RESUMO
Plants, grown in the immobile soils, have evolved various strategies in response to environmental stresses, including the "stress memory" and "defense priming" mechanisms. The environmental stresses cannot immediately change the DNA base sequence in plants in the short-term. Therefore, epigenetic inheritance is a key mechanism for stress memory and defense priming. In particular, histone modification is considered to be the most important mechanism, which offers the possibility of stress memory. We summarized research advances in plant histone modifications involved in stress memory and defense priming under biotic and abiotic stresses, and proposed pro-blems in the field and the focus and directions in the future research. In-depth understanding of the relationship between histone modification and environmental stresses would facilitate the quick adaptation of plants to harsh environments, and provide theoretical and technical guidance for plant phenotype shaping, organ regeneration, and crop genetic improvement.
Assuntos
Regulação da Expressão Gênica de Plantas , Código das Histonas , Epigênese Genética , Histonas/genética , Plantas/genética , Estresse FisiológicoRESUMO
Bauxite residue disposal areas (BRDA) appear to result in the heavy metal pollution of the farm fields surrounding them. In total, 194 topsoil samples were collected from the fields surrounding a BRDA in Guangxi in order to comprehensively understand the pollutant characteristics. These characteristics and their ecological risks were assessed by the Nemerow and Harkanson indices, whilst the sources and correlations of eight heavy metals (V, Cr, Ni, Cu, Zn, As, Pb, and Co) were analyzed by means of the spatial interpolation method, correlation analysis, and principal component analysis (PCA). The results demonstrated that the surrounding fields were seriously polluted by heavy metals. Ninety-two percent of samples were polluted, including 36% that showed serious pollution, and As was the dominant contaminant. The ecological risk results showed that the risks of the surrounding fields were medium, and As was responsible for 68% of this. Spatial interpolation suggested that concentrations of heavy metals in the northeastward and southwestward areas were higher, however the southeastward areas were lower. Multivariate statistics indicated that the possible source of As contaminant was different to those of V, Ni, Zn, Pb, and Co; As was primarily influenced by anthropogenic contamination, including atmospheric sedimentation, and agricultural fertilization. Cr was affected by both soil parent material and atmospheric sedimentation, whereas V, Ni, Zn, Pb, And Co levels were mainly affected by soil parent material.