Journal of Plant Process and Function

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Marine algae are known to contain a wide variety of antioxidant compounds. Natural antioxidants, found in many algae, are important bioactive compounds that play an important role against various diseases and aging processes through protection of cells from oxidative damage. At present, there is a global interest in finding new and safe antioxidants from natural sources. Algae can have a variety of primary and secondary metabolites including biosynthesis, metabolism, accumulation and secretion, including carotenoids, phenolic compounds, phycobilins, sulfated compounds, as well as vitamins. All of these compounds are of great value in the medical, pharmaceutical, nutritional, and cosmetic industries. The purpose of this study is to introduce algae as a valuable rich antioxidant natural resource that can be used in various industries.

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Abstract: Effect of different salinity levels (0, 50, 100, 150 and 200 mM NaCl) on photosynthetic characteristics and yield of two forage millet cultivars (Nutrifeed and Bastan) were investigated at this experiment. A factorial test based on randomized complete block design was conducted during 2010-2011 growing season in three replica-tions. The results showed that with increasing salinity, dry matter yield, leaf relative water content (RWC) and stomatal conductance were decreased.While, traits such as proline and relative membrane permeability (RMP), were increased as salinity level increased,. The highest total dry matter in control treatment of Nutrifeed millet (83.2 g. plant-1) was observed and the lowest was measured in 200 mM in the case of Bastan millet (23.5 g. plant-1). The Leaves relative water content of Bastan cultivar in the 100, 150 and 200 mM NaCl declined sharply and caused leaf necrosis. There were no significant differences between control, 50 and 100 mM NaCl in photochemical quenching of Nutrifeed cultivar. In Bastan cultivar, a significant difference between control and 50 mM NaCl was abserved. As salinity level increased, the proline in shoots of two cultivars increased. Stomatal conductance had a effective role in increasing the performance of dry matter of nutrifeed millet in salt stress conditions, and osmotic potential decreasing also improved dry matter conditions in this plant. Generally, photosynthetic characteristics of Nutrifeed millet were better than the Bastan millet.

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Water deficit is one of the most important environmental stresses limiting plant growth and productivity around the world including Iran. Plants adapted to environmental stress with several strategies such as changes in antioxidant enzyme metabolism. Pennyroyal (Mentha pulegium L.) is an aromatic and medicinal plant of the Labiatae family that is widely used in traditional medicine. In this research, the effects of water deficit stress on growth, photosynthesis and antioxidant enzyme activities in leaf and root organs of M. pulegium plants were studied. Complete randomized block design have been used with four replications. Water deficit was studied at four field capacity levels (100, 75, 50 and 25%). Results showed that the growth, productivity and photosynthesis parameters significantly decreased under water deficit stress. Water deficit significantly increased the activity of antioxidant enzyme such as superoxide dismutase, peroxidase and ascorbate peroxidase in both organs, but the level of increase was more in roots than leaves of plant. Unlike to other enzymes, catalase activity decreased with the increase of water deficit levels, and highest activity was observed in leaves. It seems that pennyroyal plants can tolerate water deficit stress by dedicating less carbon source for growth, increase of antioxidant enzyme activity and regulation of antioxidant enzyme distribution in different organs.

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Regarding the differences between shoot and root optimum growth temperature and the impress of temperature on root function specially nutrient absorption this study was aimed to investigate the effect of low root temperature with three nitrogen levels in lettuce. The experiment was conducted in factorial completely randomized trial design with five replication. Treatments were used including three nitrogen levels (100, 75 and 50) % Johnson nutrient solution and two temperature levels (15ºC: stress condition, 25ºC: optimum condition). The experiment was performed in greenhouse of Isfahan University of Technology. Results indicated that by decreasing nitrogen and temperature levels prolin and root exudate phenol in T2×N3 treatment were 98 and 8 % higher than control treatments respectively. Furthermore in photosynthesis rate and stomata conductivity with 80 and 56 % reduction from control treatment the lowest amount of them observed. Also photosynthetic water efficiency and chlorophyll index were 69 and 70 % more than control treatment respectively. Shoot and root fresh weight were 50 % more than other treatments. Under low temperature stress photosynthesis rate, evaporation, stomata conductivity and the amount of phenolic compounds and proline mostly impressed. Based on present results in order to obtain lettuce greatest yield we should satisfied its temperature and nutritional needs but plants will be resistance under stress condition by releasing prolin and phenolic compounds.

