ABSTRACT Plant biostimulants are commercial products based on different chemical substances used to enhance plant growth and productivity. The effects of biostimulants, Megafol and Viva, with different dominant compositions (amino acids and humic acids) on two tomato cultivars (cv. Gravitet F1 and cv. Minaret F1) exposed to conventional and low-input macronutrient nutrition were investigated. Application of both biostimulants positively affected yield at conventional nutrition. In low-input nutrition variant, biostimulant application prevented yield loss only in cv. Minaret F1. Inter-cultivar differences were noticed in fruit characteristics (total phenol content, total flavonoids content and total antioxidative capacity) where application of biostimulants leads to opposite results in the examined cultivars. We considered the possibility of biostimulant usage as an effective nutritional addition for overcoming the problem of excessive fertilisation.

This study revealed the effects of pyrophyllite ore materials on heavy metals mobility in soil plots located near the steel mill in Zenica (Bosnia and Herzegovina). The experiment was set up in a randomized block design with four pyrophyllite treatment rates i.e. 0, 200, 400 and 600 kg ha in three replications. Analyses of the heavy metals (Cu, Zn, Mn, Ni, Cr, Pb, Cd) in soil and plant samples were performed using atomic absorption spectrophotometry. Pyrophyllite addition in soil was found to reduce the availability of all tested heavy metals in the studied soil. The pyrophyllite addition at a rate of 200 kg ha reduced Mn, Cu and Zn available forms in soil by 11.1, 20.4 and 11.2%, respectively, compared with control. The pyrophyllite addition at higher rates i.e. 400 and 600 kg ha had an even higher impact on the decrease in Mn and Zn mobility in studied soil in comparison with 200 kg ha. Additionally, these pyrophyllite rates have the ability to reduce Ni mobility in studied soil. The study also found a positive effect of all pyrophyllite treatments to reduce heavy metals accumulation in the leaves of potato grown on the studied soil. In sum, the results of this study indicate that pyrophyllite treatment could be an effective technique for improving the environmental quality of soils and alleviating the hazards of heavy metals to plants. However, further studies are necessary to confirm or denied this

Two commercial tomato cultivars were used to determine whether grafting could prevent decrease of Ca2+ concentration under salt stress conditions. The cultivars Buran F1 and Berberana F1 were grafted onto rootstock "Maxifort" and grown under three levels of the elevated soil salinity (S1 EC 3.80 dS m-1, S2 6.95 dS m-1 and S3 9.12 dS m-1). Ca2+ concentration of non-grafted plants of both examined hybrids was lower at all salinity levels in comparison to the control. In the fruits of grafted plants salt stress significantly decreased Ca2+ concentration only at the third salinity level (EC 9.12 dS m-1). The possibility of grafting tomato plants to improve influx of Ca2+ under salt stress conditions is discussed.

Salinity is one of the most important ecological problems that affect irrigated agriculture in the world. Increased soil salinity inhibits plant growth through osmotic and ionic stress, but can also decrease availability of certain micronutrients. Copper is an essential metal for normal plant growth and development that participates in numerous biochemical and physiological processes and it is an essential cofactor for many metalloproteins. Copper concentration in two commercial tomato cultivars (grafted and non-grafted) was investigated under different levels of elevated soil salinity. Soil with EC 9.1 dS m-1 led to the highest copper deficiency, approximately by 37% in the non-grafted and 25% in the grafted tomato plants. The effect of a grafting technique is considered as an environmentally friendly tool for overcoming soil salinity problem.

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.

1 University of Banja Luka, Faculty of Agriculture, Banja Luka, Republic of Srpska, Bosnia and Herzegovina 2 University of Banja Luka, Faculty of Natural Sciences and Mathematics, Banja Luka, Republic of Srpska, Bosnia and Herzegovina 3 University of Sarajevo, Faculty of Agricultural and Food Sciences, Sarajevo, Bosnia and Herzegovina 4 University of Novi Sad, Faculty of Agriculture, Novi Sad, Serbia

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.

