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Salinity is one of the primary abiotic stresses that seriously hampers plant quality and productivity. It is feasible to reduce or reverse the negative effects of salt through the supplementation of silicon (Si) and aspartic acid (Asp). However, the question of how exogenous Si and Asp induce salt tolerance in celery remains incipient. Thus, this study was performed to determine the synergistic effects of Si and Asp on the alleviation of salt stress in celery. To this end, the celery plants were cultivated in a controlled regime (light for 14 h at 22 °C; darkness for 10 h at 16 °C) and treated with one of five treatments (CK, 100 mM NaCl, 100 mM NaCl + 75 mg/L Si, 100 mM NaCl + 100 mg/L Asp, and 100 mM NaCl + 75 mg/L Si + 100 mg/L Asp). Results showed that solely NaCl-treated celery plants developed salt toxicity, as characterized by decreased growth, declined photosynthetic ability, disturbed nutritious status and internal ion balance, and a boosted antioxidant defense system (Improved antioxidant enzymes and reduced ROS accumulation). In contrast, these adverse effects of NaCl were ameliorated by the additions of Si and Asp, regardless of Si, Asp, or both. Moreover, the mitigatory impacts of the co-application of Si and Asp on salt stress were more pronounced compared to when one of them was solely applied. Collectively, exogenous Si and Asp alleviate the degree of salt stress and thereby improve the salt tolerance of celery. [ABSTRACT FROM AUTHOR]

The spectral quality of light regulates plant growth through a variety of physiological, biochemical, and molecular processes. Earlier research on ginseng sprouts have largely focused on the impact of monochromatic lights, with limited attention to combinations with white light. The present study explored the influence of white light supplemented with different wavelengths on ginseng sprout growth at both low (30) and high (200) µmol m− 2 s− 1 PPFD intensities. Significant variations in growth were noted between the two light intensities. Specifically, the green light combination proved advantageous for enhancing both growth and photosynthesis across both intensity levels. The chlorophyll fluorescence characteristics, stomatal properties, total soluble sugars, total soluble proteins, and root activity were notably enhanced by W + G (200 PPFD) treatment. Enzymatic and non-enzymatic antioxidant activities were predominantly influenced by W + R treatments at both intensity levels. Low light, particularly, W + R (30 PPFD) and W + G (30 PPFD) significantly increased mineral content in both the shoot and root. Low light intensities positively influenced the accumulation of ginsenosides Rd, F2, and Rg1 in treatments W, W + R, and W + G, respectively while Rd2 accumulation was greatly promoted by high intensity white light treatment, W (200 PPFD). Gene expression involved in the ginsenoside biosynthesis pathway aligned with ginsenoside accumulation. Therefore, to meet the growing demand for ginseng sprouts, optimizing light quality, particularly by incorporating green or red light in conjunction with white light, might serve as a promising approach for enhancing both the quality and yield of ginseng sprouts within the controlled environment agriculture system.Key message: Under high light intensity, W + G LEDs enhanced growth and photosynthesis, while W + R LEDs boosted antioxidant activity. Conversely, at low light intensity, they boosted the minerals and ginsenosides of ginseng sprouts. [ABSTRACT FROM AUTHOR]

The strawberry (Fragaria × ananassa Duch.) "Sulhyang" is a typical seasonal flowering (SF) strawberry that produces flower buds in day lengths shorter than a critical limit (variable, but often defined as <12 h). There is a trade-off between photoperiod-controlled flowering and gibberellin (GA) signaling pathway-mediated runnering. Some related genes (such as CO, FT1, SOC1, and TFL1) participating in light signaling and circadian rhythm in plants are altered under blue light (BL). Sugars for flowering and runnering are mainly produced by photosynthetic carbon assimilation. The intensity of light could affect photosynthesis, thereby regulating flowering and runnering. Here, we investigated the effect of the intensity of supplemental blue light (S-BL) or night-interrupting blue light (NI-BL) in photoperiodic flowering and runnering regulation by applying 4 h of S-BL or NI-BL with either 0, 10, 20, 30, or 40 μmol·m−2·s−1 photosynthetic photon flux density (PPFD) in a 10 h short-day (SD10) (SD10 + S-BL4 or + NI-BL4 (0, 10, 20, 30, or 40)) or 14 h long-day (LD14) conditions (LD14 + S-BL4 or + NI-BL4 (0, 10, 20, 30, or 40)). Approximately 45 days after the photoperiodic light treatment, generally, whether S-BL or NI-BL, BL (20) was the most promotive in runnering, leading to more runners in both the LD and SD conditions. For flowering, except the treatment LD14 + S-BL, BL (20) was still the key light, either from BL (20) or BL (40), promoting flowering, especially when BL acted as the night-interrupting light, regardless of the photoperiod. At the harvest stage, larger numbers of inflorescences and runners were observed in the LD14 + NI-BL4 treatment, and the most were observed in the LD14 + NI-BL (20). Moreover, the SD10 + NI-BL4 was slightly inferior to the LD14 + NI-BL4 in increasing the numbers of inflorescences and runners, but it caused earlier flowering. Additionally, the circadian rhythm expression of flowering-related genes was affected differently by the S-BL and NI-BL. After the application of BL in LD conditions, the expression of an LD-specific floral activator FaFT1 was stimulated, while that of a flowering suppressor FaTFL1 was inhibited, resetting the balance of expression between these two opposite flowering regulators. The SD runnering was caused by BL in non-runnering SD conditions associated with the stimulation of two key genes that regulate runner formation in the GA pathway, FaGRAS32 and FaGA20ox4. In addition, the positive effects of BL on enhancing photosynthesis and carbohydrate production also provided an abundant energy supply for the flowering and runnering processes. [ABSTRACT FROM AUTHOR]

Basil (Ocimum basilicum L.) contains abundant nutrients and is considered an economically important edible vegetable. The optimal nutrient levels will increase the productivity and basil quality. However, prominent research on basil regarding the diagnostic nutrient deficiency standard and the corresponding nutrient uptake is still scarce. To this end, the basil plants were hydroponically cultured and subjected to one of 14 nutrient solution treatments, corresponding to the omission of a single nutrient element (designated as -N, -P, -K, -Ca, -Mg, -NH4+, -NO3−, -S, -Fe, -Mn, -B, -Zn, -Mo, and -Cu) and a complete nutrient solution (CS) as the control. The most common nutrient deficiency symptoms were chlorosis, stunted roots and growth, and even leaf necrosis and abscission, in particular of -N, -P, -NO3−, and -Fe. We also found that basil is a NH4+-sensitive species. The photosynthetic capacity (photosynthesis pigments, Fv/Fm ratio, and greenness index) was disturbed to varying degrees when a single nutrient was omitted from the nutrient solution. Additionally, the omission of a specific single nutrient confers significant differences in the tissue nutrients, regardless of the macronutrients and micronutrients considered. Concomitantly, multivariate analysis suggested the correlations among certain important nutrients were distinctly different under different treatments (correlation analysis); the influences of different nutrient deficiencies on the tissue nutrient concentrations showed similarity (principal component analysis). Collectively, the growth, physiological, and biochemical changes studied in this trial not only improved our knowledge for diagnosing nutrient deficiency symptoms for practical cultivation but also provided a comprehensive understanding of the internal nutrient associations in basil. [ABSTRACT FROM AUTHOR]

Compared to the traditional production of ginseng roots, Panax ginseng sprouts (PGSs) are currently regarded as a substitute due to the relatively short-term culture but still high nutrition. However, the optimal light intensity for the growth ability of PGSs and the characterizations of the responses of PGSs to the light intensity have been largely neglected. This study aimed to determine the influences of the light intensity on the growth, morphogenesis, and photosynthetic responses in PGSs. To this end, two-year-old ginseng rootlets were subjected to one of six light intensities (from 30 to 280 PPFD with 50 PPFD intervals) in a plant factory with artificial lighting (PFAL) via LED light for 10 weeks. On the whole, the recorded parameters of the PGSs showed gradually decreasing trends in response to the increasing light intensities. However, the 80 PPFD-treated PGSs possessed similar or greater root dry weights, leaf areas, carotenoids levels, and photosynthesis (the maximal PSII quantum yield) compared to those in the 30 PPFD regime. Additionally, photoinhibition symptoms as evidenced by chlorosis, necrosis, and stunted growth were observed as the light intensity attained 180 PPFD. Thus, 130 PPFD could be considered a safe point for the appearance of photoinhibition in PGSs. Taken together, we show that the light intensity range of 30–80 PPFD is suitable for maximizing the production of PGSs in PFALs. [ABSTRACT FROM AUTHOR]

