Horticulturae, Volume 9, Issue 7 (July 2023) – 120 articles

Salvia officinalis, commonly known as sage, is highly valued for its medicinal and ornamental properties. In the present work, 12 native sage populations of north-west Greece were evaluated for eight ornamental traits. Populations from the locations of Aristi, Kefalovryso and Igoumenitsa were selected as the best performing and for their preservation and availability in the market, their asexual propagation was investigated by (a) shoot cutting and (b) in vitro techniques. Propagation by cuttings was investigated during the four seasons. Aristi exhibited the highest rooting (65%) in spring with a well-developed root system (4.7 root number and 5.0 cm length) by applying 0.5 g·L⁻¹ Indole-3-butyric acid, potassium salt (K-IBA), established on perlite under a fog system. However, the rooting performance of Aristi spring cuttings was not affected by different substrates of peat:perlite (0:1, 1:1, 1:2 v/v) or rooting systems (mist, fog) tested. Furthermore, the in vitro propagation of the selected sage populations was investigated using shoot tips as explants. After successful disinfection, the effect of Murashige and Skoog (MS) medium in ten different combinations of Indole-3-acetic acid (IAA), 6-Benzylaminopurine (BAP) and Thidiazuron (TDZ) were tested on shoot multiplication. Aristi presented the highest number of newly formed shoots on MS9 (0.1 mg·L⁻¹ IAA and 0.8 mg·L⁻¹ TDZ) and MS5 (0.1 mg·L⁻¹ IAA and 0.8 mg·L⁻¹ BAP) (3.35 and 3.21 new shoots/explant, respectively) with the highest shoot length (2.23 cm and 3.2 cm) and unexpected spontaneous root formation (64%) at MS5. The rooting ability of Aristi microshoots was further investigated in order to enhance their response. Of the three rooting variants tested, optimal rooting formation (100%) was observed on 0.9 mg·L⁻¹ IAA (R3) combined with successful acclimatization (100%). Aristi exceeded the other populations in both the tested propagation systems, thus holding a strong potential for its introduction in the market as a competitive ornamental variety. Full article

In the present work, we investigated the effect of light conversion using europium (Eu(III))-based photoconversion covers on the cultivation of agricultural plants and their resistance to stress conditions. Two types of europium nanoparticles were used. The first one was obtained from europium oxide (Eu₂O₃) by laser fragmentation. The second one was Eu³⁺:LaF₃ nanocrystals obtained by hydrothermal-microwave treatment, the content of europium ions in which was 50% of the total amount of cations. Tomatoes (Solanum lycopersicum) and cucumbers (Cucumis sativus) were used as model plants. It was shown that plants grown under cover with Eu₂O₃ (PCC-Eu₂O₃) were 30–40% larger, gave a higher yield, and the activation of gas exchange processes and the light phase of photosynthesis in the leaves in response to the lighting was faster. On the contrary, plants grown under cover with Eu³⁺:LaF₃ (PCC-Eu³⁺:LaF₃) tended to slow down the rate of biomass accumulation and decrease the rate of gas exchange activation. It was shown that photoconversion covers change the resistance of plants to stress conditions: if plants grown under PCC-Eu₂O₃ became more sensitive to heat (+40 °C) and cold (+4 °C) treatment, then plants grown under PCC-Eu³⁺:LaF₃ became more resistant to high and low temperatures. It was found that PCC-Eu₂O₃ inhibited the development of the phytopathogen Phytophthora infestans on tomato plants. It was assumed that changes in the illumination spectrum by the photoconversion covers cause both the activation of plant growth in the case of Eu₂O₃ and an increase in plant resistance in the case of Eu³⁺:LaF₃ applications. Full article

In response to Pi deprivation, phosphate 1 (PHO1) is a significant regulator at trans-eQTL hotspots in Brassica rapa. Brassica rapa short-read sequencing data analysis revealed four PHO1 paralog genes, PHO1_A, PHO1_B, PHO1_C, and PHO1_D, placed in tandem with very high sequence similarity. However, based on short-read genomic sequence data, only three transcripts are accessible. Five bacterial artificial chromosomes (BACs) can be sequenced using a long-read sequencer, which improves de novo assembly and identifies structural variants. The PHO1 gene’s quadruplicating tandem positions in the genomic sequence were confirmed by an analysis of long-read data. Transcript analysis identified only three groups of PHO1 paralogs (ortholog AT1G14040 in Arabidopsis), i.e., PHO1_A, PHO1_B, and PHO1_D, expressed in B. rapa leaf tissues under Pi deficiency. PHO1_A, with transcript ID XM_009150437.2, has five different splice variants found. These splice variants’ truncated proteins demonstrated PHO1_A’s function in P control as opposed to protein encoding. Full article

The winter pot kalanchoe (Kalanchoe blossfeldiana) is an ornamental plant with succulent leaves and clustered flowers in Crassulaceae, widely used as a potted flower or garden decoration. In nature, the bicolor petal is an interesting phenomenon, and breeders have succeeded in cultivating the winter pot kalanchoe with bicolored petals. However, its potential molecular mechanism of pigmentation is poorly understood. This study collected a yellow-red colored winter pot kalanchoe to investigate the molecular mechanism underlying its bicolor formation using the integrative analyses of metabolome and transcriptome. The metabolome results showed that both flavonoid and carotenoid co-existed in the winter pot kalanchoe petals, whereas only anthocyanin accumulation showed significant differences—about nineteen times higher in the red region than that in the yellow region. The differentially expressed genes were significantly enriched in the anthocyanin biosynthesis pathway, and the expression level of biosynthetic genes, including KbCHS, KbCHI, KbF3H, KbDFR, KbANS and KbGTs, were significantly upregulated in the red region. Moreover, transcription factors potentially regulating anthocyanin biosynthesis were predicted, and KbMYB2 and KbbHLH1 might play important roles in positively regulating anthocyanin biosynthesis in the red region. The findings reported here provide new insights into the understanding of petal bicolor formation mechanisms and will assist cultivar innovation in winter pot kalanchoe. Full article

