Heavy metal stress induced alterations in the activities of several representatives of the enzymatic antioxidant defense system such as guiacol peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX) were comparatively studied in barley seedlings treated by Zn and Cd. Although roots were the main sites of metal accumulation, the oxidative damage was detrimental mainly in the leaves. Our experiments clearly show that the investigated heavy metals have quite different effects on plant metabolism and induce the protective enzymatic system in different ways. It is inevitable that we should cope with the environmental damages induced by increased concentration of heavy metals. One of the common characteristics of these events is the oxidative stress generating active oxygen species (AOS) (Salin 1987). Plants have evolved various protective mechanisms to eliminate or reduce AOS species. One of them is the enzymatic antioxidant system, including SOD, POD, CAT and APX. Each of these enzymes has physiological function under non-stressed conditions, but their activity/or quantity is increased under oxidative stress. The comparison of the the antioxidative enzymatic system in seedlings exposed to two essentially different heavy metals, namely Zn and Cd should reveal essential elements of this defense system. While Zn is an essential microelement that is indispensable for normal plant growth at low concentration and is toxic only at high concentration, Cd has no vital function in plants developing under “natural” conditions.
This study was conducted to select the most appropriate RNA isolation method that can be used successfully in case of stone fruits. The changing pattern of gene expression during the ripening process of stone fruits may elucidate the molecular background of several phenotypical or phytochemical alterations present among different genotypes. Our laboratory aims to study the expression of genes encoding for enzymes that catalyze crucial steps in the flavonoid biosynthesis pathway. RNA isolation from fruit mesocarp is a challanging task due to high levels of sugars and polyphenolics accumulating during fruit development. Therefore, at first, the optimal techniques eligible for RNA isolation from fruit tissues at different ripening stages must be selected. Our study compares three different RNA isolation protocols and describes their potential applicability according to different fruit species and ripening stages.
The effects of zirconium ascorbate (Zr-ASC) were examined on wheat seedlings (Triticum aestivum L. cv. 'MV. 20'). Plants grown hydroponically for nine days were exposed to solutions having various concentrations of Zr-ASC. The investigated plants were able to take up the Zr-ASC complex, accumulation and translocation of the metal has also been observed. Translocation mechanisms seem to be working efficiently to a certain concentration limit where from the translocation between root and shoot is limited. An interesting phenomenon was noticed in the case of boron, namely that the concentration change tendencies of boron and Zr were similar. A significant change was observed in the case of amino acid content, the total amino acid content increase was pronounced both in roots and shoots.
The alfalfa ferritin overproducing CaMVF9 transgenic tobacco and the alfalfa aldose reductase overexpressing ALR1/9 line showed higher Fv/Fm ratios than SR1 plants during ROS generating low temperature stress. The chlorophyll content of CaMVF9 and ALR1/9 lines proved to be much more favourable than that of SR1 plants whereas there was no difference in the electrolyte leakage. Activities of all the tested antioxidant enzymes (POD, CAT, APX, GR, GST) in the leaves were significantly higher in CaMVF9 and ALR1/9 lines, the malondialdehyde content was significantly lowered in the transgenic lines. The antioxidant enzyme systems induced through several redox-signalling mechanisms have simultaneously contributed to the greater tolerance of CaMVF9 and ALR1/9 lines. Acta Biol Szeged 46(3-4):97-98 (2002)
• In China, its centre of origin, apricot (Prunus armeniaca) is self-incompatible. However, most European cultivars are self-compatible. In most cases, self-compatibility is a result of a loss-of-function mutation within the pollen gene (SFB) in the SC haplotype. Controlled pollinations performed in this work revealed that the cross 'Ceglédi óriás' (S8S9) × 'Ceglédi arany' (SCS9) set well, as expected, but the reciprocal cross did not. • Apricot S8, S9 and SC haplotypes were analysed using a multilevel approach including fruit set evaluation, pollen tube growth analysis, RNase activity assays, polymerase chain reaction (PCR) analysis and DNA sequencing of the S-RNase and SFB alleles. • SFB 8 was revealed to be the first known progenitor allele of a naturally occurring self-compatibility allele in Prunus, and consequently SC = . The first intron of SC-RNase is a phase one intron, indicating its more recent evolutionary origin compared with the second intron. Sequence analysis of different cultivars revealed that more single nucleotide polymorphisms accumulated in SC-RNase than in SFBC. New methods were designed to allow high-throughput analysis of S genotypes of apricot cultivars and selections. • S-RNase sequence data from various sources helped to elucidate the putative origin and dissemination of self-compatibility in apricot conferred by the SC haplotype.
With 3 figures and 2 tables Abstract Consensus polymerase chain reaction (PCR) primers amplifying the first and second intron regions of the S‐RNase gene and DNA sequencing as well as fruit set analysis after controlled pollinations were used for S ‐genotyping of Eastern European almond cultivars. Complete S ‐genotypes have been proposed for 19 accessions, and partial S ‐genotypes have been proposed for three additional accessions. Based on DNA sequences and fruit set analysis, two novel cross‐incompatibility groups have been proposed: group XXI ( S 11 S 31H ) including ‘Szigetcsépi 55’ (3/9) and ‘Eriane’ and group XXII ( S 36 S 37 ) for ‘Nikitskyi’ and ‘Óriás kagyló’ (4/4). Four new alleles were identified, S 36 ( FJ529211 ), S 37 ( FJ529212 ), S 38 ( FJ529213 ) and S 39 ( FJ529214 ). The combination of consensus PCR primers amplifying the first and second intron regions could reliably discriminate the S‐RNase alleles identified in this study from those described previously. Our results supply long‐awaited information on almond S ‐allele diversity from regions between the main cultivation centres and the centre of origin of this species.
