Journal of Plant Physiology and Breeding
Volume:12 Issue: 1, Winter-Spring 2022

Drought is the most important stress factor that reduces plant growth and yield. However, the application of moisture absorbents may decrease the negative effects of drought. This study aims to investigate the effect of irrigation levels (irrigation after 140, 100, and 70 mm evaporation from pan evaporation) and moisture absorbents (without moisture absorbent, superabsorbent, vermiculite, zeolite, and the combined use of all three moisture absorbents) on yield components and physiological characteristics of safflower (Carthamus tinctorius L. cv. Goldasht). This experiment was performed in 1397 and 1398 as the split-plot design using the randomized complete block design with three replications. Results showed that under 140 mm evaporation due to the severe drought, seed yield and oil yield declined by 36.3% and 46.6%, respectively, as compared to the 70 mm evaporation. As usual, drought increased the malondialdehyde content significantly. Water absorbent treatments increased the grain yield as compared to the control. However, there were no significant differences in the effect of water absorbents on the grain yield but the most effective moisture absorbent to increase the oil yield was zeolite. Oleic and palmitic acids percent increased due to drought, while the amount of linoleic acid decreased with increasing the irrigation intervals. In conclusion, the results showed that the use of moisture absorbents alleviated the adverse effects of drought stress on the safflower yield and some yield components.

Water deficiency limits nutrient availability and causes physiological disruptions resulting in decreased crop productivity in the field. The spray of Fe and Zn on drought-stressed plants may reduce some of the detrimental impacts of this stress on crop performance. Thus, this research was laid out as a split-plot design based on a randomized complete block design with three replications to assess the effects of exogenous iron (Fe: 1 g/l) and Zinc (Zn: 1g/l) on safflower (Carthamus tinctorius L.) under different irrigation intervals (irrigation after 70, 100, 130, and 160 mm evaporation as normal irrigation, and mild, moderate, and severe water deficits, respectively). Water deficiency decreased green ground cover by reducing plant growth. Leaf water content, chlorophyll content index, capitols per plant, grains per plant, and 1000-grain weight also decreased but leaf temperature increased due to water limitation, leading to a significant loss in the grain yield per unit area under moderate and severe stresses. Foliar sprays of Zn and especially Fe considerably improved the grain yield of safflower under different irrigation intervals, via increasing leaf chlorophyll content, grains per capitol, and grains per plant. However, this superiority in the grain yield decreased with increasing water deficit, which shows that foliar sprays of Fe to a larger extent and Zn to a lesser extent can alleviate some detrimental impacts of mild and moderate water limitations on safflower plants.

Chlorophyll a fluorescence measurement is a useful tool for studying the herbicides' effects with different modes of action on the photosynthetic apparatus. In this research, the chlorophyll a fluorescence response of common cocklebur (Xanthium strumarium L.) plants was studied two days after the sole application of different doses of the Lumax herbicide (s-metolachlor + mesotrione + terbuthylazine), and combined with the almond oil. The quantum yield of energy dissipation (F0/Fm) and minimum fluorescence (F0) values of the plants treated with the 100% herbicide dose increased significantly from 0.16 to 0.25 and 296 to 391, respectively, two days after treatment. These changes in PSII resulted in the reduction of the maximum quantum yield of PSII (Fv/Fm) and the PSII function index (PIABS). Moreover, the application of high doses of the herbicide decreased the variable fluorescence (Fv), the maximum fluorescence (Fm), the size of the plastoquinone pool on the reducing side of photosystem II (Area), the maximum efficiency of water-splitting complex on the donor side of the photosystem II (Fv/F0), the energy needed for the closure of reaction centers (Sm), and the intermediate redox state of quinone A in the period from F0 to Fm. Our study revealed that the use of almond oil with the Lumax herbicide caused further reduction of the chlorophyll a fluorescence parameters in common cocklebur. The correlation between dry weight taken 28 days after the herbicide application and Fv/Fm measured two days after the herbicide application showed that assessing the chlorophyll a fluorescence parameters can speed up the rate of herbicide performance evaluation up to 12 times. The steeper slope of the regression line for herbicide with almond oil compared to the herbicide alone showed that almond oil could be a proper adjuvant to increase the herbicide efficiency.