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To evaluate the effect of airborne dust on some physiological characteristics and yield of different wheat varieties, a field experiment was conducted at Research Farm of Razi University, Kermanshah, Iran in 2013. The evaluated treatments were washing and un-washing shoots of various wheat varieties including Pishgam, Zarin and Behrang. Measured traits were as relative water content (RWC), SPAD, chlorophyll content (Chl), soluble protein of flag leaf (SP), stomatal conductance (SC), leaf temperature (LT) and chlorophyll fluorescence (Fv/Fn). Results of this study showed that washing wheat shots aimed at removing dust particles had significant effect on grain yield and grain number per spike, leaf area index, leaf soluble protein, SPAD, stomatal conductance and leaf temperature. The results of the counting of number of seed position per spikelet and grain weight per spikelet showed that washing enhance the quality of both traits. In general, under dusty conditions, Phishgam cultivar had the highest grain yield.

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To study the effects of both drought stress and seed zinc and iron concentrations on the photosynthesis, chlorophyll fluorescence, and proline and carbohydrate accumulations in soybean (Glycine max (L.) Merr. cv. M9) leaf, a split plot experiment was carried out in 2012 based on a randomized complete block design with three replications in greenhouse conditions at Yasouj University. Drought stress, based on 70% depletion of the available soil water, was designated as the main-plot that included drought stress at the flowering, pod filling, and seed filling stages. Zinc and iron concentrations were designated as sub-plot factors that included high zinc, iron and zinc+iron contents of the seed, and control as well as seed soaking in distilled water, 3% zinc sulfate, 3% iron sulfate, and 3% zinc+3% iron sulfate solutions. Results showed that photosynthesis characteristics, net photosynthesis rates, stomatal conductance, and transpiration rates decreased under the drought stress conditions. Drought stress also led to decreased water use efficiency (WUEi). Moreover, leaf proline and soluble carbohydrate contents increased in response to drought stress. While PSII quantum yield reduced under drought stress, it increased under high seed zinc and iron concentrations. It was concluded that enhanced seed zinc and iron concentration was capable of ameliorating the impacts of drought stress on leaf proline and carbohydrate concentrations.

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Silicon is a chemical element that has many positive effects on some qualitative and quantitative characteristics of many plant species such as ornamental plants. The aim of this research was to investigate the impact of silicon spray on growth and photosynthetic characteristics of chrysanthemum. This study was performed as a factorial completely randomized design with 2 factors: silicon source in 2 forms (sodium and calcium silicate) and the concentration of silicate in five levels (0, 50, 100, 150 and 200 mM) in perlite: coco-peat medium with 3 replications and 2 observations. Traits such as leaf area, leaf number, leaf temperature, fresh and dry weight of leaves, chlorophyll index, chlorophyll a and b, net photosynthesis, transpiration and stomata conductivity were measured. The results showed that sodium and calcium silicate reduced leaf temperature but, increased other measured indices compared to control. The effect of silicon on these indices may be because of its effect on plant metabolism and photosynthetic system such as the concentration of Rubisco enzyme, increasing the transmission of photoassimilates from source to sink, increasing photosynthesis efficiency, changing the distribution of photosynthetic products, reducing oxidative substances, increasing carbohydrates and changing the concentrations of internal hormones.

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Conservatiion with respect to physiological aspects of crops is a crucial factor for ideal photosynthesis and appropriate yield in arid and semi-arid agro-ecosystems. In order to investigate the effect of planting pattern on stability of physiological parameters of fenugreek and black cumin under drought stress, an experiment was conducted in the University of Shahrekord in 2014. Three drought levels, i.e. W1: complete irrigation (irrigation based on 100% of the field capacity), W2: moderate stress (irrigation based on 75% W1), W3: severe stress (irrigation based on 50% W1) were assigned to as main factor and five planting patterns including fenugreek and black cumin sole cropping, and three intercropped ratios (1:2, 1:1, 2:1 fenugreek: black cumin) as sub factor. Results showed that by increasing drought stress, the amount of chlorophyll a and chlorophyll b were increased especially for fenugreek: black cumin intercropped as by as their sole cropping. In fenugreek, the greatest amount of proline was obtained in fenugreek: black cumin (1:1) and sole cropping treatments as high as 10.51 and 11.5 mg/g, respectively, and the lowest amount (9.75 mg/g) was recorded in fenugreek: black cumin (2:1). Moreover, the highest rate of essence was recorded in sole-cropping (12.9 g/kg) and fenugreek: black cumin (1:1) (12.6 g/kg). Although the essence rate of sole cropped plant was higher in back cumin, but intercropped plant had more essence in drought conditions. Also more relative water content and less soluble sugar and essence were seen in intercropping patterns, with increasing drought stress. Generally, it could be concluded that creation of interspecific competition could be an important strategy to protect physiological parameters against drought stress damages.

