JOURNAL OF PLANT PHYSIOLOGY AND BREEDING
Year:2018 | Volume:8 | Issue:2|Papers Count:12

Barley (Hordeum vulgare L. ) as a salt-tolerant crop species has considerable economic importance in salinity-affected arid and semiarid regions of the world. In the present study, three barley genotypes (Sahara3771 and an Iranian advanced line as salt tolerant and Clipper as salt susceptible) were exposed to 100 and 200 mM NaCl at the seedling stage and non-NaCl treatment was used as check. The root samples were harvested 24 hours, three days and three weeks after salt treatment in three replications. The root length and root fresh and dry weight were measured and expression pattern of Atls1 gene was analyzed on root samples by quantitative Real-time-PCR. The effects of genotype and sampling time were significant for root characters and with the advancement of salt treatment duration, root length and root fresh and dry weight were significantly reduced. The expression of Atls1 gene was significantly affected by NaCl level, genotype, sampling time and their interactions. In all three genotypes, with the increase of NaCl concentration, expression of Atls1 gene was reduced. Under 100 mM NaCl, mRNA level of Atls1 was significantly decreased in Clipper as compared with the salt tolerant genotypes, Sahara3771 and Advanced line. In addition, long-term salt treatment (three weeks) significantly reduced the expression of Atls1 in all three genotypes. Down-regulation of Atls1 gene under long term salt treatment indicates that this gene may be involved in response to salinity stress at the beginning of salt stress.

To evaluate the inheritance of some physiological and agronomic traits in barley, the F1 seeds of a 5×5 half diallel cross, along with their parents were grown in well-watered and drought stress under greenhouse condition at the agricultural research station of Islamic Azad University, Ardabil, Iran in 2016. Physiological and agronomic traits such as relative water content, excised leaf water loss, stomatal conductance, cell membrane injury, chlorophyll fluorescence parameters, specific leaf area, leaf thickness, root length, root dry weight and grain yield were measured. Results showed that all traits had high broad sense heritability. Among the traits, cell membrane injury had the highest narrow sense heritability (0. 47), followed by specific leaf area (0. 369), excised leaf water loss (0. 353) and relative water content (0. 311). The average degree of dominance was higher than unity for all traits, indicating the presence of over-dominance gene action in the control of these traits. Results showed that for grain yield and specific leaf area, dominant alleles, and for cell membrane injury, recessive alleles are favorable. F1 progenies had lower specific leaf area, excised leaf water loss, relative water content, stomatal conductance and higher root dry weight than their parents. Due to the importance of dominance in the control of characters under study, it was suggested that the evaluation of traits under study should be done at advanced generations of inbreeding.

Drought is the main abiotic stress seriously influencing wheat production and quality in the world. Information about the inheritance of drought tolerance is necessary to determine the type of breeding program and to develop tolerant cultivars. In this study, Bayesian inference was used to explore the nature and amount of gene effects controlling yield and its components under water deficit and normal conditions by assessment of contrasting bread wheat parents (Bam and Arta) and derived generations from them. Bayesian inference using the Gibbs Variable Selection (GVS) approach and the Deviance Information Criterion (DIC) were applied to identify the most important gene effects and to compare models including different gene effects. The GVS and DIC provided an efficient way to perform the analysis and to introduce the more appropriate models. It can be inferred from the results that the Bayesian analysis provides a robust inference of genetic architecture of yield and yield components in wheat. Since the additive, dominance and epistatic gene actions involved in the inheritance of agronomic characters under both water stress and normal conditions, methods which utilize all types of gene effects, such as hybrid seed production, may be useful in improving yield and its stability in wheat.

Fenugreek (Trigonella foenum-graecum L. ) is a medicinal plant used as a traditional medicine. Two of the most important medicinal components are diosgenin and trigonelline that have many medicinal properties including anticancer, decreasing blood sugar and cholesterol. In vitro optimization of callus induction and shoot regeneration is the first step in the optimum production of secondary metabolites through plant tissue culture techniques and genetic engineering. To achieve this goal, leaf, hypocotyl and embryo axis explants were cultured on Murashige-Skoog (MS) medium containing various concentrations of naphthalene acetic acid (NAA) (0, 0. 5, 1. 5 and 2 mg L-1) in combination with 6-benzyl adenine (BA) (0, 0. 5, 1 and 1. 5 mg L-1) producing 48 treatments. The data were analyzed by the non-parametric Kruskal-Wallis test and the means were compared by the U test of Mann Whitney at 5% probability level. The result of the analysis indicated a significant difference between treatments. Simultaneous callus induction and shoot regeneration occurred in the MS medium supplemented with 0. 5 mg L-1 NAA without BA for the embryo axis explant. However, higher frequency of callus induction for leaf and hypocotyl explants was obtained in the higher concentration of NAA (2 mg L-1).