Nowadays, not only the roots, but also leaves and flowers of ginseng are increasingly popular ingredients in supplements for healthcare products and traditional medicine. The cultivation of the shade-loving crop, ginseng, is very demanding in terms of the light environment. Along with the intensity and duration, light direction is another important factor in regulating plant morphophysiology. In the current study, three lighting directions—top (T), side (S), or top + side (TS)—with an intensity of 30 ± 5 μmol·m−2·s−1 photosynthetic photon flux density (PPFD) were employed. Generally, compared with the single T lighting, the composite lighting direction, TS, was more effective in shaping the ginseng with improved characteristics, including shortened, thick shoots; enlarged, thick leaves; more leaf trichomes; earlier flower bud formation; and enhanced photosynthesis. The single S light resulted in the worst growth parameters and strongly inhibited the flower bud formation, leading to the latest flower bud observation. Additionally, the S lighting acted as a positive factor in increasing the leaf thickness and number of trichomes on the leaf adaxial surface. However, the participation of the T lighting weakened these traits. Overall, the TS lighting was the optimal direction for improving the growth and development traits in ginseng. This preliminary research may provide new ideas and orientations in ginseng cultivation lodging resistance and improving the supply of ginseng roots, leaves, and flowers to the market. [ABSTRACT FROM AUTHOR]

Panax ginseng sprouts (PGS) have the advantage of requiring short-term cultivation while maintaining higher ginsenoside contents than traditional ginseng seedlings. It is feasible to improve their yield capacity by manipulating physical factors such as temperature and light. This study therefore investigated the effects of the DIF (difference between day and night temperature) and LI (light intensity) on the growth and photosynthetic characteristics of PGS. To this end, four DIF treatments (18/22 °C, 20/20 °C, 22/22 °C, 22/18 °C), corresponding to two LI regimes (20 PPFD, 200 PPFD), were applied on one-year-old ginseng rootlets in closed-type plant production systems (CPPSs). The PGS had distinctly different responses to the eight treatments. In particular, we found that negative DIF considerably hampered the growth and development of roots, shoots, leaves, and photosynthesis, regardless of the LI considered. The PGS treated with 20/20 °C combined with 20 PPFD displayed the best root growth, shoot development, leaf area, as well as optimal photosynthetic ability. On the other hand, we further showed that the root growth rate was positively correlated with the stem diameter, leaf traits, and photosynthetic ability, whereas it was negatively correlated with the petiole length, stem length, and shoot length. Collectively, 20/20 °C combined with 20 PPFD was the optimal condition in the current study, and may be regarded as a successful strategy for large-scale productions of PGS. [ABSTRACT FROM AUTHOR]

Ammonium sensitivity is considered a globally stressful condition that affects overall crop productivity. The major toxic symptom associated with ammonium nutrition is growth retardation, which has been associated with a high energy cost for maintaining ion, pH, and hormone homeostasis and, eventually, the NH3/NH4+ level in plant tissues. While certain species/genotypes exhibit extreme sensitivity to ammonium, other species/genotypes prefer ammonium to nitrate as a form of nitrogen. Some of the key tolerance mechanisms used by the plant to deal with NH4+ toxicity include an enhanced activity of an alternative oxidase pathway in mitochondria, greater NH4+ assimilation plus the retention of the minimum level of NH4+ in leaves, and/or poor response to extrinsic acidification or pH drop. Except for toxicity, ammonium can be considered as an energy-efficient nutrition in comparison to nitrate since it is already in a reduced form for use in amino acid metabolism. Through effective manipulation of the NH4+/NO3 − ratio, ammonium nutrition can be used to increase productivity, quality, and resistance to various biotic and abiotic stresses of crops. This review highlights recent advancements in ammonium toxicity and tolerance mechanisms, possible strategies to improve ammonium tolerance, and omics-based understanding of nitrogen use efficiency (NUE) in plants. [ABSTRACT FROM AUTHOR]

Petunia hybrida Hort. "Easy Wave Pink", a qualitative long-day plant (LDP), was investigated to study the effects of the night interruption light (NIL) provided by light-emitting diodes (LEDs) quality shifting on the morphogenesis, blooming, and transcription of photoreceptor genes. Plants were grown in a closed-type plant factory employing white (W) LEDs at an intensity of 180 μmol·m−2·s−1 PPFD provided for short day (SD, 10 h light, 14 h dark), long day (LD, 16 h light, 8 h dark), or SD with 4 h night interruption (NI) with LEDs at an intensity of 10 μmol·m−2·s−1 PPFD. The NIL quality was shifted from one light spectrum to another after the first 2 h of NI. Light treatments consisting of all possible pairings of W, far-red (Fr), red (R), and blue (B) light were tested. The SD and LD were referenced as the control, while 12 NI treatments involved altering LED NIL qualities, as follows: from R to B (NI-RB), from B to R (NI-BR), from Fr to R (NI-FrR), from R to Fr (NI-RFr), from Fr to B (NI-FrB), from B to Fr (NI-BFr), from B to W (NI-BW), from W to B (NI-WB), from W to Fr (NI-WFr), from Fr to W (NI-FrW), from W to R (NI-WR), and from R to W (NI-RW). The NI-RFr resulted in the longest shoots, while the NI-WR and NI-RW resulted in the shortest shoots. NI-WR, NI-RW, NI-BW, NI-WB, NI-RFr, NI-RB, NI-BR, and LD all exhibited flowering. High-level expressions of photoreceptor genes were confirmed in the NI-RFr, NI-FrR, NI-BFr, NI-RW, and NI-WR treatments. Morphogenesis and blooming were both impacted by the photoperiod. The first NIL had no effects on the flowering or the morphogenesis, but the second NIL had a profound impact on both. [ABSTRACT FROM AUTHOR]

This study examines how the day neutral plant (DNP) Pelargonium × hortorum L.H. Bailey 'Ringo 2000 Violet' is impacted by LED night-interruption light (NIL) quality shifting in terms of flowering, morphogenesis, and transcription of photoreceptor genes. A closed-type plant factory with white (W) LEDs providing 180 μmol·m−2·s−1 PPFD light for long day (LD, 16 h light, 8 h dark), short day (SD, 10 h light, 14 h dark), or SD with 4 h night interruption (NI) with 10 μmol·m−2·s−1 PPFD LEDs was used to grow the plants. Two NIL qualities were employed, where after the first two hours, the NIL quality was switched from one to another among white (W), far-red (Fr), red (R), and blue (B). A total of 12 SD treatments with NIL quality shifting were used, with the LD and SD serving as the control: NI-BR (from B to R), NI-RB (from R to B), NI-RFr (from R to Fr), NI-FrR (from Fr to R), NI-BFr (from B to Fr), NI-FrB (from Fr to B), NI-WB (from W to B), NI-BW (from B to W), NI-FrW (from Fr to W), NI-WFr (from W to Fr), NI-RW (from R to W), and NI-WR (from W to R). LD refers to a 16 h long-day treatment. Geranium plants were taller in NI treatments that included Fr light than those in other NI treatments and were the shortest in the NI-WB treatment. Flowering was seen in all treatments and was notably encouraged by NI with Fr light, regardless of the sequence of light quality applied. In NI-FrR and NI-RFr, high expressions of phyA, phyB, and cry1 were observed. Flower formation and plant morphogenesis were both impacted by the photoperiod. Both morphogenesis and flowering were strongly impacted by the second NIL, but the first NIL had no effects on either. These findings indicate that NI-RFr and NI-FrR improve flowering, which may be used for commercial DNP production. [ABSTRACT FROM AUTHOR]

The flowering of chrysanthemum (Chrysanthemum morifolium Ramat.), inhibited by long-day lighting, can be reversed with a short period of low supplemental blue light (S-BL). Both flowering and the reactive oxygen species (ROS) scavenging processes are primarily driven by sugars created by photosynthetic carbon assimilation. In addition, the antioxidant ability potentially affects flowering in photoperiod- and/or circadian rhythm-dependent manners. This indicates that there is an interactive relationship among blue (B) light, photosynthetic efficiency, sugar accumulation, and antioxidant ability in flowering regulation. Here, 4 h of 30 μmol·m−2·s−1 photosynthetic photon flux density (PPFD) S-BL was applied at the end of a 13-h long-day period (LD13 + 4B) at different intervals during 60 days of experimental duration. The five experimental groups were named according to the actual number of days of S-BL and their intervals: applied once every day, "60 days-(LD13 + 4B) (100.0%)"; once every other day, "30 days-(LD13 + 4B) (50.0%)"; once every three days, "15 days-(LD13 + 4B) (25.0%)"; once every five days, "10 days-(LD13 + 4B) (16.7%)"; and once every seven days, "7 days-(LD13 + 4B) (11.7%)". Two non-S-BL control groups were also included: 60 10-h short days (60 days-SD10) and 13-h long days (60 days-LD13). At the harvest stage, varying degrees of flowering were observed except in "60 days-LD13" and "7 days-(LD13 + 4B) (11.7%)". The number of flowers increased and the flower buds appeared earlier as the proportion of S-BL days increased in LD13 conditions, although the "60 days-SD10" gave the earliest flowering. The proportion of initial, pivotal, and optimal flowering was 16.7% ("10 days-(LD13 + 4B)"), 50.0% ("30 days-(LD13 + 4B)"), and 100.0% ("60 days-(LD13 + 4B)"), respectively. Meanwhile, a series of physiological parameters such as the production of enzymatic or non-enzymatic antioxidants, chlorophyll content, photosynthetic efficiency, enzyme activities, and carbohydrate accumulation were significantly improved by "30 days-(LD13 + 4B) (50.0%)" as a turning point until the peaks appeared in "60 days-(LD13 + 4B) (100.0%)", as well as the expression of florigenic or anti-florigenic and some antioxidant-synthetic genes. Furthermore, the results of principal component analysis (PCA) indicated that S-BL days positively regulated flowering, photosynthesis, carbohydrate accumulation, and antioxidant production. In aggregate, the pivotal and optimal proportions of S-BL days to reconcile the relationship among flowering, photosynthetic carbon assimilation, and antioxidant ability were 50.0% and 100.0%, respectively. However, there are still significant gaps to be filled in order to determine the specific involvement of blue light and antioxidant abilities in flowering regulation. [ABSTRACT FROM AUTHOR]