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Today Grafting is important because of its advantageous in increasing plant resistance to temperature stress and salinity in Cucurbitaceae. In order to investigated the effect of grafting of Cucumis sativus var. Super daminos on babol and Cucurbita moschata var Ferro and Cucumis sativus collected in Isfahan comparing with non-grafting and self grafting of Cucumis sativus var. Super daminos as a control an experiment was design. The experiment based on carried out as Pilot experiment based on complete randomized design (CRD) with 4 replications. Treatments were temperature included optimum temperature (27±2) and cold temperature (12±2) and cucumber (cucumis sativus var super daminos) in greenhouse of Isfahan University of Technology. Results was shown that the highest chlorophyll, mesophyll conductance, stomata resistance was in Babol. Fresh and dry weigh decreased in non-grafted and self grafted in low temperature but it did not change for Ferro and Babol. The lowest chlorophyll content was in non-grafted in both low and optimum temperature. Stomata resistance decreased in Ferro in low temperature compare with optimum and did not change in other rootstock between two temperatures significantly. Photosynthesis in Babol and transpiration in non-grafting, Ferro and Isfahan cucumber decreased but they are not change in other rootstock with decreasing temperature significantly. Generally, grafting on Ferro decreased the hazardous effect of low temperature on height, fresh and dry weight of shoot, photosynthesis and photosynthesis water efficiency and transpiration. Cucumber grafting on most of these rootstock can alleviated the deleterious effect of low temperature.

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This study was conducted to evaluate the response of germination, seedling growth and antioxidant enzymes activity 15 chickpea cultivars to salinity at the University of South Korea Dankook a factorial experiment in a randomized complete block design with four replications. The treatments include chickpea cultivars and, salinity levels of water (water with electrical conductivity 0.7 dS/m as a witness and as salinity salinity level 5 dS/m), respectively. The results showed that salt stress decreased seed germination and enzyme activity of alpha amylase was on the soil surface. Salinity reduced leaf dry weight and photosynthesis chickpea varieties of chickpea cultivars, but increased respiration rate. Cultivars of MCC873, MCC10, MCC78, MCC870, MCC537 and MCC392 highest leaf dry weight and photosynthesis, respectively, and at the same time cultivars MCC776 and MCC552 with 6.10 g dry weight and plant 0.63 from a low dry weight respectively. Activity of catalase and glutathione peroxidase guaiacol was increased by salinity. The highest concentrations of malondialdehyde, indicating that the degradation of plant cell membranes in the cultivars of MCC759, MCC361 and MCC101 of 0.95, 0.94 and 0.92 nmol per gram fresh weight of seedlings were observed. MCC392 while the lowest concentrations of malondialdehyde was under salt stress. The results showed that under salinity stress cultivars of MCC 873, MCC 10, MCC78, MCC870, MCC537 and MCC392 with enzyme activity were more antioxidants had higher rates of photosynthesis and plant weight.

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Iron (Fe) absorption control by pH of substrate or nutrient solution that during growth and nutrient absorbtion of nutrient solution its pH will change and will affect Fe absorbtion. In order to study of different pH levels and different iron concentration on vegetative and photosynthesis traits of cucumber cv. N3 this experiment was designed. Experiment was conducted as a factorial experiment based on CRD with 3 level of pH included 5(acidic), 7(natural) and 8 (alkaline) and Fe concentration with 25, 50 and 100 % of Fe concentration of Johnson nutrient solution with 3 replications in greenhouse of Isfahan University of technology. The result of this experiment showed that transpiration and stomatal conductance decreased with acidification compared to natural and alkaline conditions. Photosynthesis and phenol content of shoot and root increased in acidity condition compared to other conditions. The highest stomata conductance, transpiration and photosynthesis were observed with 25 and 100% Fe, respectively. The result of interaction between Fe and pH showed that alkaline condition caused a reduction of shoot phenol and photosynthesis and by using high Fe concentration it was improved. In general, with acidification of nutrient solution or using high iron concentration the deleterious effect of gradual alkaline nutrient solution was improved in cucumber.