Artemisia melanolepis Boiss is an endemic species in Iran distributed in north and north west of the country. In the present work, metabolites’ content of the aerial parts of A. melanolepis was analyzed at three growth stages. The non-volatile primary and volatile secondary metabolites of the plants were obtained by extraction and hydro distillated methods, respectively, and then were analyzed using a GC-MS. Our results showed that the non-volatile primary metabolites from amino acids, organic acids, sugars, and sugar alcohols declined considerably from the vegetative state to fruiting period of the plants. The results also indicated that thymol was the main constituent of the volatile oils at all phonological stages with various percentages in each stage. The major volatile secondary metabolite was alpha-terpineol at the vegetative and flowering stages (6.09 and 6.92%, respectively), followed by 4-carene (4.96%) at the fruiting stage. It was concluded that the metabolites profile of A. melanolepis was considerably altered at different stages of the life cycle.

Pollution of the environment by toxic metals creates stress conditions that generally negatively affect plant growth and development. Cadmium is a highly toxic metal that enters the environment mainly through industrial activities and affects crops and other agricultural plants. In the current investigation, the influence of different concentrations of CdCl2 on Cd uptake, growth parameters, and antioxidant responses of Trigonella foenum-graecum L. were investigated. Results showed that H2O2 and malondialdehyde contents were increased by Cd treatments compared to the control plants. Cd stress differently altered the activity of antioxidant enzymes such as catalase, superoxide dismutase, peroxidase, and polyphenol oxidase. The content of antioxidant compounds such as phenols, flavonoids, anthocyanins, soluble proteins, and proline was also increased by the Cd treatment. In addition, our results demonstrated the decrease in seed germination percentage, growth parameters, and chlorophyll and carotenoid contents that may be considered circumstantial evidence for the toxicity of cadmium.

The South American plant, Stevia rebaudiana Bertoni, is a good source of steviol glycosides, antioxidants, all of the essential amino acids, and other important nutritional compounds. The present study was conducted to investigate the effects of 5 and 10 mg L-1 concentrations of selenium nanoparticles (SeNPs) and 50 mg L-1ancymidol (ANC) on physiological and biochemical characteristics of S. rebaudiana colonized by the root endophytic fungus Piriformospora indica at vegetative and initial flowering stages. Results indicated that ANC decreased root colonization rate and antioxidant enzyme activities, but increased the content of H2O2 (vegetative stage), malondialdehyde (initial flowering stage), and phosphorus uptake (initial flowering stage( significantly and had no effect on total carbohydrate content. The adverse effects of ANC reduced after P. indica colonization and somewhat with SeNPs application. Our results suggest that the P. indica colonization and SeNPs application can alter the equilibrium between the production of free radicals and enzymatic defence reactions in S. rebaudiana by enhancing the scavenging capacity of free radicals and by decreasing membrane lipid peroxidation during both vegetative and initial flowering stages. Moreover, the effects of ANC, SeNPs, and P. indica on the measured characteristics at the vegetative stage were higher than those observed at the initial flowering stage.

Arsenic (As) is one of the most hazardous metalloids for plants, however, little is understood about the role of silicon nanoparticles (Si-NPs) in improving rice tolerance under As toxicity. An experiment was conducted in 2020 at Islamshahr Branch, Islamic Azad University, Islamshahr, Iran, to examine the impacts of As (50 M) and Si-NPs (50 and 100 mg/L) on rice growth, chlorophyll and proline metabolism, antioxidant defense system, ionic homeostasis, and expression of Si/As transporters under hydroponic conditions. The results showed that Si-NPs by boosting the activities of antioxidant enzymes, diminished hydrogen peroxide and superoxide anion, and hence, protected the photosynthetic apparatus and enhanced plant growth during As toxicity. Si-NPs increased Si uptake and declined As uptake in As-treated seedlings by adjusting the relative expression of Si/As transporters (Lsi1, Lsi2, Lsi6). Si-NPs maintained ionic homeostasis under As stress by increasing the uptake of mineral nutrients. In general, Si-NPs increased rice growth and biomass during As toxicity, which might be exploited to develop effective fertilizers to improve crop growth and yield in As-contaminated areas.