With the improvement in living standards, consumers have become more aware of healthy diets and pay more attention to the quality and safety of fruits and vegetables. Therefore, it is essential to strengthen the research on rapid detection of the quality and safety of fruits and vegetables. This study mainly outlines five Raman spectroscopy techniques. It introduces their principles and advantages and the current research progress of their application in fruit and vegetable quality and safety detection. Based on the characteristic Raman spectroscopy analysis of different fruits and vegetables, researchers found that Raman spectroscopy techniques can quickly and accurately detect classification identification, ripeness, freshness, disease infestation, and surface pesticide residues of fruits and vegetables. In addition, Raman spectroscopy techniques can also detect the content and distribution of material components of fruits and vegetables. This paper also discusses Raman spectroscopy’s current technology and application difficulties in fruit and vegetable quality and safety testing. It looks forward to its future development trend, expecting to promote the broad application of Raman spectroscopy in fruit and vegetable quality and safety testing. Full article

The strawberry (Fragaria × ananassa Duch.) is an important horticultural crop that is widely grown all over the world. Its sweetness, aroma, nutritional value and bright color make it popular. The woodland strawberry (Fragaria vesca) is a model plant for studying non-climacteric fruits because its respiration rate does not change significantly during fruit ripening. The B-box (BBX) protein family is made up of zinc-finger transcription factors important in plant growth and development. In this study, we identified 22 FveBBX genes from the newly released woodland strawberry genome database by comprehensive bioinformatics analysis. Phylogenetic analysis divided these FveBBX genes into five subfamilies. A promoter cis-acting element analysis detected 29 elements related to plant development, light response, abiotic stress and hormone response in the promoter of FveBBX genes. According to transcriptome data, relatively few BBX genes had tissue-specific expression, with examples including FveBBX12, which was expressed only in pre-fertilization cortex and pitch, and FveBBX19, which was specifically expressed in mature anthers. During fruit ripening, the expressions of eight FveBBX genes decreased by more than two-fold, and three FveBBX gene expressions increased more than two-fold both in “Ruegen” and “Yellow Wonder”. After cold and heat stresses, around half of the FveBBX genes displayed altered expression, especially FveBBX16 which showed an 8.3-fold increase in expression after heat treatment, while FveBBX14 showed at least an 11-fold decrease in expression after cold treatment. According to the result of quantitative real-time PCR (qRT-PCR), FveBBX genes’ expression differed depending on the photoperiod. Notably, FveBBX7 gene expression was the opposite during the first 16 h of the long-day (LD) and short-day (SD) conditions. This study provides helpful information for further research on BBX gene activity of the woodland strawberry in plant growth and development and adaptation to temperature and photoperiod environmental conditions. Full article

Studies on the morpho-physiology of cryo-derived pineapple plants after acclimatization have been quite limited. Therefore, in the present study, the morpho-anatomical and physiological characteristics of cryo-derived Ananas comosus var. comosus ‘MD-2’ plants after acclimatization were investigated. Plants obtained from cryopreserved and non-cryopreserved shoot tips, as well as in vitro stock cultures (control), showed similar morphological development (viz. plant height, number of leaves, D leaf length, D leaf width, D leaf area, diameter of stem base, number of roots, plant fresh weight and plant dry weight) to conventionally micropropagated and non-cryopreserved plants. The pineapple plantlets developed efficient anatomical leaf structures that allowed them to adapt to the transition process from in vitro to ex vitro. In all groups of plants, the content of water and chlorophylls (a, a + b, a/b) decreased during the first 15 days of acclimatization and then remained constant until the end of the evaluation. The mesophilic succulence index increased to its maximum value after 15 days, then decreased and remained constant up to 45 days. Although physiological indicators fluctuated during the 45 days of acclimatization, no differences were observed in any of the indicators evaluated when plantlets obtained from cryopreserved shoot tips were compared with controls. The results of the plants from cryopreserved shoot tips show that they switched from C3 to Crassulacean acid metabolism, which denoted metabolic stability during acclimatization. Full article

The mechanism by which LED red light irradiation regulates postharvest banana ripening was evaluated in this study by the continuous irradiation of banana fruits at the mature-green stage. In this study, a self-developed LED banana fresh-keeping container lid was used to continuously irradiate the immature banana fruit. The light wavelength was 655.0 ± 1.0 nm, the light intensity was 800.0 ± 10.0 LX, and the height between the LED lamp and the fruit was 15.0 ± 0.5 cm. Bananas stored under dark conditions were used as the negative control group, and bananas stored under dark conditions after spraying with 500.0 mg/L ethephon diluent were used as the positive control group. Changes in physiological parameters related to postharvest banana ripening, such as the respiration rate, ethylene release, texture, color, carotenoid content, chlorophyll content, adenosine triphosphate content, and energy metabolism-related enzyme activities, were measured during 8 days of storage at 20.0 ± 0.1 °C to analyze the key factors determining postharvest banana ripening in response to red light. The red light-irradiated bananas had higher total color differences and higher rates of chlorophyll degradation and carotenoid synthesis than those of the ethephon-treated group during the storage period. Red light irradiation promoted banana fruit ripening and senescence mainly by promoting carotenoid synthesis, capturing absorbed light energy, accelerating energy metabolism, effectively enhancing the activities of the respiratory and energy metabolism-related enzymes H⁺ adenosine triphosphatase, Ca²⁺ adenosine triphosphatase, succinate dehydrogenase, cytochrome C oxidase, and malic enzyme, and promoting organic acid degradation. In conclusion, LED red light can be used as a new physical ripening technology for bananas, with a similar effect to that of traditional ethephon treatment. Full article

