Volume 33 (2021): Issue 1 (June 2021)

Research concerning endophytic fungi has recently received a remarkable boost following a general trend to investigate and exploit biodiversity in all its forms, and because of the easier access to equipment and methods, which enables quicker identification procedures. The available data highlight that, besides the plant hosts, endophytes consistently interact with the other components of biocoenosis, and that the assortment of the microbial consortium is also to be considered on account of the reciprocal influence between the several species which are part of it. Unravelling these complex ecological relationships is fundamental because of possible translational applications, particularly regarding crop management. However, this requires that the available information concerning plant species, ecological contexts or functional categories of endophytes is examined fully. In this aim, a coordinated effort appears to be necessary to organise the current knowledge to increase the significance and the practical impact of new findings.

In 2-year outdoor pots experiment, which was realised in the vegetation cage situated in the campus of Slovak University of Agriculture in Nitra, both the impact of different doses of vermicompost (Vc) (0%, 10%, 20%, 25% and 50%) and the number of earthworms (EW) (0, 10 and 20 individuals/pot) in the soil substrate were studied on the quantitative and qualitative parameters of radish yield. The achieved results show that along with the increasing quantity of Vc, the total chlorophyll content also increased proportionally. The content of vitamin C declined and the content of nitrates increased in both the aboveground and underground biomass. The weight of the roots and leaves of radish increased until the content of Vc in the substrate did not exceed 20%. Vermicompost abundance >20% led to the decline of root and leaf biomass formation. The root yield and leaf biomass were higher in the presence of 50% Vc content in the substrate, compared with the control. The EW had mostly a negative impact on radish phytomass formation, particularly both weight and root diameter. The highest percentage of roots weight decline cultivated in the treatment with EW were obtained with the least dose of Vc (10%), thereby the least quantity of fodder for the EW. The impact of EW on the total chlorophyll, vitamin C and nitrates contents in roots and leaves was non-significant. The number of EW did not influence the root diameter and content of vitamin C; however, it affected the root weight.

The aim of the experiment was to assess the effects of supplemental lighting of cucumber grown in greenhouse using lamps with differentiated light spectra: sodium lamps – high-pressure sodium (HPS) and light emitting diodes (LEDs). Plants (cucumber ‘Pacto’ F₁) were grown in two greenhouse compartments with five light treatments: I – HPS + LED (top light with HPS LEDs as interlighting), II – only HPS as top light, III – LED R (LED chips on board (COB) type with an increased level of red band), IV – LED W (LED COB type, white), V – LED B (LED COB type with an increased level of blue spectrum). Light treatments: HPS + LEDs and HPS were grown in one greenhouse compartment and the other three light treatments: LED R (red light supplementation), LED W (without additional supplementation) and LED B (red spectrum supplementation) in the second compartment in analogous climatic conditions. The LED lamps using COB technology are known to be a very efficient source of light. Plants were cultivated from December 2018 to March 2019 in mineral wool slabs Grotop Master (100 × 15 × 10) with four plants on one mat. They were illuminated for 18 h (from 5 am to 11 pm), setting the threshold value (on and off) at 130 W. The plants were drip-irrigated with a complete nutrient solution. The irrigation was controlled based on a weighting system. The assessment of the effect of lighting on early yield and quality of cucumbers was completed after 8 weeks of cropping. It was shown that it was possible to obtain 3.59 kg from one plant during the 8-week period of evaluation by illuminating plants with sodium lamps (HPS), while using HPS and LEDs as additional illuminated inter-rows 3.89 kg. The yield of plants illuminated by LED lamps varied depending on the variant of the spectrum used and was respective for LED R, LED W and LED B, 3.30 kg, 3.90 kg and 3.25 kg. The obtained results indicated that the yield of cucumber ‘Pacto’ F₁ grown with HPS lamps at top lighting and at the same time using interlighting with LED lamps was similar to LED W lamps (i.e. without additional supplementation in the range of red (LED R) and blue (LED B) light). Due to good results of LED lamps (type COB for top lighting or as interlighting) used for the cucumber supplemental lighting and high energy efficiency of LEDs, the promising future for that type of lamps compared with traditionally used HPS during winter cultivation in a greenhouse was demonstrated.

