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Abstract
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Plants face significant challenges from abiotic stresses such as drought and heavy metal
contamination, which damage their growth, physiological processes, and productivity. This study
examines how exogenous putrescine application can reduce the combined effects of drought and
nickel (Ni) stress in Tanacetum balsamita L., a medicinal plant with phytoremediation potential. Under
controlled greenhouse conditions, plants experienced drought (50% field capacity), Ni contamination
(0, 165, 220 mg kg⁻1 soil), and foliar putrescine (0.2 mM) treatments. Results showed that drought
and Ni stress together reduced photosynthesis [Fv/Fm, Y(II)], chlorophyll, and biomass, and increased
oxidative stress markers (H₂O₂, MDA) and antioxidant enzymes. Foliar application of putrescine
alleviated stress by boosting photosynthesis, restoring chlorophyll content, reducing oxidative
damage, decreasing Ni levels in shoots, increasing osmolytes such as proline and carbohydrates, and
enhancing biomass and essential oil yield. The study shows that putrescine fortifies stress tolerance
and phytoremediation potential in T. balsamita, aiding sustainable growth in Ni-contaminated, dry
areas. These findings underscore the importance of polyamines in plant stress physiology and their
potential for combating the effects of stressors.
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