The 9-cis-epoxy carotenoid dioxygenase (NCED) is an enzyme that is crucial in abscisic acid (ABA) biosynthesis, and its role is vital in plant development and abiotic stress. However, the function of the NCED family in Rosaceae plant species remains unclear. Through genome-wide screening, we identified 10, 10, 11, 12 and 13 NCED genes in Prunus mume, Prunus apricot, Prunus salicina, Prunus persica, and Rosa chinensis, respectively. Phylogenetic analysis showed that these NCED genes were divided into six groups. Gene structure analysis showed that the number and size of introns were relatively constant in each subfamily, while the motif composition differed significantly among them. Collinearity analysis revealed a high homology of NCEDs in the Prunus genus. Promoter cis-acting element analysis showed that eight PmNCEDs contained abscisic acid-responsive elements (ABRE). Furthermore, expression profile analysis based on qRT-PCR revealed that PmNCED3, PmNCED8 and PmNCED9 were up-regulated in response to low temperature stress, suggesting their significant role in the plant’s response to cold stress. These findings provide insights into the structure and evolution of PmNCEDs and lay the foundation for further studies regarding their function during cold stress. Full article

The aim of the present study was to evaluate the possible effects of two different biostimulant formulations at different application regimes and combined or not with mineral fertilizers (e.g., W1–W8, including the control treatment (no formulations added)) on the yield parameters and fruit quality of watermelon plants. The highest yield was recorded for the W5 treatment due to the formation of more fruit. The highest content of fat, proteins and ash was recorded for treatment W1, whereas carbohydrates were the most abundant in the control treatment, resulting also in the highest energetic value. The main detected sugars in all the tested samples were sucrose and fructose, which were the highest for the W4 and W5 treatments (sucrose) and W4 treatment (fructose). Malic and citric acid were the most abundant compounds, especially in the W4 treatment. In terms of tocopherols, only α-tocopherol was detected, with the highest amounts being recorded for the W4 treatment. Regarding bioactive properties, the lowest IC₅₀ values for OxHLIA were recorded for the W2, W3 and W8 formulations. Moreover, all the extracts exhibited significant anti-inflammatory activity comparable to the positive control, while a variable efficacy of the tested extracts against the studied bacteria and fungi was recorded. In conclusion, our results indicate that simple agronomic practices such as biostimulant application may improve crop performance and improve the proximal composition and the overall quality of watermelon fruit within the context of sustainable crop production. Full article

The precise management of the nutrient solution pH is substantial for optimizing the growth and yield of hydroponically cultivated crops. Nutrient solution pH affects the solubility and availability of essential nutrients; however, during hydroponic cultivation, the pH of nutrient solution fluctuates due to unbalanced ion absorption by plants. Nutrient solution pH fluctuations might be passively controlled using a supplementary buffering agent. Nutrient solution characteristics such as pH and buffering agent molarity must be addressed simultaneously. Therefore, in this study, we aimed to evaluate hydroponically cultivated lettuce’s physiological response to minor nutrient solution pH differences and the impact of supplementary buffering agent molarity on its growth, antioxidant activity, and mineral nutrient uptake. Green lettuce (Lactuca sativa (L.)) ‘Hugin’ was cultivated in deep water culture (DWC) hydroponics in a controlled environment replicating common vertical farming conditions, and nutrient solution pH impact within the range of 5.0–6.5 was evaluated every 0.5 pH unit. Initial nutrient solution buffer capacity was enhanced by adding MES (2-(N-morpholino) ethanesulfonic acid) at 0, 1, 3, and 5 mM concentrations. Results show that even small nutrient pH differences are reflected in plant physiological responses, indicating the significance of precise pH management. Even though dry weight accumulation is not affected by the pH 5.0–5.5 treatment, it increases root antioxidant response according to ABTS (2,2-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) radical scavenging activity. An initial nutrient solution buffer capacity increment with 3 mM of MES (2-(N-morpholino) ethanesulfonic acid) supplementary buffering agent resulted in a 17% yield increase compared to a nutrient solution without an additional buffering agent. MES buffer can provide adequate, passive, and precise nutrient solution pH control within the pH range of 6.0–6.5. Full article

Jujube (Ziziphus jujuba Mill.) is a fruit tree that is gaining increasing importance in drought-affected regions worldwide. The fruit size is an important quantitative agronomic trait that affects not only the fruit yield and attractiveness but also consumer preference. Genetic enhancement of fruit appearance is a fundamental goal of jujube breeding programs. The genetic control of jujube fruit size traits is highly quantitative, and development of high-density genetic maps can facilitate fine mapping of quantitative trait loci (QTLs) and gene identification. However, studies regarding the construction of high-density molecular linkage maps and identification of quantitative trait loci (QTLs) targeting fruit size in jujube are limited. In this study, we performed whole-genome resequencing of the jujube cultivars “JMS2” and “Xing16” and their 165 F₁ progenies to identify genome-wide single-nucleotide polymorphism (SNP) markers and constructed a high-density bin map of jujube that can be used to assist in the selection of multiple traits in jujube breeding. This analysis yielded a total of 116,312 SNPs and a genetic bin map of 2398 bin markers spanning 1074.33 cM with an average adjacent interval of 0.45 cM. A quantitative genetic analysis identified 15 QTLs related to fruit size and the observed phenotypic variation associated with a single QTL ranged from 9.5 to 13.3%. Through the screening of overlapping and stable QTL regions, we identified 113 candidate genes related to fruit size. These genes were ascertained to be involved in cell division, cell wall metabolism, synthesis of phytohormones (ABA, IAA, and auxin), and encoding of enzymes and transcription factors. These candidate genomic regions will facilitate marker-assisted breeding of fruits with different sizes and shapes and lay a foundation for future breeding and manipulation of fruit size and shape in jujube. Full article

