Research paper
Yoko Miyama
Abstract
Intumescence is a physiological disorder in which cell walls are disrupted. Intumescence causes leaf deformation, browning and defoliation, and commonly affects tomato plants. This is a limitation in seedling production. The causes of intumescence are not known; however, ultraviolet (UV) deficiency is ...
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Intumescence is a physiological disorder in which cell walls are disrupted. Intumescence causes leaf deformation, browning and defoliation, and commonly affects tomato plants. This is a limitation in seedling production. The causes of intumescence are not known; however, ultraviolet (UV) deficiency is considered as one of the causes of intumescence. Other possible causes include high humidity and rapid changes in the water environment. In this study, tomato seedlings were grown in a commercially-available closed seedling production system under either newly installed LEDs with a low UV light intensity or conventional fluorescent lamps sources. The relationship between the shoot/root (S/R) ratio and incidence of intumescence was evaluated. In addition, the effects of different light sources were evaluated on the xylem pressure potential in the seedlings under rapidly fluctuating water conditions. As a result, the S/R ratio of seedlings grown under LEDs, with low UV intensity, was greater than that of seedlings grown under fluorescent lamps. There was a positive correlation between the S/R ratio and the incidence of intumescence of four types of seedlings with different combinations of light sources and varieties. Xylem pressure potential decreased more in seedlings grown under LEDs, compared to seedlings grown under fluorescent lamps and dry conditions, but increased significantly when irrigated. These results suggest that reducing the occurrence of intumescence in seedling production systems can be possible by a light source that can help seedlings grow with small S/R ratios and reduce fluctuations in the water condition.
Research paper
Morteza Mofid Bojnoordi; Rezvan Ramezannezhad; Mahnaz Aghdasi; Mohammad Fatemi
Abstract
As a valuable industrial compound, cichoric acid has antiviral, antioxidant, and anti-inflammatory properties. It is effectively used in obesity prevention and for neuroprotective purposes. Here, we aimed to compare the effects of plant growth regulators and UV-B radiation on the induction of cichoric ...
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As a valuable industrial compound, cichoric acid has antiviral, antioxidant, and anti-inflammatory properties. It is effectively used in obesity prevention and for neuroprotective purposes. Here, we aimed to compare the effects of plant growth regulators and UV-B radiation on the induction of cichoric acid production under tissue culture conditions. For this purpose, Lactuca undulata, an herbaceous medicinal plant, was used as a new source of cichoric acid. Leaf explants were initially cultured on ½ MS (Murashige and Skoog) medium containing 0.1, 1 mg/L Kinetin (Kin) and 2,4 Dichlorophenoxyacetic acid (2,4-D). The callus was then exposed to different UV-B exposure times (0, 20, 40, and 60 min) and was harvested after 5, 10, and 15 days. The highest amounts of total phenol, cichoric acid, chlorogenic acid, and caffeic acid were achieved in callus samples that were treated with 20 and 40 minutes of UV-B radiation for 10 days. Cichoric acid content reached an amount of 6.15±0.292 mg/g DW after 20 min of radiation. Pearson’s correlation coefficient analysis (PCC) showed that Phenylalanine Ammonia Lyase (PAL) activity did not correlate with the production of caffeic acid derivatives. These results suggested that UVB irradiation can be used as an elicitor to induce the production of cichoric acid in Lactuca undulata callus cultures.
Research paper
Vences C Valleser; Glenn Dayondon; Andrew Melencion
Abstract
The massive establishment of new plantations supported by the basic needs of a crop are technical approaches for an increased crop productivity. Water and decreased light levels by shade (i.e. intercropping) are considered basic needs of cacao plants, especially during the early vegetative growth stage. ...
