ORIGINAL RESEARCH article
Front. Plant Sci.
Sec. Plant Physiology
This article is part of the Research TopicPolyamines in Plant Stress Responses and DevelopmentView all 9 articles
Exogenous putrescine enhances salt tolerance in Populus nigra × maximowiczii: Growth, physiological, and biochemical responses
Provisionally accepted
- 1Virginia Tech, Blacksburg, United States
- 2University of New Hampshire, Durham, United States
- 3USDA Northern Research Station, Durham, New Hampshire, United States, Durham, United States
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Introduction: Putrescine, a polyamine involved in plant growth and stress responses, has shown potential in mitigating abiotic stress effects. However, little is known about the effects of exogenous addition of putrescine regarding salt tolerance in trees. Methods: This study was conducted to investigate whether exogenous putrescine application via foliar spray enhances growth in a hybrid poplar (Populus nigra x maximowiczii, clone NM6) under a short duration of salt stress. Salt stress was induced by irrigating roots with 100 mM and 200 mM NaCl, followed by foliar spraying of putrescine on several days. Measurement of growth including plant height and stem diameter for each plant were recorded in the greenhouse every 15 days throughout the experiment. Gas exchange, total chlorophyll, carotenoids, soluble sugars and proteins, amino acids, polyamines, and relative water content were analyzed in foliage collected 3, 6, 7, 13, 20, 35 days after treatment. Results: Foliar putrescine application significantly promoted growth, increasing stem height by ~20% and stem diameter by ~15% under 100 mM NaCl compared to untreated plants. Foliar spray significantly enhanced fructose accumulation, with ~37% higher levels at day 6 under 100 mM NaCl compared to unsprayed plants and increased sucrose by ~28% at day 13. Based on metabolic responses, plants treated with 100 mM NaCl fared better when sprayed with putrescine than those treated with 200 mM NaCl. Discussion: Exogenous application of putrescine alleviated salt-induced growth inhibition, likely through its role in maintaining osmotic balance and energy metabolism. These findings highlight the potential of exogenous putrescine treatment as a practical strategy to enhance salt tolerance in young poplar trees, with implications for forestry and land reclamation in saline environments.
Keywords: Amino Acids, Foliar spray, Growth, Hybrid poplar, Metabolism, Polyamines, Putrescine, salt stress
Received: 04 Jun 2025; Accepted: 28 Nov 2025.
Copyright: © 2025 Kundu, Weerasinghe, Gagne, Long, Minocha and Minocha. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence:
Sanchari Kundu
Subhash Minocha
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