The detoxification of crops grown in Cadmium (Cd)-contaminated acid soil has been widely studied, but for contaminated alkaline soil, there is still inadequate research or information. In order to investigate the effects of calcium and sulfur fertilizers, accompanied by different side elements, on the growth and Cd uptake of Spinacia oleracea grown in Cd-contaminated alkaline soil, the plants were subjected to five treatments, including calcium silicate (Ca-Si), calcium biphosphate (Ca-P), magnesium sulfate (S-Mg), ferric sulfate (S-Fe), and zinc sulfate (S-Zn), and a control group. The results showed that the S-Fe achieved the highest shoot fresh mass and dry mass and the highest shoot Cd concentration and accumulation, which were 30%, 68%, 4.6%, and 73% higher than the control group, respectively. The Ca-Si, Ca-P, S-Mg, and S-Zn reduced the root Cd concentration by 18%, 42%, 7%, and 49%, respectively, and reduced the shoot Cd concentration by 25%, 36%, 15%, and 27%, respectively, as compared to the control. S-Fe increases plant N uptake and photosynthesis, which is beneficial to biomass accumulation. Ca-P improves soil and plant P nutrition status, as well as plant K and Ca status, and helps alleviate plant Cd stress. Overall, calcium fertilizers accompanied by phosphorus have the potential to reduce plant Cd contamination risk, while sulfur fertilizers accompanied by iron show potential for enhancing Cd extraction. Full article

Camellia oleifera Abel., which produces fruits of high comprehensive utilization value, is an important woody oil tree in China. ZEITLUPE (ZTL) is a blue light receptor and clock component protein that is involved in various physiological and biochemical processes. However, the expression pattern and function of C. oleifera ZTL (CoZTL) remain unclear. In this study, the coding sequence of the CoZTL gene was isolated and the protein function was explored using bioinformatics and expression analyses and heterologous expression techniques. The results showed that the CoZTL protein was highly conserved during evolution and was on the same branch of the evolutionary tree as the ZTL proteins from Ipomoea nil and Nicotiana attenuata. CoZTL was mainly expressed in the fruit shells and stems of C. oleifera, and its expression level fluctuated greatly during flower bud development. Transgenic CoZTL-overexpressing Arabidopsis plants showed delayed flowering under long-day conditions as well as light-dependent promotion of hypocotyl elongation. Furthermore, yeast two-hybrid library screening revealed that seven C. oleifera proteins (CoAAT, Coβ-GAL, CoLAT52-like, CoCAR4-like, CoAO, CoUQCC1, and CoADF 2) interacted with CoZTL. Our results indicate that CoZTL plays an important role in C. oleifera flowering and hypocotyl growth. Full article

Lycorine is an important Amaryllidaceae alkaloid showing anti-cancerous activity on numerous cell lines; and it also demonstrates antiviral activity against several viruses including SARS-CoV-2 responsible for COVID-19. The in vitro cultivation of plant parts is a good alternative for elicitor mediated secondary metabolite synthesis, mass propagation, and cloning of elite genotypes. In this study, the quantification of lycorine from Zephyranthes candida, Zephyranthes grandiflora, and Zephyranthes citrina was evaluated, and the influence of methyl jasmonate (MJ) treatments on accumulation of lycorine yield was observed in the in vitro cultivated tissues. The influence of methyl jasmonate (MJ) on accumulation of lycorine was investigated for the first time in in vitro regenerated bulb, leaf, and root tissues of Zephyranthues. The efficient in vitro shoot regeneration was achieved in Z. candida (73.9%), Z. grandiflora (85.5%), and Z. citrina (76.5%) on Murashige and Skoog (MS) medium amended with 2.0 mg·L⁻¹ Naphthalene acetic acid + 0.5 mg·L⁻¹ Benzylaminopurine. The regenerants had the highest i.e., 7.46 mean numbers of bulblets per shoot. The best root induction (80.66%) was achieved on 2.0 mg/L Indole butyric acid (IBA). The lycorine content was quantified through High performance thin layer chromatography (HPTLC) in three field grown Zephyranthes species, was highest in Z. candida (1.93 µg g⁻¹ dry wt.), followed by Z. grandiflora (1.87 µg g⁻¹ dry wt.) and Z. citrina (1.62 µg g⁻¹ dry wt.). The yield of lycorine was observed in this order i.e., bulb > leaf > root. The regenerated plants were supplemented with MJ and maximum lycorine yield was noted at 100 µM in bulb tissues of Z. candida (2.74 µg g⁻¹ dry wt.) with an increase in percentage of 39.08. The enhancement could be due to MJ-induced stress as the biochemical attributes and anti-oxidant enzyme activity were high with elevated level of MJ. This enrichment may auger commercial manufacturing and utilization of lycorine in future. Full article

