The aim of this study was to assess the ability of oyster mushrooms (Pleurotus ostreatus (Jacq.) P. Kumm.) to absorb heavy metals (Fe, Zn, Cu, Co, Mn, Ni, Cr, Cd, and Pb) from different plant-based substrates and to determine the bioaccumulation factor of the aforementioned heavy metals from the substrate to the oyster mushroom basidiomes. The substrate used in this study were: maize straw, beech sawdust supplemented with wheat bran at a rate of 20%, a mixture of maize straw and spent coffee grounds in a ratio of 70:30, and a mixture of maize straw and spent coffee grounds in a ratio of 50:50. Heavy metal contents in substrate and mushroom samples were analyzed by atomic absorption spectroscopy using the Shimadzu AA-7000 device, while the bioaccumulation factors of oyster mushroom for each investigated heavy metal were calculated from the heavy metal content in mushrooms divided by that found in substrates. The study showed that oyster mushrooms have a high capacity to absorb Zn and Cd from the growing medium and bioaccumulation factor values for Zn and Cd determined in this study strongly support this observation. On the other hand, bioaccumulation factor values for Ni, Fe, and Mn were less than 0.3 and ranged from 0.04 to 0.05, from 0.09 to 0.12, and from 0.10 to 0.25, respectively. In general, the results of this study lead to the conclusion that substrate chemical composition strongly affects the heavy metal accumulation in oyster mushroom basidiomes. The results of this study also showed that oyster mushrooms can be considered a promising species for Cd and Zn bioremediation.

The objective of this study was to evaluate the impact of cultivar and covering with nonwoven agrotextile on vegetative growth parameters and the productivity value of sweet potato (Ipomoea batatas L.). A field experiment was conducted during the 2018 growing season, at the experimental field of the Biotechnical Faculty in Ljubljana (46° 04′ N latitude; 14° 31′ E longitude, 305 m above sea level). The soil was gravel clay with a pH of 6.7, and a soil depth of 40–60 cm. The research involved the following Slovenian cultivars of sweet potatoes: Lučka, Janja, and Martina. Distance between rows was 1.2 m, while in-row distance was 1.4 m. The experiment was conducted in a randomized complete block design with plots arranged factorially and replicated four times. The seedlings were planted on 20 May. A half of the plots were covered with polypropylene nonwoven textile (17 g/m2). The uncovered half of the plots served as control plots. The recommended cultural practices were performed as needed during the experiment. The temperature under the covers was on average 5.5 °C higher than in the unprotected area. The crops were harvested 132 days after planting. Covering significantly and positively affected vegetative growth – that is the height of the vines, leaf number, leaf area index, and haulm dry weight. In contrast, the nonwoven polypropylene cover had no significant effect on the number of branches per crop. The use of agrotextile significantly increased tuber length and diameter, tuber number, tuber weight, and total yield in comparison with traditional cultivation with no plant cover. Statistical analysis showed that cv. Janja had the significantly higher yield (7.49 t/ha) compared to cv. Lučka (6.68 t/ha) and cv. Martina (6.16 t/ha).

With a significant economic value, pepper (Capsicum annuum L., Solanaceae) represents a major vegetable crop worldwide. Simple sequence repeats (SSR) markers and expressed sequence tags (EST-SSR) are powerful tools for genetic studies and the breeding of pepper. In this study, the genetic variability among local pepper species was assessed by using 8 EST/SSR markers. The pepper varieties were collected locally, based on old sorts, hybrids, and sorts found in markets, with a total of 14 pepper varieties.  Mean expected heterozygosity (He) ranged from s 0.30 to 0.83 in the populations studied, whereas the mean polymorphic information content (PIC) was 0.62. The average polymorphic number of alleles per primer was 2.5 per locus. The genetic relationships among the populations revealed by Neighbor-Joining dendrogram showed a clear clustering to three sub-populations making distinct clusters.  As expected, all local varieties make up one cluster, together with the hybrid Istra, concluding that this hybrid evolved from the cross-breeding of local varieties.  These results indicate and confirm the regional and physiological differences between the pepper sorts.

Fifteen Brassica oleracea L. var. acephala DC accessions were collected and evaluated for their genetic diversity and molecular characteristics using 10 previously developed and used codominant SSR markers. The SSR loci used revealed a total of 51 alleles. The domestic kale varieties were collected locally and the hybrids kales were found in markets. The averages of total heterozygosity (H) and polymorphic information content (PIC) was 0.6774 and 0.6201, respectively. The average number of alleles was 4.2 per locus, where 8 of 10 markers showed high polymorphic information content (PIC), being more than 0.5. The genetic relationships among the populations revealed by Unweighted Pair Group Method with Arithmetic mean (UPGMA), showed a clear clustering into three distinct groups. As expected, all local varieties were separated within two separated clusters, whereas only two domestic varieties shared one cluster with the group of hybrids, indicating similar genetic background shared by domestic and hybrid varieties. These results indicate and confirm the regional and physiological differences between the kale varieties and confirm the SSR marker efficiency for genetic characterization assays.

