Medicinal Plants
M. Moradi; B. Abedi; H. Arouiee; S. Aliniaeifard; K. Ghasemi Bezdi
Abstract
Background and objectives Light is the main environmental factor for plant growth and development. Different attributes of light such as intensity, quality and duration affect plant growth and productivity. Light spectrum of growing environment is a determinant factor for plant growth and ...
Read More
Background and objectives Light is the main environmental factor for plant growth and development. Different attributes of light such as intensity, quality and duration affect plant growth and productivity. Light spectrum of growing environment is a determinant factor for plant growth and photosynthesis. The photosynthetic reactions are directly affected by various light parameters including its spectrum and intensity. Photosystem I and II (PSI and PSII) in the electron transport chain of photosynthetic apparatus are involved in converting solar energy to chemical compounds in plants. It has been found that the PSII is sensitive to light quality. Using The OJIP test, we can investigate the efficiency of various biological phases of the electron transport system. Light sources such as metal-halide, fluorescent, high-pressure sodium, neon lamps and light-emitting diode (LED) can be used for production of plants in closed environments instead of sunlight. Manipulation of the light spectrum of the lamps could trigger potential benefits by enhancing plant growth. Nowadays, by using the LED technology, it is possible to study the physiological effect of different light spectra for optimization of growth conditions and for increase the production of plants in controlled environments. This research was conducted to investigate photosynthetic apparatus, growth parameters, stomatal characteristics, transpiration rate and essential oil content of Salvia officinalis under different light spectra. Materials and Methods In this study, the effects of different light spectra were implemented and performed as a pot experiment using soilless media in the plant growth chamber based on a completely randomized design with 6 lighting spectra including White, Blue, Red and three combinations of R and B lights (R30:B70, R50:B50 and R70:B30) with three replications. The light intensity in all growth chambers was adjusted to photosynthetic photon flux density (PPFD) of 250 ±10 μmol m-2s-1 and light spectrum were monitored using a sekonic light meter (Sekonic C-7000, Japan). Growth condition was set at 14/10 h day/night cycles, 25/22oC day/night temperatures and 40% relative humidity. Three month following plant growth under different light spectra, the plants were evaluated for their growth parameters, stomatal characteristics (stomatal length, stomatal width, pore length or aperture) transpiration rate (E), relative water content (RWC), photosynthetic apparatus (evaluation of OJIP) and essential oil content. Data analysis of variance (ANOVA) was performed using IBM SAS software (Version 9.1) and the differences between means were assessed using Duncan’s multiple range tests at p≤ 0.05. Results The results showed that the stomata characteristics, photosynthetic performance, growth characteristics and essential oil content of Salvia officinalis were affected by different light spectra. Increasing the ratio of red light especially combined Red and Blue lights (R70:B30) led to the improvement of growth characteristics. Transient induction of chlorophyll fluorescence showed that the highest fluorescence intensities at all OJIP steps were detected in Red light. The lowest Fv/F0 and Fv/Fm were obtained in plants grown under Red light. Occurrence of leaf epinasty and decrease in Fv/Fm indicative of phenomenon of red light syndrome in the plants under Red treatment. Red light caused a reduction in performance index per absorbed light efficiency of (PIABS) and increase in quantum energy dissipation (ΦD0), light absorption (ABS/RC) and electron trapping (TR0/RC) per reaction center. The highest Fv/F0, Fv/Fm and PIABS were obtained under combination of Red and Rlue light. The highest ΦE0 was also detected in combination of Red and Blue light. The narrow and large stomatal apertures were detected under Red and Blue light, respectively. The highest transpiration rate was achieved in plants grown under Blue light LED. Increasing the ratio of Red light resulted in reduction in transpiration rate and improvement of leaf capacity to control water loss via reducing the opening of stomata. The highest amount of essential oil (1/75% v/w) was achieved in plants exposed to combination of Red:Blue light spectra (R70:B30).Conclusion light spectrum during plant growth can change plant metabolism, LED can be used in favor of producing good-quality food in controlled environment agriculture due to their ease of application, waveband manipulation and limited heat production. Our result showed that photosynthetic apparatus, growth parameters, stomatal characteristics, transpiration rate, relative water content and essential oil content of plants were considerably influenced by light spectra. Using OJIP test confirmed that plants grown under monochromatic Red and Blue lights were less efficient to successfully transfer the excitons and most of the absorbed energy by the photosystems was dissipated as heat. In conclusion, combined Red and Blue lights (especially R70:B30) caused favorable growth, photosynthetic functionality and maximum essential oil content of Salvia officinalis. Therefore, combination of R and B lights (R70:B30) should be considered for production of Salvia officinalis under artificial light systems during commercial controlled environment production of plants.
