests, to simulate carbon limitation through artificial 25%, 50%, and 75% defoliation treatments and explore the effects on root, stem, and leaf morphology, biomass accumulation, and carbon allocation strategies. At the 60th d after treatment, under 25% defoliation treatment, the plant height, specific leaf weight, root surface area and volume, and concentrations of non-structural carbohydrates in stem and root were significantly increased by 9.13%, 20.00%, 16.60%, 31.95%, 5.12%, and 9.34%, respectively, relative to the control. There was no significant change in the growth indicators under 50% defoliation treatment, but the concentrations of non-structural carbohydrates in the leaf and stem significantly decreased, showing mostly a negative correlation between them. The opposite was observed in the root. Under 75% defoliation treatment, the plant height, ground diameter, leaf number, single leaf area, root, stem, and total biomass were significantly reduced by 14.15%, 10.24%, 14.86%, 11.31%, 11.56%, 21.87%, and 16.82%, respectively, relative to the control. The concentrations of non-structural carbohydrates in various organs were significantly reduced, particularly in the consumption of the starch concentrations in the stem and root. These results indicated that carbon allocation strategies can be adjusted to increase the concentration of non-structural carbohydrates in root and meet plant growth needs under 25% and 50% defoliation. However, 75% defoliation significantly limited the distribution of non-structural carbohydrates to roots and stems, reduced carbon storage, and thus inhibited plant growth. Defoliation-induced carbon limitation altered the carbon allocation pattern of P. talassica × P. euphratica, and the relationship between carbon reserves in roots and tree growth recovery after defoliation was greater. This study provides a theoretical basis for the comprehensive management of P. talassica × P. euphratica plantations, as well as a reference for the study of plantation carbon allocation strategies in the desert and semi-desert regions of Xinjiang under carbon-limitation conditions.

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