Abstract
Salinity is one of major factors in limiting crop production in the world, and improving plant salt tolerance is very crucial and urgent. Silicon (Si) is the second most abundant element on the surface of the earth, and many studies have shown its beneficial effect for plant growth and development and as well as stress tolerance. To test the function of Si in salt stress, we applied Si on sorghum under hydroponic condition. We found that Si could maintain both shoot and root growth under salt stress significantly. To further explore the mechanism of Si-induced salt tolerance, we investigated the effect of Si on polyamines (PAs) and ACC (1-amino- cyclopropane-1-carboxylate) accumulation, and also the expression of SbSAMDC (S- adenosylmethionine decarboxylase) gene. With Si, PAs level was increased, especially putrescence and spermidine which increased 2-4 times, while ACC content was decreased under salt. Moreover, the expression of SbSAMDC was up-regulated by Si. It suggests that Si-induced improvement of salt tolerance is related with the regulation of PAs and ethylene synthesis, and PAs which are essential for plant growth and survival may play an important role in this process.
