Silicon mediates the changes in physiological performance, nutrient uptake, root colonization morphology and secondary metabolite activity in rubber rootstock seedlings (Hevea brasiliensis) inoculated with Rigidoporus microporus

Abstract

White root disease (WRD) of rubber, caused by Rigidoporus microporus, is a severe soilborne disease in rubber plantations. Although several studies have addressed the potential use of silicon (Si) to combat plant diseases, the exact mechanisms underlying Si-improved physiological performance and resistance to WRD in rubber rootstock seedlings are still unknown. This study evaluated the effect of soluble Si supplementation in controlling R. microporus on 13-month-old rubber rootstock seedlings of clones RRIM 2002 and RRIM 2024. The application of soluble Si twice a month on the RRIM 2002 clone increased the relative chlorophyll content, photosynthesis rate, stomatal conductance and transpiration rate to 55.0%, 179.0%, 277.8% and 173.0% higher, respectively, than untreated seedlings 9 months postinoculation with R. microporus. Soluble Si supplementation reduced the disease by 55.0%, compared to only 25.6% disease reduction on rubber rootstock seedlings treated with propiconazole.The application of soluble Si enhanced the accumulation of Si and the production of total phenolic compounds (TPCs) in the rubber rootstock seedling roots by 40% and 25%, respectively, compared to untreated seedlings 9 months postinoculation with R. microporus. Based on scanning electron microscopy observations, the root tissue of rubber rootstock seedlings treated with soluble Si showed the absence of R. microporus hyphae, and the accumulation of Si granules was observed. Thus, this work proved that soluble Si in the form of silicic acid shows promising results as an alternative fertilizer in controlling WRD.

Green Extraction of Valuable Compounds from Rubber Seed Trees: A Path to Sustainability

“…Phenolic compounds are secondary metabolites widely distributed in plants, including rubber seeds [37]. These compounds encompass a broad spectrum of molecules, such as flavonoids, phenolic acids, and tannins, known for their potent antioxidant properties.…”

Enhanced rock weathering increased soil phosphorus availability and altered root phosphorus‐acquisition strategies

“…We tested the following hypotheses: (1) ERW would enhance soil microbial CUE and C sequestration; (2) ERW would increase soil total P concentrations by releasing P contained in the added minerals, and enhance P availability mainly based on indirect effects, i.e. by affecting root P‐acquisition traits (such as carboxylates and phosphatases released by roots) and microbial P cycling (such as inorganic P solubilization, organic P mineralization); (3) Silicon or other minerals in ERW may enhance rubber growth (Abd Hadi et al., 2022) and thus the demand for P beyond what scavenging fine roots can provide, so the plant P‐acquisition strategy shifts towards reliance on mycorrhizal collaboration.…”