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BENEFICIAL EFFECTS OF SILICON IN WHEAT (TRITICUM AESTIVUM L.) UNDER SALINITY STRESS

MUKKRAM ALI TAHIR¹, RAHMATULLAH¹, TARIQ AZIZ², M. ASHRAF, SHAMSA KANWAL¹ & MUHAMMAD AAMER MAQSOOD

Abstract: We evaluated growth performance of two wheat genotypes (Auqab-2000 & SARC-5) differing in salinity tolerance to applied silicon under saline conditions. Plants were grown in pots filled with normal (EC=1.16 dSm^-1) and saline soil (developed EC=10 dSm^-1). Silicon was applied @ 0, 50 and 130 µg Si/g soil using calcium silicate. Plants were harvested at maturity and different physical and chemical parameters were recorded. Salinity stress significantly (p<0.01) reduced dry matter production and grain yield of both wheat genotypes; however reduction was lower in SARC-5 than in Auqab-2000. Silicon application in growth medium significantly (p<0.01) improved dry matter and grain yield of both genotypes grown either in normal and/or in saline conditions. Potassium concentration was significantly increased in plants grown with Si in saline soil. Potassium concentration was lower in plants grown with salinity than those grown in normal soil only in –Si plants. Sodium uptake was higher in plants grown under salinity, however Si application significantly reduced Na uptake, resulting in a significant increase in K:Na ratio in shoots. Sodium concentration in shoots had a significant negative correlation (r>0.81, p<0.01) with shoot dry matter in both genotypes, however, reduction in SDM was more in Auqab-2000. Percent increase in Na concentration due to salinity was significantly reduced in plants receiving Si in root environment. Shoot Si concentration significantly correlated with shoot K concentration (r=0.83, p<0.01) and negatively with shoot Na concentration (r=0.57, p<0.05). Increased K concentration and reduced Na uptake or translocation may be one of the possible mechanisms of increased salinity tolerance by Si application in wheat.

¹Institute of Soil & Environmental Sciences, University of Agriculture, Faisalabad, Pakistan
² Sub-campus University of Agriculture, Faisalabad at Depalpur, Pakistan