Ornamental plants
D. Kazemi; M. Dehestani Ardakani
Abstract
Introduction Different aspects of light including intensity, quality (spectra), and duration (photoperiod) can influence plant growth and development. The growth and development of ornamental plants are also influenced by light intensity and quality. Energy saving in greenhouse production has received ...
Read More
Introduction Different aspects of light including intensity, quality (spectra), and duration (photoperiod) can influence plant growth and development. The growth and development of ornamental plants are also influenced by light intensity and quality. Energy saving in greenhouse production has received much attention lately. One reason for the interest in utilizing light quality to modulate plant growth and morphology is the recent development of light-emitting diodes (LEDs) as a lighting source in greenhouse production. Such small diodes can easily be placed close to the canopy and can be used to apply a narrow-band light spectrum to the plants. Specific requirements for light spectral distribution for specific processes like morphogenesis, photosynthesis, chlorophyll and anthocyanin synthesis have been determined in different species. The aim of the current study was to investigate the biophysical properties of chlorophyll fluorescence of Hypoestes phyllostachya plants in response to different light spectra.Materials and Methods Research experiments were conducted on Hypoestes phyllostachya in a completely randomized design with six treatments of different light quality and three replications. The seeds were planted in plugs and in a mixture of 70% peat moss and 30% perlite. Seedlings were grown in natural greenhouse (control) and LED (100% Blue, 15% Blue +85% Red, 30% Blue +70% Red, 15% Blue +65% Red + 20% White and 30% Blue +50% Red + 20% White). Since the main goal of the study was to compare the effect of LED light quality with sunlight in conventional greenhouse conditions. The LED treatments were applied from fourth month old seedlings until five weeks in a growth chamber with the light/dark regime of 15/9 hours, 23±5°C temperature, and 65±5% relative humidity. While, their pots in the greenhouse with 55±5 mol.m-2.d-1 DLI, 21±5°C average daily temperature and 65±5% relative humidity (Data logger 8808 temp. + RH) were regarded as the control treatment. After five weeks, the fluorescence chlorophyll was measured.Selected leaves were dark-adapted prior to the measurements and OJIP protocol was applied using a fluorometer (FluorPen FP 100-MAX, photon system instruments, Drasov, Czech Republic). The fluorescence measurement was performed using a saturating. FluorPen software was used to extract data from the original measurement. Data extracted were used to analyze the following data according to the equations of the JIP test: fluorescence intensities at 50 μs (F 50 μs, considered as the F0), 2 ms (J-step denoted as FJ), 60 ms (I-step, FI), and maximum fluorescence intensity (FM, FP). The JIP-test was used to quantify the amount of energy that flow via the PSII. Performance index was measured on the absorption basis (PIABS, a multi-parametric expression). Probability that a trapped exaction promote an electron in electron transport chain (ETC) beyond the primary acceptor Quinone (QA−), maximum quantum efficiency of PSII (FV/FM), specific energy fluxes per reaction center (RC) for energy absorption (ABS/RC), trapped energy flux (TR0/RC), electron transport flux (ET0/RC) and dissipated energy flux (DI0/RC) were calculated according. Finally, the data were statistically analyzed with SAS (9.4) software package, and the means were compared by LSD test at p < 0.05 level. Results and Discussion Fast Chl fluorescence induction curves (OJIP) was the main parameters used for the screening of different light treatments. OJIP test is shown to be a proxy to detect PSII bioenergetics and indicates changes in the status and function of PSII reaction centers, antenna, as well as in donor and acceptor sides of PSII. The maximum quantum yield of PSII (FV/FM) and relative maximal variable fluorescence (Fm/F0), significantly increased in 15% Blue +85% Red, 30% Blue +70% Red, 15% Blue +65% Red + 20% White. PIABS, one of the OIJP test parameters that provide valuable awareness about photosynthtic performance, considerably decreased under control and 30% Blue +50% Red + 20% White treatment. Unlike PIABS, ET0/RC did not show a significant difference under different treatments. The specific energy fluxes per RC for energy absorption (ABS/RC) significantly increased under control and 30% Blue +50% Red + 20% White treatment. TR0/RC increased in plants under control and 30% Blue +50% Red + 20% White treatment. Treated plants under 15% Blue +85% Red and 30% Blue +70% Red showed the lowest in dissipated energy flux (DI0/RC). During an ideal condition without any additional stress, the total PSII pool can be completely inactivate and retrieve without a detectable photoinhibition.Conclusion When plants exposed to 100% Blue and 30% Blue +50% Red + 20% White treatments as well as in control plants, FM/F0, FV/FM and PIABS significantly decreased. Also ABS/RC, TR0/RC and DI0/RC, significantly increased.
Medicinal Plants
Zhaleh Zandavifard; Majid Azizi
Abstract
Introduction: St. John’s wort (Hypericum perforatum L.) is a medicinal plant which used mainly in treatment of mild depression, neurological disorders and has been recently shown to have anticancer potential. The principle medicinal components of St. John’s wort are hypericin, pseudohypericin, ...
Read More
Introduction: St. John’s wort (Hypericum perforatum L.) is a medicinal plant which used mainly in treatment of mild depression, neurological disorders and has been recently shown to have anticancer potential. The principle medicinal components of St. John’s wort are hypericin, pseudohypericin, and hyperforin. Light is one of the most important environmental factors affecting plant growth, survival, reproduction and distribution. The light quality, light intensity, duration and photoperiod directly affect plant growth. Light quality refers to the color or wavelength reaching the plant's surface. A prism (or raindrops) can divide sunlight into respective colors of red, orange, yellow, green, blue, indigo and violet. Red and blue have the greatest impact on plant growth. Green light is least effective (the reflection of green light gives the green color to plants). Blue light is primarily responsible for vegetative leaf growth. The principle objective of the current study was to evaluate the effects of different spectral quality including red, blue, green and white on the growth factors and production of hypericin.Materials and Methods: This experiment was conducted on the basis of Completely Randomized Design with four treatments and 10 replications in the growth chamber in the Department of Horticulture, Ferdowsi University of Mashhad (FUM), Iran. In this study, seeds were obtained from the research greenhouse of FUM. Seeds after soaking in running water for 24 hours were planted in small pots (250g). After the seedlings have reached to height of 25cm, each 10 pots were put inside the boxes (20×30cm) made of colored filters. Experiment continued in a growth chamber with day and night temperature 25 and 21°C, respectively, relative humidity 45%, 16 hours of light with the intensity of 1000 lux and 8 hours of darkness for 50 days. Then morphological parameters including plant height, number of stems, number of leaves, number and length of internodes, fresh and dry weight of shoot and root were measured. To count the number of black nodules, the upper, middle and lower parts of seedling were evaluated individually. Hypericin content of the H. perforatum plantlets were measured according to the previous work of Azizi & Omidbaigi, 2002. Data were analyzed statistically by using SAS and Excel software. The significant differences between means were assessed by Tukeyʼs test at P < 0.05.Results and Discussion: The results showed that morphological parameters including plant height, leaf number, internode length, root fresh weight, dry weight of stem and root were affected significantly by light treatments. Minimum and maximum of plant height was related to white and red lights, respectively. Increasing plant height under the influence of red light was due to the variation in levels of growth regulators. Red and blue light by changing of the GA hormone level in the plant and affected elongation of plant stem. Minimum and maximum of leaf number was related to blue and white light respectively. Also, other morphological traits including internode length, fresh and dry weights of stem and root showed significant differences. Internode length for