Ssamchoo is recently attracting attention as a household hydroponic vegetable in Korea. It has a refreshing texture and a rich content of vitamins and fiber. Ssamchoo with a wide leaf area is suitable for traditional ssam or vegetable wraps, as well as a vegetable for salads; thus, it can be used in a variety of dishes. However, Ssamchoo plants responds sensitively to the nutrient solution, and it is often difficult to secure sufficient leaf area and robust growth using a commercial nutrient solution for leafy vegetables. This study consisted of three experiments conducted to develop the nutrient solution for Ssamchoo grown in a newly developed home hydroponic cultivation system using light-emitting diodes as the sole source of light. In the first experiment, growth and development of Ssamchoo in a representative commercial nutrient solution, Peters Professional (20-20-20, The Scotts Co., Marysville, OH, USA), was compared with laboratory-prepared nutrient solutions, GNU1 and GNU2. As a result, the Ssamchoo grown in Peters Professional had a high NH4+ content in the tissue, leaf yellowing, darkened root color, and suppressed root hair development. In addition, adverse effects of ammonium such as low fresh weight and shorter shoot length were observed. In the second experiment, Peters Professional was excluded, and the ratio of NO3− to NH4+ in the GNU1 and GNU2 nutrient solutions was set to four levels each (100:0, 83.3:16.7, 66.7:33.3, and 50:50). As a result, the fresh weights of 83.3:16.7 and 66.7:33.3 were the greatest, and the leaf color was a healthy green. However, at 100:0 and 50:50 NO3−/NH4+ ratios, the fresh weight was low, and leaf yellowing, tip burn, and leaf burn appeared. The nutrient solution with a 83.3:16.7 NO3−- to-NH4+ ratio, which gave the greatest fresh weight in the second experiment, was chosen as the control, while the solution with a 50:50 NO3−/NH4+ ratio with a lower nitrate content among the two unfavorable treatments was selected as a treatment group for the next experiment. In the third experiment, NH4+ was partially replaced with urea to make four different ratios of NO3− to NH4+ to urea (83:17:0, 50:50:0, 50:25:25, and 50:0:50) in combination with two levels of Si (0 and 10.7 mmol·L−1 Si). The greatest fresh weight was obtained in the treatment in which the NO3−/NH4+/urea ratio was 50:25:25. In particular, when Si was added to the solution, there was no decrease in the number of leaves, and plants with the greatest fresh weight, chlorophyll content, and leaf area were obtained. The number of leaves and leaf area are important indicators of high productivity since the Ssamchoo is used in ssam dishes. It can be concluded that a solution with a NO3−/NH4+/urea ratio of 50:25:25 and supplemented with 10.7 mmol·L−1 Si is the most suitable nutrient solution for growing Ssamchoo in the home hydroponic system developed. [ABSTRACT FROM AUTHOR]

As a commercial high-grade cut flower, the marketability of herbaceous peony (Paeonia lactiflora Pall.) is limited by its short vase life in water. Si (silicon) is an alternative to improve the postharvest life of cut flowers. However, the effects of the combined application of Si and preservatives on the postharvest performance of cut peony flowers are unknown. In this study, the effects of a Si application and a preservative alone and collegial on the longevity of the vase life, water loss, antioxidant defense system, and stock carbohydrates level of cut flowers of three peony cultivars were investigated. It was observed that Si effectively prolonged the vase life, while the preservative alone, to a lesser extent, but markedly induced an early flowering and a greater flower diameter (flower open degree). The simultaneous use of Si and the preservatives not only showed larger flowers, but also improved the postharvest performance as characterized by an extended vase life and delayed the water loss. In addition, the Si supplementation dramatically intensified the antioxidant defense system (ameliorated antioxidant enzymes and alleviated ROS accumulation) in petals but did not increase the stock carbohydrates (starch and soluble sugars) levels, as compared to the treatment with the preservative alone. We show that a Si supplementation to a preservative is highly recommended for a large-scale use to promote the postharvest performance and competitiveness of marketed cut flowers. [ABSTRACT FROM AUTHOR]

The ornamental plant Cotoneaster wilsonii Nakai is a rare endemic species to the Ulleung Island in Korea. There is an urgent need to develop efficient propagation methods to preserve this endangered plant species. The cytokinin thidiazuron (TDZ) at a concentration of 0, 1.0, 2.0, or 3.0 mg·L−1 combined with 0, 0.5, 1.0, or 1.5 mg·L−1 a-naphthaleneacetic acid (NAA) was used to induce calli from young leaf explants on the Murashige and Skoog (MS) medium. The TDZ and/or 6-benzyladenine at a concentration of 0, 0.5, or 1.0 mg·L−1 combined with 0.2 mg·L−1 NAA was supplied to the MS medium to induce shoots from calli. Four auxins at 0, 0.2, 0.4, 0.6, 0.8, or 1.0 mg·L−1 were supplied to half-strength MS medium for root induction. The treatment of TDZ at 1.0 mg·L−1 combined with 1.5 mg·L−1 NAA not only had 100% callus induction ratio, but also induced the heaviest calli. The shoot induction ratio was the greatest with TDZ at 1.0 mg·L−1, and the greatest root induction ratio was obtained with IAA at a concentration of 0.8 mg·L−1. In conclusion, an effective indirect organogenesis system was established for C. wilsonii Nakai. [ABSTRACT FROM AUTHOR]

Deficiency or excess of iron (Fe) and improper medium pH will inhibit the growth and development of plants, reduce the transfer and utilization of energy from the root to the leaf, and affect the utilization efficiency of inorganic nutrients. The most common symptom of Fe deficiency in plants is chlorosis of the young leaves. In this study, the effects of the iron source, in combination with the medium pH, on plant growth and development, plant pigment synthesis, and nutrient uptake in a model plant Petunia hybrida cultured in vitro were investigated. Iron sulfate (FeSO4·7H2O) or iron chelated with ethylenediaminetetraacetic acid (Fe-EDTA) were supplemented to the MNS (a multipurpose nutrient solution) medium at a concentration of 2.78 mg·L−1 Fe, and the treatment without any Fe was used as the control. The pH of the agar-solidified medium was adjusted to either 4.70, 5.70, or 6.70 before autoclaving. The experiment was carried out in an environmentally controlled culture room with a temperature of 24 °C with 100 µmol·m−2·s−1 photosynthetic photon flux density (PPFD) supplied by white light emitting diodes (LEDs) during a photoperiod of 16 h a day, 18 °C for 8 h a day in the dark, and 70% relative humidity. Regardless of the Fe source including the control, the greatest number of leaves was observed at pH 4.70. However, the greatest lengths of the leaf and root were observed in the treatment with Fe-EDTA combined with pH 5.70. The contents of the chlorophyll, carotenoid, and anthocyanin decreased with increasing medium pH, and contents of these plant pigments were positively correlated with the leaf color. The highest soluble protein content and activities of APX and CAT were observed in the Fe-EDTA under pH 5.70. However, the GPX activity was the highest in the control under pH 4.70. In addition, the highest contents of ammonium (NH4+) and nitrate (NO3−) were measured in the FeSO4-4.7 and EDTA-5.7, respectively. More than that, the treatment of Fe-EDTA combined with pH 5.70 (EDTA-5.7) enhanced nutrient absorption, as proven by the highest tissue contents of P, K, Ca, Mg, Fe, and Mn. The genes' ferric reduction oxidase 1 and 8 (PhFRO1 and PhFRO8), iron-regulated transporter 1 (PhIRT1), nitrate transporter 2.5 (PhNRT2.5), and deoxyhypusine synthase (PhDHS) were expressed at the highest levels in this treatment as well. In the treatment of EDTA-5.7, the reduction and transport of chelated iron in P. hybrida leaves were enhanced, which also affected the transport of nitrate and catalyzed chlorophyll level in leaves. In conclusion, when the medium pH was adjusted to 5.70, supplementation of chelated Fe-EDTA was more conducive to promoting the growth and development of, and absorption of mineral nutrients by, the plant and the expression of related genes in the leaves. [ABSTRACT FROM AUTHOR]