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The massive establishment of new plantations supported by the basic needs of a crop are technical approaches for an increased crop productivity. Water and decreased light levels by shade (i.e. intercropping) are considered basic needs of cacao plants, especially during the early vegetative growth stage. Thus, this study aimed to evaluate the influences of irrigation, intercropping, and intercrops on the performance of 39 cacao plantations at the establishment phase. The performance of each cacao plantation, after establishment, was evaluated and rated from 1 to 7 (1- poor; 3- satisfactory; 5- very good; and 7- outstanding) as a rating scale. In general, the results revealed that cacao plantations supplied with irrigation or under decreased light levels by intercrops (regardless of their nature), as well as a combination of these, made the plants perform better than those in plantations without irrigation and when plants were highly exposed to sunlight. The results suggested the importance of irrigation and decreased light levels by intercropping as prerequisites for a successful establishment of cacao plantations.
Research paper
Vahideh Narjesi; Javad Fatahi Moghadam; Ali Akbar Ghasemi-Soloklui
Abstract
A prevalent problem in pomegranate fruit (Punica granatum L.) is sun damage that decreases the quantity and quality of fruit. The objective of the current research was to evaluate the effects of different photoselective shade net colors and shading percentages on growth traits and pomegranate fruit quality ...
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A prevalent problem in pomegranate fruit (Punica granatum L.) is sun damage that decreases the quantity and quality of fruit. The objective of the current research was to evaluate the effects of different photoselective shade net colors and shading percentages on growth traits and pomegranate fruit quality for two years (2019 and 2020). Plots of pomegranate trees (cv. Malase Saveh) were covered to full canopy with two colors of photo-selective shade nets (white and green) and with two shading percentages (30 and 50%), compared to uncovered plots (control). The experiment was carried out in the Saveh region in the same orchard at the time of fruit set (10 June) and the shading treatments were maintained on the trees for four months. The findings showed that shade nets increased relative leaf water content while decreasing temperature and light intensity in the canopy, compared to the control. Pomegranates under nets had a much higher fruit weight and yield than those on uncovered trees. The percentage of sunburn on fruits was dramatically reduced when a shade net was used. In uncovered trees, the percentage of sunburn was 27.85%, whereas in shade treatments, the percentage of sunburn was 0 - 4.5%. The white shade net allowed 50% PAR (Photosynthetically Active Radiation) and caused the highest fruit weight, juice percentage, aril weight and yield, maximum color of fruits and arils, as well as the lowest level of proline content among the shading treatments. The highest values of total anthocyanin (55.13 mg/100 mL), total phenolics (34 mg GAE/100 mL) and vitamin C (21.32 mg/100 mL) were observed after using the white shade net of 50% PAR. As a result, this type of net is recommended for pomegranate orchards because of its efficiency in improving yield and marketable fruits.
Review paper
Aida Shomali; Oksana Vladimirovna Lastochkina; Mohammad Mohammadian; Anshu Rastogi; Massimo Bosacchi; Tao li; Sasan Aliniaeifard
Abstract
Acclimation to the privileged lighting environment is an important step for the survival of newly developed horticultural plants such as transplants, tissue culture-generated plants, and mature plants when a change occurs in light intensity during the growth period or even during one full day. Capturing ...
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Acclimation to the privileged lighting environment is an important step for the survival of newly developed horticultural plants such as transplants, tissue culture-generated plants, and mature plants when a change occurs in light intensity during the growth period or even during one full day. Capturing excess light energy without an antecedent to acclimation imposes photooxidative cellular damage and photoinhibition in plants. Since carbon utilization may not keep pace with reductive energy production, it renders electron acceptors in the electron transfer chain oversaturated. However, plants are usually equipped with photoprotective mechanisms to attenuate the detrimental effects of excess light energy on the photosynthesis apparatus. In this review, we discussed how different controlled environment horticulture (CEH) systems are embedded with immense opportunities for improving yield and quality. Current understandings of the direct and indirect functional roles of light spectra are discussed in the context of photoinhibition, photoprotection, and their regulatory mechanisms.
Research paper
Mohammad Adibian; Yosef Hamidoghli; Sasan Aliniaeifard
Abstract
In the past decade, light-emitting diodes (LEDs) have been increasingly regarded as a suitable replacement for many other types of light source. They have attracted lots of attention. Supplemental lighting improves growth and yield of greenhouse vegetables such as sweet pepper, cucumber and tomato all-year ...
