Beneficial effects of silicon nutrition in alleviating salinity stress in hydroponically grown canola,Brassica napusL., plants

Abstract

Silicon (Si) is the second most abundant element in soil and effectively counteracts the effects of various abiotic stresses, such as drought, heavy metal toxicity and salinity, on plants. In the present study the ameliorating effects of Si nutrition supplied as 2 mmol L )1 sodium silicate were investigated on hydroponically grown canola (Brassica napus L.) plants under salinity stress (i.e. 150 mmol L )1 sodium chloride). Salinity decreased plant growth parameters such as tissue fresh and dry weights. These decreases were accompanied by increased lignin contents, Na + ion accumulation, increased lipid peroxidation and decreased chlorophyll contents in plants. Silicon nutrition, however, enhanced plant growth parameters and led to the prevention of lignin and the Na + accumulation in shoots, reduced levels of lipid peroxidation in the roots and higher levels of chlorophyll. As a result of salinity, catalase activity in the whole plant and both soluble and cell wall peroxidase activities in the shoots decreased. Silicon nutrition, however, increased the reactive oxygen species scavenging capacity of saltstressed plants through increased catalase and cell wall peroxidase activities. Thus, silicon nutrition ameliorated the deleterious effects of salinity on the growth of canola plants through lower tissue Na + contents, maintaining the membrane integrity of root cells as evidenced by reduced lipid peroxidation, increased reactive oxygen species scavenging capacity and reduced lignification.

Potential of calcium silicate to mitigate water deficiency in maize

“…The greater Ψ w (Figure 4) of maize leaves may explain the higher silicon content of leaves which increases the efficiency of gas exchanges. These results agree with those of Hashemi et al (2010), who suggested Si to be an element that confers greater resistance to biotic and abiotic stress in plants. Figure 7 compares grain production between the different proportions of calcium silicate according to irrigation depth.…”

Anatomical differences of poplar (Populus × euramericana clone I-214) roots exposed to zinc excess

“…As previously observed for the suberinization of the endodermis, the development of xylem elements might be enhanced also by other environmental stresses. Increased contain of lignin was observed by Hashemi et al (2010) in Brassica napus exposed to high salinity. We suppose that the increased content of lignin might be a kind of defense mechanism and premature xylogenesis is induced by the high amount of Zn in the rhizosphere.…”

O alto teor de silício no solo inibe o crescimento radicular de cafeeiros sem afetar as trocas gasosas foliares

“…A maior parte dos estudos que comprovam os benefícios do Si na agricultura foi realizada com espécies herbáceas de rápido crescimento (Goto et al, 2003;RomeroAranda et al, 2006;Hattori et al, 2007;Côté-Beaulieu et al, 2009;Savvas et al, 2009;Hashemi et al, 2010;Zanão Júnior et al, 2010). O hábito de crescimentolento em espécies arbóreas, como o cafeeiro, ou rápido em espécies herbáceas, como o arroz -parece ser um fator adicional que altera a resposta ao Si, sendo o benefício mais evidente nas espécies anuais.…”

“…O Si é um elemento que confere às plantas maior resistência a estresses bióticos e abióticos (Goto et al, 2003;Romero-Aranda et al, 2006;Hattori et al, 2007;Côté-Beaulieu et al, 2009;Savvas et al, 2009;Hashemi et al, 2010), assim como melhora o manejo fitossanitário de cafeeiros (Reis et al, 2008) e plantas de trigo (Zanão Júnior et al, 2010).…”