Different Nitro-Oxidative Response of Odontarrhena lesbiaca Plants from Geographically Separated Habitats to Excess Nickel

Abstract

Odontarrhena lesbiaca is an endemic species to the serpentine soils of Lesbos Island (Greece). As a nickel (Ni) hyperaccumulator, it possesses an exceptional Ni tolerance; and it can accumulate up to 0.2–2.4% Ni of its leaves’ dry weight. In our study, O. lesbiaca seeds from two geographically separated study sites (Ampeliko and Loutra) were germinated and grown on control and Ni-containing (3000 mg/kg) soil in a rhizotron system. Ni excess induced significant Ni uptake and translocation in both O. lesbiaca ecotypes and affected their root architecture differently: plants from the Ampeliko site proved to be more tolerant; since their root growth was less inhibited compared to plants originated from the Loutra site. In the roots of the Ampeliko ecotype nitric oxide (NO) was being accumulated, while the degree of protein tyrosine nitration decreased; suggesting that NO in this case acts as a signaling molecule. Moreover, the detected decrease in protein tyrosine nitration may serve as an indicator of this ecotype’s better relative tolerance compared to the more sensitive plants originated from Loutra. Results suggest that Ni hypertolerance and the ability of hyperaccumulation might be connected to the plants’ capability of maintaining their nitrosative balance; yet, relatively little is known about the relationship between excess Ni, tolerance mechanisms and the balance of reactive nitrogen species in plants so far.

Interspecific trait differences drive plant community responses on serpentine soils

“…O. lesbiaca is the only hyperaccumulator species in our communities, with differences in Ni hyperaccumulation among its populations being consistent with nickel availability in the soil (Kazakou et al 2010; Adamidis et al 2014c). In a rhizotron experiment, individuals of O. lesbiaca from Ni rich soils (Ampeliko) proved to be more tolerant in terms of root growth relative to those from sites with lower nickel content (Loutra), as Ni-induced nitric oxide accumulation was observed in their root tips along with a decrease in the degree of protein tyrosine nitration (Feigl et al 2020). The difference in traits of the O. lesbiaca could also be linked to high resistance to low nutrient and water availability (Kazakou et al 2008; Harrison et al 2017), as species strictly restricted to serpentine habitats are found to have higher drought tolerance than more generalist Mediterranean species (Hidalgo-Triana et al 2023).…”

Investigation of the Allelopathic Effect of Two Invasive Plant Species in Rhizotron System

“…The use of soil-filled rhizotrons can be a good compromise between in vitro systems and field studies, allowing real-time, non-invasive studies of root system development [48]. Root responses of agricultural crops to different stressors have been investigated in such systems in several cases, e.g., treated with zinc [49] or nickel [50], combined heavy metal treatment modeling wastewater [51], polypropylene surgical mask fragments [52], or raw and nutrient-enriched pomegranate peel powder [53].…”

Broomrape Species Parasitizing Odontarrhena lesbiaca (Brassicaceae) Individuals Act as Nickel Hyperaccumulators

“…Odontarrhena lesbiaca P. Candargy (≡ Alyssum lesbiacum (P. Candargy) Rech. f.) is a micro-edaphic endemic species of serpentine soils of the island of Lesbos, Greece [ 28 , 29 ] and highly capable of hyperaccumulating Ni in its aboveground parts [ 30 , 31 , 32 , 33 , 34 ].…”