Capsicum chinense Jacq. is classified under the Solanaceae family, which is an extensively consumed spice and vegetable globally. Therefore, to gain more knowledge and insight into the diversity of Capsicum chinense Jacq. metabolites, a total of 18 placental tissues from various development stages were collected and untargeted metabolomics was conducted by means of ultra-performance liquid chromatography (UPLC) and mass spectrometry (MS). Principal component analysis (PCA) analysis established the existence of distinct metabolite distribution patterns as observed at 16 days post anthesis (DPA), compared with the metabolites at 36 and 48 DPA groups, whereas there was a difference in metabolites between the orange ripening period (B) and the red ripening period (C), which intersected with each other. Furthermore, several pathways including metabolic pathways, biosynthesis of phenylpropanoids, ABC transporters, alanine, aspartate and glutamate metabolism, fatty acid biosynthesis, pentose and glucoronate pathways, secondary metabolites biosynthesis, cutin, biosynthesis of suberine and wax were significantly enriched across the fruit ripening stages. The capsaicin content was observed to be less in the early ripening stages, but gradually increased to a high concentration during the late ripening stages. In conclusion, our study findings submit a suitable approach for interpreting the biochemical variances of non-targeted metabolomics in hot pepper developmental stages, as well as offer new findings that can be applied in the development strategies in breeding of Capsicum chinense Jacq.

The increasing interest in healthy and natural foods has raised the attention towards uncommon or unexplored ingredients, such as edible flowers. These products are proven to be a rich source of bioactive compounds, for example, vitamins or polyphenols that play an important role in health promotion and disease prevention. However, plant species with edible flowers are numerous and most of them still need to be studied with this aim. The high species richness of North-Western Italy provides interesting perspectives in the use of wild edible flowers, which are currently underutilized, but can be a valuable food source or food supplement for healthy diets. In this framework, the phytochemical composition of 22 wild edible flowers was analysed and compared with that of four cultivated species (Borago officinalis L., Calendula officinalis L., Tagetes patula L. and Tropaeolum majus L.) to evaluate their potentiality as sources of bioactive compounds. The total polyphenol content (TPC) and antioxidant activity of the fresh flowers were assessed, together with their phenolic profiles and vitamin C content, through spectrophotometric and chromatographic analyses. The evaluated parameters varied widely among species, with Paeonia officinalis L. and Rosa pendulina L. showing the highest values of polyphenols (1,930 mg gallic acid equivalents (GAE) · 100 g⁻¹ and 1,774 mg GAE · 100 g⁻¹, respectively), followed by Rosa canina L. (1,397 mg GAE · 100 g⁻¹) and Geranium sylvaticum L. (1,268 mg GAE · 100 g⁻¹). The same species also showed the highest antioxidant activity, measured with three different assays [ferric reducing antioxidant power (FRAP), 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis-3-ethylbenzthiazoline-6-sulfonic acid (ABTS)]. The phenolic profile differed among the studied species, with Dianthus pavonius Tausch and R. pendulina having the highest sum of detected polyphenols (2,522 mg · 100 g⁻¹ and 2,366 mg · 100 g⁻¹, respectively). Vitamin C was identified in all but two flowers (Allium ursinum L. and B. officinalis) and Primula veris L. had the highest amount (45 mg · 100 g⁻¹). The study showed that wild edible flowers outperformed the cultivated species, except for T. majus, providing new insights for the use of wild edible flowers as sources of bioactive compounds.

The common fig (Ficus carica L.) is a tree species and is one of the oldest fruit trees cultivated in Turkey. The Western Anatolian region of Turkey produces nearly a quarter of the total dried fig production of the world. This region also harbours a rich fig germplasm. However, so far this germplasm has remained largely uncharacterised. In this study, using 14 simple sequence repeat (SSR) primer pairs, we analysed a total of 310 fig accessions from six different regions of Anatolia. In structure analyses, Western Anatolian accessions formed a group, which was correlated with their geographical distribution. In addition, 7 identical, 36 synonymous, and 22 homonymous fig accessions were identified. In multilocus lineages (MLLs) analysis a total of 54 accessions were matched to different accessions as clone assignment. The results will facilitate future germplasm management and breeding efforts in this economically important tree species by identifying genetic diversity, genetic relations and characterising the structure of studied populations and accessions.