Basil (Ocimum basilicum L.) is one of the main condiments for fresh consumption and essential oil production. The aim of the present work was to assess the agronomic characterization and analyze the essential oil of 63 basil accessions. The experiment was conducted in two stages in a greenhouse using vases and a hydroponic cultivation system. Oil extraction was performed employing the Soxhlet method. There was a significant variation in the agronomic characteristics among the evaluated accessions. The estimated total contents of essential oils ranged from 0.05 to 0.40%, and the major volatile fraction was methyl-eugenol. In the present study, accessions with superior performance compared to commercial varieties were found. Accession BL11 presented agronomic characteristics suitable for cultivation in a hydroponic system due to its better plant structure and late flowering. Accession BL24 stood out for essential oil extraction, producing 17.6% of linalool and a high intensity of color and odor. Accessions BL11 and BL24 presented market potential, given their higher mass productivity and higher essential oil yield, respectively. These accessions can be made available as new varieties in addition to being used in genetic improvement programs for this species. Full article

Water scarcity in agriculture can limit crop production and trigger the need for more effective water resource management. As a result, it is critical to identify new crop genotypes that are more drought tolerant and perform better under low irrigation or even rain-fed conditions. The olive tree is a high-value crop that is well adapted to dry Mediterranean conditions. However, different genotypes may have developed different mechanisms of tolerance to water stress. To investigate such mechanisms, we examined three Italian olive cultivars (‘Giarraffa’, ‘Leccino’, and ‘Maurino’) grown in a greenhouse under drought stress. We found that single genotypes responded differently to the drought, though not all parameters revealed significant differences. The first major difference among the cultivars was in transpiration: the lower stomatal density and stomatal conductance of ‘Giarraffa’ allow this cultivar to use water more conservatively. In parallel with the reduction in stomatal and mesophyll conductance, the drought-stressed group of ‘Giarraffa’ maintained the electron transport rate and effective efficiency levels of photosystem II similar to those of the control until the fourth week of stress. The fluorescence parameters revealed the earlier closure of reaction photosynthetic centres in ‘Leccino’. Finally, the higher rate of electrolyte leakage in ‘Maurino’ indicated a significant ions loss in this cultivar when it was subjected to the drought. Both water management under stress conditions and the effect of drought on photosynthesis make ‘Giarraffa’ interesting to researchers studying its use in breeding or water-saving programmes. Full article

In order to ensure food security worldwide in the face of current climate changes, a higher quality and quantity of crops are necessary to sustain the growing human population. By developing a sustainable circular economy and biorefinery approaches, we can move from a petroleum-based to a bio-based economy. Plant biostimulants have long been considered an important source of plant growth stimulants in agronomy and agro-industries with both macroalgae (seaweeds) and microalgae (microalgae). There has been extensive exploration of macroalgae biostimulants. A lack of research and high production costs have constrained the commercial implementation of microalgal biostimulants, despite their positive impacts on crop growth, development, and yield. The current knowledge on potential biostimulatory compounds from algae, key sources, and their quantitative information has been summarised in the present review. Our goal is to provide a brief overview of the potential for microalgal biostimulants to improve crop production and quality. A number of key aspects will be discussed, including the biostimulant effects caused by microalgae extracts as well as the feasibility and potential for co-cultures and co-application with other biostimulants and biofertilisers. This article will also discuss the current knowledge, recent developments, and achievements in extraction techniques, types of applications, and timings of applications. Ultimately, this review will highlight the potential of microalgal biostimulants for sustainable agricultural practices, the algal biochemical components that contribute to these traits, and, finally, bottlenecks and involved prospects in commercialising microalgal biostimulants. Full article

Elaborating on the methods and means of enriching nutrition, including that of plants, with a number of microelements that are vital for humans is now very important due to the unresolved acute problems of micronutrient deficiency and imbalance, which affect the majority of the population of various countries in the world. Promising solutions for the implementation of biofortification in terms of safety, efficiency, size, biocompatibility, and transportability are the water-soluble derivatives of C₆₀ or C₇₀ fullerene. By now, the use of water-soluble fullerenes (C₆₀(OH)_22–24 or C₇₀(OH)_12–14 fullerenols, C₆₀ fullerene with glycine or with arginine: C₆₀-L-Gly or C₆₀-L-Arg) with various functional groups for plant enrichment is pioneering. Experimental research work was carried out at the agrobiopolygon of the Agrophysical Research Institute under controlled microclimate conditions. This work constituted an assessment of the influence of C₆₀(OH)_22–24 fullerenol introduction into the soil on the content of macro- and microelements in the soil and in plants, for example, cucumber, as well as on the plants’ physiological state (photosynthetic pigments, the intensity of lipid peroxidation, the activity of peroxidase and catalase enzymes), growth, and element content. Its aim was to study the possibility of enriching the plants’ production (Chinese cabbage, tomato, and cucumber) with compositions of the fullerene derivatives (C₆₀-L-Gly or C₆₀-L-Arg, C₆₀(OH)_22–24 or C₇₀(OH)_12–14 fullerenols) and selenium or zinc compounds by introducing them into a nutrient solution or by foliar treatment of plants. It was revealed that the introduction of solutions of C₆₀ fullerenol in various concentrations (1 mg/kg, 10 mg/kg, and 100 mg/kg) into soddy-podzolic sandy loamy soil contributed to the activation of the processes of nitrogen transformation in the soil, in particular, the enhancement of the process of nitrification, and to the increase in the content of mobile forms of some macro- and microelements in the soil as well as of the latter in plant organs, for example, in cucumber plants, especially in their leaves. Along with this, the plants showed an increase in the content of photosynthetic pigments, a predominant decrease in the activity of the oxidative enzyme peroxidase and in the intensity of lipid peroxidation, and an increase in the content of the reducing enzyme catalase. The improvement in the physiological state of plants had a positive effect on the growth rates of cucumber plants. The compositions of solutions of amino acid fullerenes (C₆₀-L-Gly or C₆₀-L-Arg) and sodium selenate as well as C₆₀ or C₇₀ fullerenols and zinc sulfate, selected on the basis of different charges of molecules or functional groups of fullerene derivatives, showed higher efficiency at low concentrations in enriching the plant products of Chinese cabbage, tomato, and cucumber with selenium and zinc, respectively, compared with mineral salts of the indicated elements and control (edible part of Chinese cabbage: by 31.0−89.0% relative to that in the control and by 26.0–81.0% relative to the treatment of plants with a sodium selenate; tomato fruits: by 33.7–42.2% relative to that in the control and by 10.2–17.2% relative to the treatment of plants with a sodium selenate; cucumber fruits: by 42.0–59.0% relative to that in the control and by 10.0–23.0% relative to the treatment of plants with a zinc sulfate). At the same time, the quantitative characteristics of growth, productivity, and/or quality of the obtained products increase and improve accordingly. The prospects for further research include an in-depth study into the mechanisms of the compositions of fullerene derivatives and various compounds of trace elements’ influence on the plants, as well as the synthesis and study of the various exo- and endo derivatives of fullerenes’ properties, including C₆₀ complex compounds with transition metals and fullerenes, which, inside their carbon networks, contain atoms of various chemical elements, such as lanthanum and others. Full article

