فصلنامه فرآیند و کارکرد گیاهی
سال دوازدهم شماره 6 (پیاپی 59، Feb and Mar 2024)

Lactuca undulata Ledeb. is a medicinal plant belonging to the Asteraceae family. Chicoric acid is one of the main derivatives of caffeic acid, with various pharmacological and biological properties. This study was conducted to optimize cell suspension culture and enhance chicoric acid production in L. undulata by eliciting secondary metabolites using silver nitrate (AgNO3) and silver nanoparticles (AgNPs). Seeds were cultured on ½ MS medium to produce sterile seedlings. In order to produce callus, leaf and root explants were obtained from 2 months old sterile seedlings and placed on ½ MS medium containing 2 mg/L 2,4-D/ plus 0.5 mg/L Kin and 2 mg/L 2,4-D/ plus 2 mg/L Kin, respectively. Cell suspension cultures from leaf and root-derived calluses were established and treated with different concentrations (0, 2, and 4 mg/L) of AgNO3 and AgNPs during the logarithmic growth phase. Then cells were harvested after 24, 48, and 72 hours. Overall, elicitation by AgNPs was more effective on chicoric acid production compared to AgNO3. The highest amounts of chicoric acid (9.7 ± 0.48 mg/g DW) and caffeic acid (15.3 ± 0.8 mg/L) were found in leaf and root cell suspension cultures after 48 hours of exposure to 4 and 2 mg/L AgNPs, respectively. In contrast, 4 mg/L of AgNO3 stimulated the greatest accumulation of chlorogenic acid (4.56 ± 0.3 mg/g DW) in root cell culture at 72 h after elicitation. The current results revealed that the use of AgNPs can be an efficient strategy to improve cichoric acid accumulation in cell suspension culture.

In the current study, the effect of different silicon dioxide nanoparticles (SiO2 NPs) concentrations was investigated on biomass yield, chlorophyll (Chl a) pigment, antioxidant enzymes, and defence metabolites of Spirulina platensis alga. The alga sample was cultured in the Zarrouk medium supplemented with various SiO2 NPS concentrations (0, 50, 100, and 150 mg L-1) for two weeks. Results showed that SiO2 NPs at 100 mg L-1 increased significantly dry weight, specific growth rate, and Chl pigment, possibly due to the induction of protein content and antioxidant enzyme activities of catalase and peroxidase. Secondary metabolites such as phycobiliprotein, phycocyanin, allophycocyanin, phycoerythrin, carotenoids, and extracellular polymeric substances increased upon all concentrations of SiO2 NP, although their contents were more increased under 100 mg L-1 treatment. Treatment of SiO2 NP at 150 mg L-1 induced toxicity in the algal growth along with the accumulation of H2O2, inhibition of antioxidant enzyme activities, and decline in the content of secondary metabolites. The findings suggest that 100 mg L-1 SiO2NPs is an optimum concentration for sustainable production of S. platensis, and may act as an elicitor to stimulate antioxidant metabolites for suppressing oxidative injuries.

Chilling injury limits the storage life of nectarine fruit at low temperatures. Therefore, increasing the resistance to chilling injury will provide long-term maintenance of nectarine fruit at low temperatures. In this research, the effect of threonine at 250 and 500 µM on chilling injury and fruit quality of nectarine during storage at 1°C with 95% relative humidity for 30 days was studied. The measured traits included chilling injury, hydrogen peroxide, lipid peroxidation, TSS, organic acids, antioxidant capacity and antioxidant enzyme activity. The results showed that chilling injury decreased hydrogen peroxide production and lipid peroxidation in treated fruits with threonine compared to control during storage. The amount of organic acids, TSS, antioxidant capacity and activity of antioxidant enzymes in treated fruits increased until the end of storage. In general, the 500 µM threonine had the most significant effect on maintaining the quality of nectarine fruits during storage.

