Medicinal Plants
Mehdi Moradi; Bahram Abedi; Hossein Arouiee; Sasan Aliniaeifard; Kamal 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 ...
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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.
Medicinal Plants
Mehdi Moradi; Hossein Nastari Nasrabadi; Kamal Ghasemi Bezdi
Abstract
Introduction The Genus Thymus is one of the most important genera of the Lamiaceae family. According to Jalas (1971), Thymus is divided into eight sections: Micantes, Mastichina, Piperella, Teucrioides, Pseudothymbra, Thymus, Hyphodromi, and Serpyllum. About 18 species exist in some areas of Iran ...
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Introduction The Genus Thymus is one of the most important genera of the Lamiaceae family. According to Jalas (1971), Thymus is divided into eight sections: Micantes, Mastichina, Piperella, Teucrioides, Pseudothymbra, Thymus, Hyphodromi, and Serpyllum. About 18 species exist in some areas of Iran and most of them belong to Serpyllum Section and kotschiani Subsection. Chromosomal information is an important key for taxonomy, phylogeny, evolution, genetics and breeding in thyme. Therefore, this work was carried out to study the cytogenetic characteristics of genus Thymus belonging to the Subsection Kotschyani for breeding purposes and taxonomy.Materials and MethodsSeeds were collected from 5 wild populations and germinated on wet filter paper at 20 oC. One cm long roots were pretreated with 8-hydroxyquinolin and then washed in distilled water and fixed in carnoy solution for 24 hours. Hydrochloric acid (1N) was applied for 7 min to hydrolyze the roots. Staining was done by orcein for 24 h at room temperature. Stained roots squashed in one drop of 45% acetic acid and examined by a ZEISS Axiophot compound microscope. Cells in metaphase stage were photographed with a D450; Canon Inc. Japan digital camera. Ten well prepared metaphasic cells were selected and some chromosomal characteristics such as total chromosomal length (TL), long arm length (L), short arm length (S), the arm ratio (AR) [LA/SA], and centromeric index (CI), were measured using Micro Measure ver. 3.3 software. The following karyological parameters were determined: total chromosome form (TF%), intrachromosomal asymmetry index (A1) and interchromosomal asymmetry index (A2). Karyotypic characteristics have been determined using the symmetry classes of Stebbins (SC). Karyotype formula was determined from chromosome morphology based on centromere position in accordance with the classification of Levan.Results and Discussion This study reports the chromosome number and meiotic behavior of 31 populations belonging to 8 species of Thymus Subsect. kotschyani from Iran. In most species of this subsection, the base number of chromosome x = 15 and two diploid and tetraploid ploidy levels with chromosome number of 2n = 30 and 60 were observed. Only in T. migricus species, the base number of chromosome x = 14 was reported with two levels of diploid and tetraploid ploidy and chromosome numbers of 2n= 28 and 56. The chromosomes were mostly metacentric (m) or sub-metacentric (sm) in all species Among the various species with basic number of x= 15, the highest percentage of TF and the lowest amount of A1 were observed in populations belonging to T. eriocalyx (T7) indicating that this species has the most symmetric karyotypes. The lowest percentage of TF and the highest amount of A1 are in population of T. lancifolious (27) and T. fedtschenkoi (T28) species; this shows that the species has the most asymmetric karyotype among the species of this subsection. The highest amount of A2 was observed in T. eriocalyx (T7) species, indicated the asymmetry between chromosomes and chromosomal length. The difference in the number of chromosomes, ploidy levels and karyotype asymmetry in the populations and different species may be related to different environmental conditions in their habitat, pollination system (cross pollination) or polyploidy (Aneuploidy) in this genus.Conclusion The results showed that basic chromosome number in most species is 15 (x= 15). Two ploidy levels (diploid and tetraploid) were observed among different species. Chromosomes in most species, were metacentric and sub-metacentric. Based on intra- chromosomal symmetry (A1 and TF) T. eriocalyx species (T7) has the most symmetric and most primitive karyotype and the species T. lancifolius (T27) and T. fedtschenkoi (T28) have the most complete and the most asymmetric karyotypes. Also based on inter- chromosomal symmetry, (A2) T. eriocalyx (T) species has the most asymmetric karyotype.