The lack of dwarf stock with good cold resistance has affected the production of apples in northern China. Annual dormant branches of ‘Tianhong 2’ apple were grafted on 10 different dwarf interstocks (the rootstocks were the seedlings of Malus hupehensis var. Pingyiensis) as test materials. Among these 10 interstocks, Huang 6, 244, NO.1, 53, 24-5, ZC9-3, Jizhen 1 were newly developed by us (Apple Research Group of Hebei Agricultural University), and three interstocks with different degrees of cold resistance (GM256–with strongest cold resistance, SH40–with stronger cold resistance, M9–with poor cold resistance) were used as controls. The semi-lethal temperature (LT50) and related physiological indexes of the branches in the overwintering process were studied. Based on the comprehensive physiological indexes, the effects of 10 interstocks on cold resistance of the ‘Tianhong 2’ apple were analyzed. The results showed that the effects of 10 kinds of interstocks on the cold resistance of ‘Tianhong 2’ apple were quite different. The order of effects on cold resistance from strong to weak was as follow: GM256 > Huang 6 > 244 >NO.1> 53 > 24-5 > ZC9-3 >Jizhen 1 > SH40 > M9. The purpose of this study was to screen out the interstocks with strong cold resistance, in order to provide some basis for the selection and utilization of interstocks with strong cold resistance in apple cultivation to further promote the development of the apple industry in China. Full article

Sub-irrigation of greenhouse crops has the potential to increase water and nutrient use efficiency; however, fertilizer salts that are not absorbed by the plants tend to accumulate in the substrate and eventually raise the substrate’s electrical conductivity (EC). The objective of this study was to determine the optimum EC of the nutrient solution in sub-irrigated tomatoes to allow maximum yield. Total fruit yield was higher in sub-irrigated plants with solutions at 2.0 dS m⁻¹ (5105 g per plant), and it was comparable to that obtained for drip-irrigated plants (4903 g per plant); however, the yield of fruits from the second truss was 37% higher in sub-irrigated than in drip-irrigated plants when the EC was 2.0 dS m⁻¹. In contrast, at the end of the growing season, the yield of plants sub-irrigated with nutrient solutions of 2.0 dS m⁻¹ was the lowest, being surpassed by 37% by that of plants treated with 1.4 dS m⁻¹. The dry weight of vegetative plant parts was reduced in sub-irrigated plants, suggesting a shift in dry mass partitioning. Our results show that with sub-irrigation, the growing season should be started using nutrient solutions with higher EC, but eventually, this EC should be decreased to maintain proper substrate EC and high yield. Full article

Salinity currently affects more than 20% of agricultural land and is expected to pose potential challenges to land degradation and agricultural production in the future. It is a leading global abiotic stress that affects general plants and cultivated crops adversely. The utilization of biostimulants can enhance the efficiency of plant nutrition, facilitate the uptake of nutrients, boost crop yield, improve the quality characteristics of fruits and enhance plants’ ability to withstand abiotic stresses. Biostimulants serve as a vital reservoir of macro- and microelements and plant hormones, such as auxins, cytokinins and gibberellins. Therefore, the current study was conducted to examine the effect of the foliar application of some biostimulants on relieving the side effects of salinity on olive trees (Olea europaea) cv. Kalamata. The olive trees were sprayed three times with moringa leaf aqueous extract (MLE) at 2, 4 and 6%, seaweed extract (SWE) at 1000, 2000 and 3000 ppm and their combinations: 2% MLE + 1000 ppm SWE (combination 1), 4% MLE + 2000 ppm SWE (combination 2) and 6% MLE + 3000 ppm SWE (combination 3). The results revealed that the application of biostimulants had a beneficial effect on the overall growth and development of olive trees, surpassing the performance of untreated trees. Spraying MLE and SWE, particularly at concentrations of 6% and 3000 ppm, respectively, significantly enhanced various aspects of olive tree performance. Notably, there were significant increases in leaf chlorophyll content, flower number, fruit set percentages, fruit yields, fruit oil content, fruit firmness, total soluble solid (TSS) percentage and leaf macro- and micronutrients. Furthermore, the combined application of MLE and SWE resulted in a greater effect when compared to using each one individually. In both seasons, combination 3 outperformed the other treatments that were applied. Full article