Intercropping and biofertilizers are the effective components of sustainable agriculture that improve the yield quality and quantity of the plants. A two-year factorial field experiment was conducted to find out the effect of phosphate solubilizing bacteria (PSB) on yield, yield components and some physiological aspects of intercropping of rain-fed chickpea and dragon's head. The first factor included five intercropping patterns that were sole cropping chickpea (30 and 40 plant m-2), dragon's head (160 plant m-2) and additive intercropping of both plants. The second factor was the use and non-use of phosphate solubilizing bacteria (Bacillus lentus and Pseudomonas putida). The results indicated that sole cropping of 30 plants m-2 of chickpea and 160 plants m-2 of dragon's head had the maximum of 1000-seed weight, seed yield, biological yield and harvest index with PSB inoculation. In both plants, the highest leaf nitrogen (2.97 and 2.76%), total soluble carbohydrates (1.12 and 1.47 mg g-1 fresh leaf) and chlorophyll (3.42 and 2.94 mg g-1 fresh leaf) obtained from intercropping of dragon's head+30 plant m-2 of chickpea inoculated with PSB. The maximum values of LER (>1) for PSB-inoculated (1.72) and non- PSB (1.66) were observed in dragon's head +30 plant m-2 of chickpea intercropping of. In general, intercropping of dragon's head-chickpea increased yield and yield components resulted in higher land use efficiency.

Damask rose is one of the aromatic and medicinal plants belonging to the Rosacea family whose essential oil has nutritional and economic value. The purpose of this research was to determine the location of the hormones effects in organ tissues for the formation of calluses, buds and roots. For this, we have studied hormone effects on the callus, shoot, root formation, and anatomical alternate. We found IAA and 2, 4-D with BAP were affected by callus, shoot, and root production from damask shoot explants. Regeneration organs were undifferentiated to callus after two weeks. To avoid this problem, we suggest that it is better to subculture explants in a new medium with fewer hormones. The site of callus, shoot, and root formation was the node on the explant. This explant node had a lateral meristem. The anatomical study of explants showed that the origin of callus, shoot, and root formation is cambium parenchymal cells.

In order to evaluate the effect of irrigation regimes and sowing dates on linolenic acid (Omega-3) content in dragon's head (Lallemantia iberica), an experiment was conducted factorial as a randomized complete block design in three replications in the research farm of Shahed University on crop year 2021–2022 in the research farm of Shahed University. The experimental treatments included: Irrigation regimes at three levels: I20: Irrigation after 20% depletion of soil available water (SAW); I40: An irrigation after 40% depletion of SAW; and IS20: Irrigation at sowing and before flowering based on 20% depletion of SAW. The second factor was the sowing dates of autumn (November 15) and spring (March 15). The interaction effect of autumn sowing date and irrigation regime I20 produced the greatest seed yield (680.1 kg.ha-1), harvest index (0.28), chlorophyll b content (0.457 mg.g-1 Fw), seed number per plant (469.0), and branch number per plant (9.83). Also, the amount of linolenic acid was greater under the treatment of sowing date and irrigation regime I20, with values of 64.07% and 64.33%, respectively. A water shortage in the soil also decreased linolenic acid content under deficit irrigation treatments (IS20 and I40) although in I40 it was not statistically different from I20. Totally, it was clearly determined that the low temperature of autumn increased Omega-3 in the Dragon's head.

High concentrations of nutrients in medicinal plants may be harmful to humans and animals. Therefore, the aim of this study was to determine the concentration of some macro-nutrients (calcium, sodium, phosphorus and potassium) and micro-nutrients (iron, manganese, copper, and zinc) in five famous native medicinal plants grown in the rangelands of the Darab region, southern Iran. The concentrations of micro-nutrients, calcium and magnesium, were obtained by atomic absorption spectrometry, sodium and potassium by flame photometer, and the concentration of phosphorus by spectrophotometer in the extract obtained from the dry combustion method and dissolved in 2 N HCl. The results showed that the variation range in the concentration of measured elements was wide. The studied medicinal plants contained significant amounts of calcium (0.325-1.925%), phosphorus (0.096-0.266%), and potassium (0.188-4.312%). The highest concentrations of iron (517.45 mg kg-1 DM) and copper (11.8 mg kg-1 dry weight) were observed in Maryam nokhodi (Tecurium persicum). The greatest concentrations of zinc (22.5 mg kg-1 DM) and manganese (200.75 mg kg-1 DM) were observed in Shekar shapha (Otostegia persica) and Konar (Ziziphus spina-christi) plants, respectively. The content of micronutrients in the studied medicinal plants (except copper) was higher than the standard limit reported by the World Health Organization (WHO) for edible plants. Finally, in the case of excessive and continuous consumption of these medicinal plants, harmful side effects are not far from expectation. The amount and time interval of the studied medicinal plant consumption must be done according to the opinion of medicinal plant experts.

