Different substances from the natural origin which have beneficial effects on plant growth and development, stress resistance, and crop yield and quality can be called biostimulants or ...biostimulators. Their physiological effects depend on their composition as they contain various organic and mineral compounds which plants can use as metabolites, growth regulators, and nutrients; however, biostimulants cannot be considered biofertilizers. Biostimulants applied in plant production have been widely considered as an environment‐friendly agricultural practice—and so are now among tools used in sustainable agriculture. Here, we discuss the results of the biostimulants’ effect investigations performed in Croatia, focused on horticultural crops, with edible plant species, such as tomato, garlic, bell pepper, lettuce, strawberry, garden cress, and basil, as well as ornamentals, such as wild rose, wax begonia, Mexican and French marigold, moss rose, everlasting flower, common zinnia, English primrose, and scarlet sage. The investigated biostimulants were applied at all plant growth stages, from germination to full plant and fruit or flower commercial maturity, using the seed treatment, foliar application, or irrigation. To evaluate biostimulant effectiveness, various morphological, physiological, and quality traits were analyzed. In this wide array of studies, the evaluated biostimulants mostly enhanced seed and transplant vigor, stimulated vegetative growth, improved nutrient acquisition and distribution within the plant, increased antioxidative capacity of plant tissues, contributing to higher stress tolerance, and improved plant yield and fruit/flower quality. In general, the research reviewed here implies possible benefits of biostimulant application in horticultural production, especially in stressful growth conditions, such as the transplant stage, reduced fertilization, or incidence of other abiotic stress. Considering possible interactions among the contained physiologically active compounds, the effects on plants may depend on dose, time of treatment, growth conditions, and plant species. Therefore, further research of biostimulant applications in horticultural production is suggested.
Biostimulant application has been considered as environmental‐friendly tool for lowering chemical inputs in agriculture (fertilizers and pesticides), and at the same time for increasing crop stress resistance, with the achievement of satisfying crop yield and quality. This review paper covers research on biostimulant effects on growth and productivity of sixteen horticultural species, from commonly grown vegetables to some rarely investigated ornamentals. The research reviewed here implied possible benefits of biostimulant application in horticultural production, especially in stressful growth conditions, such as the transplant stage, reduced fertilization, or incidence of other abiotic stress.
Leaf removal (LR) treatments improve the photosynthetic capacity of the remaining leaves and induce flavonoid synthesis as a stress response in the common grapevine (Vitis vinifera L.). However, ...excessive exposure of grape berries to UV‐B radiation as a result of cultural practices in the Mediterranean climate may have negative effects on berry composition. This 2‐year study determined the effects of defoliation on the autochthonous red grape variety ‘Babica’ in a Mediterranean climate (wine‐growing region Dalmatia, Croatia). Six leaves were removed before flowering (FLR) and at the end of véraison (the onset of grape ripening; VerLR) and were compared to the untreated control. Yield parameters, sugar content, grape must pH, total polyphenols (TP), total anthocyanin (TA) content, and individual anthocyanin compounds were measured in grape skin extracts and wines. However, the greater mean daily temperature during the vegetation period and lesser rainfall before harvest in 2018 increased yield per vine, average cluster weights, density, and total acidity, compared to 2017. Both defoliation treatments significantly reduced TP in grape extracts, but these differences were not observed in wine. Compared to the control (NLR), VerLR treatment significantly reduced TA in grape skin extracts and wine. Significantly lesser TP concentrations, in grape skin extracts and wine, as well as TA were noticed during the 2017 season. VerLR treatment reduced the concentration of nine individual anthocyanins compared to the control in grape skin extracts, while this effect was not observed in wine. Season year was a statistically significant source of variability of the individual anthocyanin contents in wine. Under specific environmental conditions LR can decrease polyphenols, especially anthocyanins, and negatively impact grape and wine quality.
This 2‐year study determined the effects of defoliation on the autochthonous red grape variety ‘Babica’ in a Mediterranean climate (wine‐growing region Dalmatia, Croatia). Six leaves were removed before flowering (FLR) and at the end of véraison (the onset of grape ripening; VerLR) and were compared to the untreated control. Yield parameters, sugar content, grape must pH, total polyphenols (TP), total anthocyanin (TA) content, and individual anthocyanin compounds were measured in grape skin extracts and wines.