white light was less than red, green and blue light. Maximum of the fresh and dry weight of shoot and root of seedlings was observed under white light. Results suggest that photosynthetic compounds move in plant under the influence of light quality. Also the number of black nodules in three different parts of plant and hypericin content were compared in plantlets under the effect of light quality. Results analysis also confirmed that different lights had the significant impact on the number of black nodules in upper and middle leaves of H. Perforatum seedlings. Seedlings treated with the red light had the highest number of black nodules in the middle section of H. perforatum. In the top third of St. John’s wort seedlings, red, blue and green light was inducted the highest number of black nodules formation than white light. The highest level of hypericin was related to red, white, blue and green lights, respectively. The number of black nodules in the plant and the hypericin content have positive correlation. It seems that in the seedlings treated with the red light, carbohydrates made from photosynthesis most used in biosynthesis of secondary metabolites than plant growth. In fact, carbon allelochemical compounds such as terpenes and phenolics have such metabolism direction to explain the increasing in secondary metabolites.Conclusion: Different light spectra affects plant hormones levels and with alteration in the primary and secondary metabolites lead to a change in the morphological and biochemical traits of plant. In general, it can commented that the quantity and quality of light is able to affect the growth and the active metabolites of medicinal plants and using red and white mixture of light during seedling growth period have an effective role on generation of more strong seedlings with higher potential production of active ingredients.
Pariya Dehkhodaei; Saeid Reezi; Masud Ghasemei Ghehsareh
Abstract
Introduction: The light is not only a photosynthesis energy source but also is a plant growth and development stimulation from germination to flower initiation process. The light quality plays an important role in all steps of growth process particularly in photosynthesis and morphological properties ...
Read More
Introduction: The light is not only a photosynthesis energy source but also is a plant growth and development stimulation from germination to flower initiation process. The light quality plays an important role in all steps of growth process particularly in photosynthesis and morphological properties of plant species. Studies have reported that, LEDs present the maximum PAR efficiency among artificial lighting systems. LED lamps contribute to energy saving by 75 and 30 percent as compared to incandescent light bulbs and fluorescent lamps, respectively. LEDs emit blue, red, orange, yellow, green, red, and infrared light and can be used as a hybrid spectrum. For these reasons, an experiment was conducted to investigate the effect of quality of LED light on morphological and physiological characteristics of Solenostemon and petunia.
Materials and Methods: Research experiments were conducted on Solenostemon escutellariodes ‘Wizard Scarlet’ and Petunia × hybrida ‘Scarlet Eye’ in a completely randomized design with three treatments of different light quality and 10 replications. The seeds were planted in 105-cell seedling trays and in a mixture of 70% peat moss and 30% perlite. Seedlings were grown in natural greenhouse (control) and LED (50% blue + 50% red and 100% white light). The light intensity was 60 ± 5 µmol.m-2.s-1 for LEDs and the daily greenhouse cavity was 5 ± 14 µmol.m-2.d-1. Since the main goal of the study was to compare the effect of LED light quality with sunlight in conventional greenhouse conditions. The LED treatments were applied from the germination until seedling production stage in a growth chamber with the light/dark regime of 18/6 hours, 23±1°C temperature, and 50±5% relative humidity. While, their tray in the greenhouse with 55±5 mol.m-2.d-1 DLI, 21±5°C average daily temperature and 50±5% relative humidity (Data logger 8808 temp. + RH) were regarded as the control treatment. After eight weeks, the morphological and physiological traits were recorded. Finally, the data were statistically analyzed with SAS (9.4) software package, and the means were compared by LSD test at p < 0.05 level.
