Alleviation of Salt-induced Deleterious Effects in Chrysanthemum Plant and Soil by Silicon Supplement

Abstract

Chrysanthemums (Dendranthema grandiflorum ‘Iwanohakusen’) were grown in a greenhouse with complete nutrient solution system to investigate the effect of silicon (Si) supplement on salt induced deleterious effects in chrysanthemum plants. The experiment was conducted in plastic pots supplemented with a mixture of upland soil : leaf mold : river sand (3:3:4, v:v:v). Si and salinity were treated in combination with two levels of NaCl (0 and 100 mM) and two sources of silicon (K2SiO3, KSi and silicate fertilizer, SiF) at the same concentration (1.8 mM Si) by weekly-drenching for 12 weeks. Chrysanthemum plants supplemented with Si increased in fresh and dry matter enhancing water content and salinity tolerance. The plants grown under salt stress produced less fresh and dry matter than control plant. However, Si supplement to plants under salt stress ameliorated negative effects of salt stress. In soil, EC and NaCl increased by salt stress were mitigated by Si supplement. Salt stress significantly decreased the contents of K and P in leaf, but Si supplement under salt stress significantly recovered the decreased contents with enormous desorption of K and P in soil. Added Si significantly increased content of available SiO2 with its adsorption by salt stress in soil, which was directly related to Si accumulation in leaf. However, Si uptake by roots was suppressed by salt stress irrespective of Si supplement. Si supplement did not ameliorated the negative effects of salt stress on chlorophyll content and membrane integrity in leaf of chrysanthemum plant although significantly increased Si content in leaf, but reversed pest (Liriomyza trifolii) resistance to above-control level.