In this work, the quality parameters of the oils of seven different varieties of olives (Olea europaea cvs, “Arbequina”, “Arbosana”, “Cobrançosa”, “Cornicabra”, “Koroneiki”, “Cacereña”, and “Chiquitita”) grown in hedgerow under cold conditions during three consecutive seasons were analyzed in order to evaluate their adaptation to this growing system. For this purpose, virgin olive oils (VOOs) were extracted, and, in addition to evaluating the indices of hydrolytic, oxidative, and sensory deterioration of the oils, their content in photosynthetic pigments and their composition in fatty acids and phenolic compounds were determined. The correlation between oxidative stability and the parameters evaluated has been studied, with the highest correlation coefficients found for the ratio MUFA/PUFA (0.871) and the content of secoiridoid phenolic compounds (0.816). Furthermore, principal component analysis was performed with the phenolic composition data from each season, which demonstrated the major influence of genetic factors in the phenolic composition of VOO. None of the VOOs presented hydrolytic, oxidative, or sensory deterioration, so all of them remained in the “extra” category. However, it should be noted that the mean ultraviolet absorbance values were significantly higher in “Cornicabra” and significantly lower in “Cacereña” oils. In spite of this, the oxidative stability was significantly higher in “Cornicabra” oils (125 h), which also had the highest mean phenolic content (1035 mg kg⁻¹ oil), while the lowest phenolic content values were found in “Arbequina” and “Chiquitita” (58 and 52 h, respectively). Full article

Tomato as a fresh fruit has a large market share in China, but few new materials have been developed for such cultivar breeding in recent years. This study aims to create innovative breeding materials for fresh fruit tomatoes with consistent genetic backgrounds and take advantage of beneficial genes from wild germplasm resources. An introgression line (IL) population was constructed using freshly cultivated tomato S. lycopersicum 1052 and wild tomato S. pennellii LA0716 through hybridization and five consecutive backcrossings, with molecular marker-assisted selection techniques during seedling stages. A total of 447 cleaved amplified polymorphic sequences (CAPS) and 525 simple sequence repeat (SSR) markers were used to screen polymorphic markers among the two parental lines, resulting in 216 polymorphic CAPS and 236 polymorphic SSR markers, with 46.5% parental polymorphism. Then, 200 molecular markers uniformly distributed over the entire genome were further selected, and 107 ILs were finally obtained from 541 BC₅ candidate plants. The physical distance between adjacent markers was 6.3~10.0 cm, with an average interval of 7.29 cm, and the IL population constructed covered the whole genome of S. pennillii LA0716, with an average introgression segment of 31.5 cm. Moreover, phenotype data of major agronomic traits in BC₅ progeny after selfing two times, were analyzed for quantitative trait locus (QTL) mapping, and a total of 11 QTLs distributed on 6 chromosomes were identified, including 3 QTLs regulating plant height, 1 QTL regulating leaf size, 1 QTL regulating fruit color, 4 QTLs regulating fruit weight, and 2 QTLs regulating soluble solids content in ripening fruits. The IL population constructed in this study provided good materials for fresh fruit tomato breeding with improved yield and quality in the future. Full article

Onion (Allium cepa L.) is a food crop of economic importance. In Brazil, the crop typically occurs in a conventional tillage system (CT), which favors the mineralization and decomposition of soil organic matter (SOM) and the loss of carbon (C) and nitrogen (N). On the other hand, the no-tillage vegetable system (NTVS) operates based on sustainable pillars and bypasses the adverse effects of CT. This study evaluated the total C and N stocks and particle-size fractions of SOM in NTVS with single and intercropped cover plants compared to vegetable crops under CT. The NTVS evaluated treatments were as follows: (1) spontaneous vegetation (SV); (2) black oats (BO); (3) rye (RY); (4) oilseed radish (OR); (5) RY + OR; and (6) BO + OR. A treatment under CT with millet cover, a no-tillage system with (NTS) millet + velvet + sunflower cover, and a forested area as the original condition was also evaluated. Soil samples were collected in 0–5, 5–10, and 10–30 cm layers. Stocks of total organic C (TOC), total N (TN), particulate OC (POC), particulate N (PN), mineral-associated OC (MAOC), and mineral-associated N (MN) were evaluated. The highest stocks of TOC, TN, POC, and NM were found in NTVS compared to CT, and RY + OR showed the best results. The NTVS showed higher TOC and TN stocks with grasses and cruciferous intercropped than NTVS with SV and CT. POC and PN stocks increased in areas with single and intercropped RY and OR treatments. MAOC and MN stocks were higher than forest in RY + OR intercrop in the topsoil layer. RY and OR intercrop efficiently added C and N to the soil under NTVS. The consortium of millet + velvet + sunflower in NTS showed higher TOC, TN, POC, and PN stocks compared to the other treatments (0–5 and 0–30 cm). In general, the intercrop of cover plants is ideal for obtaining the NTVS maximum potential, favoring several mechanisms between soil, plant, and atmosphere, resulting in improved soil quality, increased organic matter, and higher stocks of C and N. Full article