Results and Discussion: At the end of study, some morphological and physiological traits were evaluated. The results showed that the leaf area average (3.63 cm2), height (5.04 cm), internode length (18.62 mm), stem diameter (2.52 mm), shoot fresh weight (1.74 g) and chlorophyll fluorescence (0.83) of Solenostemon seedlings in 100% white light were more than 50% blue + 50% light green and greenhouse light. Also, the highest leaf area temperature (27.4 ° C), total chlorophyll (0.8 mg g-1 fw) and carotenoids (2.229 mg g-1 fw) were related to control treatment and the highest number of leaves (21), shoot dry weight (0.165 g), fresh (1.65 g) and root dry weight (0.114 g) were observed in 50% blue + 50% red light composition. According to the results of petunia, white LED light increased leaf area (1.74 cm2), shoot fresh weight (0.51 g) and root dry weight (0.03 g). The leaf surface temperature (26 oC) and total chlorophyll content (1.44 mg g-1 fw) in the control group were higher than the other treatments, and the carotenoids content (3.12 mg g-1 fw) was obtained in 50% red + 50% blue LED. The leaf surface temperature and total chlorophyll content in greenhouse light were higher than other treatments and the highest carotenoids (3.119 mg / g) were obtained from 50% red + 50% blue LED.
Conclusion: Light quality has a great impact on the growth and development of plants and is a powerful tool for controlling various processes .The results showed that different light sources with different qualities had different effects on different plant species and that LEDs could replace natural light in growing chambers and in areas where light was insufficient. Due to the increased quality and reduced transplant losses in the transplant phase and their low utilization, they are justified in terms of production costs. It should be noted that in addition to light; temperature, humidity and other environmental factors are also effective in transplant production. Based on the measured indices in Solenostemon, it can be concluded that the red + blue LED light transplanting stage is superior to other treatments. In petunia, white LED treatment caused the highest shoot and fresh and dry weights of roots and leaves respectively. Like Solenostemon, the highest chlorophyll and leaf surface temperatures were related to the control treatment and was superior to the petunia transplant in terms of the sum of measured indices of white light treatment.
Azadeh Rashidi; Seyyed Hossein Nemati; Narges Bozorg
Abstract
Introduction: Transplant production is one of the most important commercial production of melon. Transplanting of seedlings with strong and healthy stems and roots will be successful. Environmental conditions, such as light, affect the proper growth of healthy transplants. The light provides the necessary ...
Read More
Introduction: Transplant production is one of the most important commercial production of melon. Transplanting of seedlings with strong and healthy stems and roots will be successful. Environmental conditions, such as light, affect the proper growth of healthy transplants. The light provides the necessary energy for photosynthesis. Due to the stimulation of the activity of photosynthetic pigments and light receptor pigments, it can be expected that plant performance increase by improving the quality and quantity of light. High pressure sodium and fluorescent lamps are common artificial light sources in greenhouses but because of their high power consumption, heat generation and the light spectrum that the plant does not use, application of LED is taken into consideration. The production of specific spectrum of light and the possibility of spectral composition are advantages of LED lamps. The aim of this experiment was to investigate the effect of light quality and cultivar on some physiological and vegetative characteristics of two melon cultivar seedlings, Ghasri and Khatooni, which are among the most important melon cultivars in Iran.