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In the past decade, light-emitting diodes (LEDs) have been increasingly regarded as a suitable replacement for many other types of light source. They have attracted lots of attention. Supplemental lighting improves growth and yield of greenhouse vegetables such as sweet pepper, cucumber and tomato all-year round. In the present study, the growth and photosynthetic functionality of two greenhouse sweet pepper cultivars, i.e. ‘Padra’ and ‘Shadleen’, were evaluated in response to the quality of LED lighting on sweet pepper seedlings. For this purpose, three combinations of red (R) and blue (B) LEDs (R90B10, R80B20, and R70B30 were used, with a light intensity of 200 μmol m-2 s-1 in all LED light treatments. Evaluations were done in two growing seasons, winter and summer, in Rasht, Iran. Seedlings exposed to supplemental light had thicker stems, wider leaf area, higher biomass, and greater photosynthetic functionality. We observed an increase in the ratio of B-light LED to the positive effects on the growth and photosynthesis functionality of the seedlings. However, no significant difference was observed between the cultivars. The effect of supplemental light was more emphasized in the winter. Thus, the control seedlings were weak and pale, while strong seedlings with dark green leaves were produced under the supplemental light. In conclusion, supplemental LED lighting appeared as a practical tool for the commercial production of greenhouse seedlings.
Research paper
Fahimeh Aghakarim; Hassan Sarikhani; Ali Azizi
Abstract
Increasing day length during the short photoperiod in fall and winter is a beneficial method of increasing biomass production and altering plant morphology and phytochemistry. The objective of this study was to examine the effects of light quality at the end of the day (EoD) on the growth and phytochemical ...
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Increasing day length during the short photoperiod in fall and winter is a beneficial method of increasing biomass production and altering plant morphology and phytochemistry. The objective of this study was to examine the effects of light quality at the end of the day (EoD) on the growth and phytochemical characteristics of lemon balm. During shortday photoperiods in autumn, lemon balm (Melissa officinalis L.) seedlings were exposed to red, blue, and combined red/blue light using light-emitting diodes for 2 hours at the EoD. The results showed that exposure to red light significantly increased biomass. Plants grown under blue light yielded the highest percentage of dry matter and their leaves had the highest chlorophyll content and flavonoids. The highest carotenoid content was found in plants irradiated with blue light and later with red+blue light. The highest levels of total phenols, anthocyanins, and antioxidant activity were found in plants grown under red light. In addition, light quality had a significant effect on essential oil content. The highest essential oil content was obtained in the red and red+blue light treatments. The light quality at the EoD significantly changed the essential oil composition. The blue light significantly increased the citronellal content but decreased the geranial and linalool content. This study provided insights into the effects of EoD light quality on plant growth and metabolite accumulation in lemon balm with a short photoperiod. In conclusion, supplemental light at the EoD can effectively improve plant growth and secondary metabolite quality in medicinal plants.
Research paper
Pet Roey Lasquites Pascual; Jean Jannin Aleguin Alimento; Rodolfo S Anulacion; Kent Marcial L Catubis; Marciano Tangpos; Nonna Fatima Hilot Abello; Danny E Carabio
Abstract
Kale is known for its anticancer properties and is rich in nutrients. Light plays a major role in plant growth. This study determined the effects of different light conditions on kale in terms of morphological, yield, and physiological responses. The treatments used in this study were Ambient Light (AL) ...
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Kale is known for its anticancer properties and is rich in nutrients. Light plays a major role in plant growth. This study determined the effects of different light conditions on kale in terms of morphological, yield, and physiological responses. The treatments used in this study were Ambient Light (AL) and 16:8 light-dark period schemes on Red LED (RL), Green LED (GL), and Blue LED (BL). The treatments were applied six days before harvest. Kale grown under GL and BL became the tallest, four times taller than the kale treated with AL. However, in terms of leaf length and width, AL resulted in the most significant values, compared to seedlings grown under controlled lighting. Regarding the yield response, no significant differences were noted on fresh weight, dry weight, and estimated yield. In terms of physiological responses, RL, GL, and BL increased the average vapor pressure deficit. In terms of the average photosynthetic rate, BL performed better than AL. However, AL caused a higher stomatal conductance compared to LED lights. The average transpiration rate showed improvements under RL. These results suggested that GL and BL are most suited for plant height development while AL enhance the number, length, and width of leaves. Moreover, when grown under BL, the photosynthetic rate increased. On the other hand, exposure to AL improved stomatal conductance. The increase in photosynthetic rate led to the production of more secondary metabolites such as glucosinolate.