Tissue culture through somatic embryogenesis is one of the methods found most useful in the plants’ breeding process. A key issue to deal with during somatic evolution is its synchronization. Nitrogen has been known to play an important role here. Therefore, we evaluated the tomato explant embryogenesis cultured on B5 basal medium, subject to oxidized, reduced and organic nitrogen. Two separate experiments were conducted consisting of eight treatments with four replications each, using completely randomized design. In the experiment in which treatments were applied during the induction phase, maximum synchrony, based on relative number of torpedo embryo to all formed embryos, was obtained using nitrate as the sole nitrogen source (0. 81). However, in the case in which treatments were applied during the realization phase, maximum synchrony was obtained through the combined nitrate and casein hydrolysate (0. 51). Furthermore, in both experiments the highest number of somatic embryos was obtained in the standard B5 medium (91. 58 in the first experiment and 59. 19 in the second experiment).

We investigated in vitro regeneration ability of Fittonia verschaffeltii using different explants (leaf, node) and plant growth regulators ((2, 4-D, indoleacetic acid, indolebutyric acid (IBA), 6-benzylaminopurine (BAP), thidiazuron)). Percentage of callus induction, number of shoots, shoot length, percentage of rooting and root length were measured. The leaf explant showed higher frequency of callus induction in comparison with the node explant, while node had higher frequency of shoot formation. There were significant differences among plant growth regulators in terms of percentage of callus induction, number of shoots, percentage of rooting and root length, however, the difference was dependent on the type of explant. The highest percentage of callus induction (86. 12%) was obtained for the leaf explant at Murashige and Skoog (MS) medium supplemented with 1 mg/L 2, 4-D and 1 mg/L IBA. The highest number of shoots (5. 9 per explant) and shoot length (7. 95 cm) were observed for the node explant at MS medium supplemented with 2 mg/L BAP + 1 mg/L IBA and MS medium containing 1mg/L BAP + 1 mg/L IBA, respectively. The highest percentage of root formation (87%) and root length (10. 1 cm) were obtained at MS medium supplemented with 0. 2 mg/L IBA and MS medium with no hormones, respectively.

Wheat is a pivotal crop plant in Iran. However, it is mostly grown in drought prone areas of Iran. On the other hand, the trend of global warming is increasing. Therefore, in order to better use the limited water sources, it is needed to improve wheat yield by studying the mechanisms of enhancing water use efficiency (WUE). This study was conducted to determine the effect of stomatal conductance (gs) on water use efficiency and its components in wheat (Triticum aestivum L. ). Seven bread wheat cultivars (Marvdasht, B. C. Roshan, Darab2, Vee/Nac, Shiraz, Chamran, Maroon) were grown in pots under well-watered conditions. The pattern of variation for WUE and its components was different for cultivars. Stomatal conductance showed a positive correlation with total water use, transpiration efficiency and grain yield. A path analysis revealed that transpiration efficiency had a higher direct effect on grain yield (0. 91) than did harvest index (0. 40). Although gs showed a direct effect of almost zero on grain yield, but imposed its effect indirectly via transpiration efficiency (0. 47).

Salinity is one of the most important factors that limit plant growth in many regions of the world. In order to evaluate the effects of salinity stress on germination, growth and some physiological characteristics of flax, two separate experiments were carried out in the laboratory and greenhouse. The experimental factors included three ecotypes of flax (Kurdistan Native, L18, E37) and four salinity levels (0, 50, 100 and 150 mM NaCl). The results showed that with increasing salinity, germination percentage, germination rate, seedling vigor index, length and dry weight of hypocotyl and radicle decreased as compared to the control. At 150 mM salinity, Kurdistan Native and E37 ecotypes had the highest and lowest germination and seedling growth, respectively. Also, salinity decreased shoot and root length, shoot and root dry weight and relative water content, whereas, increased electrolytes leakage and soluble sugars. Kurdistan Native had the highest shoot and root dry weight, relative water content and total soluble sugar at 150 mM salinity followed by L18 and E37 ecotypes. At salinity of 150 mM, Kurdistan Native had the lowest electrolyte leakage and L18 and E37 ecotypes had the highest electrolyte leakage. In general, the most sensitive and most tolerant ecotypes were E37 and Kurdistan Native, respectively. Therefore, Kurdistan Native has potential for cultivation in areas with saline water.