Due to the eco-systemic hazardous effects of surfactants, biosurfactants are recommended as wetting agents to increase the efficiency of foliar application of nutrients. Moreover, some of them could act as plant growth promoting agents. The aim of the present study was to assess the biosurfactant effect on iron foliar nutrition and its effects on bean growth. Biosurfactant production was investigated in seven Bacillus isolates from compost. Among them, B. nealsonii 104C, with the ability to produce glycolipid biosurfactant, was selected for the greenhouse study. Three concentrations of Fe, including zero, one, and two percent, and two levels of biosurfactant (zero and 50 mgL-1) were tested in a factorial experiment with a randomized complete block design on the bean plants growing hydroponically. The results showed that foliar application of iron without adding biosurfactant at one and two percent concentrations increased the plant yield by 2.08 and 2.8 times, respectively. Zero, one, and two percent iron plus biosurfactant increased the yield up to 4, 3.3, and 4.2 times compared to the control. The highest bean height, total dry weight, leaf and stem weight, and number of pods were observed in the biosurfactant treatment plus 2% iron. It seems that biosurfactants could be used in the bean plant organic farming as an iron transition facilitator via foliar application or as a plant growth stimulator.

High absorption and accumulation of lead in the cultivated Amaranthus caudatus L. make this plant suitable for the purpose of phytoremediation of lead-contaminated soils. The present factorial experiment was carried out based on a completely randomized design with three replications in the Greenhouse of the Faculty of Agriculture, Lorestan University, during 2019. The factors considered in the study included zeolite (0, 5 and 10℅), biochar (0, 7.5 and 15℅), and mycorrhizal fungi (no mycorrhiza and use of mycorrhiza). The highest plant height (1.93 m) and root dry weight (2.55 g) were obtained in the combined treatment of not using zeolite, biochar 15% by weight, and mycorrhiza. Also, the highest biological yield (54.05 g) and accumulated lead in roots (20.05 mg/kg) were obtained in the combined treatment of zeolite 5%, biochar 15%, and no mycorrhiza. Moreover, the highest number of sub-branches (26.67) was recorded in the combined treatment of zeolite 10% + no biochar + no mycorrhiza (Z2B0M0). Furthermore, the highest concentrations of lead in the soil around roots (49.92 mg/kg) were observed in the treatment consisting of zeolite 5% + biochar 7.5% + mycorrhiza. Findings also showed the highest activities of catalase, peroxidase, and superoxide dismutase enzymes in the combined treatment of the plants with zeolite 10% + biochar 15% + no mycorrhiza were obtained. On the other hand, the highest activities of ascorbate peroxidase and glutathione reductase were recorded in the combined treatments of zeolite 5% + biochar 7.5% + no use of mycorrhiza and zeolite 10% + biochar 15% + the use of mycorrhiza, respectively. The highest concentration of lead in leaves (17.71 mg/kg) was obtained in none zeolite + none mycorrhiza + biochar 15%, which was among the best treatments of the study resulting in a high biological performance of the plants (41.55 g). Finally, the most favorable treatment with the highest biological yield (54.05 g) and maximum lead contents of the roots (20.05 mg/kg) was obtained by zeolite 5% + biochar 15% + none mycorrhiza. The maximum biological yield of the plant (54.05 g) and the highest concentration of lead in roots (20.05 mg/kg) were observed in the combined treatment of zeolite 5%, biochar 15%, and no mycorrhiza (Z1B2M0). This is the best treatment for phytoremediation, in which the plants absorb the highest concentration of lead. On the other hand, the highest accumulation of lead in leaves (17.71 mg/kg) was obtained in the treatment with no zeolite and mycorrhiza + using biochar 15% (Z0B2M0). In view of the high biological performance of Amaranthus caudatus L. in this treatment (41.55 g), it is considered one of the most effective plants in bioaccumulation.