Materials and Methods: To investigate the effect of light quality and cultivar on vegetative characteristics of melon (Cucumis melo Gr. Inodorus) transplants, a research was conducted from April 4 to May 10, 2016 as split plot experiment in completely randomized design with five replications and the seedlings of Khatoonia and Ghasri cultivars were treated under different light quality include two combinations of blue and red spectrum with ratios of 15%B : 85%R , 30%B : 70%R, fluorescent lamp and HPS lamp. In order to set spectra combinations, LED lamps of Red (R625nm ) and Blue (B476nm) were used. The 85%R: 15%B ratio was obtained through using of 340 R lamps plus 60 B lamps and the 70%R: 30%B ratio was obtained by the usage of 280 R lamps plus 120 B lamps on separate Plexiglass plate. Closed growth chambers without natural light were used. The size of LED growth chambers were 70×60×60 cm3 and the size of HPS lamp growth chamber was 120×60×60 cm3. The seeds were planted at a depth of 4 cm and were transplanted to growth chamber equipped with the desired light compounds. Light intensity was 65 mmol and duration of light was 16 hours. Data was collected when transplant had four leaves. Emergence speed index, mean time for emergence of transplants, fresh and dry weights of foliage and root, root volume, leaf area and thickness, leaf number, height, height to diameter ratio, stem caliper, chlorophyll a, chlorophyll b, chlorophyll total and carotenoids contents were measured.
Results and Discussion: The result showed that the interaction effect of light quality and cultivar was significant on fresh and dry weights of foliage and root, root volume, leaf area and thickness, height to diameter ratio, chlorophyll a, chlorophyll b, chlorophyll total and carotenoids contents. The fresh and dry weights of foliage of Ghasri cultivar and fresh weight of root of Khatooni cultivar under 15%B: 85%R ratio, the dry weight and root volume of Ghasri cultivar under, 30%B: 70%R ratio, the chlorophyll a and carotenoids contents of Ghasri cultivar under, 30%B: 70%R ratio, the chlorophyll b and chlorophyll total contents of Khatooni cultivar under, 30%B: 70%R ratio were superior. The results of this study showed that the use of compounds of blue and red lights increased the dry matter and development of roots in studied plants. Proper dry matter and root development are important because they make the plant resistant to environmental stress. However, the effect of light quality was affected by the cultivar. For example, Ghasri cultivar showed the highest fresh and dry weights of foliage under 15%B: 85%R ratio and with the increase of blue light level, these two traits decrease significantly, but this results was not obtained in Khatooni cultivar. The results showed that the light quality affected leaf area and thickness of two cultivars in a different way. In Ghasri cultivar the highest leaf area and thickness were obtained under, 30%B: 70%R ratio. In Khatooni cultivar, under, 30%B: 70%R ratio, the highest leaf area and under fluorescent light, the highest leaf thickness were observed. The effect of blue light on the variation of leaf area among plants has been reported differently. The leaf area plays an important role in photosynthesis in plants and with its increase, photosynthesis and plant growth improved. The result showed that the interaction effect of light quality and cultivar was not significant on emergence speed index, mean time for emergence of transplants, leaf number, stem caliper and height. The highest emergence speed index and mean time for emergence of transplants were obtained under, 30%B: 70%R ratio without significant difference with 15%blue: 85%red ratio. Leaf number was lowest under HPS lamp and there is no significant difference in leaf number among 15%B: 85%R ratio, 30%B: 70%R ratio and fluorescent lamp. The highest stem caliper and lowest height were obtained under, 30%B: 70%R ratio. Interaction of phytochromes and cryptochromes due to different levels of blue and red lights lead to the formation of different concentrations of gibberellins and this affects the height of the plants. In some plants, increasing the amount of blue light leads to a decrease in the secretion of this hormone and as a result, plant heights are reduced. The results showed that the blue light had a positive effect on the increase of stem caliper and increasing transplant diameter has a positive effect on its establishment and development after their transfer to the main planting site.
Conclusions: The result showed that the application of the blue and red spectra compared to fluorescent and HPS lamps improved the quality of transplants growth. Improve or mitigate results and the performance in traits such as fresh and dry weights of foliage and root, root volume, leaf area and thickness, height to diameter ratio, chlorophyll a, chlorophyll b, chlorophyll total and carotenoids contents depend on light quality and cultivar.
