A role for nickel in osmotic adjustment in drought-stressed plants of the nickel hyperaccumulator Stackhousia tryonii Bailey

Abstract

The hypothesis that hyperaccumulation of certain metals in plants may play a role in osmotic adjustment under water stress (drought) was tested in the context of nickel hyperaccumulator Stackhousia tryonii. Field-collected mature plants of S. tryonii, grown in native ultramafic soil, were pruned to soil level and the re-growth exposed to five levels of water stress (20, 40, 60, 80 and 100% field capacity; FC) for 20 weeks. Water stress had significant (P<0.05) influence on growth (biomass), water potential and shoot Ni concentrations, with progressively more impact as water stress was increased from 80 to 40% FC. Shoot Ni concentration increased significantly from 3,400 microg g(-1) dry weight (at 100% FC) to 9,400 microg g(-1) dry weight (at 20% FC). Assuming that Ni is uniformly distributed through the shoot tissue, the Ni concentration could account for 100% at the 80 and 60% FC conditions, and 50% at the 40 and 20% FC conditions of plant osmotic regulation. The results are consistent with a role of Ni in osmotic adjustment and protection of S. tryonii plants against drought.

Effect of Soil Water Stress and Nickel Application on Micronutrient Status of Canola Grown on Two Calcareous Soils

“…Presumably, a decline in canola shoot biomass eventuated from suppressed cell expansion and cell growth arising from low turgor pressure (Mengel and Kirkby, 2001). The results are in contrast to the findings of Bhatia et al (2005) who stated that the growth of Stackhousia tryoni Bailey plant was adversely affected by FC conditions in a clay soil due to the poor porosity and root anaerobiosis.…”

“…6). The results were in agreement with the findings of Bhatia et al (2005), who observed a significant increase in SNC in drought-stressed S. tryonii plants. They suggested the positive osmoregulatory role in Ni.…”

“…However, values were not significantly changed by increasing levels of water stress. In contrast, Bhatia et al (2005) observed a significant increase in SNC under decreased soil moisture levels in S. tryonii plants. They suggested that Ni had a positive osmoregulatory role.…”

Role of transpiration in arsenic accumulation of hyperaccumulator Pteris vittata L.

“…The hyperaccumulation of certain metals may be important in the osmotic adjustment of plants under water stress, based on the discovery that the nickel (Ni) hyperaccumulation in Stackhousia tryonii is a trait protecting the plant from drought in serpentine soils, with Ni acting as an osmoregulatory agent (Bhatia et al 2005). Arsenic is closely related to the water consumption in hyperaccumulators.…”

Evolutionary aspects of elemental hyperaccumulation

“…whiting et al (2003) found no evidence that Ni or Zn can protect plants from polyethylene glycol (PeG)-induced osmotic stress. On the other hand, Bhatia et al (2005) reported that Ni may play a role in osmotic adjustment in the hyperaccumulator Stackhousia tryonii, thereby protecting it from drought stress. while not a hyperaccumulator, it is interesting to note that Yao et al (2012) found that Se treatment improved recovery of wheat seedlings from drought stress.…”