Celosia argentea var. cristata is an edible plant mainly cultivated as an ornament for its spectacular flowering and is highly appreciated by horticulturists for its originality, unique appearance of flower and better vase life. Utilisation of plant growth regulator [salicylic acid (SA)] and mineral nutrition [zinc (Zn)] is a sustainable approach to ameliorate crop health and yield. A field experiment was performed on a randomised complete block design with 12 treatments in 36 blocks to investigate the effectiveness of the combined application of SA (50 ppm and 100 ppm) and Zn (ZnSO₄: 0.5 ppm, 1.5 ppm and 2.5 ppm) as well as when each one is applied separately on vegetative, reproductive, physiochemical attributes in C. argentea var. cristata. Results analysed through Tukey's honestly significant difference (HSD) test, biplot and heat map indicated a significantly greater improvement up to 2.5 folds in the growth attributes when plants received foliar application of 100 ppm of SA combined with 2.5 ppm of Zn as compared to control group. All treatments modified the physiobiochemical responses of plants by lowering catalase (CAT) activity significantly, and enhancing photosynthetic pigments, total protein content and peroxidase (POX) and polyphenol oxidase (PPO) activities as compared to the control group. It was concluded that foliar application of SA (100 ppm) + Zn (2.5 ppm) at pre-flowering stage could be applied to obtain better growth and flower quality in cockscomb.

This work aimed to investigate the interaction between salt stress and the application of silicon dioxide-nanoparticles. In this study, gerbera plants grown in soilless culture were supplied with nutrient solutions with different NaCl concentrations (0, 5, 10, 20 and 30 mM) in combination with SiO₂-NPs spray (0, 25 and 50 mg · L⁻¹). Exposure of gerbera to salinity increased sodium concentration but decreased potassium and calcium concentrations in leaf as well as stem length/diameter, fresh/dry weight, leaf/flower number, flower diameter and leaf area. It also increased the activities of antioxidant enzymes and electrolyte leakage. Results indicated that SiO₂-NPs could improve growth, biochemical and physiological traits. It increased stem thickness but slightly affected stem length. Flower diameter was not affected by salinity rates up to 10 mM of NaCl. However, a significant difference was observed between controls and plants treated with 30 mM of NaCl. Salinity increased the electrolyte leakage (32.5%), malondialdehyde (83.8%), hydrogen peroxide (113.5%), and the antioxidant enzyme activities such as ascorbate peroxidase (3.4-fold) and guaiacol peroxidase (6-fold) where SiO₂-NPs activated them more, except for superoxide dismutase. Under salinity (30 mM), the increase in SiO₂-NPs (especially at 25 mg · L⁻¹) led to the increase in the uptake of Ca²⁺ (25.3%) as well as K⁺ (27.1%) and decreased absorption of Na⁺ (6.3%). SiO₂-NPs has potential in improving salinity tolerance in gerbera. It seems that the sensitivity threshold of gerbera to the salinity was 10 mM and the use of SiO₂-NPs is also effective in non-saline conditions.

The two-spotted spider mite (TSSM) Tetranychus urticae is a polyphagous pest which infests several wild and cultivated species of plants worldwide. To date, this mite is the most deleterious pest attacking the strawberry plant under a protected environment. Exogenously applied salicylic acid (SA) has been found to induce resistance to biotic and abiotic stresses. Morpho-anatomical changes in strawberry leaflets and TSSM preference tests were investigated in response to SA treatment. Plants grown in a greenhouse were foliar sprayed with different concentrations of SA (0 mg · L⁻¹, 25 mg · L⁻¹, 50 mg · L⁻¹, 75 mg · L⁻¹ and 100 mg · L⁻¹). After the third application, certain parameters including the number of glandular and non-glandular trichomes, thickness of leaflet, abaxial cell wall, adaxial cell wall, palisade and lacunous parenchyma and mesophyll were measured using scanning electronic microscopy (SEM). Two-choice and non-choice assays were employed to verify the TSSM preference. Exogenous treatment with SA promoted morpho-anatomical changes in the following parameters, namely: thickness of the leaflets, mesophyll, lacunous and palisade parenchyma, cell wall (abaxial and adaxial) and the number of glandular and non-glandular trichomes in strawberry leaflets. In general, TSSM preferred less leaflets treated with SA compared with the control in a two-choice assay. A lesser number of TSSM eggs and live females were also recorded in leaflets treated with SA compared with the control plants in no-choice assays. The values of the number of eggs and live females correlated negatively with those obtained for the morpho-anatomical traits induced by exogenous SA.