Ammonium (NH4+) toxicity seriously hampers the yield and quality of salvia plants because most varieties or sub-species are highly sensitive to NH4+. Silicon (Si) is an alternative that is used to minimize these disturbances and maintain better growth under NH4+ toxicity. Nevertheless, the mitigatory effects of Si on NH4+-stressed salvia are unknown. Therefore, this study was carried out to determine how Si assists to alleviate the NH4+ toxicity degree in salvia. To this end, salvia plants were cultivated in a controlled environment supplied with a constant N (nitrogen) level (13 meq·L−1) in the form of three NH4+:NO3− ratios (0:100, 50:50, 100:0), each with (1.0 meq·L−1) or without Si. Physiological disorders and typical NH4+ toxicity symptoms, as well as interrupted photosynthesis, were observed in the 100% NH4+-treated plants. Furthermore, cation uptake inhibition and oxidative damage were also imposed by the 100% NH4+ supply. In contrast, in the presence of Si, the NH4+ toxicity degree was attenuated and plant growth was ensured. Accordingly, the NH4+ toxicity appearance ratio decreased significantly. Furthermore, Si-treated plants showed an ameliorated photosynthetic ability, elevated internal K and Ca levels, and enhanced antioxidative capacity, as reflected by improved major antioxidant enzyme activities, as well as diminished accumulation of ROS (reactive oxygen species) and MDA (malondialdehyde). Our findings enlightened the agronomic importance of additional Si to nutrient solutions, especially pertaining to bedding plants at risk of NH4+ toxicity. [ABSTRACT FROM AUTHOR]

Kalanchoe (Kalanchoe blossfeldiana) is a qualitative short-day plant with a high aesthetic value. When the night length is less than a specified cultivar-dependent critical value, however, it does not develop flowers. This study investigated the effects of low-intensity supplementary or night interrupting (NI) blue (B) light on the plant performance and flower induction in kalanchoe 'Rudak'. During the photoperiod in a closed-type plant factory with day/night temperatures of 23 °C/18 °C, white (W) LEDs were utilized to produce a photosynthetic photon flux density (PPFD) of 300 μmol m−2 s−1, and B LEDs were used to give supplementary/NI light at a PPFD of 10 μmol m−2 s−1. The control plants were exposed to a 10-h short day (SD, positive control) or a 13-h long day (LD, negative control) treatment without any B light. The B light was used for 4 h either (1) to supplement the W LEDs at the end of the SD (SD + 4B) and LD (LD + 4B), or (2) to provide night interruption (NI) in the SD (SD + NI-4B) and LD (LD + NI-4B). The LD + 4B and LD + NI-4B significantly enhanced plant growth and development, followed by the SD + 4B and SD + NI-4B treatments. In addition, the photosynthesis, physiological parameters, and activity of antioxidant systems were improved in those treatments. Except in the LD and LD + NI-4B, all plants flowered. It is noteworthy that kalanchoe 'Rudak' flowered in the LD + 4B treatment and induced the greatest number of flowers, followed by SD + NI-4B and SD + 4B. Plants grown in the LD + 4B treatment had the highest expression levels of certain monitored genes related to flowering. The results indicate that a 4-h supplementation of B light during the photoperiod in both the SD and LD treatments increased flower bud formation, promoted flowering, and enhanced plant performance. Kalanchoe 'Rudak' flowered especially well in the LD + 4B, presenting a possibility of practically inducing flowering in long-day seasons with B light application. [ABSTRACT FROM AUTHOR]

Silicon (Si) has beneficial effects on not only plant growth but also against biotic and abiotic stresses. However, a few studies focus on how Si application helps strawberry (Fragaria × ananassa Duch.) resist powdery mildew. The aim of this work was to find out the optimal Si application method before cutting propagation to enhance the resistance to powdery mildew in strawberry "daughter" plants. Naturally infected "mother" plants of 'Sulhyang', 'Maehyang', and 'Kuemsil' strawberries were supplied with Si. Potassium silicate (K2SiO3) at a final concentration of 75 mg·L−1 Si was either added to the medium for drenching or sprayed to the leaves of the "mother" or "daughter" plant, or soluble Si fertilizer was used to dress the "mother" plant. The Si application significantly increased the shoot fresh weight of the "daughter" plants. Supplemental Si also increased the contents of phosphorus (P), potassium (K), and magnesium (Mg). In addition, the Si treatment decreased the damage of powdery mildew by increased level of proline content and suppressive reactive oxygen species. After applying Si, the length and density of hyphae on the leaf surface decreased. In addition, the infected area of "daughter" plant leaves covered with powdery mildew decreased. This study also demonstrated that Si increased the expression of resistance-gene and decreased the expression of susceptibility-gene of strawberry. Overall, Si application promoted the growth of the "daughter" plants regardless of the application method. Direct foliar Si spray to the "daughter" plants before cutting propagation is recommended to increase their resistance to powdery mildew. [ABSTRACT FROM AUTHOR]

Plant disease and insect pests are major limiting factors that reduce crop production worldwide. The ornamental indoor cultivation cash crop dwarf coffee Punica arabica 'Pacas' is also troubled by these issues. Silicon (Si) is one of the most abundant elements in the lithosphere and positively impacts plant health by effectively mitigating biotic and abiotic stresses. Several studies have shown that Si activates plant defense systems, although the specific nature of the involvement of Si in biochemical processes that lead to resistance is unclear. In our study, Si significantly promoted the growth and development of dwarf coffee seedlings grown in plant growth chambers. More than that, through natural infection, Si suppressed disease and insect pests by improving physiology (e.g., the strong development of the internal structures of roots, stems, and leaves; higher photosynthetic efficiency; more abundant organic matter accumulation; the promotion of root activity; the efficient absorption and transfer of mineral elements; and various activated enzymes) and up-regulating defense genes (CaERFTF11 and CaERF13). Overall, in agriculture, Si may potentially contribute to global food security and safety by assisting in the creation of enhanced crop types with optimal production as well by mitigating plant disease and insect pests. In this sense, Si is a sustainable alternative in agricultural production. [ABSTRACT FROM AUTHOR]

The ammonium (NH4+) tolerance of plants is an important issue in agriculture, associated with several plant characteristics. So far, plant tissue acidification has been shown as the primary cause of NH4+ toxicity. Suppressed plant growth caused by excess NH4+ can be counteracted by potassium (K+) application. However, the effects of NH4+ tolerances on the differences regarding pH changes together with K+ uptake remain to be determined. Here, we performed an 84 h hydroponic cultivation of five species with different NH4+ tolerances, subjected to three NH4+:NO3− solutions (0:100, 50:50, or 100:0), to investigate the pH changes and ion uptakes. Consequently, the solution pH was lowered over time to varying extents in the presence of NH4+. The NH4+-tolerant ageratum and lettuce, shown to be tolerant to NH4+ in this trial, rapidly lowered the solution pH, whereas extremely NH4+-sensitive salvia and cabbage only gave a minor decrease in the solution pH when grown with 100:0 NH4+:NO3−. Additionally, the increased external NH4+ level led to a substantial decline in the net cation influxes (K+, Ca2+, and Mg2+). As compared to solely NH4+-fed salvia and cabbage, solely NH4+-fed ageratum and lettuce ultimately showed a relatively greater net K+ influx. Taken together, this study discusses how the decreases in pH and K+ are related to NH4+ tolerance in five hydroponically cultured species. [ABSTRACT FROM AUTHOR]

Seleno-amino acids are safe, health-promoting compounds for humans. Numerous studies have focused on the forms and metabolism of seleno-amino acids in vegetables. Based on research progress on seleno-amino acids, we provide insights into the production of selenium-enriched vegetables with high seleno-amino acids contents. To ensure safe and effective intake of selenium, several issues need to be addressed, including (1) how to improve the accumulation of seleno-amino acids and (2) how to control the total selenium and seleno-amino acids contents in vegetables. The combined use of plant factories with artificial lighting and multiple analytical technologies may help to resolve these issues. Moreover, we propose a Precise Control of Selenium Content production system, which has the potential to produce vegetables with specified amounts of selenium and high proportions of seleno-amino acids. [ABSTRACT FROM AUTHOR]

Air pollution is regarded as an increasingly threatening, major environmental risk for human health. Seven million deaths are attributed to air pollution each year, 91% of which is due to particulate matter. Vegetation is a xenobiotic means of removing particulate matter. This review presents the mechanisms of PM capture by plants and factors that influence PM reduction in the atmosphere. Vegetation is ubiquitously approved as a PM removal solution in cities, taking various forms of green infrastructure. This review also refers to the effectiveness of plant exploitation in GI: trees, grasslands, green roofs, living walls, water reservoirs, and urban farming. Finally, methods of increasing the PM removal by plants, such as species selection, biodiversity increase, PAH-degrading phyllospheric endophytes, transgenic plants and microorganisms, are presented. [ABSTRACT FROM AUTHOR]

