Sodium (Na⁺) and silicon (Si) coexistence promotes growth and enhances drought resistance of the succulent xerophyteHaloxylon ammodendron

Abstract

Haloxylon ammodendron (C. A. Mey), a C 4 perennial woody species of the desert areas of northwest China, is a succulent xerophyte that has excellent adaptability to adverse arid environments. Our previous investigations showed that sodium (Na + ) has a positive effect on the growth and drought resistance of Haloxylon ammodendron under drought conditions, which was closely related to high Na + accumulation in photosynthesizing stems (PS). In this study, we further investigated the effect of Na (as sodium chloride, NaCl), Si (as silicic acid, H 2 SiO 3 ) and Na and Si coexistence (NaCl + H 2 SiO 3 ) on the growth and drought resistance of Haloxylon ammodendron under water deficit (30% of field water capacity) in a pot culture experiment. The results indicate that 0.3 g kg −1 NaCl, 0.2 g kgH 2 SiO 3 and Na and Si coexistence (0.3 g kg −1 NaCl + 0.1 g kg −1 H 2 SiO 3 ) could effectively mitigate deleterious impacts of drought stress on the growth of Haloxylon ammodendron, and the coexistence of 0.3 g kg −1 NaCl + 0.1 g kg −1 H 2 SiO 3 could more effectively mitigate deleterious impacts of drought stress on the growth of Haloxylon ammodendron than the 0.3 g kg −1 NaCl or 0.2 g kg −1 H 2 SiO 3 . The coexistence of 0.3 g kg −1 NaCl + 0.1 g kgH 2 SiO 3 encourages plant height, crown diameter, biomass and main root length and, concomitantly, accumulates a higher concentration of Na + and Si (SiO 2 ) than Potassium (K + ) to adapt to arid environments. In comparison with the 0.3 g kg −1 NaCl or 0.2 g kg −1 H 2 SiO 3 , a significant increase in total Na + concentrations by 18.4% and 135.3%, and a significant increase in total Si (SiO 2 ) concentrations by 92.6% and 15.6% (compared with 0.3 g kg −1 NaCl or 0.1 g kg −1 H 2 SiO 3 ) were observed in plants grown in the presence of the coexistence of 0.3 g kg −1 NaCl + 0.1 g kgH 2 SiO 3 . These findings suggest that the positive roles of Na and Si coexistence in the drought resistance of Haloxylon ammodendron might be due to the ability of the plants to accumulate a high concentration of Na + as an important physiological osmoregulator, while still absorbing and accumulating a large amount of Si (SiO 2 ) to cope with drought stress. However, the physiological mechanisms underlying how Si, Na, and Si and Na coexistence promote growth and enhance drought resistance of Haloxylon ammodendron need further research.

Consistent alleviation of abiotic stress with silicon addition: a meta‐analysis

“…Si was shown to reduce impacts Cd stress on mangroves, where the high availability of Si in the sea water could play a key role in the tolerance of heavy metals of mangroves (Zhang et al 2013b). Kang et al (2014) demonstrated a positive impact of Si on the growth of Haloxylon ammodendron, a woody C4 arid-zone species, in drought conditions, but in a complicated association with NaCl. Si contributes to the salt tolerance of the marsh grass Spartina densiflora, despite its other adaptations to salinity and may contribute to the invasive success of this weed (Mateos-Naranjo, Andrades-Moreno & Davy 2013).…”

“…Kang et al . () demonstrated a positive impact of Si on the growth of Haloxylon ammodendron , a woody C4 arid‐zone species, in drought conditions, but in a complicated association with NaCl. Si contributes to the salt tolerance of the marsh grass Spartina densiflora , despite its other adaptations to salinity and may contribute to the invasive success of this weed (Mateos‐Naranjo, Andrades‐Moreno & Davy ).…”

“…; Habibi ; Hajiboland & Cheraghvareh ; Kang et al . ; Khoshgoftarmanesh, Khodarahmi & Haghighi ; Kim et al . ,b; Kostopoulou & Therios ; Bokor et al .…”

Na compound fertilizer stimulates growth and alleviates water deficit in the succulent xerophyte Nitraria tangutorum (Bobr) after breaking seed dormancy

“…After 4 weeks, plants were thinned out and five uniform plants were kept, and then plants were divided into three groups: control (C), drought (D) and drought with additional NaCF treatment (D+Na). The amount of fertilizer in each pot culture treatment was calculated as T a = 4×T f (Kang et al 2013(Kang et al , 2014, where T a is the total amount of fertilizer in each pot, and T f is the amount of fertilizer in 1 kg dried soil. The SWC in the C group was maintained at 70% of FWC by irrigating with water during the experimental period.…”

Severe Water Deficiency during the Mid-Vegetative and Reproductive Phase has Little Effect on Proso Millet Performance

“…Plants have evolved a variety of morphological and physiological adaptations to resist drought and thus to preserve optimal relative water content in their tissues [12,13]. The accumulation of silicon (Si) in plant tissues can increase plant resistance against various abiotic and biotic constraints, including water shortage [14,15]. The beneficial impact of Si on plant water status during water shortage has been shown for many plant species [15].…”