Natural priming as an important metabolic event in the life history of Wigandia urens (Hydrophyllaceae) seeds

Abstract

Natural priming promotes fast and synchronic seed germination and enhances the establishment of seedlings from Wigandia urens seeds. In this study, seeds of this species were buried in the field in three different sites, and each site was divided into three different microsites (natural priming). They were then exhumed and air-dried at the beginning of the rainy season. The control and exhumed W. urens seeds were tested for differences in germination, and in the protein patterns derived from heat-stable and phospho-protein enriched fractions, sucrose concentrations, amylase isoenzyme patterns, as well as catalase activity and H 2 O 2 levels. All the exhumed seeds germinated faster and more synchronically than the control seeds. Nevertheless, the germinative pattern showed a microsite effect related to the microenvironmental conditions. Most exhumed samples kept the germinative advantages acquired from the soil during natural priming for 2 years but seeds from the most heterogeneous site (a forest gap) did not. Natural priming also promoted mobilization of 7-S globulin-like proteins, solubilization of the 11-S globulinlike proteins as well as sucrose consumption before radicle protrusion. Although there were no changes in starch concentration during the germination of either the control or buried seeds, a different isoenzyme amylase pattern was observed. Catalase activity decreased and hydrogen peroxide levels were lower in exhumed seeds during germination. The changes in the protein and sucrose patterns were related to advances in the germinative process acquired during burial. Metabolic advantages were maintained systematically in all seed samples along the 2 years. The ecological significance of natural priming is discussed.

Chemo-priming with mannose, mannitol and H2O2mitigate drought stress in wheat

“…Seed priming and salinity induced variations in wheat (Triticum aestivum L.) leaf protein profiles have been reported (Hameed et al 2010). Seed priming induces the mobilization and solublization of globulins and the synthesis of late embryogenesis abundant proteins (Gamboa-de Buen et al 2006). Priming also enhances the activities of antioxidants in treated seeds (Wang et al 2003).…”

Priming effects on seed germination in Tecoma stans (Bignoniaceae) and Cordia megalantha (Boraginaceae), two tropical deciduous tree species

“…Precipitation in these forests changes soil moisture and promotes a natural conditioning process in T. stans seeds buried in soil which improves its germination and reserve mobilization. This positive effect of natural priming on various germination parameters has been reported for seeds of wild species growing in an xerophilous shrubland (Gonz alez- Zertuche et al, 2001;Gamboa-de Buen et al, 2006;Alvarado-L opez, 2009;Benítez-Rodríguez et al, 2014). In seeds of C. megalantha, natural priming had a negative effect on germination.…”

“…The heat-stable fraction mainly contains globulins, seed reserve proteins that are an amino acid source for the early germinations events (Müntz et al, 2001;Gamboa-de Buen et al, 2006). For T. stans seeds, the percentage of free amino acids increased after the priming treatments and after germination whereas no significant changes were observed in C. megalantha primed seeds although a decrease of amino acid percentage was observed during germination (Fig.…”

“…The mobilisation of the proteins of the thermostable extract of both species furnished evidence for the mobilisation of globulins (Gamboa-de Buen et al, 2006). The mobilisation of these reserve proteins promotes the formation of soluble peptides, modifies the protein pattern, and ultimately promotes an increase in free amino acids (Müntz et al, 2001;Rajjou et al, 2012).…”

“…The permanence of seeds buried in the soil seed bank, during the period that precedes the rainy season ("natural priming") promotes the synchronicity of germination of small tree species tolerant to soil water stress in a lava field shrubland in M exico (Gonz alez-Zertuche et al, 2001;Benítez-Rodríguez et al, 2014). As a result of this "natural priming", seeds of these species showed mobilisation of reserve proteins indicating a biochemical response to this treatment (Gamboa-de Buen et al, 2006;Alvarado-L opez, 2009).…”