30 June 2023

Adding silicon to the soil protects canola from its pathogens

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According to a Canadian research, silicon, a widespread and cheap element, helps plants fight clubroot. But it also helps them withstand drought and extreme heat

by Matteo Cavallito

 

Adding silicon to the soil could help fight clubroot, a disease caused by a parasite called Plasmodiophora brassicae, that affects canola crops. This is supported by a research from the University of Alberta in Edmonton, Canada. The results of the study, the first to explore the effects of the element on plant pathology, seem to be definitely encouraging.

Greenhouse experiments, observes a statement from the Canadian university, revealed that infection was slowed by reducing mold formation. In addition, the silicon salt used was absorbed by the soil, promoting the growth and fortification of the plants themselves.

Disease incidence halved

The researchers mixed the element with soil, adding sodium silicate, a compound used among other things as a fungicide. Different concentrations were applied throughout the experiment, ranging from 0.1 to 1 gram of silicate for each gram of potting soil.

Depending on the different applications, the authors observed up to 46 percent reduction in overall clubtroot symptoms in plants susceptible to the disease.

“Among the different concentrations, the highest amount of Si amendment, resulted in partial resistance to clubroot with an average disease index of 54%, while the moderate amounts, caused mild susceptibility with an index of 83–80%,” the study states. Finally, “The plants grown in lower Si concentrations, were completely susceptible to clubroot disease with an index of 95–100%.” And there’s more.

Plants become stronger with silicon

The uptake of water-soluble silicon salt by the soil brought additional benefits. In addition to slowing infection and reducing mold growth, the element would in fact result in increased plant height and root length and increased drought tolerance , even in the presence of the crucifer hernia pathogen.

The overall plant health was evaluated by measuring the shoot height and root length at the end of the experiment, that is, 50 days post inoculation,” the study reports.

“Si treatment improved shoot height for all treatments and was statistically significant for Si0.1 grams, Si0.75, and Si1.0 treatments, while the root lengths were significantly greater for all Si treatments.” Finally, “The average pH of the soil mix ranged from 6.50 to 8.14; this demonstrated a trend of increasing pH with the increase in Si concentration.”

Valutazione dei parametri vegetali a seguito del trattamento con silicio in presenza di Plasmodiophora brassicae, il fungo che causa l'ernia delle crucifere. (A) indice di malattia (Iincidenza in %), (B) altezza dei germogli, (C) lunghezza delle radici, (D) pH delle miscele di terreno e (E) immagini rappresentative delle radici per tutte le piante trattate con silicio e misurate 50 giorni dopo l'infezione con P. brassicae. Fonte: Ananya Sarkar et al., “Silicon ameliorates clubroot responses in canola (Brassica napus): A ‘multi-omics’-based investigation into possible mechanisms” https://doi.org/10.1111/ppl.13900, Physiologia Plantarum, Volume 175, Issue 2, March/April 2023 Open Access Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0)

Evaluation of plant parameters due to Si treatment in presence of Plasmodiophora brassicae, the fungi which causes clubroot.. The (A) disease index (ID)%, (B) shoot height, (C) root length, (D) pH of the soil mixes, and (E) representative root images for all Si-treated plants measured 50 days post infection (dpi) with P. brassicae. Source: Ananya Sarkar et al., “Silicon ameliorates clubroot responses in canola (Brassica napus): A ‘multi-omics’-based investigation into possible mechanisms”, Physiologia Plantarum, Volume 175, Issue 2, March/April 2023 Open Access Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0)

The benefits for producers

According to Ananya Sarkar, study leader and a doctoral student in plant science at the University of Alberta’s Faculty of Agricultural, Biological and Environmental Sciences, the experiment “shows the potential benefits of silicon as an effective, economical tool for canola producers.” This crop, the study recalls, generates a global production of more than 70 million tons. But the spread of clubtroot, detected today in more than 60 countries, can reduce crop yields by 15 percent.

Silicon “is the second most abundant element on earth after oxygen, accounting for 28.8% of the mass of the earth’s crust,” the authors recall. Silicon has also been shown to improve plant response to environmental stresses such as drought and extreme heat. One aspect that makes the discovery even more significant in the context of climate change and its impact on food security.