Stomatal crypts, the depressions of the epidermis containing stomata, are among the most frequently cited as examples of an adaptation that reduces water loss. The effect of stomatal crypts, despite the considerable assumption regarding its possible impact on gas diffusion, has never actually been quantified. In accordance with Fick’s law of diffusion, assuming the structure of the crypt as a tube, we hypothesized that as the depth of the crypt increases, the diffusion path length increases, and as a consequence, the resistance to the diffusion of gas increases as well. Hence, at a constant cross-sectional area, leaves with a deeper crypt should have lower water loss. Despite assumptions about the function of stomatal crypts, there are surprisingly few published studies on the physiological effects of crypts. This study evaluated the micromorphology of stomatal modifications in a range of Banksia species as well as the impact of stomatal crypts on leaf gas exchange. We hypothesized that as crypt depth increased, transpiration and photosynthesis would decrease for a given VPD. If this were the case, this would support the idea that crypts are an adaptation to reduce water loss in arid environments. Leaf cross-sections and micrographs of over 110 species of the Proteaceae family were examined. Fourteen species of Banksia, as well as Dryandra praemorsa, were selected for this study. Two-year-old seedlings of the 15 species were obtained from Protea World, Adelaide, Australia, and grown for one year in 2 L pots containing premium potting mix (Premium Potting Mix, Australian Standard, AS3743) in a glasshouse at the University of Adelaide, Australia. The current study demonstrated that crypts occurring in the epidermis of the Banksia species examined at different depths and widths did not impact on gas diffusion through stomata. Also, the present results showed that deeper stomatal crypts did not have a significant impact on transpiration compared with leaves that had shallower crypts. The positive relationship between leaf thickness and depth of crypts and the negative relationship between leaf thickness and stomatal density in Banksia species found in this study might suggest that stomatal crypts possibly act as a means of overcoming mesophyll resistance to CO2 diffusion. Further studies are required to investigate this possibility.

Abiotic stress from drought inhibits plant growth and decreases yields. Salicylic acid (SA) is classified as a compound that effectively reduces crop susceptibility and environmental stress by mitigating the harmful effects of many stressors. Numerous levels of SA protect several plant species from environmental stresses by initiating different processes involved in the stress tolerance mechanism. Fruit productivity and quality under dry stress conditions were examined by evaluating the effects of the application mode and various concentrations of SA. The split factorial experiment based on a completely randomized block design with four replicates in the Jiroft University Research Greenhouse was carried out. In this study, drought stress is the main factor at three levels (control, moderate and severe stress). Factorial treatment included interaction at two levels of (SA application method as foliar spray and soil drench) and (SA concentration include control, 1 and 1.5 mM SA). The results showed that relative water content (RWC), electrolyte leakage, titratable acidity (TA), average fruit weight, fruit yield, and the number of fruits per plant were affected by the interaction of drought stress, SA concentration and consumption method. Strawberry fruit production per plant was highest with 315.20 g from non-stress treatment with 1.5 mMof SA. Under severe drought stress, the maximum fruit production per plant of 201.80 g with 1.5 mM of SA was obtained, which increased the strawberry fruit productivity with an ascending concentration of SA. In strawberry plants, drought stress manifests in elevated levels of antioxidant enzyme activities, including catalase (CAT) and peroxidase (POD) in the leaves. Interestingly, moderate and high drought stress led to improvements in certain fruit quality indices such as vitamin C content, compared to those not subjected to stress. Another significant finding was that the application of SA increased the activities of CAT and POD enzymes, while also elevating the concentrations of chlorophyll and proline considerably. Finally, it is recommended to use 1.5 mM of SA as a foliar spray under drought stress conditions on greenhouse strawberries.