Salinity in the soil and irrigation water is an environmental problem and a major constraint for crop production. Coriandrum sativum as a leafy vegetable is great interest for vegetable producers in the world. However, due to gradual increase in soil and water salinity, especially in Northwest Iran, the production of this vegetable has been faced with many constraints. This experiment was conducted to study the effect of salinity on some morphological and physiological traits of Coriandrum sativum. The factors were arranged as factorial based on randomized complete block design with five NaCl levels (0, 50, 100, 150 and 200 mM NaCl) and local ecotypes (Tabriz, Malayer) with three replications. The results revealed that there was interaction of salinity levels with ecotypes in terms of proline content and relative water content. The highest amounts for proline content (77 μ g-1 FWt) was recorded for Tabriz clone under 200 mM NaCl. The greatest relative water content was obtained by Tabriz clone × NaCl 0 and Malayer × NaCl 0 and 50 mM combinations. The highest dry weight of leaves, K+/Na+ ratio and K+ belonged to the non-salinity condition. Highest amounts of Na+ accumulation, MDA and H2O2 level and ion leakage were attained with 200 mM NaCl level. Soluble sugars content were affected by both salinity and ecotype. The highest content of soluble sugars was achieved by Malayer ecotype. With increasing salinity level, the content of soluble sugars increased and the highest amount of soluble sugars content was recorded at 200 mM NaCl.

A split plot experiment based on randomized complete block design with three replications was carried out in 2015 to determine the best stage for harvest of three dill (Anethum graveolens) ecotypes (Varamin, Isfahan, Malayer) under different irrigation conditions (irrigation after 70, 100, 130 and 160 mm evaporation from class A pan), in order to produce high quality seeds. Results clearly showed that seed quality of all ecotypes under different irrigation intervals was increased with improving seed development on the mother plants. Maximum seed quality on the basis of electrical conductivity of seed leachates, germination percentage and rate and seedling dry weight was obtained at about 2-12 days after mass maturity, depending on ecotypes and irrigation intervals. Earlier harvests due to immaturity and later harvests because of aging reduced seed germination and vigor. Seed vigor of all dill ecotypes gradually diminished with declining water availability to the mother plants. It was, therefore, concluded that irrigation of dill plants particularly during seed filling could improve the quality of seeds. Nevertheless, the best seed moisture content for harvesting dill plants and producing high-quality seeds was about 15-20%. The most vigorous seeds on the basis of germination rate and seedling dry weight were produced by Varamin, followed by Malayer ecotypes.

Chrysanthemum (Chrysanthemum morifolium) is a major ornamental plant with high economic importance. The effect of various rates of salicylic acid (SA) (50, 100, 150 and 200 mg l-1) and thiamine (100 and 150 mg l-1) was studied on some morphological, physiological and biochemical traits of cut chrysanthemums in an experiment on the basis of a randomized complete block design with three replications. The results showed that the highest stem diameter, stem length, flower diameter, flower number, cut flower number, carotenoid, shoot fresh weight and root uptake were related to thiamine rate of 100 mg l-1. Thiamine rate of 150 mg l-1 was associated with the highest vase life, chlorophyll a and b and total chlorophyll. The highest reduced sugar and the lowest flowering time were observed in flowers treated with 150 mg l-1 SA. Also, the highest peroxidase was related to SA rate of 200 mg l-1. In total, it was found that thiamine and SA play an important role in improving morphological, physiological and biochemical traits of cut chrysanthemums. However, different rates of these two compounds entailed various impacts.

Salinity stress has been known as an important constraint limiting agricultural production especially in arid and semi-arid regions. Among several strategies to improve crop growth under salt stress, using of salinity tolerant Trichoderma isolates and silicon application could be an effective and easily adaptive strategy. In order to evaluate silicon and Trichoderma virens inoculation effects on some physiological and morphological properties of wheat grown under saline condition, a greenhouse experiment arranged as factorial based on completely randomized design with three replications was carried out. The factors included three levels of salinity (E1: 3, E2: 7 and E3: 10 dS m− 1) from NaCl, CaCl2 and MgCl2 sources (3: 2: 1 ratio, respectively), two levels of Si, 0 (S1) and 1. 5 mM (S2), from the source of Na2SiO3 and two levels of Trichoderma virens (with and without inoculation). It was shown that salt stress caused very significant reduction in plant height, chlorophyll content, grain yield and other measured properties. Salinity stress increased proline and soluble sugar concentration, Na/K and Na/Ca ratios in leaves. Application of Si to the growth medium significantly increased chlorophyll content, grain yield of wheat grown under normal as well as under saline environments, but those influences were lower than the fungus effect. These results seem to show that silicon may alleviate salt stress in wheat due to decreased Na/K and Na/Ca ratios and proline concentration in leaves. Tirchoderma inoculation significantly increased chlorophyll content and grain yield of wheat under salt stress. Trichoderma virens deteriorate salt stress by significantly decreasing Na/K and Na/Ca ratios and proline concentration and increasing soluble sugar in the leaves.