The aim of this study was to examine the concentration of total and available forms of heavy metals (Ni, Cr, Cu, Zn, Pb and Mn) in the greenhouse soils as well as the distribution of these metals in the different parts of tomato plants grown on these soils. Atomic Absorption Spectroscopy (AAS) was used to determine heavy metals concentration. The concentration of available forms of all examined heavy metals in the soils and in tomato fruits were low, although the total concentration of hazardous heavy metals Ni and Cr in soils exceeded the maximum permissible values, prescribed by legislative rules in Bosnia and Herzegovina. The reasons for the low uptake of heavy metals by tomato plants are mainly related to the chemical properties of soil which are not favorable for heavy metal availability. In addition, the results of this study also showed that the accumulation of all examined heavy metals especially Cr and Ni were much higher in the roots than in the fruits. The low accumulation of heavy metals in tomato fruits is the result of synergy of different plant defense mechanisms that limiting or reducing heavy metal transport from root to fruits.

An experiment was carried out to determine the effect of foliar application of seaweed extract (0.2 %) on the growth, yield and quality of cherry tomato under stress and non-stress conditions. The greenhouse experiment was set up in a randomized block design with four treatments in three replications. Treatments were as follows: V1 - seedlings treated by seaweed extract and subjected to drought; V2 - seedlings treated by seaweed extract and regularly watered; V3 - non-treated seedlings subjected to drought; V4 - non-treated seedlings regularly watered. Cherry tomato seedlings treated by seaweed extract had a lower content of proline and higher leaf water potential compared to non-treated seedlings under stress conditions, indicating that application of this fertilizer contributes to better adaptation of cherry tomato seedlings to stress. Treatment with seaweed extract also positively influenced the yield and quality of cherry tomato (total soluble solids, vitamin C, lycopene) under both standard and drought stress conditions as compared to untreated plants in same conditions. Positive effects of seaweed extract on growth and quality of cherry tomato are result of its specific composition, as well as ability of cherry tomato plants to utilize bioactive substances in seaweed extracts for its growth and development.

Murtic, S., R. Oljaca; M. S. Murtic; I. Koleska; L. Karic and J. Avdic, 2018. Effect of microbiological fertilizer for mitigating water stress in cherry tomato. Bulg. J. Agric. Sci., 24 (1): 106–111 This study was carried out to examine the effect of microbiological fertilizer ‘Slavol’ (MB) on selected physiological parameters for evaluating drought tolerance of seedlings (content of proline, leaf water potential, leaf area, content of photosynthetic pigments, total phenolic and fl avonoids) and subsequently on the yield and fruit quality of cherry tomato (Lycopersicon esculentum Mill. var. cerasiforme). Cherry tomato seedlings treated by MB had a lower content of proline and higher leaf water potential compared to non-treated seedlings under water stress, which indicates that microorganisms present in fertilizers contributes to better adaptation of cherry tomato seedlings to stress. The research results also showed that application of MB contribute to increasing of phenolic compounds and consequently strengthening of cherry tomato antioxidant defense system. Fruit quality parameters (TSS, TA, TPC, TFC, FRAP, content of ascorbic acid and lycopene) were signifi cantly higher in fruits of cherry tomato subjected to drought, regardless of MB treatment, suggesting that exposure of plant to controlled water stress conditions may represent a very promising approach to enhance the nutritional quality of cherry tomato.

Murtic S., Oljaca R., Koleska I., Karic L., Todorovic V. (2018): Response of cherry tomato seedlings to liquid fertiliser application under water stress. Hort. Sci. (Prague), 45: 22–28. The aim of this study was to examine the impact of different liquid fertilisers on selected physiological parameters in order to evaluate the drought tolerance of cherry tomato seedlings. The following physiological parameters were investigated: total phenolic and flavonoid content, total antioxidant capacity and proline content of leaf extracts. Total phenolic and flavonoid content were determined using the Folin-Ciocalteu and aluminium chloride colorimetric methods, respectively. The ferric-reducing/antioxidant power (FRAP assay) was used to measure the total antioxidant capacity, while proline content was evaluated according to the method of Bates. The contents of proline, total phenolics and flavonoids were significantly higher in the leaves of cherry tomato seedlings exposed to water stress, which suggests that the higher synthesis of these substances by plants represents an important defence mechanism of drought tolerance. The results also indicate that the application of all the used fertilisers in accordance with the manufacturer’s instructions can significantly increase the content of phenol compounds and total antioxidant capacity of plants under normal growth conditions, thus improving survival under subsequent stress.