جستجوی مقالات مرتبط با کلیدواژه « محتوای کلروفیل » در نشریات گروه « زیست شناسی »

Eryngium caucasicum from the Apiaceae family, is native to the northern regions of Iran and has significant medicinal and nutritional properties. This paper has provided detailed morpho-anatomical characteristics of the leaves, peduncles, leaf tail, stem, and roots of Eryngium caucasicum by bright-field light microscopy. Also, the amount of phenol, flavonoid, and antioxidant activity with a spectrophotometer and the analysis of essential compounds of the aerial part with GC and GCMS have been presented. Morpho-anatomical features include the dicot-like leaves with palmate venation, isolateral mesophyll with palisade tissue on the upper and lower regions of the leaf, and much reduced spongy parenchyma; characteristic arrangement of the mechanical collenchyma tissue, especially in leaves; and characteristic wrinkles in the leaf cuticle. The stem and peduncle with longitudinal ribs contain collenchyma; there is a presence of aerenchyma in the peduncle and root; calcium oxalate druses and secretory channels in all the studied plant parts; and an absence of sclerenchyma in all investigated parts of the plant. The aerial parts of E. caucasicum had 37% essential oil, 53.9 mg of flavonoids per gram of dry matter, 48.79 mg per gram of dry matter, and 62.97 percent antioxidant activity. The main compounds in the essential oil of the aerial part include Piperitone (48.78%), ß-Sesquiphellandrene (12.64%), and (Z)-Falcarinol (7.85%), and (Z) ß-Farnesene (6.36 percent).

Soil application of farmyard manures and moisture-absorbing materials such as natural zeolite is considered a simple and cheap way to conserve soil moisture in arid areas and light soils. To study the effect of two soil amendments on the physiological properties of “Bidaneh Sefid” grapevines under drought stress, an experiment was conducted in factorial based on a randomized block design in the research vineyard of Malayer University, Hamadan, Iran during the 2022 and 2023 growing seasons. The treatments included two levels of irrigation cycle (7 and 21 d intervals) and four levels of soil amendments (control, 12 kg zeolite vine-1, 15 kg sheep manure vine-1, a combination of 12 kg zeolite + 15 kg sheep manure vine-1). Results showed that the drought stress led to a decrease in chlorophyll content, leaf relative water content, and leaf water potential. Drought stress also led to an increase in electrolyte leakage and the activity of antioxidant enzymes. Application of farmyard manure and zeolite moderated all the investigated indicators, due to their ability to absorb and retain water in the soil. The results of the study showed that it is possible to mitigate the adverse effects of drought stress on grapevine by retaining the moisture of light soils by the application of natural zeolite, alone or in combination with farmyard manure.

Water limitation is the most severe stress factor limiting plant growth and crop production in arid and semi-arid regions. Several strategies have been developed in order to decrease water limitation effects caused by the rainfed condition on plant growth. Among them, the use of putrescine and bio-fertilizers such as plant growth promoting rhizobacteria (PGPR) and Mycorrhiza play a significant role in yield improvement. Therefore, to study biofertilizers and putrescine’s effect on biomass and some physiological and biochemical traits of vetch (Vicia villosa) under rainfed conditions, a factorial experiment was conducted based on a randomized complete block design with three replications in a research farm at the University of Mohaghegh Ardabili in 2019. Experimental factors included biofertilizers (no biofertilizer as control, application of Rhizobium, Mycorrhiza, combined application of Mycorrhiza and Rhizobium, Rhizobium and Azotobacter, Mycorrhiza and Azotobacter, Rhizobium with Mycorrhiza and Azotobacter) and foliar application of putrescine in three levels (water as control, 0.5 and 1mM putrescine). The results showed that both application of Azotobacter with Mycorrhiza and Rhizobium and foliar application of 1 mM putrescine increased catalase, peroxidase and polyphenol oxidase enzymes activity )37.08, 37.54 and 34.41% respectively (, maximum fluorescence and anthocyanin content )56.94 and 4.57% respectively( compared to no application of biofertilizers and foliar application of putrescine. Also, both application of Azotobacter with Mycorrhiza and Rhizobium and foliar application of 1 mM putrescine increased total biomass by about 56.9% compared to no application of biofertilizer and putrescine. It seems that the application of biofertilizers and putrescine can increase the total biomass of Vica villosa under rainfed conditions due to improving the physiological and biochemical traits.

