Importance of plant species and external silicon concentration to active silicon uptake and transport

Abstract

Summary• Here, we characterized silicon (Si) uptake and xylem loading in Oryza sativa , Zea mays , Helianthus annuus and Benincase hispida in a series of hydroponic experiments. Both active and passive Si-uptake components co-exist in all the plants tested. The active component is the major mechanism responsible for Si uptake in O. sativa and Z. mays .• By contrast, passive uptake prevails in H. annuus and B. hispida at a higher external Si concentration (0.85 m M ), while the active component constantly exists and contributes to the total Si uptake, especially at a lower external Si concentration (0.085 m M ).• Short experiments showed that Si uptake was significantly suppressed in O. sativa and Z. mays by metabolic inhibitors or low temperature, regardless of external Si concentrations. By contrast, Si uptake in H. annuus and B. hispida was inhibited more significantly by metabolic inhibitors or low temperature at lower (for example, 0.085 m M ) than at higher (for example, 1.70 m M ) external Si concentrations.• It can be concluded that both active and passive Si-uptake components co-exist in O. sativa , Z. mays , H. annuus and B. hispida , with their relative contribution being dependent much upon both plant species and external Si concentrations.

Silicon uptake by wheat: Effects of Si pools and pH

“…5). This confirms the suggestion that Si uptake by wheat includes an active component (Liang et al, 2006;Rains et al, 2006). For all other treatments, the real Si-uptake rates were on average 40% smaller than the theoretical rates of the respective treatment with regard to Si pool and pH (Fig.…”

Silício melhora produção e qualidade do girassol ornamental em vaso

“…Em arroz, trigo e cevada, sua absorção é um processo ativo (RAINS et al, 2006), enquanto no girassol ele é absorvido tanto ativa, quanto passivamente, dependendo da sua concentração externa (LIANG et al 2006). Os teores foliares de Si variam conforme a espécie.…”

Silicon potentiates the activities of defense enzymes in the leaf sheaths of rice plants infected by Rhizoctonia solani

“…The increased blast resistance of rice plants when supplied with Si has been attributed to a higher density of long and short silicate cells in the leaf epidermis and/or the existence of a thick silica layer below the cuticle forming a physical barrier that prevents or slows Pyricularia grisea penetration (Kim et al, 2002). Increased concentrations of phenolics, lignins and phytoalexins, enhanced activity of defense-related enzymes (chitinases, β-1,3-glucanases and phenylalanine ammonialyases) and the rapid and strong induction of genes related to host defense against pathogens are the biochemical mechanisms that are potentiated by Si in rice (Rodrigues et al, 2003(Rodrigues et al, , 2004(Rodrigues et al, , 2005Liang et al, 2006;Brunings et al, 2009). This study aimed to determine the effects of Si on the activities of defense enzymes in rice leaf sheaths associated with reduce sheath blight development.…”