Effect of silicon and arbuscular mycorrhizal fungi on root morphology of tomato plants under copper toxicity

Afzal, Muzamil

Effect of silicon and arbuscular mycorrhizal fungi on root morphology of tomato plants under copper toxicity - Pathum Thani, Thailand : Asian Institute of Technology, 2024 - 93 leaves : ill. + 1online resource - Thesis ; no. AS-24-03 . - Asian Institute of Technology. Thesis ; no. AS-24-03 .

A Thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Agricultural Systems and Engineering

Thesis (M. Sc.) - Asian Institute of Technology, 2024

The excessive use of Copper (Cu)-based fungicides in agriculture has led to significant pollution of agricultural land with heavy metals, presenting risks to both plant and human health. Notable stress of Cu ruins plant health, initiating physiological and biochemical disturbances that cause decline in biomass and stunted growth. Application of silicon (Si) supplementation and arbuscular mycorrhizal fungi (AMF) association showcase potential in mitigating Cu buildup in contaminated soils and reducing its adverse effects on plants, offering a potential long-term solution to the challenges posed by Cu pollution. This study investigated the efficacy of Si (0 and 60 kg ha1 ) and AMF (+AMF and AMF) in alleviating Cu toxicity in plants and enhancing its tolerance to Cu toxicity (0, 75, 150, 300, 600 mg kg1 ) using soil as a growth medium. We found that Cu addition at low to optimal levels (up to Cu150) generally improved plant root health parameters. However, at higher concentrations, there was a definite reduction in biomass, with the most stressed plants (Cu600) showing a decrease compared with the control. Other root growth parameters, such as root length, root diameter, and root volume, also followed this declining trend. Despite that, application of Si and AMF mitigated these adverse effects; at Cu150, root dry matter increased relative to the control, which exhibited the highest biomass under this treatment combination. Additionally, these treatments significantly reduced P accumulation in the roots at Cu600 and increased both Si and Cu content proportionally with increasing Cu stress, peaking at the highest Cu toxicity levels. The combined application of Si and AMF led to notable improvements in root volume. Moreover, significant increases in root length, root diameter, and root dry matter were observed, while Si and P root concentration was significant, which enhanced the overall plant resilience. Under the combined application of Si and AMF, root Cu concentration was non-significant and Cu concentration increased gradually up to the highest toxicity level of Cu600. Furthermore, root colonization was the significant parameter among others, which demonstrated significant symbiotic association under each individual and combined treatments. Interestingly, while the mean Si concentration in roots increased with rising Cu levels, the application of Si and AMF not only countered the detrimental effects but also supported better growth as compared to the controls. The finding emphasizes the integration of Si and AMF into agricultural practices to combat Cu toxicity, suggesting a promising strategy for enhancing crop performance and sustainability in Cu-contaminated environments.


Vesicular-arbuscular mycorrhizas
Mycorrhizal fungi
Tomatoes
Copper--Toxicology
Silicon
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