Phosphorus (P) availability is usually low in soils around the globe. Most soils have a deficiency of available P; if they are not fertilized, they will not be able to satisfy the P requirement of plants. P fertilization is generally recommended to manage soil P deficiency; however, the low efficacy of P fertilizers in acidic and in calcareous soils restricts P availability. Moreover, the overuse of P fertilizers is a cause of significant environmental concerns. However, the use of arbuscular mycorrhizal fungi (AMF), phosphate–solubilizing bacteria (PSB), and the addition of silicon (Si) are effective and economical ways to improve the availability and efficacy of P. In this review the contributions of Si, PSB, and AMF in improving the P availability is discussed. Based on what is known about them, the combined strategy of using Si along with AMF and PSB may be highly useful in improving the P availability and as a result, its uptake by plants compared to using either of them alone. A better understanding how the two microorganism groups and Si interact is crucial to preserving soil fertility and improving the economic and environmental sustainability of crop production in P deficient soils. This review summarizes and discusses the current knowledge concerning the interactions among AMF, PSB, and Si in enhancing P availability and its uptake by plants in sustainable agriculture. [ABSTRACT FROM AUTHOR]

The current study has determined the effect of red and blue lights on the enhancement of growth, antioxidant property, phytochemical contents, and expression of proteins in Scrophularia kakudensis. In vitro -grown shoot tip explants of S. kakudensis were cultured on the plant growth regulator-free Murashige and Skoog (MS) medium and cultured under the conventional cool white fluorescent lamp (control), blue light-emitting diodes (LED) light, or red LED light. After 4 weeks, growth, stomatal ultrastructure, total phenols and flavonoids, activities of antioxidant enzymes, and protein expressions were determined. Interestingly, blue or red LED treatment increased the shoot length, shoot diameter, root length, and biomass on comparison with the control. In addition, the LED treatments enhanced the contents of phytochemicals in the extracts. The red LED treatment significantly elicited the accumulation of flavonoids in comparison with the control. In accordance with the secondary metabolites, the LED treatments modulated the activities of antioxidant enzymes. Moreover, the proteomic insights using two-dimensional gel electrophoresis system revealed the proteins involved in transcription and translation, carbohydrate mechanism, post-translational modification, and stress responses. Taken together, the incorporation of blue or red LED during in vitro propagation of S. kakudensis can be a beneficial way to increase the plant quality and medicinal values of S. kakudensis. [ABSTRACT FROM AUTHOR]

Callus induction is an important stage in micropropagation. In this study, embryos, cotyledons, and hypocotyls of tree peony (Paeonia ostii 'Fengdan') were used as explants to induce callus formation. Callus induction was largely influenced by the medium, plant growth regulator, and explant. All combinations of the medium and plant growth regulator were conducive to callus induction from zygotic embryos, where the ratio of explants with callus induction was very high in all of the combinations. The greatest ratio of explants with callus induction from the cotyledon explants was found on Woody Plant Medium (WPM) or Murashige and Skoog (MS) medium supplemented with both 0.5 mg L−1 thidiazuron (TDZ) and either 0.5 mg L−1 2,4-dichlorophenoxyacetic acid (2,4-D) or 0.5 mg L−1 1-naphthaleneacetic acid (NAA), and on the WPM containing 0.5 mg L−1 NAA and 0.5 mg L−1 6-benzylaminopurine (BA). The ratio of explants with callus induced from the hypocotyl explants was the greatest on either MS medium or WPM supplemented with both 0.5 mg L−1 2,4-D and 0.5 mg L−1 TDZ. In contrast, a combination of 0.5 mg L−1 2,4-D and 0.5 mg L−1 TDZ, or 0.5 mg L−1 NAA and 0.5 mg L−1 TDZ was highly likely to cause a browning problem during culture. For browning suppression, calcium chloride (CaCl2), polyvinyl pyrrolidone (PVP), gallic acid, and caffeic acid were much more effective than other reagents. The efficacy on browning suppression was concentration-dependent, and the best results were obtained at a concentration of 4.0 mg L−1 CaCl2, 1.0–2.0 g L−1 PVP, 0.5–1.0 mg L−1 gallic acid, and 0.5–1.0 mg L−1 caffeic acid, respectively. In summary, callus formation was successfully induced from the zygotic embryo, cotyledon, and hypocotyl explants, and callus browning was effectively suppressed by caffeic acid (0.5–1.0 mg L−1), gallic acid (1.0 mg L−1), CaCl2 (4.0 mg L−1), and PVP (1.0 g L−1). [ABSTRACT FROM AUTHOR]

Chrysanthemum (Dendranthema grandiflorum Kitamura), a qualitative short-day plant, does not produce flowers when the night length is shorter than a cultivar-dependent critical value. Flowering is effectively inhibited when the required uninterrupted night period is broken by short periods of exposure to night interruption lights (NILs). The effects of the quality and positioning of the NIL on the morphogenesis, flowering, and photoperiodic gene expressions of chrysanthemum were investigated. Blue (NI-B), red (NI-R), far-red (NI-Fr), and white (NI-W) light-emitting diodes (LEDs) at an intensity of 10 μmol m−2 s−1 photosynthetic photon flux density (PPFD) were used to interrupt the dark period or plants grown in a closed walk-in growth chamber at night for a total of 4 h. The NILs were positioned to illuminate either the shoot tip, youngest mature leaf (vigorously growing third leaf from the shoot tip), or old leaf (third leaf from the stem base). The NI-R on the shoot tip and all NI-Fr treatments increased the plant extension growth, to a similar height observed in plants in long-day (LD) treatments. Extension growth was generally suppressed for plants in the NI-B, and plant height was the smallest when NI-B was shed onto the old leaf. Plants in all NIL treatments except NI-Fr showed a negative correlation between the plant height and the age of the leaf (or tissue) exposed to the NIL. Flowering was observed for plants in all treatments except for NI-R shed onto the shoot tip. The transcriptional factor PHYA was slightly expressed in plants which showed a flowering response. However, the CRY1, PHYB, and TFL was not expressed to levels reported previously, and the reason for low expression of these genes in these plants may be due to a combined effect of these genes with other flowering promoting and/or inhibiting genes. These results suggest that both the NIL quality and the age of the leaf (or tissue) exposed to the NIL affect the morphogenesis, flowering, and expression of transcriptional factors. Moreover, the previously known effects of the NIL quality on the morphogenesis as well as the vegetative to reproductive phase transition of plants were the most pronounced when the NIL irradiated the shoot tip, and the least pronounced when the NIL was shed onto the old leaf. Therefore, it seems that not only the appropriate quality, but also the appropriate positioning of the NIL, is important for optimizing flowering and plant extension growth. [ABSTRACT FROM AUTHOR]

The aim of the current study was to compare the effects of the culture method—conventional solid medium culture and temporary immersion system (TIS)—on the growth and development of carnation 'Dreambyul' plantlets. At the same time, different immersion intervals and immersion durations of TIS culture were also tested to find the optimal setting for mass production of high-quality carnation plantlets in vitro. In the first experiment, the results showed that the shoot length, root length, and number of nodes of plantlets cultured in the TIS were highest when the immersion interval was 8 h. Compared with that of plantlets cultured in the conventional solid medium culture, the fresh weight of plantlets cultured in the TIS was at least 3 times greater. The greatest total chlorophyll content, stomata with normal shapes was observed for plantlets grown in the TIS with an 8-h immersion interval. The lowest H2O2 level was recorded in plantlets cultured with the 8-h immersion interval. In the second study, growth traits such as the shoot length, root length, and stem diameter, as well as the number of shoots and roots tended to increase with immersion durations, and reached their peaks when the immersion duration was 90 s. Excessive water accumulation in tissues and a higher incidence of hyperhydricity were observed in plantlets where the immersion duration was 120 and 150 s. These findings suggest that an immersion interval of 8 h, combined with an immersion duration of 90 s, could be the optimal setting for growth and development of carnation 'Dreambyul' plantlets cultured in the TIS. [ABSTRACT FROM AUTHOR]

Among air pollutants, particulate matter (PM) has been identified as a major cause of environmental pollutants due to the advancement of industrial development and the generation of smaller particles. Particulate matter, in particular, is defined only by the size of particles and thus is not enough to study its composition yet. However, edible crops grown in contaminated atmospheres can be contaminated with heavy metals contained in particulate matter in the atmosphere, which can seriously damage food safety. In this study, we investigated the influence of the accumulation of particulate matter on leafy vegetables cultivated at areas with different levels of PM in atmosphere. Four districts of Gyeongsangnam-do were chosen to conduct this experiment: outdoor spaces of three respectively located in industrial, near-highway, and rural areas were considered, and research plant growth chambers at Gyeongsang National University were used as the control. After 3 weeks of cultivation in those conditions, the results showed that Pb in milligrams per kilogram of fresh weight (FW) was 0.383 in Chrysanthemum coronarium and 0.427 in Spinacia oleracea that were grown near the highway, which exceeded the 0.3 mg kg−1 FW standard set by the Republic of Korea, EU, and CODEX. However, when those vegetables were sufficiently washed with tap water, it was confirmed that the heavy metal content fell into the safety standard range. [ABSTRACT FROM AUTHOR]

