Is auxin involved in the induction of genetic instability in barley homeotic double mutants?

The Butterfly Effect: Mild Soil Pollution with Heavy Metals Elicits Major Biological Consequences in Cobalt-Sensitized Broad Bean Model Plants

Among the heavy metals (HMs), only cobalt induces a polymorphic response in Vicia faba plants, manifesting as chlorophyll morphoses and a ‘break-through’ effect resulting in the elevated accumulation of other HMs, which makes Co-pretreated broad bean plants an attractive model for investigating soil pollution by HMs. In this study, Co-sensitized V. faba plants were used to evaluate the long-term effect of residual industrial pollution by examining biochemical (H₂O₂, ascorbic acid, malondialdehyde, free proline, flavonoid, polyphenols, chlorophylls, carotenoids, superoxide dismutase) and molecular (conserved DNA-derived polymorphism and transcript-derived polymorphic fragments) markers after long-term exposure. HM-polluted soil induced a significantly higher frequency of chlorophyll morphoses and lower levels of nonenzymatic antioxidants in Co-pretreated V. faba plants. Both molecular markers effectively differentiated plants from polluted and control soils into distinct clusters, showing that HMs in mildly polluted soil are capable of inducing changes in DNA coding regions. These findings illustrate that strong background abiotic stressors (pretreatment with Co) can aid investigations of mild stressors (slight levels of soil pollution) by complementing each other in antioxidant content reduction and induction of DNA changes.

Response of Tradescantia plants to oxidative stress induced by heavy metal pollution of soils from industrial areas

Numerous investigations have demonstrated that even soil in which concentrations of individual elements do not exceed permissible limits can cause harmful effects in living organisms. In the present study, polluted-soil-induced oxidative stress was evaluated using Tradescantia clone 4430, which is widely used for genotoxicity evaluations, employing biochemical (superoxide dismutase (SOD), contents of ascorbic acid (AA), carotenoids (Car), hydrogen peroxide (H₂O₂), chlorophyll (Chl) a/b ratio), and molecular (RAPD and differential display (DD-PCR)) markers after long-term exposure. The activity (staining intensity) of SOD isoforms in Tradescantia leaves was higher in plants grown in all heavy-metal-polluted test soils compared to the control. No direct link between the soil pollution category and the contents of AA, Car, Chl a/b in Tradescantia leaves was revealed, but the concentration of H₂O₂ was shown to be a sensitive biochemical indicator that may appropriately reflect the soil contamination level. Both short-term (treatment of cuttings with H₂O extracts of soil) and long-term (0.5 and 1.0 year) exposure increased MN frequencies, but the coincidence of the MN induction and the soil pollution level was observed only in some cases of long-term exposure. Soil (geno)toxin-induced polymorphism in the RAPD profile was determined with two primers in plants after long-term exposure to soils of an extremely hazard category. Transcript profiling of plants after long-term cultivation in test soils using DD-PCR showed that the majority of differentially expressed transcript-derived fragments (TDFs) were homologous to genes directly or indirectly participating in photosynthesis, the abiotic stress response, and signal transduction cascades.