It is well known that some plants have the capability of taking up sulfur as a nutrient from the atmosphere through foliar absorption and can survive well in polluted environments. In order to observe the effects of the relationship between atmospheric hydrogen sulfide (H₂S) deposition and soil sulfur nutrition, the current study used Brassica pekinensis as a model plant. The objective in conducting this study was to understand the regulatory mechanisms engaged in the uptake and assimilation of sulfate (SO₄²⁻) in plants by studying the modulation of transcription levels of sulfate transporter genes (STGs) (Sultr1;1 and Sultr1;2), changes in growth physiology, and the potential of roots to uptake the SO₄²⁻ when allowed to grow in the presence or absence of SO₄²⁻ in a hydroponic nutrient solution. Changes in growth, physico-chemical parameters, and gene expression levels of Group 1 STGs were observed when sulfur-treated and non-treated plants were exposed to phytotoxic H₂S levels in the air. Sulfur deficiency enhanced nitrate and free amino acid (FAA) concentrations in the shoot and root regions of the plant. However, there was a significant decrease in the biomass, shoot/root ratio (SRR), chlorophyll content, and thiol content, with p-values < 0.01. This, in turn, increased the sulfur-uptake capacity of plants from the atmosphere through foliar absorption. When the sulfur-uptake capacity of plants increased, there was an increase in the expression level of Group 1 sulfate transporter genes (Sultr1;1 and Sultr1;2), which regulate sulfur transportation through roots. The growth, physico-chemical characteristics, and level of gene expression of Group 1 STGs were unaffected by the availability of excess sulfur in the atmosphere of up to 0.3 μL l⁻¹. Full article

Walnut (Juglans regia) populations are considered a valuable genetic resource for genetic variability conservation and walnut cultivar improvement. In the current study, two walnut selections from Central Greece, “FM3” and “FM6”, were evaluated for their characteristics to determine their perspective as new cultivars. Their main phenological and pomological characteristics were assessed according to IPGR (1994) and UPOV-TG/125/6 (1999) criteria for 10 consecutive years and compared with “Chandler”. Results revealed that “FM3” presents high lateral flowering (70–80%), whereas “FM6” is 30–35%. Although the date of bud break and male blooming of both selections did not differ from “Chandler” (p > 0.05), the female blooming phase of “FM6” occurred earlier (p < 0.05) than “Chandler” and nut harvest was earlier than both “Chandler” and “FM3” (p < 0.05). Nut dimensions of both selections were higher than “Chandler” (p < 0.001). The mean in-shell nut weight and kernel weight of “FM3” were higher than “FM6” and “Chandler”, and those of “FM6” were higher than “Chandler” (p < 0.001). Other positive nut characteristics were their light kernel color, the well kernel fill, and the easy removal of the kernel halves. Thus, the current results indicate that “FM3” and “FM6” could be considered promising gene pools in crossbreeding activities. Full article

The recognition of fresh tea leaf sprouts is one of the difficulties in the realization of the automated picking of fresh tea leaves. At present, the research on the detection of fresh tea leaf sprouts is based on a single variety of tea leaves for a specific period or specific place, which has no advantage for the spread, promotion, and application of the methods. To address this problem, an identification of multiple varieties of tea sprouts (IMVTS) model was proposed. First, images of three different varieties of tea (ZhongCha108 (ZC108), ZhongHuangYiHao (ZH), ZiJuan (ZJ)) were obtained, and the multiple varieties of tea (MVT) dataset for training and validating models was created. In addition, the detection effects of adding a convolutional block attention module (CBAM) or efficient channel attention (ECA) module to YOLO v7 were compared. In the detection of the MVT dataset, YOLO v7+ECA and YOLO v7+CBAM showed a higher mean average precision (mAP) than YOLO v7, with 98.82% and 98.80%, respectively. Notably, the IMVTS model had the highest AP for ZC108, ZH, and ZJ compared with the two other models, with 99.87%, 96.97%, and 99.64%, respectively. Therefore, the IMVTS model was proposed on the basic framework of the ECA and YOLO v7. To further illustrate the superiority of the model, this study also conducted a comparison test between the IMVTS model and the mainstream target detection models (YOLO v3, YOLO v5, FASTER-RCNN, and SSD) and the IMVTS model on the VOC dataset, and it is clear from the test results that the mAP of the IMVTS model is ahead of the remaining models. Concisely, the detection accuracy of the IMVTS model can meet the engineering requirements for the automatic harvesting of autumn fresh famous tea leaves, which provides a basis for the future design of detection networks for other varieties of autumn tea sprouts. Full article

Cork spot is a common physiological disorder in pear fruits, which has been found in some pear cultivars. Mineral nutrition imbalance in fruit is regarded as the principal influence factor for disorder incidence, with some ongoing confusion and controversy. In our research, we explored the cork spot characteristics in Japanese pear ‘Akizuki’ (Pyrus pyrifolia Nakai), adopted metabolome and mineral content analysis for healthy and disordered fruits, and made a correlation analysis of mineral and metabolites. Cork spots are mainly distributed on the outer flesh beneath the fruit peel. In cork spotted tissues, superoxide (SOD) and peroxidase (POD) activities, as well as malondialdehyde (MDA) content, increased. A total of 1024 known metabolites were identified from all the samples and more changes in metabolism were detected between normal and cork spotted flesh tissues. Correlation analysis displayed that Ca, especially the Mg/Ca in fruits, could be used to predict whether an orchard will develop cork spot disorder; Mg and B were associated with the appearance of symptoms, and the contents of Zn, Fe, and Mg, as well as Mg/B and Zn/B, might be strongly tied to the formation of cork spots in pears. This research provides insights into the occurrence of pear cork spot disorder and clarifies the role of minerals. Full article