Seedling production is the basis of most agricultural, especially horticultural, cultivation and is important for crop cultivation. The quality of seedlings directly affects the quality and yield of crops after transplanting. The scale of seedling production in the Republic of Korea has increased gradually and significantly, and the proportion of grafted seedlings of fruit vegetables has become increasingly important. The quality of grafted vegetable seedlings is valued by farmers more than before; thus, the quality of grafted seedlings of fruit vegetables has become an important area of study. To determine the direction of this research, we surveyed several representative seedling production growers in different provinces of the Republic of Korea. We investigated the graft healing methods used by Korean growers of fruit vegetable plug seedlings, including the light intensity, air temperature, and relative humidity in plug seedling cultivation greenhouses, graft healing tunnels, and closed-type graft healing factories in summer and winter seasons. It was found that the graft healing methods used by different growers varied. There were vast differences in air temperature and relative humidity between graft healing tunnels and closed-type healing factories. In greenhouses, the temperature in winter was low and the light intensity was insufficient, while the temperature in summer was high and relative humidity was too low to be optimal for grafted seedlings. Due to the differences in covering materials, the light spectrum in cultivation greenhouses and the graft healing spaces also varied among growers. In general, there were no standardized production models or environmental conditions for grafted plug seedling cultivation. Therefore, follow-up studies will be needed for the development of the grafted plug seedling industry in Republic of Korea. [ABSTRACT FROM AUTHOR]

Adenophora triphylla (Thunb.) A.DC., a well-known herbaceous medicinal species, has been reported to protect against human obesity, cancer, and inflammation. Supplementary lighting is a practical strategy to improve crop quality, especially at a propagation stage. However, there has been no study available on the optimal supplementary light source for the commercial production of A. triphylla seedlings. In this study, plug seedlings were cultivated in a greenhouse for four weeks under an average daily light intensity of 490 μmol·m−2·s−1 PPFD coming from the sun and a supplemental lighting (16 h per day) at 120 μmol·m−2·s−1 PPFD provided by high pressure sodium (HPS), metal halide (MH), far-red (FR) light, white LED (red: green: blue = 2:4:3, LED-w), or mixed (red: green: blue = 4:1:4) LED (LED-mix). The results showed that LED-mix, with a higher percentage of red and blue light, substantially promoted seedling growth compared to other treatments by increasing stem diameter, biomass, specific leaf weight, and root to shoot ratio. The LED-mix also promoted accumulation of soluble sugar, starch, and chlorophyll in the tissue and increased contents of total phenols and flavonoids. Moreover, stomata density and pore area per leaf area under the LED-mix were remarkably greater than those under other treatments. Furthermore, the Western blot analysis revealed that the expression of photosynthetic protein, D1, was notably enhanced by the LED-mix as compared with other light sources. In addition, the LED-mix alleviated the oxidative damage of seedlings by improving enzymatic and nonenzymatic antioxidant systems. Collectively, these results suggest that the LED-mix was the optimal supplementary light source for the production of highest quality A. triphylla seedlings. [ABSTRACT FROM AUTHOR]

Addressing the deterioration effects due to chlorine salt use as an anti-freezing agent to prevent the deposition of ice on roads during heavy snowfall is a serious issue to protect the ecosystem. Therefore, the present study was conducted to determine the effects caused by deicing agents on three different creeper plant species that commonly grow on roadsides, such as Trachelospermum asiaticum, Euonymus fortunei, and Gelsemium sempervirens. The two chlorine salts calcium chloride (CaCl2) and magnesium chloride (MgCl2) were applied to plants either as a splash or spray in different concentrations at different intervals. After 6 days of treatments, the results suggested that application of both CaCl2 and MgCl2 affected the chlorophyll content and physiological processes of the creepers in a dose-dependent manner. Further analysis of oxidative stress related parameters such as lipid peroxidation, superoxide, and hydrogen peroxide content showed that both CaCl2 and MgCl2 affected redox homeostasis. While the application of deicing agents induced the activities of antioxidant enzymes, they also decreased the content of ascorbate and proline, which are efficient osmolytes, in the dose-dependent manner. Nevertheless, comparatively oxidative stress induced by CaCl2 is higher than the MgCl2 in all three creeper-type plants included in our analysis; still the frequent application and higher concentration of both deicing agents interrupt the growth of roadside vegetation. Despite the relative toxicity of the deicers, T. asiaticum was affected lesser than E. fortunei and G. sempervirens. [ABSTRACT FROM AUTHOR]

We investigated the effects of the quality of light used for interrupting the night period, termed the night interruption light (NIL), on morphogenesis, flowering, and the expression of photoperiodic genes in chrysanthemum (Dendranthema grandiflorum) cultivar 'Gaya Yellow', a qualitative short-day (SD) plant. Plants were raised in a closed-type plant factory under white (W) light-emitting diodes (LEDs) providing a light intensity of 180 μmol m−2 s−1 photosynthetic photon flux density, under a condition of long-day (LD, 16 h light/8 h dark), short-day (SD, 10 h light/14 h dark), or SD with a 4-h night interruption (NI) provided by 10 μmol m−2 s−1 PPF green (NI-G), blue (NI-B), red (NI-R), far-red (NI-Fr), or W (NI-W) LEDs. Plants grown in the LD condition were the tallest. The SD, NI-B, and NI-Fr conditions induced flowering. Phytochrome A (phyA) and cryptochrome 1 (cry1) were expressed at high levels in plants in NI-B, NI-Fr, and SD conditions. These results suggest that the NIL quality has significant implications on morphogenesis, flowering, and the expression of photoperiodic genes. Flowering was positively affected by the expression of phyA, cry1, and FLOWERING LOCUS T (FT), whereas it was negatively affected by the expression of phyB and anti-florigenic FT/TFL1 (AFT). [ABSTRACT FROM AUTHOR]

This study reports the effect of explant type and plant growth regulators (PGRs) on callus induction in Cnidium officinale. Compared to stem, root explant showed maximum percent callus formation of 75% on Murashige and Skoog (MS) medium containing 2.3 µM 2,4-dichlorophenoxyacetic acid (2,4-D) and 2.2 µM benzyladenine (BA). At 30th day of callus culture on the said medium, callus fresh weight was sevenfold higher than other tested PGRs treatments. It was noted that MS medium supplemented with 27.1 µM 2,4-D showed the highest 0.30 mg g−1 DW of total phenols, while total flavonoids content reached to a maximum of 0.05 mg g−1 DW on the MS medium supplemented with 4.5 µM 2,4-D and 2.2 µM BA. Conversely, maximum (83.9%) DPPH free radical scavenging activity was observed in calli grown on the MS medium supplemented with 2.3 µM 2,4-D and 2.2 µM BA. The high-performance liquid chromatography (HPLC) analysis revealed higher phthalide content in callus than intact roots of in vitro plants. While 3-butylidenephthalide content in callus was comparable to the intact shoots and roots of in vitro grown C. officinale. The concentrations of 2,4-D played a significant role in the production of phthalide and 3-butylidenephthalide. Additional measures are recommended to further enhance their production in vitro.Graphical abstract: [ABSTRACT FROM AUTHOR]

The ice plant (Mesembryanthemum crystallinum L.), widely known to be an effective cure for diabetes mellitus, is also a functional crop. This study was conducted to examine the effects of light quality and intensity of monochromatic light-emitting diodes (LEDs) on ice plant growth and phytochemical concentrations in a closed-type plant production system. Ice plant seedlings were transplanted into a deep floating technique system with a recycling nutrient solution (EC 4.0 dS m−1, pH 6.5). Fluorescent lamps, as well as monochromatic red (660 nm) and blue (450 nm) LEDs, were used at 120 ± 5 or 150 ± 5 µmol m−2 s−1 PPFD with a photoperiod of 14 h/10 h (light/dark) for 4 weeks. Ice plants showed higher growth under the high light intensity treatment, especially under the red LEDs. Furthermore, the SPAD value and photosynthetic rate were higher under the red LEDs with 150 µmol m−2 s−1 PPFD. The ice plant phytochemical composition, such as antioxidant activity and myo-inositol and pinitol concentrations, were highest under the blue LEDs with 150 µmol m−2 s−1 PPFD. Total phenolic concentration was highest under the blue LEDs with 120 µmol m−2 s−1 PPFD. Despite a slightly different dependence on light intensity, phytochemical concentrations responded positively to the blue LED treatments, as compared to other treatments. In conclusion, this study suggests that red LEDs enhance ice plant biomass, while blue LEDs induce phytochemical concentrations. [ABSTRACT FROM AUTHOR]

The present study was to determine the factors that can reduce hyperhydricity in in vitro-propagated carnation genotypes. The carnation genotypes (Green Beauty, Purple Beauty, and Inca Magic) were grown in vitro under normal and hyperhydric conditions in white fluorescent light (FL) in which half of the hyperhydric plants were grown in red and blue LEDs (light emitting diodes). It was observed that hyperhydricity leads to oxidative stress in terms of TBARS (thiobarbituric acid reactive substances) content, whereas stress was alleviated by R (red) and B (blue) LEDs. The multiprotein complex proteins such as ATPase (RCI + LHC1) PSII-core dimer, PSII-monomer/ATPs synthase, and PSII-monomer/cyt b6f had decreased levels in hyperhydric conditions grown in white FL; however, the expression level of these photosynthetic proteins was retained in hyperhydric plants grown in R and B LEDs. Moreover, the immunoblots of two photosynthetic proteins (PsaA and PsbA) and stress-responsive proteins such as superoxide dismutase, ascorbate peroxidase, and catalase showed recovery of hyperhydricity in carnation genotypes grown in R and B LEDs. Our present study signifies that red (R) and blue light (B) LEDs reduced the hyperhydricity to control levels by maintaining the composition of thylakoid proteins and antioxidative defense mechanisms in carnation genotypes. [ABSTRACT FROM AUTHOR]