The efficacy of plant growth regulators (PGRs) has been demonstrated in the flowering of economically significant orchid hybrids, but studies of their effects in wild species with commercial potential are scarce. The effect of three doses of gibberellic acid (GA₃) and 6-benzyladenine (BA), individually or in combination, and a control without PGRs, were evaluated during three flowering periods in Laelia anceps subsp. anceps, in the temporal behavior of flowering, morpho-floral quality parameters and in potential residual effects and malformations. Significant effects were observed between the experimental periods and doses used, with a single application of PGRs in the first period reducing the days to visible flower induction (DVFI), days to anthesis (DAN) and days of flower life (DFL), mainly in the first period. There were no significant differences between doses for morpho-floral quality parameters within each period, but differences existed between experimental periods, where the life and size of the flower increased in the first period, and the number of flowers and flower stems increased significantly in the second period. The doses of 2.37 mg · L⁻¹ BA + 100 mg · L⁻¹ GA₃ showed highest significant consistency in the reduction of DVFI, DAN and increase of DFL and flower stems in the study. There were no floral malformations, and a positive residual effect was observed in temporal variables in the second period. Most of the doses used encourage beneficial effects in the various aspects of flowering evaluated.

Quinoa (Chenopodium quinoa Will.) is an annual herbaceous Andean plant. In recent years there is a growing interest on it due to its high quality as food, its wide adaptation to agroecological conditions and resistance to different abiotic stresses. In this work, we evaluate the growth pattern of quinoa plants cv. ‘Titicaca’, subjected to different levels of salinity, focusing on leaf production and nutrient content. In this sense, the results have shown that a high concentration of salinity negatively affects the growth of quinoa plants. In fact, plants grown with 200 mM NaCl reduced the photosynthetic rate and levels of chlorophylls and carotenoids in comparison with the rest of the treatments. Likewise, it has been proven how the progressive increase in salinity has negative effects on transpiration, stomatal conductance and photosynthetic rate, with significant subsequent reductions in shoot biomass, leaf area and nutrient adquisition, but without a decline in leaf dry weight (DW) production. However, the treatment of 200 mM NaCl demonstrated the best results regarding the water-use efficiency, as well as the number of saline glands. According to our results, the quinoa plant cv. ‘Titicaca’ seems to be tolerant to moderate concentrations of salinity (50–100 mM NaCl). This study could serve as a reference on this little known and cultivated species in the Mediterranean region, since it could become an alternative crop in areas with moderate salinity problems.

This study examines genetic diversity and structure of a Croatian garlic germplasm collection using 13 simple sequence repeat (SSR) markers. A total of 71 alleles were observed across 64 accessions representing 3 Croatian regions (Istria, Dalmatia and continental Croatia) and 16 foreign landraces, with an average of 5.46 alleles per locus. Among the 80 accessions analysed, 61 distinct multilocus genotypes (MLG) were identified, of which 51 represented unique genotypes and the remaining accessions were divided into 10 MLG groups, comprising potential duplicates or redundant genotypes. Model-based Bayesian and hierarchical UPGMA clustering approaches revealed five major groups within the collection which partially correlated with geographical origin. The analysis of molecular variance (AMOVA) showed that the majority (87.71%) of the total molecular diversity is within the Croatian groups of accessions, even though a significant share (12.29%) of diversity derived from genetic diversity among groups. These results support regional structuring, as well as the existence of significant diversity within local populations. This study is the first comprehensive report on an extensive evaluation of genetic resources of garlic maintained by Croatia with the aim of setting the course for future preservation strategies with particular emphasis on the value of diversity in the context of climate change both on macro and micro levels.

Pollen characteristics are very important for Iris interspecific hybridisation. In this study, the pollen viability and male meiosis were studied in yellow-flowered Iris dichotoma (Y2), I. domestica (S3) and their hybrids F₁, F₂ and BC₁ (BC₁-Y and BC₁-S). The BC₁-Y hybrids showed higher pollen viability than that of F₁, F₂ and BC₁-S hybrids, which were between I. dichotoma (26.1%) and I. domestica (35.1%). Two sterile hybrids, F₂-1 and BC₁-S-1, exhibited more meiotic abnormalities (57.3% and 58.7%) than other individuals. During the first meiotic division, a diffuse diplotene stage was observed for the first time in the genus Iris. The meiotic abnormalities included non-congressed chromosomes, chromosome bridges, lagging chromosomes, unequal division, abnormally oriented spindle fibres, nonsynchronous division and polyad, and resulted in reduced pollen fertility. The relatively high frequency of 2n pollen grains was found in hybrids of BC₁-Y-2, BC₁-Y-1, BC₁-S-2, BC₁-S-3 and BC₁-S-4. Our research provides a new resource for meiotic behaviour and pollen fertility of the genus Iris.