The occurrence of inter-specific hybrids between two species in nature has the potential ability to develop new fruit trees with desirable traits. In this study, flower morphology, viability, and in vitro germination of pollen grains and self-(in) compatibility, using fruit set (%) and fluorescence microscopy methods were examined in three promising natural Prunus interspecific hybrids [P. armeniaca × P. salicina (Bavanat) and P. cerasifera × P. armeniaca (Shiraz and Shahriar)]. Bavanat and Shiraz had the highest flower diameter, while the highest number and length of stamens, as well as stamen number/pistil length ratio, belonged to Shahriar. The highest and lowest pollen viability and in vitro germination were observed in Shahriar and Bavanat, respectively. In general, sucrose concentrations of 150 to 250 g/l increased in vitro pollen germination rate, although concentrations of more than 150 g/l had a negative effect on Bavanat. The three-year average (2018-2020) of final fruit set by self-pollination ranged from 0% in Shiraz to 1.3% in Shahriar. A strong positive correlation was found between the occurrence of twin pistils and the mean temperature from July-August in the previous year. According to field self-pollination and fluorescent microscopy, all three genotypes were considered self-incompatible and needed pollinizer varieties.

To investigate the combining ability of sunflower (Helianthus annuus L.) inbred lines and also the inheritance of several physiological traits of this plant in normal irrigation and water-deficit-stress conditions, eight inbred lines with different drought tolerance were crossed with three cytoplasmic male sterile lines. The resulting 24 hybrids, 11 parents, and a commercial hybrid (Barzghar) as the control were evaluated in a split-plot design based on the randomized complete block design with three replications. Irrigation was applied in the main plots at two levels, normal (irrigation based on 100% water requirement) and stress (irrigation withhold after the appearance of the inflorescence), and 36 sunflower genotypes in subplots. During the growing season, chlorophyll content (Chl), relative water content (RWC), leaf water loss (LWL), early growth rate (EGR), leaf temperature (LT), and grain yield (GY) were measured. The analysis of variance showed the significant effect of water-deficit stress on Chl, RWC, LT, and GY. According to the results of the line × tester analysis, the effect of lines was significant for Chl, LWL, EGR, and GY in normal conditions, and on Chl and EGR in the water-deficit-stress conditions. In the case of the testers, there was a significant difference in Chl, EGR, and GY under normal conditions, and in LWL, EGR, and GY under stress conditions. The significant effect of lines and testers on these traits indicated a difference between their general combining ability (GCA) and the existence of additive gene effects. The interaction of line × tester was significant only for GY in normal conditions. Chl and EGR had a relatively high broad-sense and narrow-sense heritability at both conditions. The GY had also relatively high broad-sense heritability in both conditions but its narrow-sense heritability was only relatively high at the water-deficit-stress conditions. The C122 and C123 lines and the A19 tester had the highest positive GCA for GY in both conditions. The hybrid A196 × C41 in the normal conditions and A112 × C111 in the stress conditions had a positive SCA. Among the physiological traits, only LWL showed a significant correlation with GY in normal conditions. Under water-deficit-stress conditions, LWL and EGR had a positive correlation with GY, while LT showed a negative correlation with GY. In conclusion, it seems that LWL, EGR, and LT can be used to indirectly improve GY of sunflower under water-deficit stress conditions.