We examined the effect of source, concentration, and application method of silicon (Si) on the growth, development, and photosynthetic capacity of Fragaria × ananassa ‘Maehyang’ and ‘Seolhyang’. We applied 0, 35, or 70 mg L−1 Si in a potassium silicate (K2SiO3), sodium silicate (Na2SiO3), or calcium silicate (CaSiO3) solution to plants via subirrigational supply or foliar application. Plant height of ‘Maehyang’ was highest with the 70 mg L−1 Si Na2SiO3 foliar application, but it was not significantly different among treatments in ‘Seolhyang’. Crown size was not significantly affected by source, concentration, or application method in both cultivars. Elemental concentrations in the shoot and root of ‘Maehyang’ were the highest in the 35 mg L−1 Si Na2SiO3 treatment for both application methods. Elemental concentrations in the shoot and root of ‘Seolhyang’ were the highest in the 70 mg L−1 Si K2SiO3 foliar application. Photosynthetic proteins abundantly increased in both cultivars with the 35 or 70 mg L−1 Si K2SiO3 treatment, for both application methods. Moreover, two important photosynthetic proteins, viz. PsaA and PsbA, were expressed and their expressions were higher with the 35 or 70 mg L−1 Si K2SiO3 treatment, for both application methods. These results suggested that 35 or 70 mg L−1 Si, supplied in the form of K2SiO3, promoted photosynthetic protein expressions the greatest, regardless of the application method, in both ‘Maehyang’ and ‘Seolhyang’. [ABSTRACT FROM AUTHOR]

Silicon (Si) is considered one of the most beneficial elements for plant growth and development. Its advantageous effects are visible during abiotic and biotic stresses. In this experiment, the effect of Si on redox homeostasis and protein expression was studied in Rosa hybrida ‘Rock Fire.’ Acclimatized plantlets were grown hydroponically under salt stress (50 mM NaCl) for 15 days with or without 0 or 1.8 mM of potassium silicate (K2SiO3). Exposure of R. hybrida ‘Rock Fire’ to salinity restricted root growth. The addition of Si with NaCl significantly improved fresh and dry weights of roots. The presence of Si in the nutrient solution induced the growth of root hairs during both normal and stress conditions. Under salt stress, higher lipid peroxidation and excessive accumulation of reactive oxygen species (ROS) such as superoxide (O2−) and hydrogen peroxide (H2O2) affect the redox homeostasis potential of plants. However, addition of Si decreased the content of malondialdehyde, O2−, and H2O2. Detoxification of ROS was highly correlated with the enhanced activity and expression of antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), and guaiacol peroxidase (GPX). In addition, the two-dimensional gel electrophoresis results illustrated the improved abundance of protein on roots to overcome the salinity stress due to the addition of Si. Out of 70 spots identified, 59 proteins [except hypothetical (6%)] were functionally classified into 8 groups such as redox homeostasis/defense (15%), transcription/translation (26%), lipid metabolism (14%), signaling (13%), energy and carbohydrate metabolism (10%), transportation/metal ion-binding (7%), terpene synthesis (3%), and cell-wall regulation (6%). The observed results suggest that the substantial improvement of redox homeostasis by Si could facilitate preventive mechanism(s) to overcome the metabolic disorder emanate under salt stress. [ABSTRACT FROM AUTHOR]

The present study depicted the role of silicon in limiting the hyperhydricity in shoot cultures of carnation through proteomic analysis. Four-week-old healthy shoot cultures of carnation "Purple Beauty" were sub-cultured on Murashige and Skoog medium followed with four treatments, viz. control (-Si/-Hyperhydricity), hyperhydric with no silicon treatment (-Si/+Hyperhydricity), hyperhydric with silicon treatment (+Si/+Hyperhydricity), and only silicon treated with no hyperhydricity (+Si/-Hyperhydricity). Comparing to control morphological features of hyperhydric carnations showed significantly fragile, bushy and lustrous leaf nature, while Si supply restored these effects. Proteomic investigation revealed that approximately seventy protein spots were differentially expressed under Si and/or hyperhydric treatments and were either up- or downregulated in abundance depending on their functions. Most of the identified protein spots were related to stress responses, photosynthesis, and signal transduction. Proteomic results were further confirmed through immunoblots by selecting specific proteins such as superoxide dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT), PsaA, and PsbA. Moreover, protein-protein interaction was also performed on differentially expressed protein spots using specific bioinformatic tools. In addition, stress markers were analyzed by histochemical localization of hydrogen peroxide (H2O2) and singlet oxygen (O21-). In addition, the ultrastructure of chloroplasts in hyperhydric leaves significantly resulted in inefficiency of thylakoid lamella with the loss of grana but were recovered in silicon supplemented leaves. The proteomic study together with physiological analysis indicated that Si has a substantial role in upholding the hyperhydricity in in vitro grown carnation shoot cultures. [ABSTRACT FROM AUTHOR]

Background: Grafting is an established practice for asexual propagation in horticultural and agricultural crops. The study on graft unions has become of interest for horticulturists using proteomic and genomic techniques to observe transfer of genetic material and signal transduction pathways from root to shoot and shoot to root. Another reason to study the graft unions was potentially to observe resistance against abiotic stresses. Using physiological and proteomic analyses, we investigated graft unions (rootstock and scions) of tomato genotypes exposed to standard-normal (23/23 and 25/18°C day/night) and high-low temperatures (30/15°C day/night). Results: Graft unions had varied responses to the diverse temperatures. High-low temperature, but not standard-normal temperature, induced the production of reactive oxygen species (ROS) in the form of H2O2 and O2-1 in rootstock and scions. However, the expression of many cell protection molecules was also induced, including antioxidant enzymes and their immunoblots, which also show an increase in their activities such as superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX). The graft interfaces thus actively defend against stress by modifying their physiological and proteomic responses to establish a new cellular homeostasis. As a result, many proteins for cellular defense were regulated in graft unions under diverse temperature, in addition to the regulation of photosynthetic proteins, ion binding/transport proteins, and protein synthesis. Moreover, biomass, hardness, and vascular transport activity were evaluated to investigate the basic connectivity between rootstock and scions. Conclusions: Our study provides physiological evidence of the grafted plants’ response to diverse temperature. Most notably, our study provides novel insight into the mechanisms used to adapt the diverse temperature in graft unions (rootstock/scion). [ABSTRACT FROM AUTHOR]

Silicon- (Si-) induced salinity stress resistance was demonstrated at physiological and proteomic levels in Capsicum annuum for the first time. Seedlings of C. annuum were hydroponically treated with NaCl (50 mM) with or without Si (1.8 mM) for 15 days. The results illustrated that saline conditions significantly reduced plant growth and biomass and photosynthetic parameters and increased the electrolyte leakage potential, lipid peroxidation, and hydrogen peroxide level. However, supplementation of Si allowed the plants to recover from salinity stress by improving their physiology and photosynthesis. During salinity stress, Si prevented oxidative damage by increasing the activities of antioxidant enzymes. Furthermore, Si supplementation recovered the nutrient imbalance that had occurred during salinity stress. Additionally, proteomic analysis by two-dimensional gel electrophoresis (2DE) followed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) revealed that Si treatment upregulated the accumulation of proteins involved in several metabolic processes, particularly those associated with nucleotide binding and transferase activity. Moreover, Si modulated the expression of vital proteins involved in ubiquitin-mediated nucleosome pathway and carbohydrate metabolism. Overall, the results illustrate that Si application induced resistance against salinity stress in C. annuum by regulating the physiology, antioxidant metabolism, and protein expression. [ABSTRACT FROM AUTHOR]

The current study deals with in vitro propagation, antioxidant property estimation, and assessment of acacetin content in Scrophularia kakudensis Franch. Adventitious shoot induction was achieved from the nodal explant with the highest number of adventitious shoots per explant (17.4) on Murashige and Skoog’s (MS) medium fortified with 2.0 mg·L−1 6-benzyladenine (BA) and 0.5 mg L−1 indole-3-acetic acid (IAA). Maximum number of roots per plant (16.5) was noted in half strength MS medium supplemented with 0.5 mg·L−1 IAA. The regenerated plants displayed successful survival ratio (95%) in the greenhouse. The highest content of acacetin, a pharmaceutically important flavonoid, was observed in the shoot extracts (in vitro: 32.83 µg·g−1 FW; in vivo: 30.05 µg·g−1 FW) followed by root extracts. Total phenol and flavonoid contents along with free radical scavenging assays revealed the occurrence of larger amount of antioxidants in shoot extract in comparison with callus and root extracts of S. kakudensis. Thus, the outcome of the present study can be highly beneficial for the germplasm conservation and commercial cultivation of S. kakudensis for therapeutic purposes. [ABSTRACT FROM AUTHOR]