Hippeastrum sp. is a popular cut flower and a popular potted plant, currently occupying the 11^th position among cut flowers sold on the Dutch flower auctions. Hippeastrum × chmielii was bred by Henryk Chmiel at the Warsaw University of Life Sciences (WULS), Poland. The aim of this study was designed to test the ability of two clones of H. × chmielii to reproduce generatively by pollinating by three cultivars of Hippeastrum hybridum – ‘Gervase’, ‘Rio Negro’ and ‘Royal Velvet’. Pollen viability was tested by germination on the medium and by acetocarmine staining. The receptiveness of the stigmas and ovules of H. × chmielii and thus their ability to possibly accept compatible pollen were checked by staining with red alizarin. The viability of pollen grains of tested cultivars was estimated at 66.4–83.0% and their high ability to develop pollen tube was found. It was determined that the embryos of both H. × chmielii clones were fully receptive. A total of 72 crossings were performed in 6 combinations. Seeds collected about 1 month after pollination were germinated immediately after harvest either on moist tissue paper on Petri dishes or in jars with distilled water. After 28 days the percentage of germinated seeds ranged between 48.3% and 77.9%, for different crosses. In the case of seeds obtained from crossing H. × chmielii clone 18 × H. hybridum ‘Gervase’ a higher average percentage of germinated seeds was obtained in jars while no differences were noted between the germination methods in other cases.

Growing citrus involves cultural treatments such as girdling and foliar potassium treatment to increase fruit size, yield and quality. The aim of the study was to evaluate the effects of single and double stem girdling, potassium nitrate (KNO₃) treatment on leaves and combinations of these treatments on the fruit yield, size and quality characteristics, leaf chlorophyll concentration and leaf nitrogen content, leaf fluorescence (PSII) and leaf sugar content of the ‘Fremont’ mandarin variety. Girdling treatments were applied on the stem by removing 4 mm wide ring of bark at the end of anthesis and after the June fruit drop. Foliar KNO₃ applications were applied at a concentration of 4% twice (90 days and 120 days after full anthesis) in the experiment. The single girdling (SG) and double girdling (DG) treatments on stems increased fruit yield (kg · tree⁻¹) by approximately 40% relative to the control (C). Treatments did not significantly affect the internal fruit quality of the ‘Fremont’ mandarin variety except in fruit colour and appearance. The highest impact on fruit size was found in the DG + KNO₃ treatment. According to treatments and periods, the SPAD values varied between 62.08 and 70.67, whereas the PSII values varied between 0.698 and 0.756. The treatments significantly increased the leaf nitrogen (N) concentration and the fructose, glucose and sucrose concentrations relative to the control. The highest N concentration content was detected in the foliar potassium treatment, and the highest total sugar content was detected in the SG treatment.

Prevention of postharvest losses has been a very important concern in the scientific world for many centuries, since adoption of an effective means to curtail such losses is believed to help in reaching sustainability in horticultural production and prevention of hunger around the world. The main means of deterioration in fruits, which may occur after harvest, include physiological changes/losses, physical losses, biochemical changes, changes in enzymatic activities and pathological deterioration. Among these, diseases cover the most important part; the losses due to diseases range from 5% to 20%, and this figure may extend up to >50% in the cases of certain susceptible cultivars. Fungicides have been the most important tool for the management of postharvest diseases for many years, together with hygiene, cold storage and packaging. However, due to the scientifically confirmed hazards of agro-chemicals on environment and human health, the acceptability of agro-chemicals decreased and scientists turned their attention towards natural alternatives. Most tropical and subtropical fruits contain a superficial cuticle, which helps them to regulate respiration and transpiration and protects against microbial decay. However, the waxy cuticle is generally being removed or damaged during washing or other handling practices. Therefore, the application of protective coatings (including wax) has been used in the fruit industry since the twelfth century, against microbial decay and for maintaining an acceptable standard of postharvest quality. This review aims to summarise and discuss the main natural products used for this purpose, to provide a broad-in-scope guide to farmers and the fruit storage sector.