Salinity is one of the environmental factors limiting cultivation of ornamental violet (Viola wittrickiana cv. Queen Yellow Bee). This study was conducted as a factorial experiment in a completely randomized design with four replications at Islamic Azad University, Science and Research Branch in 2019. Studied factors were sodium selenate (0, 0.002, 0.004 and 0.008 mg/L), sodium selenate application (foliar application and soil application) and salinity stress (0 (control), 3 and 6 dS/m). The results showed that salinity significantly reduced flower height, flower number, stem diameter, flower diameter, fresh and dry flower weight, fresh and dry root weight, chlorophyll a and b. At salinity of 6 dS / m, the application of sodium selenate in soil increased the fresh and dry weight of flower by 11.34% and 10.39%, respectively, while the foliar application of sodium selenate increased fresh and dry weight of viola flowers by 25.10% and 25.41%, respectively. Chlorophyll a increased by 12.93%. in salinity of 6 dS / m with application of sodium selenate at 0.008 mg / l compared to control. In salinity stress of 6 dS / m superoxide dismutase enzyme reduced by 26.13%. when sodium selenate was used at 0.008 mg / l in comparison with control. Salinity stress increased the amount of chlorine and sodium in shoots and roots and decreased potassium. Foliar application of sodium selenate  at 0.008 mg / L improved the growth of ornamental violet.

Iran, is classified as arid and semi-arid regions of the world. Therefore, it is important to identify and planting of drought tolerant plants such as quinoa (Chenopodium quinoa Willd.). Zinc is involved in vital processes of the plant therefore; the supply of this element to the plant has a major impact on the quantity and quality of production. This study was conducted as a pot experiment to investigate the effect of zinc sulfate on quinoa under drought stress in a factorial randomized complete design with three replications. Drought stress was prepared with PEG 6000 at four levels (0, -3, -6 and -9 bar) and zinc element from zinc sulfate source with four levels (2 (control), 4, 6, and 8 μM) and in the four-leaf stage, the treatments were applied simultaneously to Hoglandchr('39')s nutrient solution for two weeks. According to the results, an increase in drought stress caused a 68% increase in catalase compared to the control. Maximum leaf soluble protein at -6 bar level with 8 μM zinc sulfate level, highest total soluble sugars and leaf proline at the highest level of drought and 6 μM zinc sulfate were observed. With increasing drought, chlorophyll a (34%), chlorophyll b (187%) and leaf carotenoid increased two-fold but decreased shoot dry weight (38%) and leaf area (37%) compared to control. In general, the use of zinc reduced the damage caused by drought stress by improving the level of osmolytics, and to alleviate the effect of drought stress, the use of 6 μM zinc sulfate in nutrient solutions is recommended.

In order to investigate the effect of drought stress and nano-TiO2 and salicylic acid foliar application on some physiological traits of Echinaceae purpurea under water, an experiment was conducted in split plot factorial based on RCBD in three replications at the Research Station of the Islamic Azad University, Tabriz Branch, during growing seasons of 2017-2018. The main factors were water deficit stress at three levels of 50, 75, and 100% filed capacity, thefactorial combination of nano-TiO2 (n-TiO2) foliar application at two levels (0.02 and 0.04%) and salicylic acid foliar application at two levels (0.02 and 0.04%), and also distilled water foliar application as control treatment. Findingsshowed a significant effect of water deficit stress on relative water content (RWC) and proline (p≤0.01). Also, interaction of the effects of water deficit stress and nano-TiO2 and salicylic acid foliar application on Chl. b, total Chl., and hydrogen peroxide contents was significant (p≤0.01). Application of water deficit stress treatment up to 50% FC increased proline content by 40% and reduced RWC by 10% compared to complete irrigation (100% FC). Furthermore, 0.04% n-TiO2 and 0.04% SA foliar application increased hydrogen peroxide content by 50% compared to complete irrigation group and the control. The maximum total Chl. Contents of leaves was obtained under 100% FC irrigation and and 0.04% n-TiO2 and 0.02% SA foliar application showing 79.52% increase compared to 100% FC irrigation and no foliar application.

