Physiological Responses of Rice Plants Supplied with Silicon to Monographella albescens Infection

Abstract

This study investigated the effect of silicon (Si) on the resistance of rice plants of the cv. ‘Primavera’ cultivar that were grown in a nutrient solution with 0 (−Si) or 2 mm (+Si) Si to leaf scald, which is caused by Monographella albescens. The leaf Si concentration increased in the +Si plants (4.8 decag/kg) compared to the −Si plants (0.9 decag/kg), contributing to a reduced expansion of the leaf scald lesions. The extent of the cellular damage that was caused by the oxidative burst in response to the infection by M. albescens was reduced in the +Si plants, as evidenced by the reduced concentration of malondialdehyde. Higher concentrations of total soluble phenolics and lignin‐thioglycolic acid derivatives and greater activities of peroxidases (POX), polyphenoloxidases (PPO), phenylalanine ammonia‐lyases (PAL) and lipoxygenases (LOX) in the leaves of the +Si plants also contributed to the increased rice resistance to leaf scald. In contrast, the activities of chitinases and β‐1,3‐glucanases were higher in the leaves of the −Si plants probably due to the unlimited M. albescens growth in the leaf tissues, as indicated by the larger lesions. The results of this study highlight the potential of Si in decreasing the expansion of the leaf scald lesions concomitantly with the potentiation of phenolic and lignin production, and the greater activities of POX, PPO, PAL and LOX rather than simply acting only as a physical barrier to avoid M. albescens penetration.

Leaf Gas Exchange and Chlorophyll a Fluorescence Imaging of Rice Leaves Infected with Monographella albescens

“…In total, 1.63 g of calcium phosphate monobasic was added to each plastic pot. Plants were fertilized weekly with 50 ml of a nutrient solution containing KCl at 192 mg liter - (37). This isolate was preserved in glass vials containing potatodextrose-agar (PDA), covered with mineral oil, and maintained at 4°C.…”

Silicon‐mediated cell wall modifications of sorghum root exodermis and suppression of invasion by fungus Alternaria alternata

“…Although the ameliorating effects of Si seem to be undeniable, the mechanism of its action remains unclear. Two main hypotheses have been proposed in the literature: the already mentioned structural/mechanical reinforcement of plant tissues via Si polymerization and deposition (Resende et al ., ; Tatagiba et al ., ), and an enhancement of plant defence responses mediated by the biochemical activity of soluble Si (Rodrigues et al ., ; Cai et al ., ; Fortunato et al ., ).…”

Silicon fertilization improve yield and quality of rice and pearl millet in cerrado soils

“…For rice, which is a Si-accumulation plant (EPSTEIN, 2009), it can lead to an increase in photosynthetic activity, yield (CARVALHO-PUPPATTO et al, 2004;DETMANN et al, 2012), number of grains per panicle (MARCHESAN et al, 2004), quality , tolerance to drought (CHEN et al, 2011), pests (RANGANATHAN et al, 2006;HOSSEIN et al, 2011), and diseases (TATAGIBA et al, 2014).…”