The wild barberry shrubs, commonly known as black barberry, are naturally widespread in the north and northeast elevations of Iran. Besides a rich gene bank, these are highly considered concerning food and medicinal purposes. The present research work was undertaken to evaluate the genetic diversity among 15 different barberry genotypes (14 wild and one cultivated genotypes) through morphological, biochemical, and molecular markers. The morphological traits of leaf, thorn, and berry were measured. The biochemical properties of the studied genotypes were also measured at the fruit ripening stage. Furthermore, the genotypes were subjected to simple sequence repeat analysis to ascertain their genetic diversity at the molecular level. The studied accessions were diverse in the case of morphological traits and they were classified into five distinct groups. Moreover, some rare and remarkable morphological characteristics were found in the fruit shape and fruit clusters of some genotypes not reported earlier. Though wide differences were obtained concerning fruit biochemical compounds, the differences didn’t have a clear trend. The accessions were characterized based on microsatellite analysis into eight groups in which the closely related genotypes had relatively higher geographical similarities. Access to the genetic diversity of these genotypes may be considered as the backbone of their future breeding programs and the reported data supported that the northeast of Iran may be assumed as a rich source for the diversity of Berberis germplasm.

To determine the gene action and inheritance of grain filling rate and remobilization of stem reserves in bread wheat, a 6×6 half diallel was performed. The F1 seeds along with parental varieties were evaluated under terminal drought stress at Islamic Azad University, Ardabil, Iran in 2018. Grain filling rate, effective grain filling period, remobilized dry matter, the contribution of remobilization in grain yield, remobilization efficiency of dry matter, carbohydrates remobilization efficiency, and specific weight of internodes were measured. Results showed the adequacy of the additive-dominance model in all of the characters except for the effective gain-filling period and contribution of remobilization in grain yield. The existence of partial dominance, complete dominance, and over-dominance was observed in control of the measured characters. Generally, broad sense heritability was high and ranged from 0.72 (carbohydrates remobilization efficiency) to 0.88 (grain filling rate). However, narrow sense heritability ranged from 0.17 (carbohydrates remobilization efficiency) to 0.66 (grain filling rate). Among the traits, grain filling rate had the highest narrow sense heritability (0.66) followed by the remobilized dry matter (0.46) and specific weight of internodes (0.44). There was also a positive relationship between dominance effects and the specific weight of internodes, where dominant alleles were favorable. Based on Griffing’s method, Rasad, Konya2002, and Pishtaz had higher general combining ability (GCA) and consequently favorable alleles for the grain filling rate. However, for remobilization, Rasad and Konya2002 had higher GCA.

Inheritance of several physiological and agronomic traits in 92 F4 lines derived from the cross between two wheat (Triticum aestivum L.) cultivars (Arg and Moghan3, tolerant and sensitive to salinity, respectively) was studied in a greenhouse at normal and salinity stress conditions using a hydroponic system in 2018. The experiment was carried out as a split-plot design based on randomized complete blocks with two replications. The two salinity levels (control and application of 150 mM NaCl at the three-leaf stage) were arranged in the main plots and the lines in the subplots. Analysis of variance showed significant differences among lines for all of the investigated characteristics, except the K+/Na+ ratio. The line × salinity interaction was significant for the majority of the traits including grain yield. Salinity stress increased leaf temperature, electrolyte leakage, 1000-grain weight, and Na+ content, and decreased other traits significantly. Transgressive segregation was detected for some traits at both normal and salinity stress conditions. At both normal and salinity stress conditions, broad-sense and narrow-sense heritability for the studied traits were estimated high (0.72 to 0.99) and moderate to low (0.11-0.62), respectively. The lowest broad-sense (0.72 and 0.66 at normal and salinity-stress conditions, respectively) and narrow-sense heritability (0.13 and 0.11 at normal and salinity-stress conditions, respectively) belonged to the grain yield. At both conditions, the magnitude of dominance genetic variance was higher than the additive genetic variance for the majority of the traits investigated. The average degree of dominance for all traits at both conditions was greater than one, which showed the existence of over-dominance gene action in controlling these traits. This research highlights the necessity of exploiting dominance gene effects in breeding programs of wheat at salinity stress conditions.