In order to investigate the effect of drought stress and nitrogen application on growth and some physiological characteristics of sorghum genotypes, an experiment was conducted in a split-split plot with randomized complete block design in three replications at Research farm of collage of agriculture, Isfahan University of Technology. Experimental treatments consisted of two irrigation regimes (50% and 85% depletion of available soil water), two levels of nitrogen fertilizer (available rate, 121.5 kg ha-1, nitrogen from Urea fertilizer, N= 45%) and 15 sorghum genotypes (Pegah, Sepideh, GS4, GS5 , GS24, GS25, GS26, GS28, KGS29, KGS33, MGS1, MGS5, SF001, SF002, SF003). The results showed that drought stress significantly decreased biological yield by decreasing plant leaf area, plant height, quantum efficiency of photosystem II and chlorophyll content. In contrast, the activity of antioxidant enzymes including catalase, ascorbate peroxidase and peroxidase was significantly increased under drought stress conditions. Application of nitrogen under normal irrigation and drought stress increased all the above traits except chlorophyll a/b ratio and ascorbate peroxidase activity, however, this increase was less in drought condition. Therefore, application of nitrogen fertilizer under drought stress can modulate the effect of stress and increase yield. Among the studied genotypes, SF001, SF002 and MGS5 genotypes had the highest response to nitrogen and the least sensitivity to drought stress. Therefore, they can be used in areas of water scarcity.

In order to investigate the effects of arbuscular mycorrhizae on some physiological characteristics of maize (SC704) under water deficit condition, a factorial experiment based on randomized complete design with three replications was conducted at the physiology laboratory of Islamic Azad University Branch Ardabili, during 2015. Studied factors were: water potential in four levels (Zero, -4, -8 and -12 MPa) and Seed pre-treatment with mycorrhizal fungus in four levels (no inoculation, Seed pre-treatment with Funneliformis mosseae, Rhizoglomus fasciculatum and Claroideoglomu etanicatum. The results showed that increasing water stress decreased chlorophyll a, b, total chlorophyll, carotenoid, relative water content and increased soluble carbohydrates and proline compounds followed, The seeds were inoculated with rhizoglomus fasciculatum of increasing traits in comparison with non-inoculated, respectively. The results of the comparison of mean interactions of drought stress and mycorrhiza showed that The highest content of chlorophyll a (85.23 mg/g fresh weight), total chlorophyll (35.33 mg/g fresh weight) and leaf water content (45.8%) related to stress-free treatment and inoculated plants with rhizoglomus fasciculatum. In general, the application of arbuscular mycorrhizal fungi increased the tolerance to water deficit stress through its effect on some physiological characteristics of corn.

In order to investigate effects of Azomite application in reducing salinity stress in basil herb, a pot factorial experiment based on completely randomized design with three replications was conducted in the research greenhouse of Agriculture Faculty, Ferdowsi University of Mashhad. Treatments were consisted of salinity stress at three levels (0, 50 and 100 mM) as the first factor and the application of Azomite mixed with soil before cultivation at four levels (0, 3, 6 and 9 g per kg of soil) as the second factor. Vegetative traits such as plant height, number of branches, inflorescence length, leaf length and leaf fresh and dry weight were significantly decreased with increasing salinity stress. Application of 9 g/kg Azomite at high levels of salinity stress improved these traits compared to control plants (non-application of Azomite). Also, the highest chlorophyll a content was obtained in control plants (non-salinity stress) and 50 mM salinity stress treatments with application of 9 g/kg Azomite which were 8.33 and 7.48 mg/g.FW, respectively. The highest antioxidant activity (90%), total phenol (0.93 mg/g.FW) and proline (0.4 mg/g.DW) was observed in 100 mM salinity stress treatment and application 9 g/kg Azomite. The highest relative water content (RWC) was obtained under non salinity stress conditions (control) and application of 9 g/kg Azomite. In general, it could be concluded that using of Azomit as a natural substance consistent with sustainable agriculture under salt stress conditions can increase plant growth and improve Basil's biochemical traits.

Compost produced from municipal waste and has suitable chemical and physical properties, which plays an important role in reducing the negative effects of environmental stress in plants. In order to evaluate the effects of compost fertilizer on photosynthetic parameters of phonological stages of lentil under drought stress, a factorial experiment in completely randomized design was conducted with three replications (p≤0.05). Experiment were carried out with five ratios of compost to soil, i.e., 0:100, 5:95, 15:85, 25:75 and 35:65, and three levels of drought stress including non-stress, moderate and severe drought stress (100, 75, and 25% of field capacity, respectively). Results showed that,adding 25 and 35% compost to the soil at seedling stage under moderate stress, led to significant increase of total chlorophyll content (12 and 15%), intercellular CO2 (8 and 8%), net-photosynthesis (16 and 17%) and efficiency of PSII (4 and 4%), compared with the control. However, under severe stress, it was effective levels of 35% compared with other levels. At flowering stage, 25 and 35% compost levels under moderate and severe stress led to significant increase in all parameters compared with control group. According to the results, this study suggests that compost plays an important role in reducing the negative effects of stress on photosynthetic performance of lentil, especially in the early stages of growth.