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In order to evaluate of the photosynthetic traits of lentil cultivars under water deficit conditions an experiment was conducted as a factorial arrangement in a completely randomized design with three replications in pot cultivation with four cultivars including Gachsaran, Kimia, Ziba, Robat and four stress levels of 25, 50, 75 and 100% of field capacity. Results showed that in all three phenological stages increasing water stress levels (25 and 50% of field capacity) leads to a significant decrease in lentil cultivars in terms of chlorophyll content, CO₂ interacellular, net-photosynthesis, F_v/F_m and transpiration rate. Under 75 and 100% of field capacity, Robat and Gachsaran cultivars in all phenological stages had the highest photosynthetic traits. Under conditions of 25 and 50% of field capacity, Robat cultivar in comparison with Kimia and Ziba had a significant increase in photosynthetic traits, especially in seedling and flowering stages but at podding stage, there was no significant difference between cultivars for most traits. In physiological traits, it was observed that Robat and Gachsaran cultivars in all water stress levels had a significant increase in the relative water content (RWC), membrane stabaility index (MSI), consenteration of  Ca, K in root and leaf. Under all stress levels, Kimia cultivar had the lowest chlorophyll content, CO₂ interacellular, net-photosynthesis, F_v/F_m, transpiration rate, RWC, MSI, consenteration of  Ca, K in root and leaf but there was no significant difference with the Ziba cultivar. According to the physiological and photosynthesis characteristics of pot cultivation, the results of this study showed that Robat and Gachsaran cultivars compared with the Kimai and Ziba cultivars are more tolerant to water deficit condition.

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In order to evaluate the salinity tolerance of six pomegranate genotypes including Malas Dane Ghermez Esfahan, Malas Yazdi, Shirin Shahvar, Meykhosh Yazd, Malas Saveh and Malas Yousofkhani, a greenhouse experiment was conducted as a factorial based on randomized complete block design with five salinity levels of 0, 25, 50, 75 and 100 mM sodium chloride at Agricultural College of Lorestan University in 2015. The results showed that with increasing salinity, photosynthesis rate, transpiration rate, stomatal conductance, leaf relative water content, relative chlorophyll content and mesophilic conduction (carboxylation efficiency) significantly decreased, and the degree of intercellular CO₂ concentration and leaf water use efficiency increased significantly. Also, comparison of meanings showed that there was a significant difference between genotypes in measured factors. Finally, the results of research showed that the genotype of Malas Yousofkhani, due to its superiority in most traits related to salinity tolerance, has more tolerant than other genotypes to salinity induced by sodium chloride.

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In this study, the effect of water defecit on the physiological characteristics of ten potato cultivars at vegetative growth stage under greenhouse conditions was investigated at collage of agriculture of Isfahan University of Technology, Iran in 2016. Treatments included two irrigation regimes of 30 and 80% depletion of soil available water. Water stress decreased quantum efficiency of photosystem II, rate of photosynthesis, stomatal conductance, stomatal transpiration, water use efficiency, chlorophyll a, chlorophyll b, total chlorophyll, carotenoids and plant dry weight but increased carbon dioxide concentration in the cavity below the hole, chlorophyll a/b ratio, chlorophyll/ carotenoids ratio. Significant difference existed among potato cultivars in terms of most measuered traits. The interaction effects of irrigation regime and cultivar were significant on rate of photosynthesis, carbon dioxide concentration in the cavity below the hole, stomatal conductance, chlorophyll a, chlorophyll a/b ratio, chlorophyll / carotenoids ratio and plant dry weight. Under both irrigation regimes the highest amount of plant dry weight was achived for Marfona and Satina and the lowest weight was obtained for Bourn cultivar. Maximum reduction in plant dry weight under water stress treatment belong to Bourn (77%) and Spirit (76%) and minimum reduction (35%) was obtained in Santa. In this experiment, based on stress torence index (STI), cultivars Agria, Santia, Marfona, Spirit and Sante compared to the other potato cultivars, were more tolerant to water stress that was imposed during vegetative stage of plants

