Chilling imbibition improves the germination tolerance of the Andean tree Alnus acuminata to arsenic
2020
Ramos-Montaño, Carolina | de Oliveira, Juraci Alves | Condori-Apfata, Jorge A.
Arsenic (As) is a toxic metalloid common in coal mining soils. We evaluated a stratification treatment of 48 h of chilling imbibition (3 °C) versus control imbibition (25 °C) in seeds of the Andean tree Alnus acuminata (Kunth). Five concentrations of As: 0, 2.5, 5.0, 7.5, and 10 mg L⁻¹ were tested in both groups of seeds to determine whether chilling imbibition affects the germination, vigor of seedlings and tolerance to arsenic. Physiological, biochemical and morphometric traits were evaluated in germinants to establish how chilling imbibition and As modulate the early development. Growth and tolerance index were estimated in seedlings of 70 days. We found that chilling imbibition enhanced the germination tolerance to arsenic and this effect was unaltered by its concentration. The germinants accumulated arsenic and the maximum reduction of growth was around 28%, but these germinants reached the stage of seedling without negative affectations in final size or biomass. The emergence of the first leaf was delayed in germinants coming from seeds imbibed at 25 °C and exposed to As. Chilling imbibition increased the allometric relationship between size and biomass in germinants exposed to As, improving the vigor and tolerance in more than 55%. Our results suggest that accumulation of As in cotyledons, a high content of carbohydrates and proteins, the activity of SOD, POX and probably the synthesis of phytochelatins are the strategies of tolerance in germinants coming from pre-chilled seeds. This treatment becomes important for the implementation of A. acuminata in forestry programs for soils affected by coal mining.
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