Research paper
Saber Gilani; Naser Askari; Hossein Meighani; Amanollah Soleimani; Reza Ghahremani
Abstract
Optimizing light and nutrient supply has a key role in seedling quality and yield of cucumber seedlings. The combined effects of light quality {blue (B), white [W; 41% B, 39% intermediate, and 20% red (R)], RB [red (80%) and blue (20%)], and red (R)} and EC value of the nutrient solution (1, 1.7, and ...
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Optimizing light and nutrient supply has a key role in seedling quality and yield of cucumber seedlings. The combined effects of light quality {blue (B), white [W; 41% B, 39% intermediate, and 20% red (R)], RB [red (80%) and blue (20%)], and red (R)} and EC value of the nutrient solution (1, 1.7, and 3 ds m-1) were evaluated on the growth and physio-logical responses of cucumber seedlings. The measurements were aimed at the growth rate, biomass distribution, water status, seedling quality, yield, and concentration of photosynthetic pigments, protein, proline, potassium, and phosphorous. The results showed that the effects of light quality on cucumber seedlings depended on the EC values of the nutrient solution. The RB treatment at EC 1.7 of the irrigation water had the highest value of seedling quality parameters and the maximum amount of osmolytes, elements, and pigments, showing adequate water performance. Moreover, in contrast to the conventional seedling production, yield and biomass production increased by 70% and 92%, respectively, in the transplanting phase. This probably resulted from a more efficient elemental uptake, higher biomass distribution, and low vegetative growth in the seedling production phase. These results can contribute to seedling production of vegetables as an efficient protocol for yield productivity. In sum, our findings showed that determining the ideal light spectrum for seedling growth should be considered together with the EC of the nutrient solution.
Research paper
Bayram Emin Develi; Natalia Miler
Abstract
In the present study, the influence of three-wide spectrum light-emitting diodes (LEDs), emitting warm light AP67 (moderate blue and red and low red:far-red), AP673L (high red and high red:far-red) and G2 (high red and low red:far-red) with different colours mixing blue, green, red and far-red was used ...
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In the present study, the influence of three-wide spectrum light-emitting diodes (LEDs), emitting warm light AP67 (moderate blue and red and low red:far-red), AP673L (high red and high red:far-red) and G2 (high red and low red:far-red) with different colours mixing blue, green, red and far-red was used for micropropagation of three Polish potato cultivars; ‘Aruba’, ‘Oberon’ and ‘Skawa’. The planlets were grown in a growth chamber with a 16-h photoperiod. The photosynthetic photon flux density was 30 μmol m-2 s-1. The tissue culture medium for shoot proliferation was a standard MS-based medium. Microtuberization was observed on MS medium supplemented with higher sugar content (40 m g/L-1). Light quality affected the number of microtubers (MTs) per plantlet, the volume (cm3) of MTs, the fresh weight (mg) of MTs, and the width (mm) of MTs. Different light qualities did not affect morphological parameters, including length (mm), perimeter (mm), and crosssection area (mm2) of microtubers, whereas the highest number of microtuber were detected under the effect of AP67 light quality. The morphological parameters mostly depended on cultivar. The lowest number of microtubers was observed in the G2 treatment. In conclusion, ‘Aruba’ and ‘Oberon’ with AP67 and AP673L, as well as LED lighting systems, were determined as most suitable in terms of the MT count per plantlet. Also, these variables were most suitable for MT volume (cm3), fresh weight (mg), and width (mm).