Climate change poses a serious threat to agricultural production. Water deficit in agricultural soils is one of the consequences of climate change that has a negative impact on crop growth and yield. ...Selenium (Se) is known to be involved in plant defense against biotic and abiotic stress through metabolic, structural, and physiological activity in higher plants. The aim of this study was to investigate the physiological response of Se-biofortified soybean (Glycine max (L.) Merrill) seedlings under osmotic stress. For this research, we used biofortified soybean grain obtained after foliar Se biofortification in 2020. The experiment was conducted in a growth chamber with two cultivars (Lucija and Sonja) grown on filter paper in three replicates. The experiment was carried out with two watering treatments: distilled water (PEG-0) and 2.5% polyethylene glycol 6000 (PEG-2.5) on Se-biofortified seeds (Se) and nonbiofortified seeds (wSe). Contents of lipid peroxidation product (LP), free proline (PRO), total phenolic content (TP), ferric reducing antioxidant power (FRAP), and ascorbic acid (AA) were analyzed in 7-days-old seedlings. Significant differences were detected in the Se content of soybean grains between the two cultivars. A milder reaction to PEG-2.5 was observed in cultivar Lucija in both Se and wSe treatments, which might represent the mitigating effects of Se on osmotic stress in this cultivar. Contrarily, in cultivar Sonja, Se adversely affected all analyzed traits in the PEG-2.5 treatment. Ultimately, Se is a pro-oxidant in Sonja, whereas it represents an anti-oxidant in Lucija. In conclusion, different soybean cultivars show contrasting physiological reactions to both osmotic stress and Se. However, the activation of antioxidant pathways in Sonja can also be interpreted as added value in soybean seedlings as a functional food.
Hydrogen sulfide (H2S) has recently been reported to be a signaling molecule in plants. It has been well established that is has such roles in animals and it has been suggested that it is included ...into the group of gasotransmitters. We have recently shown that hydrogen sulfide causes stomatal opening in the model plant Arabidopsis thaliana. H2S can be supplied to the plant tissues from donors such as sodium hydrosulfide (NaSH) or more recently from slow release H2S donor molecules such as GYY4137. Both give similar effects, that is, they cause stomatal opening. Furthermore both H2S donors reduced the accumulation of nitric oxide (NO) induced by abscisic acid (ABA) treatment of leaf tissues. Here similar work has been repeated in a crop plant, Capsium anuum, and similar data has been obtained, suggesting that such effects of hydrogen sulfide on plants is not confined to model species.
Zbog kvalitete nutritivnoga sastava, pšenična se trava (Triticum aestivum L.) smatra funkcionalnom hranom te postaje sve popularnija kao dodatak svakodnevnoj prehrani ljudi. Cilj istraživanja bio je ...utvrditi utjecaj broja otkosa i sorte na ukupnu antioksidativnu aktivnost (DPPH), sadržaj kloroplastnih pigmenata, vitamina C, fenola i flavonoida. U pokusu su ispitana dva genotipa pšenične trave, Triticum aestivum ssp. aestivum (kultivar Katarina) i Triticum aestivum ssp. sphaerococcum. U obama otkosima utvrđen je značajan utjecaj genotipa na sadržaj flavonoida i antioksidacijsku aktivnost, dok je broj otkosa značajno utjecao na fenole, vitamin C i antioksidacijsku aktivnost. T. sphaerococcum imao je veću koncentraciju flavonoida i značajno nižu antioksidativnu aktivnost u usporedbi s kultivarom Katarina. U prosjeku je za obje sorte u prvome otkosu utvrđen značajno veći sadržaj fenola i veći sadržaj vitamina C, što je bilo popraćeno i većom antioksidativnom aktivnošću. Kod kultivara Katarina značajno veći sadržaj fenola i antioksidativna aktivnost utvrđeni su u prvome otkosu. Kod T. sphaerococcum utvđen je značajan pad sadržaja ispitivanih antioksidanasa u drugome otkosu.
Due to its nutritional value, wheatgrass (Triticum aestivum L.) is considered to be a functional food, becoming increasingly popular as a supplement to the people’s quotidian diet. The study aimed to determine the influence of the number of cuttings and cultivars on the total antioxidant activity (DPPH), the content of chloroplast pigments, vitamin C, phenols, and flavonoids in the wheatgrass juice. Two genotypes of wheatgrass, T. aestivum ssp. aestivum (variety Katarina) and T. aestivum ssp. sphaerococcum, respectively, were cut twice during the experiment. In both cuttings, the genotype significantly differed in the flavonoid level and antioxidant activity, while the number of cuttings influenced the content of phenols, vitamin C, and antioxidant activity in the wheatgrass juice. T. sphaerococcum had a higher concentration of flavonoids and a significantly lower antioxidant activity when compared to the Katarina wheat variety. On an average, the first cut implicated an increased content of phenols and vitamin C concerning both genotypes, followed by a higher antioxidant value. In the Katarina variety, a significantly higher phenol content and antioxidant activity was detected in the first cut. In the T. Sphaerococcum, a decrease in the total content of the examined antioxidants was apparent in the second cut.
•Effects of elevated temperature and light were examined on apple cultivars.•The apples presented different responses under the experimental conditions.•Gala Galaxy had lower photosynthetic ...efficiency of performance index (PIABS).•Gold Rush had less damage to OEC activity and better stability of the PS II system.