Phosphorus is a major nutrient acquired by plants via high-affinity inorganic phosphate (Pi) transporters. To determine the adaptation and homeostasis strategy to Pi starvation, we compared the proteome analysis of tomato leaves that were treated with and without Pi (as KH2PO4) for 10 days. Among 600 reproducible proteins on 2-DE gels 46 of them were differentially expressed. These proteins were involved in major metabolic pathways, including photosynthesis, transcriptional/translational regulations, carbohydrate/energy metabolism, protein synthesis, defense response, and other secondary metabolism. The results also showed that the reduction in photosynthetic pigments lowered P content under –Pi treatments. Furthermore, high-affinity Pi transporters (lePT1 and lePT2) expressed in higher amounts under –Pi treatments. Also, the accumulation of Pi transporters was observed highly in the epidermis and palisade parenchyma under +Pi treatments compared to –Pi treatments. Our data suggested that tomato plants developed reactive oxygen species (ROS) scavenging mechanisms to cope with low Pi content, including the up-regulation of proteins mostly involved in important metabolic pathways. Moreover, Pi-starved tomato plants increased their internal Pi utilization efficiency by increasing the Pi transporter genes and their rational localization. These results thus provide imperative information about how tomato plants respond to Pi starvation and its homeostasis. [ABSTRACT FROM AUTHOR]

Aldose reductase (ALR2), a vital enzyme involved in polyol pathway, has befitted as a novel drug target in antidiabetes drug discovery process. In the present study, the binding mode and pharmacokinetic properties of potential polyphenolic compounds with reported aldose reductase inhibitory activity from the genus Scrophularia have been investigated. The human ALR2 enzyme (PDB ID: 2FZD) acted as the receptor in the current study. Among the compounds investigated, acacetin, a methoxy flavonoid, displayed the stable binding to the active site of ALR2 with least binding energy value. Molecular interaction analysis revealed that acacetin interrupts the proton donation mechanism, necessary for the catalytic activity of ALR2, by forming H-bond with Tyr48 (proton donor). In addition, acacetin also possessed favorable ADME properties and complies with Lipinski’s rule of 5 representing the possible drug-like nature compared to other polyphenols. Interestingly, the biological activity predictions also ranked acacetin with higher probability score for aldose reductase inhibition activity. Moreover, the molecular dynamics simulation of ALR2-acacetin complex was validated for the stability of ligand binding and the refined complex was used for generation of receptor-ligand pharmacophore model. Thus, the molecular insights of receptor-ligand interactions gained from the present study can be utilized for the development of novel aldose reductase inhibitors from Scrophularia. [ABSTRACT FROM AUTHOR]

Although grafting is broadly used in the production of crops, no information is available about the proteins involved in vascular connections between rootstock and scion. Similarly, proteome changes under the light intensities widely used for grafted seedlings are of practical use. The objective of this study was to determine the proteome of vascular connections using watermelon (Citrullus vulgaris Schrad.) ‘Sambok Honey’ and ‘Speed’ as the scion and bottle gourd (Lagenaria siceraria Stanld.) ‘RS Dongjanggun’ as the rootstock grown under different light intensities (25, 50, 75 and 100 μmol m−2 s−1). Our proteomic analysis revealed 24 and 27 differentially expressed proteins in ‘Sambok Honey’ and ‘Speed’, respectively, under different light intensities. The identified proteins were largely involved in ion binding, amino acid metabolism, transcriptional regulation and defense response. The enhancement of ion-binding, transcriptional regulation, amino acid metabolism, and defense response proteins suggests a strengthening of the connection between the rootstock and scion under high light intensity. Indeed, the accumulation of key enzymes in the biological processes described above appears to play an important role in the vascular connections of grafted seedlings. Moreover, it appears that 100 μmol m−2 s−1 results in better protein expression responses in grafted seedlings. [ABSTRACT FROM AUTHOR]

Light is a critical environmental factor that influences plant growth and development, ranging from seed germination to flowering and fruiting. This study was carried out to explore how the optimal combination of various lighting directions increases the light usage efficiency and influences the plant morphophysiology, by investigating the plant growth parameters, leaf anatomy, epidermal morphology, stomatal properties, chlorophyll content, key physiological changes, and correlated gene expressions. In closed-type plant growth chambers, rooted cuttings of two chrysanthemum (Chrysanthemum morifolium Ramat.) cultivars, "Pearl Egg" and "Gaya Glory", were subjected to a 10-h photoperiod with 600 μmol∙m−2·s−1 photosynthetic photon flux density (PPFD) provided by light-emitting diodes (LEDs) in each light-direction combination (top (1/1) (T), top (1/2) + side (1/2) (TS), top (1/2) + bottom (1/2) (TB), side (1/2) + bottom (1/2) (SB), and top (1/3) + side (1/3) + bottom (1/3) (TSB)). The TS lighting significantly enhanced the morphophysiological performance, compared to the other lighting direction combinations. Notably, the excellent branch formation and earlier flowering were induced by the TS lighting in both "Pearl Egg" and "Gaya Glory" plants. [ABSTRACT FROM AUTHOR]

Ammonium is a paradoxical nutrient because it is more metabolically efficient than nitrate, but also causes plant stresses in excess, i.e., ammonium toxicity. Current knowledge indicates that ammonium tolerance is species-specific and related to the ammonium assimilation enzyme activities. However, the mechanisms underlying the ammonium tolerance in bedding plants remain to be elucidated. The study described herein explores the primary traits contributing to the ammonium tolerance in three bedding plants. Three NH4+:NO3− ratios (0:100, 50:50, 100:0) were supplied to salvia, petunia, and ageratum. We determined that they possessed distinct ammonium tolerances: salvia and petunia were, respectively, extremely sensitive and moderately sensitive to high NH4+ concentrations, whereas ageratum was tolerant to NH4+, as characterized by the responses of the shoot and root growth, photosynthetic capacity, and nitrogen (amino acid and soluble protein)-carbohydrate (starch) distributions. An analysis of the major nitrogen assimilation enzymes showed that the root GS (glutamine synthetase) and NADH-GDH (glutamate dehydrogenase) activities in ageratum exhibited a dose-response relationship (reinforced by 25.24% and 6.64%, respectively) as the NH4+ level was raised from 50% to 100%; but both enzyme activities were significantly diminished in salvia. Besides, negligible changes of GS activities monitored in leaves revealed that only the root GS and NADH-GDH underpin the ammonium tolerances of the three bedding plants. [ABSTRACT FROM AUTHOR]

The significant effects of lighting on plants have been extensively investigated, but research has rarely studied the impact of different lighting directions for the strawberry plant. To understand the optimal lighting direction for better growth and development, this study investigated how strawberries respond to variations in the lighting direction to help fine-tune the growth environment for their development. We examined how the lighting direction affects plant morphophysiology by investigating plant growth parameters, leaf anatomy, epidermal cell elongation, stomatal properties, physiological characteristics, and expressions of runner induction-related genes (FaSOC1 and FaTFL1) and gibberellin (GA) biosyntheses-related genes (FaGA20ox2 and FaGA20ox4). In closed-type plant factory units, the rooted cuttings of strawberry (Fragaria × ananassa Duch.) 'Suhlyang' were subjected to a 10-h photoperiod with a 350 μmol∙m−2∙s−1 photosynthetic photon flux density (PPFD) provided by light-emitting diodes (LEDs) from three directions relative to the plants: top, side, and bottom. Our results demonstrated that the side lighting profoundly promoted not only morphophysiology, but also runner formation, by upregulating photosynthesis in strawberries. Side lighting can bring commercial benefits, which include reduced economic costs, easier controllability, and harmlessness to plants. This will help provide new insights for the propagation of the most commonly cultivated strawberries in South Korea. [ABSTRACT FROM AUTHOR]

The effect of light source and CO2 concentration on the growth and anthocyanin content of lettuce (Lactuca sativa L. 'Seonhong Jeokchukmyeon') grown in growth chambers was examined. The plant was grown under 140 µmol·m -2·s-1 PPF provided by either cool white fluorescent lamps (F, the control), white (W) light emitting diodes (LEDs), or a 8:1:1 mixture of red, blue and white (RBW) LEDs. Carbon dioxide concentration of the atmosphere was maintained at either 350, 700, or 1,000 μmol·mol-1 . The RBW treatment promoted vegetative growth of the shoot and root. Chlorophyll fluorescence (Fv/Fm) was not significantly affected by the light source and CO2 concentration. Total anthocyanin content of the plant supplied with 1,000 μmol·mol-1 CO2 was the greatest in the F treatment. Photosynthetic rate significantly increased with the increasing CO2 concentration. These results suggested that the RBW which provided a wider spectrum of PAR and the highest CO2 concentration provided the most the suitable environment condition for vegetative growth of lettuce among the tested light sources. To obtain plants with even higher quality, especially having greater content of anthocyanin, however, more considerations on supplemental light source including white LED are necessary in terms of optimum intensity, photoperiod, and optimum ratios of mixing with other LEDs. [ABSTRACT FROM AUTHOR]