Anna Tukiendorf

Morphological, physiological, and genetic variation between metallicolous and nonmetallicolous populations of Dianthus carthusianorum

Waste deposits produced by metal mining and smelting activities provide extremely difficult habitats for plant colonization and growth. Therefore, plants spontaneously colonizing such areas represent a very interesting system for studying evolution of plant adaptation and population differentiation between contaminated and noncontaminated environments. In this study, two populations of Dianthus carthusianorum, one originating from Zn-Pb waste deposit (a metallicolous population, M) and the other from unpolluted soil (a nonmetallicolous population, NM), were analyzed in respect of their morphological and physiological traits as well as genetic markers. It was found that the plants inhabiting the waste heap differed significantly from the NM plants in terms of leaf size and shape, and these differences were persistent between the first generation of the plants of both populations cultivated under uniform, controlled laboratory conditions. In contrast with the evident morphological differences, no significant differentiation between the populations regarding the physiological traits measured (accumulation of proline, anthocyanins, chlorophyll, carotenoids) was found. These traits can be regarded as neither population specific nor stress markers. The genetic variability was analyzed using 17 random amplified polymorphic DNA (RAPD) and four inter simple sequence repeat (ISSR) markers; this proved that the differentiation between the M and NM populations exists also at the genetic level. Analysis of molecular variance (AMOVA) showed that 24% of the total genetic diversity resided among populations, while 76% - within the populations. However, no significant differences in intrapopulation genetic diversity (Hj) between the M and NM populations of D. carthusianorum was found, which contradicts the theory that acquisition of adaptation mechanisms to adverse, isolated growth habitats is related to reduction in genetic diversity. Distinct genetic differences between the two populations in combination with evident morphological variation support the proposal to regard the M population of D. carthusianorum as a separate calamine ecotype.

Accumulation and tolerance of lead in two contrasting ecotypes of Dianthus carthusianorum.

Dianthus carthusianorum is one of the dominant plant species colonising the Zn-Pb waste deposits in Bolesław, Southern Poland. It differs in terms of morphology and genetics from ecotypes inhabiting non-metal-polluted areas. The response of waste-heap (metallicolous, M) and reference (nonmetallicolous, NM) ecotypes of D. carthusianorum to Pb in hydroponics was investigated and compared in this study. The plants of the M ecotype were more tolerant to Pb than these of the NM ecotype in spite of accumulation of higher concentrations of Pb. In both ecotypes, about 70-78% of Pb was retained in roots. In non Pb-treated plants, a higher glutathione (GSH) level was found in the M ecotype. After the Pb exposure, the GSH level decreased and was similar in both ecotypes. Lead treatment induced synthesis of phytochelatins (PCs) only in the plant roots, with significantly higher concentrations thereof detected in the NM ecotype. Malate and citrate concentrations were higher in the M ecotype; however, they did not change significantly upon any Pb treatment in either ecotype. The results indicated that neither PCs nor organic acids were responsible for the enhanced Pb tolerance of the waste-heap plants.

The effect of silicon on maize growth under cadmium stress

The effects of silicon (Si) supply (0, 0.1, 0.5, 1.5, 3.0, and 5.0 mM Si) on maize seedling growth, Si and Cd accumulation, and thiol peptide synthesis under Cd stress conditions were studied. The addition of Si to the growth medium resulted in the significantly higher Si accumulation in plant tissues. The average values of growth parameters (root and shoot fresh weights and root net elongation rates) showed a beneficial role of Si on growth of non-Cd-treated plants, while there was no evidence that silicon mitigated Cd toxicity in maize seedlings. Cadmium exposure depressed plant growth and induced phytochelatin (PC) synthesis. The accumulation of Cd and PCs in roots significantly decreased with increasing Si concentrations in the nutrient solution; however, their accumulation in shoots was not changed in the presence of Si.

The influence of heavy metal stress on the level of some flavonols in the primary leaves of Phaseolus coccineus

Qualitative and quantitative analysis of flavonols was carried out in young and older primary leaves of runner bean plants (Phaseolus coccineus L.) treated with Cd2+ (25 µM) and Cu2+ excess (25 and 300 µM) for 12 days. The presence of quercetin-3-O-D-rhamnoside, kaempferol-3-O-D-rhamnoside, quercetin-3-O-D-glucuronide and kaempferol-3-O-D-glucuronide was found in the plant. Quercetin-3-O-D-rhamnoside predominated in the control and heavy metal-stressed plants. The content of individual flavonols increased under heavy metal treatment, particularly in young plants. The flavonol level depended on the metal and its concentration. A protective role of flavonols in plants under heavy metal stress is discussed.

Physiological mechanisms of adaptation of Dianthus carthusianorum L. to growth on a Zn-Pb waste deposit - the case of chronic multi-metal and acute Zn stress

AimsThis study investigates the response of metallicolous (M) and nonmetallicolous (NM) ecotypes of Dianthus carthusianorum L. to chronic multi-metal and acute Zn stress.MethodsPlants were cultivated on the Zn-Pb waste heap substrate and under Zn excess in hydroponics. Growth parameters as well as accumulation of organic acids and thiol peptides were determined as a function of metal accumulation.ResultsWhen grown on the metalliferous substrate, the M plants showed less phytotoxicity symptoms, lower foliar metal (Zn, Pb, Cd) accumulation, higher malate and citrate but lower glutathione content than the NM plants. When exposed to Zn excess in hydroponics, the M ecotype was also more tolerant but accumulated more Zn in comparison with the NM ecotype, accompanied by greater malate and citrate concentrations in the shoots, which were however not affected by increasing Zn doses. No phytochelatins were detected under any experimental conditions.ConclusionsBoth constitutive and adaptive tolerance was found in D. carthusianorum. Under chronic metal stress, enhanced tolerance results from restricted metal uptake to the shoots and probably from detoxification by organic acids; however, under acute Zn stress it is not related to diminished metal uptake or organic acids. Glutathione and phytochelatins are not implicated in adaptive metal tolerance.