Plants are sessile organisms that are under the constant influence of the environmental conditions in which they grow. Any change in "inanimate" factors that have a significant impact on plant growth and development is collectively referred to as "abiotic stress". Extreme temperatures, especially in changed climatic conditions, are one of the most harmful abiotic factors, which cause heat stress in plants. The effects of high temperatures can be manifested through various morphological, physiological and genetic changes in the plant organism. Generally speaking, plants can be divided into three groups according to temperature requirements: psychrophilic plants, mesophilic plants and thermophilic plants. Most woody species belong to the group of mesophilic plants, which require temperatures between 10 and 30 °C for successful growth and development. As the temperature changes on a daily and seasonal basis in relation to the optimal range, certain changes occur in the plant organism that are necessary to maintain cell growth and homeostasis. Regardless of their ability to adapt to temperature oscillations, plants that have been exposed to temperatures above the optimal level for a long time can show symptoms of irreversible damage, which manifest as heat stress. Generally speaking, this type of stress is considered to occur when the temperature is 10- 15 °C higher than usual at some time of the year, and lasts long enough to cause irreversible damage or disturbances in plant growth and development. As the intensity, duration and degree of temperature change change, so do the various effects of heat stress on plants. In order to survive, plants must adapt to changes in environmental conditions through a specific response that depends on the physiology and morphology of a species. According to their level of tolerance to high temperatures, plants can be divided into three categories: heat-sensitive, relatively heat-sensitive, and heattolerant. The shape and strength of tolerance to high temperatures mostly depend on the plant species, tissue type and cells that are exposed to negative influences. The increase in ambient temperature can also jeopardize the productivity of agricultural crops and forest trees, which has been visible in recent decades in light of climate change and projections regarding the security of supply of the growing population on Earth. Injuries resulting from high temperatures during a fire can initiate a cascade of complex mechanisms that affect the physiology of trees after a fire. The discovery of exact physiological mechanisms and corresponding specific injuries that occur on individual trees, as well as in forest ecosystems, are the focus of intensive modern research. Recent studies have made critical strides in understanding the physiological processes in trees that manifest after fire injuries, and these injuries can affect the tree in combination with some other stressful conditions, such as drought and insect and pathogen attacks. The paper presents a conceptual framework that combines all these processes, their mutual interactions and possible responses, and puts these plant responses in the context of existing hypotheses about the impacts of specific disturbances on plants and ecosystems. By focusing on carbon and water as the main factors in the functioning of the plant organism, this paper presents cambium/phloem necrosis and xylem damage as the main effects of fire injuries. The resulting lack of carbon and hydraulic dysfunction of plants are associated with drought and insect attack. Assessing the precise relationships of the processes presented will be crucial to fully understanding how fires can affect tree functionality and will help improve fire risk assessment and predict tree mortality models. Knowledge of the physiological responses of trees is important for a better assessment of ecosystem dynamics after a fire and their interaction with climate disturbances, and especially taking into account the predicted increase in the frequency and intensity of fires.

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.

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.

This study was carried out to examine the impact of liquid organic fertilizer Ergonfill (LFE) on the yield and quality of cherry tomato (Lycopersicon esculentum Mill. Sakura F1) under different growth conditions. The experiment was set up in a randomized blocks design with four variants in three replications. Experiment variants were as follows: drought-stressed seedlings with and without LFE treatment, and non-stressed seedlings with and without LFE treatment. Exposure of cherry tomato seedlings to controlled water stress conditions significantly increased fruit quality parameters (total soluble solids, titratable acidity, ascorbic acid, lycopene, total phenolic and flavonoids, total antioxidant capacity), but decreased yield. LFE treatment significantly increased by the all examined parameters under normal growth conditions as compared to untreated plants, and for total phenolic and flavonoids content, total antioxidant capacity and total soluble solids this increase was statistically significant. Positive impact of the LFE application on cherry tomato quality is result of fertilizer composition, as well as ability of cherry tomato plants to use bioactive substances in fertilizer for its growth and development.

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.

Rast korjenovog sistema deset vegetativnih podloga jabuke (5 klonova podloge M9: T337; Burgmer 984; Fleuron 56; Pajam®1 Lancep i Pajam®2 Cepiland; Jork 9, Mark (MAC 9), M26, Supporter 4 i MM106) analiziran je u toku 2013. godine u dva modifikovana zemljisna supstrata u kontrolisanom kontejnerskom gajenju. Analiziran je broj, ukupna i prosjecna dužina korjenova I poretka kao i ukupan i prosjecan broj korjenova II poretka grananja. Rezultati analiza pokazuju da je kod svih ispitivanih podloga ukupna dužina korjena veca u supstratu 2 (kombinacija bastenske zemlje, treseta i pijeska) u odnosu na supstrat 1 (oranicni sloj pseudoglejnog zemljista), osim kod podloga Jork i M9 B984. Broj korjenova II poretka grananja kod svih podloga bio je veci u supstratu 2, osim podloga Jork i Pajam 2. Dobijeni rezultati analize rasta korjena vegetativnih podloga jabuke su prva istraživanja rasta ovih podloga u BiH.