The study was carried out in 2015 in the experimental orchard of the Agropodrinje apple introduction centre in the Gorazde area. The impact of different methods of calcium fertilizer application on fruit quality and calcium content in the ‘Idared’ fruit of an 8-year-old apple tree were studied. Fruit mineral composition and quality parameters were estimated after harvest. Calcium fertilizers used in this research were FolifertilCa, calcium-ammonium nitrate (CAN), and calcium oxide (CaO). Folifertil-Ca was applied through leaves, and CaO and CAN were applied through soil. The method of application where CAN was applied in combination with Folifertil-Ca significantly increased the accumulation of Ca in apple leaves and fruits. Also, this method of calcium fertilizer application had the greatest impact on apple fruit firmness increase. In the present study sugar content and acidity of apple fruit did not differ significantly, regardless of the application method of calcium fertilizers. The results of this study support the fact that the Ca uptake by plant roots and its transport to leaves and fruits are directly affected by a plant’s transpiration rate. This fact suggests that in apple cultivation is better if calcium fertilizers applied through soil or in combination with foliage treatment.

The antioxidative protection system as adaptation strategy to high soil salinity in the leaves of two tomato (Lycopersicon esculentum Mill.) hybrids (Buran F1 and Berberana F1) was investigated. Changes in the activity of superoxide-dismutase (SOD, EC 1.15.1.1), peroxidase (POD, EC 1.11.1.7), ascorbate peroxidase (APX, EC 1.11.1.11), as well as total and oxidized ascorbate concentrations (AA and DHA) in the plant leaves subjected to three salinity levels (EC 3.80 dS m−1, 6.95 dS m−1, and 9.12 dS m−1) relative to non-saline control were analyzed during the fruiting phase. The obtained results clearly indicate a relation between SOD activity and AA concentration in the antioxidative protection without any peroxidase-related H2O2 detoxification. Increased SOD activity accompanied by high AA concentration was noticed at all salinity levels, but the response of hybrids was specific for the particular salt concentration. The first salinity level (EC 3.80 dS m−1) induced the highest level of AA in the Buran F1 (70%), while in Berberana F1 hybrid leaves the highest AA concentration (64%) was noticed at the third salinity level (9.12 dS m−1). All salinity levels caused a decline in POD and APX activities in both hybrids. The possibility of a predominant role of ascorbate and SOD in the antioxidative protection of mature tomato leaves under long-term salt stress is discussed.

Tomato ( Lycopersicon esculentum , Mill) is vegetable which is relatively resistant to salt concentration in growing substrate. However, research has shown that salinity stress causes changes in the quality of the fruit, which indirectly affects the yield. So the aim of this research was to determine the change in color of ripening fruits, the amount of sugar and acid in the fruit as indicators of the quality of the fruit. Tests were conducted in a greenhouse on tomato cv. Buran F1, where were two varieties of seedlings, grafted and non grafted, grown in the control substrate (EC = 1.7 dS/m) and substrate with EC = 6.8 dS/m. The quality of fruit is observed by a difference in the maturing of the first fruit of the first and second branches of tomatoes, and through the concentration of sugar and acid in the fruit, depending on the position of the plants. The obtained results show that salinity induces higher sugar content and total acidity in grafted and non-grafted tomato fruits. Also salinity leads to faster ripening of grafted and non-grafted tomato.

ABSTRACT Plant biostimulants are substances which have the capacity to modify physiological processes in plants in a way that provides potential benefits to growth, development or stress response. Effects of biostimulant application on two tomato hybrids (Ombeline F1 and Bostina F1) submitted to reduced nitrogen, phosphorus and potassium (NPK) nutrition aiming at prevention of oxidative stress generation as well as yield and fruit quality loss were investigated in this study. According to obtained results, foliar applied Viva® biostimulant decreased superoxide dismutase (SOD, EC 1.15.1.1) and peroxidase (POD, EC 1.11.1.7) activity in tomato leaves even when recommended NPK nutrition was reduced at 40%. Fruit quality parameters (total soluble solids, total acidity, ascorbic acid and lycopene content) and yield were also maintained in reduced macronutrient fertilization when biostimulant was added. Combination of biostimulant with reduced NPK fertilizer enabled stability of cell homeostasis in tomato plants and their better adaptation to stress conditions. The possibility of biostimulant being used as environmental friendly tool in the reduction of mineral fertilizers without negative consequences regarding yield and fruit quality was discussed.