In orchards, high temperature and high light stress are the most common abiotic stresses, which negatively affect fruit yield and quality. In this study, the physiological response of apple (Malus × domestica Borkh) cultivars to combination of increased temperature and excess light, which causes disorder of photosynthesis, was investigated. The PSII functionality and regulatory mechanisms in leaves of two apple cultivars in the field, under elevated temperature and excess light at midday, were evaluated. Chlorophyll a (Chl a) fluorescence transient was recorded using Plant efficiency analyzer (PEA), analyzed according to JIP test (analysis of O-J-I-P fluorescence transient) and several parameters were derived to explain the PSII behavior and photosynthetic efficiency. Tested cultivars showed different responses to investigated conditions and PCA analysis identified the cultivar Gold Rush as more tolerant with better thermostability of PSII. The lower efficiency of PSII antenna complexes in the Gala Galaxy cultivar caused higher increase in the heat dissipation value of excess absorbed light per active reaction center (DI0/RC) and a decrease in the captured photon flow rate and energy dissipation (TR0/DI0), which significantly contributes to its lower photosynthetic efficiency of performance index (PIABS) and total photosynthetic performance (PItotal). Cultivar Gold Rush had higher connectivity of light harvesting complexes to its reaction centers, less damage to OEC activity and better stability of the PS II system. The results obtained in this study may be useful in apple breeding programs, particularly for the selection of apple cultivars more tolerant and adjustable to higher temperature and irradiation.
Plants must cope with different environmental stresses during their whole lifetime. Abiotic stresses like drought, salt, mineral nutrition disturbances and temperature stress are commonly ...interconnected through some physiological events in stressed plants, such as the synthesis of protective plant compounds as a response to stress. Many of these, produced within plant primary or secondary metabolism, act as functional compounds not exclusively in plants but in other organisms as well. Concurrently, many of the active compounds in biostimulants which can support plant stress tolerance and productivity in adverse growth conditions are the metabolites or intermediates that may influence the plant's edible parts nutritional quality. Such effects of biostimulants application are not elucidated enough, therefore, we aimed to give an overview of recent advances in the research related to the interplay among abiotic stress, plant response, biostimulants effects and plant‐derived functional food, focusing on plant metabolites as the link which connects the environment with the food chain.
Different abiotic stresses are commonly interconnected through some physiological events in stressed plants, such as the synthesis of primary and secondary compounds as a response to stress. Concurrently, many of the active compounds in biostimulants which can support plant stress tolerance and productivity in adverse growth conditions, are the metabolites or intermediates important for nutritional quality of edible plants. This paper gives an overview of the recent research related to the interplay among abiotic stress, plant response, biostimulants effects, and plant‐derived functional food, focusing on plant metabolites as the link which connects the environment with the food chain.
Hydrogen sulfide (H2S) is involved in many physiological processes and responses to the abiotic types of stress. The aim of the study was to determine the effect of sodium hydrogen sulfide (NaHS) and ...the time of application on the physiological properties of etiolated wheatgrass plants. Two genotypes of wheatgrass were grown under controlled conditions for five days without light and then with a 12-hour photoperiod, watered for three consecutive days with 100, 200, and 500 mM NaHS solutions. The plants were watered in three variants, 7-9, 10-12, and 13-15 days after sowing, respectively. The highest content of phenols, flavonoids, and hydrogen peroxide was found in wheatgrass plants watered with 100 mM of NaHS solution. The highest proline content and lipid peroxidation levels were found in the plants at 500 mM of NaHS solution. Also, the significant influence of the watering period on the examined physiological parameters was determined. The results show that H2S significantly affects the de-etiolation process and concentration of physiologically active compounds in wheatgrass plants.
The free proline content in maize ear-leaves, silk and pollen were analyzed in field grown plants which had matured to the pollination stage. Using maize hybrids PR34F02, PR35P12 and PR36B08 field ...trials were set up at two locations in eastern Croatia in two different years. Two enzymes of proline metabolism were analyzed in the same leaf samples and specific activities of synthetase (P5CS) and proline dehydrogenase (PDH). Plant productivity was evaluated at harvest by the estimation of total and fully developed grain number per ear and per plant, the mean single grain mass, and the mass of grain per plant. The year in which the plants were grown had a very significant effect on the free proline content in the leaf and pollen, as well as on the enzyme activities assayed. The differences between the plants from the two localities were very significant in all tested parameters of plant grain productivity. There was a significant genotype effect on proline content and P5CS total activity in leaf and on all the productivity parameters. Some of the correlations established suggest that the rate of proline synthesis and degradation in maize ear-leaf at pollination might contribute to the final grain production of the maize plant. Multiple regression analyses was used to further analyze the relationship between proline and grain productivity, but it is clear that future work should include other environmental conditions, plant species and organs such as roots.
Plants under attack: Surviving the stress Azevedo, Ricardo A.; Teklić, Tihana; Benavides, Maria P.
Annals of applied biology,
March 2021, 2021-03-00, 20210301, Letnik:
178, Številka:
2
Journal Article
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