Mina Ghazaeian; Gholamhossein Davarynejad; Kamal Ghasemi Bezdi; Seyyed Hossein Nemati
Abstract
Introduction: The walnut family (Juglandaceae) consists of approximately 60 species of deciduous trees is native of the American continents, Europe, and Asia. Pecan (Carya illinoensis) is belonged to the Juglandaceae family and is one of the most valuable nut products all over the world. Embryo culture ...
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Introduction: The walnut family (Juglandaceae) consists of approximately 60 species of deciduous trees is native of the American continents, Europe, and Asia. Pecan (Carya illinoensis) is belonged to the Juglandaceae family and is one of the most valuable nut products all over the world. Embryo culture techniques for plant breeding as well as basic studies in physiology and biochemistry are widely used. The low percentage of germination and the long propagation cycle and the need for stratification treatments from three to six months are the most important barriers to the development of high yielding cultivars through hybridization. Plant regeneration methods from embryo culture in vitro allows overcoming the barriers of hybridization, as well as obtaining higher and faster multiplication rate of plants of an elite genotype.
Materials and Methods: In this experiment, an adapted native genotype of pecan in Gorgan city, Golestan province, Iran was selected. The mature fruits were harvested after five months of pollination. They were immediately transferred to the laboratory. For cold pretreatment, nuts packed in a paper bag and stored in 4-5ºC for 15 days. The effect of two types of culture medium, growth regulators and seed pretreatment (15 days at 4-5 °C) on germination of mature embryos of pecan has been determined. Murashige and Skoog (MS) and Woody Plant Medium (WPM) and IBA (0 and 1 mgl-1), BAP (0, 1 and 2 mgl-1) and GA3 (0 and 1 mgl-1) media were used to embryo rescue evaluation. The data obtained were statistically analyzed in completely randomized block design (RCBD). Each treatment was replicated at least third, and each replicate consisted of two zygotic embryos. Means of germination period, percent of seed germination, root and shoot length and leaf number in different media and various PGRs combination were compared based on LSD at p ≤0.05.
Results and Discussion: The results showed, although cold pretreatment for 15 days had no effect on germination period, root length and number of leave but also, effect on germination percentage and shoot length. There are some different hypothesis about the effect of cold pretreatment on embryo germination between researchers. Some researchers believed that, there is low efficiency in embryo germination in lack of cold pretreatment and GA3. Cold pretreatment or GA3 reduce the ABA level and promote embryos germination. The others reported poor germination for somatic embryos when they treated with GA3 and cold pretreatments. Pearce et al. (1987) reported that GA3 and substrate of GA3 can be increased during the chilling process as ABA levels decrease. Furthermore, application of exogenous GA3 induces germination. Tang et al. (2000) reported that somatic embryos germination poorly happened in cold condition and addition of GA3 did not change the poor germination. Kaur et al. (2006) and Peyghamzadeh and Kazemitabar (2010), reported that the embryo germination in Juglans regia L. was higher when GA3 and cold pretreatments were simultaneously applied as compared to those when applied separately. In this experiment, media has no effect on embryo germination period but, could effect on other parameters. As the results showed, MS media showed the maximum percentage of germination, root and shoot length and number of leave in both condition (with and without cold pretreatment). In this experiment root length of germinated pecan embryo was higher in MS medium. Mapelli et al. (2001) reported that seed germination resulted in marked changes in the metabolism of free amino acids in walnut cotyledons. About 52% of the total free amino acids in one-month-old seedlings was present in the cotyledons and about 26% was in the taproot. The concentration of free amino acids in the taproot was similar to that in the embryonic axis, and greater than that in the cotyledons. T11 (1mg/l-1 IBA, 1mg/l-1BAP and 1mg/l-1 GA3) and T12 (1mg/l-1 IBA, 2mg/l-1BAP and 1mg/l-1 GA3) treatments were the highest in germination percentages in both treatment (with and without cold pretreatment). There was no significant differences between 1 mgl-1 and 2 mgl-1 of BAP.
Conclusion: Pecan as like walnut, is considered to be one of the most recalcitrant species in vitro. It is necessary to determine the optimal culture conditions to establish it for shortening time in seed propagation. This seedling could be applied as primary material for breeding programs, grafting and physiology study. The best growth of micro plant achieved in MS medium with 1 mgl-1IBA, 1 mgl-1GA3 and 2 mgl-1BAP.