Chlorophyll fluorescence parameters and chlorophyll content are the most important factors for determining photosynthetic capacity in plant. For this purpose, an experiment was conducted to compare the resistance to different levels of drought stress, to evaluate the most important physiological indices and assess the function of photocysteine II using chlorophyll fluorescence parameters, chlorophyll content (chlorophyll a, b and a + b) and carotenoids of two bean cultivars in three levels of water deficiency including 30, 60 and 100% crop capacity (FC) in factorial arrangement in a randomized complete design with three replications in the greenhouse of the University of Guilan. Comparison of mean values showed that severe drought stress reduced the amount of chlorophyll content, Fv / Fm, Fv and, in contrast, increased the amount of fluorescence and Y (NPQ). The highest Fv/Fm ratio was observed in the control plants, while the highest reduction in Fv/Fm ratio in severe stress was obtained for the 18-G cultivar. In general, the interaction of drought cultivar was significant for all traits except Y (II), PAR and Fv/Fm. Also, Pearson correlation between total chlorophyll and Fv/Fm showed a positive and significant correlation (R = 0.86 **) in Ghaffar cultivar, but was not significant in G-18. Therefore, it can be concluded that Ghaffar cultivar can tolerate relatively high levels of drought by making changes in some physiological characteristics with better performance.

A pot experiment was conducted in order to study the effects of mycorhizal inoculation on the response of sorghum genotypes to salinity. The experiment was arranged as factorial in a randomized complete block design with three replications. In this study ten sorghum genotypes were tested under two levels of salinity (0 and 100 mM Nacl), and two inoculation (mycorhizae and control) treatments. The interactions between salinity, mycorhizae inoculation and genotype were significant on evaluated traits. There was a decrease in the concentration of phosphurous and potassium and leaf relative water content in most of genotypes and in the percentage of mycorhizae infection, cholorophyll, and shoot dry matter in all genotypes under saline condition. Among tested genotypes, IUA28 was the most tolerant genotype to salinity in both inoculated and none inoculated treatments. The inoculation of plants with mycorhizae increased the concentration of phosphurous, potassium and cholorophyll and decreased the concentration of sodium in treated plants. Under saline condition, except for MGS5, the biomass yield was increased with mycorhizal inoculation and the extent of increase was geatest in MGS2 as compared to other tested genotypes. The ratio of K/Na had a significant role in increasing growth of inoculated plants under saline treatment. Under non saline condition, however, except for KGS33, plant growth was not imporoved by mycorhizal inoculation. The results of this experiment showed that inoculation with mycorhizae can alleviate the negative effects of salinity on sorghum genotypes and there is considerable varition among genotypes in this regards.

Water stress is one of the most important factors limiting the growth and yield of plants in many parts of the world. In order to evaluate the effects of water stress on some morphological, physiological and antioxidant enzyme activity traits of lentil, four lentil cultivars (i.e. Gachsaran, Kimia, Ziba and Robat) in four water deficit treatments including 25%, 50%, 75% and 100% of the field capacity (control) were studied in a factorial experiment, based on a completely randomized design with three replications. Water stress at 25 and 50% field capacity significantly decreased morpho-physiological traits and significantly increased antioxidant enzyme activity, proline and protein contents of all genotypes in comparison with the control group. Gachsaran and Robat cultivars were superior in most traits in comparison with the Kimia and Ziba cultivars. Under severe stress, the amounts of proline and protein contents, CAT and SOD enzyme activity were significantly higher in Robat and Gachsaran cultivars than those of the Kimiya and Ziba cultivars. Results showed that Robat and Gachsaran cultivars were probably affected less by water stress due to more stress tolerance using various mechanisms such as more antioxidant enzyme activity, increased proline, proteins and photosynthetic pigments contents. Studied traits were introduced as suitable markers for identification of drought tolerant genotypes. Accordingly, Robat and Gachsaran cultivars were introduced as tolerant cultivars for cultivation under rainfed conditions.

