Seed priming of Handroanthus heptaphyllus for the restoration of the mining fields

Abstract

Seed priming is a low-cost pre-sowing treatment used to improve germination and seedling establishment performance under adverse environmental conditions. The priming using signaling molecules, such as nitric oxide and hydrogen peroxide, act on plant growth and development alleviating the negative influence of abiotic stress by heavy metals. Thus, this work aimed to investigate the influence of priming with NO, H2O2, or their combination of Handroanthus heptaphyllus (Vell.) Mattos seeds on the germination and establishment of seedlings cultivated in iron mining tailings. The priming treatments were as follows: H2O, SNP (NO donor), H2O2 as well as SNP + H2O2. These primed seeds were cultivated in iron ore tailings or in a reference red oxisoil. The molecules used for the priming technique promoted distinct responses during seedlings’ establishment. Seedlings from NO-primed seeds exhibited higher Fe and Mn absorption in the tailing, with increased activities of the antioxidant system. The priming with H2O2 led to an avoidance strategy, with lower absorption of these elements by the seedlings. It can be concluded that NO and H2O2 induced different resistance mechanisms to Fe and Mn in H. heptaphyllus seedlings.