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This study was conducted to evulate the effect of water stress on soluble carbohydrates, root and leaf proline, photosynthetic pigments, petal and seed yield of pot marigold genotypes. It was performed as split plots in randomized complete block design with three replications. Three irrigation regimes (35%, 60% and 85% of available soil water depletion) designed as main plot and nine pot marigold genotypes (Ahvaz, Tehran, Isfahan1, Isfahan2, Candy-man, Gitana, Zen-Gold, Isfahan3, Isfahan4) were evaluated as sub-plot in Ahvaz in 1394-95 growing seasen. The results showed the effect of irrigation regimes and genotype were significant on studied traits, petal and seed yield. Due to drought stress, the content of carbohydrates, root and leaf proline increased but RWC, carotenoid, chlorophyll a, b and a + b, petal and seed yield of genotypes decreased significantly. The results showed high correlation between soluble carbohydrate and leaf proline content with RWC and drought sensitivity index. Resistant genotypes had a highest content of soluble carbohydrates, leaf proline and carotenoid. Based on drought sensitivity index, "Ahvaz", "Isfahan2" and "Isfahan1" genotypes divided in drought resistant group, "Tehran", "Candy-man", "Gitana" in moderately resistant group and " Isfahan4", "Zen-gold" And "Isfahan3" in sensitive group. "Candy-man" and "Ahwaz" genotype produced the highest petal and seed yield, respectively, at all drought levels.
 

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Deficiency of nitrogen may lead to decrease in yield and yield potential of crop plants. An experiment was done under glasshouse conditions in order to investigate nitrogen levels and salicylic acid interaction on some physiologic traits of borage (Borago officinials L.). In this experiment various levels of nitrogen (including; 27.5, 55, 110, 220 and 330 mg/L from ammonium nitrate) and salicylic acid (including; zero, 400, 800 and 1200 µM) was used. The results indicated that stomatal conductance, photosynthesis rate, respiration rate, chlorophyll a, chlorophyll b, carotenoids, proline, and ascorbate peroxidase, were increased by increasing of nitrogen level. However, intercellular CO₂ concentration, anthocyanin, flavonoids, soluble carbohydrates, catalase, and peroxidase were decreased. Among nitrogen levels, the maximum effect was obtained by 220 and 330 ppm treatments. Furthermore, salicylic acid spraying led to promote stomatal conductance, photosynthesis rate, transpiration rate, photosynthetic pigment content, proline, anthocyanin, flavonoids, soluble carbohydrates, and catalase, peroxidase and ascorbate peroxidase enzyme, but not intercellular CO₂ concentration. The highest values of stomatal conductance, photosynthesis rate, transpiration rate, photosynthetic pigment content, proline, anthocyanin, flavonoids, soluble carbohydrates, and activities of catalase, peroxidase, and ascorbate peroxidase enzymes were achieved by 800 and 1200 µM concentrations of salicylic acid and 330 ppm of nitrogen. The results showed that appropriate concentrations of salicylic acid can recover nitrogen shortage and improve the measured traits.

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In an orchard experiment, the effects of foliar application of kaolin, potassium, phosphorus and their different combinations were examined on photosynthesis parameter 8-years-old pistachio trees cv.Kalle-ghouchi in 2016. There were ten treatments, including two rate of P (1 and 2%), two rates of K (1.5 and 3%), kaolin 5%, kaolin 5%+ P 1%, kaolin 5%+P 2%, kaolin 5%+ K 1.5%, kaolin 5%+ K 3% and control (use of distilled water). Foliar application of above treatment were performed in mid Jane when embryo growth is started (the maximum demand for photoassimilates). Photosynthetic parameters (photosynthesis and transpiration rate, stomatal conductance and sub stomatal CO₂ concentration), chlorophyll fluorescence parameters (Fv/Fm and PI), photosynthetic pigments (chlorophyll a, b and total and total carotenoids) were measured in 5 stages (the first stage was one day after treatment and the others  were performed with one week interval). The results showed that non of treatments could improve photosynthesis parameters expect Ci while chlorophyll fluorescence parameters were improved by kaolin treatments and photosynthetic pigments were increased by most of experimental treatments. The result also showed that photosynthesis and transpiration rate and stomatal conductance were increased with time and sub-stomatal C0₂ concentration was decreased. Chlorophyll fluorescence indices and photosynthetic pigments were also increased with time. Totally, the effect of experimental treatments on photosynthetic parameters was under our expectation.
 