Compost fertilizer because of containing abundant nutrients, high capacity for holding water, plant growth regulators and helpful microorganisms can improve soil physicochemical characteristics and play an effective role in plant growth and development. In order to evaluate the effects of compost fertilizer on morpho-physiological indices of lentil under water deficit stress, a factorial experiment was conducted in a natural environment and with three replications based on a completely randomized design in the Khatam Alanbia University of Behbahan. The experiment treatments consisted of five ratios of compost fertilizer and soil (0:100, 5:95, 15:85, 25:75, and 35:65) and three levels of water stress inclding no stress, moderate stress, and severe stress (irrigation at 25, 50, and %75 of field capacity, respectively). Results showed that there were significant differences in all traits under different compost fertilizer and water stress levels. The findings also showed that under no stress and moderate water stress conditions, application of a mixture of compost and soil at %25 and %35 weight, resulted in a significant increase in the plant height, leaf area, leaf number, root dry weight, root length, root area, and Chlorophyll a and a/b ratio compared to the control levels. Under severe water stress, application of compost at 35% level led to a significant increase in the number of leaves, leaf area, root length, and Chlorophyll a content. Therefore, the use of a mixture of compost and soil (especially 35:65 ratio) is recommended to improve the morpho-physiological characteristics and yield componentsof lentil under moderate (or severe) water stress conditions.

Study of physiological reactions of recombinant inbreed lines (RILs) to drought stress could help to identify the actual drought tolerance mechanisms. In this view a field experiment was conducted to evaluate the effect of drought stress on chlorophyll content , leaf proline content, leaf length, leaf width, leaf area, peduncle length and plant height using 169 RILs, in the two separate simple Latis design with four replications using two moisture regime f normal and water deficit stress. Irrigation regimes performed based on Class A-pan of 70 and 130 mm evaporation from Class -A -pan and moisture content of soil in effected root depth. The RILs were obtained by crossing between a tolerant and sensitive wheat cultivar. The result of analysis of variance showed a significant difference among RILs. Drought stress caused a decrease in the chlorophyll content, leaf width, leaf length, peduncle length, leaf area and increase in the proline content. Although drought stress increased the proline content and decreased the peduncle length and leaf area in both tolerant and sensitive line groups, but these declines in tolerant lines was lower than sensitive lines. Therefore, It may be possible to use the physiological traits comprising proline amino acid content, peduncle length and leaf area as a selection tool for selecting drought tolerant lines in bread wheat.

The paclobutrazol is one of plant growth regulators from triazoles group that is able to protect plants against environmental stress conditions. This experiment was carried out to investigate paclobutrazol (0، 25 and 50 mg/L) effects on reduction of injuries caused by low temperature (5±1ºC) stress in two cultivars of Phaseolus vulgaris [Daneshkadeh cv. (white bean) and Sayyad cv. (red bean)]. The results showed that low temperature stress، reduced fresh weight and dry matter and also reduced length of shoots and roots and leaf chlorophyll contents but increased electrolyte leakage percentage. Paclobutrazol treatment reduced fresh weight and dry matter and length of shoots but increased root dry weight and root development. Moreover، paclobutrazol-treated plants، when exposed to the cold stress condition، showed electrolyte leakage percentage less than control plants. Treatment of seedlings with paclobutrazol led to an increase in chlorophyll contents، either in stress or non stress conditions. White bean was more sensitive to cold than red bean and paclobutrazol affected white bean more than red bean. Therefore، it could be concluded that paclobutrazol treatment improved ability of plant responses to the cold stress and this effect was more remarkable in cold sensitive cultivars.

Salinity has been identified as one of the most pervasive environmental hazards، limiting crop production mostly in arid regions of the world such as Iran. In this research، two cultivar canola seeds (H420، H308) were grown hydroponically and seedlings exposed to different concentrations of NaCl (0، 50، 100، 150 and 200 mM) Changes in fresh and dry weights of roots and shoots، chlorophyll content، membrane electrolyte leakage and relative water content (RWC)، in response to salt stress these were evaluated in 20-old days plants of two cultivars. Results showed that increasing of salinity concentration caused a reduction in fresh and dry weights of shoot and root، chlorophyll content، relative water content (RWC) but increased electrolyte leakage and these responses were more severe in H420. These results suggest that maintenance of relative water content in more resistant cultivar (H308) combined to higher chlorophyll content and more membrane integrity were considered as part of the mechanisms for resistance to salt stress in H308 cultivar.