NaCl and Na2SiO3 coexistence strengthens growth of the succulent xerophyte Nitraria tangutorum under drought

摘要

A pot trial was conducted to investigate the effect of Na (as sodium chloride, NaCl), and Na and Si (as sodium metasilicate nonahydrate, Na2SiO3 center dot 9H(2)O) coexistence (NaCl + Na2SiO3) on the growth of the succulent xerophyte Nitraria tangutorum under drought (30 % of field water capacity) in pot culture experiment. The results indicate that 1.2 g kg(-1) NaCl, and the coexistence of 0.3 g kg(-1) NaCl + 0.72 g kg(-1) Na2SiO3 can effectively promote the growth, and the coexistence can more effectively strengthen the growth of N. tangutorum than the 1.2 g kg(-1) NaCl. The coexistence encourages plant height, root/shoot, biomass and main root length and, concomitantly, accumulating a higher concentration of Na+ (shoots) and Si (SiO2) (roots) than K+ to adapt to arid environment. In comparison with the 1.2 g kg(-1) NaCl, a significant increase of Na+ in shoots by 11.9 % and Si in shoots and roots by 173.1 and 191.8 %, respectively were observed in the coexistence of 0.3 g kg(-1) NaCl + 0.72 g kg(-1) Na2SiO3. These findings suggest that the positive roles of Na and Si coexistence on the growth of N. tangutorum under drought might be due to the ability to accumulate a high concentration of Na+ as an important physiological osmoregulator, while still absorbing and accumulating a large amount of Si (SiO2) to stimulate growth under drought.