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Recently, plant-derived smoke has been included in the group of growth phytohormones due to its bioactive compounds on biological and biochemical processes. In order to evaluate the phytohormones-like effects of Papaver rhoeas L. smoke derived on some biochemical characteristics of medicinal plant basil an experiment was conducted with repeated measurements in research greenhouse of Campus of Agricultural and Natural Resources of Razi University in 2017. The Experimental treatments included eight levels of leaf foliar application (control, Smoke-water in 100, 5000, 1000 and 5000 dilutions accompanying with cytokinin, auxin and gibberellic acid (each of them with concentration 50 µM)) with 3 replications and 2 harvest stages. The results indicated that application of smoke-water (1:500 and 1:100 (v/v)) improved gas exchange status and also increased chlorophyll content, without significant difference with cytokinin. All chlorophyll fluorescence parameters also increased significantly under the application of phytohormones and smoke-water. Levels of foliar (especially SW: 1:500 and 1:100 (v/v)) reduced electrolyte leakage of plasma membrane and content of soluble carbohydrates. The highest total phenolic and anthocyanins content was obtained from leaf foliar in the smoke-water of 1:100 and 1:500 (v/v), respectively. Smoke-water at concentration 1:100 (v/v) without significant difference with phytohormones auxin and gibberellic acid significantly increased the activity of peroxidase. In general, it can be concluded that aqueous extracts of plants-smoke derived (especially SW 1:100 (v/v)) without significant differences with synthetic phytohormones have the ability to reduce the biochemical limitations of basil and can improve its growth conditions.

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Due to the dry climate and water shortage in Iran, the use of substances that can increase the plant's tolerance to water stress is very important. In this study, the effects of exogenous application of salicylic acid (SA) and kaolin (KL) on drought stress tolerance of tomato plants was evaluated in field conditions. Experimental factors included foliar application (including control, 0.5 mM SA, 2.5% KL and simultaneous application of SA + KL) and irrigation intervals (at four levels of 2, 4, 6 and 8 days). The results showed that increasing the irrigation interval in tomato plant led to a decrease in growth and yield in this plant. As compared to the controls, irrigation intervals of 4, 6 and 8 days decreased total yield as much as 9, 11 and 21%, respectively. The relative water content, total chlorophyll, transpiration and photosynthesis decreased while malondialdehyde, proline, peroxidase and hydrogen peroxide increased with the increase of irrigation intervals. Both SA and KL were effective in reducing the adverse effects of drought stress on plant growth and productivity.  Application of SA and KL improved plant growth and yield by increasing chlorophyll, relative water content, peroxidase activity, photosynthesis rate and transpiration. The highest effect of foliar spraying was observed at irrigation intervals of 6 and 8 days. The results also showed that the simultaneous application of SA + KL did not have a synergistic effect on plant growth and productivity in comparison to their separate application. According to the obtained results, the use of KL or SA is recommended to reduce the effects of prolonged irrigation on the tomato plant.

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In recent years, special attention has been paid to the consumption of plant growth stimulants such as amino acids and humic acids along with micronutrients to adjust the effects of abnormal environmental conditions such as untimely cold or salinity and drought stress in grain production programs. In order to investigate the effect of growth enhancers on compensating for the lack of transport assimilates from storage sources to the grain during the last irrigation cut in two wheat cultivars in field conditions, an experiment was conducted as a split-plot in a randomized complete block design with three replications at the Kashmar Research Station during of 2019-2020.Two wheat cultivars included Sirvan and Rakhshan (a common cultivar of the region) in the main plots and growth enhancers included amino acid fertilizer, complete micronutrient, humic acid each one with 2:1000 concentration and the control, were taken in a subplot. All these fertilizer nutrients with an 8 kg ha^-1 concentration of solo potash were sprayed in two growth stages of tillering and spiking. The results showed that the highest plant height (63.8 cm) was obtained in the Rakhshan cultivar by foliar application of humic acid. The effect of amino acid foliar application on peduncle length and weight in Rakhshan cultivar was more than other fertilizer treatments. In the Sirvan cultivar, the use of amino acid fertilizer had the highest number of seeds per spike (30.2) and grain weight per spike (1.28 g). The most number and weight of spikes per unit area were obtained from the application of amino acid fertilizer. The highest dry weight per square meter belonged to Sirvan cultivar (161 g) and Rakhshan cultivar (131 g) using humic acid fertilizer treatment. The most seed weight per unit area (91.9 g m^-2) was obtained from amino acid fertilizer treatment in the Sirvan cultivar. The highest amount of photosynthesis (13.6 mmolm^-2s^-1) and stomatal conductance (145 mmolm^-2s^-1) were obtained from amino acid fertilizer treatment. The correlation coefficients showed a positive and significant relation between yield and spike weight per unit area (r = 0.94 **) and then with the number of spikes (r = 0.70 *). In general, foliar application of amino acids and humic acid in two stages of tillering and spiking can compensate for wheat yield reduction due to the last irrigation cut by changing the physiological and metabolic processes of the plant.