نشریه روابط خاک و گیاه
پیاپی 55 (پاییز 1402)

Phosphorus deficiency and drought stress are limiting factors in wheat yield. Drought stress has different effects on the uptake, utilization and use efficiency of soil phosphorus in wheat cultivars. The purpose of this study is to investigate the response of growth and development, uptake and efficiency of phosphorus in Sirvan and Sivand wheat cultivars at three moisture stress levels of 50, 70 and 95% of soil field capacity (FC) and two phosphorus levels of 0 and 25 mg kg-1. The results showed that addition of phosphorus increased shoot dry weight, phosphorus utilization efficiency, root length and area, and soluble sugars by 42, 61, 84, 47, and 66%, respectively, and decreased electrolyte leakage by 64% under stress conditions of 50%FC. Besides, the phosphorus application of 25 mg kg-1 under drought stress conditions of 50%FC increased the shoot dry weight of the Sirvan variety by 75% compared to the Sivand variety. This increase can be due to the effect of phosphorus on metabolic activities inside the plant, which has led to an increase in root growth, soluble sugar production and cell wall resistance, and a decrease in electrolyte leakage. Therefore, the positive changes observed in different traits and indices due to the use of phosphorus increased the resistance of the Sirvan cultivar compared to Sivand under drought stress conditions. According to the results of phosphorus efficiency and some root morphological and physiobiochemical characteristics, Sirvan cultivar showed a good response to phosphorus fertilizer in modulating the effect of drought stress.

Tomato (Solanum lycopersicum L.) is an important commercial food plant. Several factors affect the growth of tomatoes in the greenhouse, and one of them is proper planting density. Investigating and suggesting the best density in hydroponic cultivation can have a significant effect on production efficiency. Therefore, a factorial experiment was conducted in the hydroponic cultivation system based on completely randomized design with three replications and two treatment of cultivar (Dafnis, Izmono and Hirad) and density (at four density levels of 2, 2.5, 3 and 3.5 plants per m2) in the greenhouse of Gorgan Agricultural and Natural Resources Research and Education Center. Characteristics of number of clusters per plant, number of flowers per cluster, percent of blossom drop, number of fruits per cluster, fruit yield per plant and per m2, number of fruits per plant, number of fruits per m2, average fruit weight, fruit diameter, fruit length, pericarp thickness, uniform fruit ripening, distance between clusters, marketable yield, total soluble solids and pH of fruit juice were measured. According to the mean comparisons, the average yield per m2 at high plant density (3.5 plants per m2) in all three cultivars was significantly higher than others. With the increase of density from 3 to 3.5, from 2.5 to 3.5 and from 2 to 3.5 plants per m2, respectively, relative increases in yield per m2 of 2.4%, 28.6% and 43.1% in Hirad, 6.8%, 21.75%, 23.4% in Dafnis and 22.7%, 35% and 51% in Izmono were observed. With the increase of plant density, the percentage of blossom drop of plants decreased significantly. The highest total soluble solids content of one cultivar (Hirad) was observed in the highest density and two other cultivars were not affected. The pH of fruit juice of Dafnis and Izmono at a density of 3.5 plants per m2 was significantly lower than other treatments, but there was no difference for this trait in Hirad cultivar between different densities. The results of this study suggest to increase the density of tomato in hydroponic greenhouse in Golestan province up to 3.5 plants per m2.

Due to the limitations of water resources and poor soil quality, the use of modern and high-quality solutions is necessary to produce agricultural products with better quality. One of the effective methods for achieving this goal is the production and cultivation of plants by hydroponic methods. This study was conducted as a factorial in a completely randomized design with the aim of investigating the effect of hydroponic cultivation systems [drip system and deep flow technology (DFT)] as the first factor on the quality and yield of two strawberry cultivars (Albion, Sabrina) as the second factor with four replications. The results showed that Sabrina had the highest fruit length and width in the drip system. Also, the highest fruit weight and yield were observed in the Sabrina cultivar under the drip irrigation system. The highest titratable acidity content was observed in Sabrina cultivar under the drip system and the highest contents of total soluble solids, total phenol and total flavonoid were recorded in the DFT system. Besides, the highest total anthocyanin content was revealed in the Albion cultivar under the drip system. In general, the results of the present study showed that most of the qualitative and quantitative characteristics of strawberry fruits were affected by the cultivation system type and the yield and fruit quality of strawberries were higher in the drip system compared to the DFT system. It can be also concluded that Sabrina had the highest biochemical properties under the drip system.

Azolla extracts are biodegradable and non-polluting to the environment, and because of its unique composition, it was subjected to integrated bio refineries for organic fertilizer and plant growth stimulants production. Here we investigated the effect of media culture on productivity and chemical composition of Azolla filiculoides and Azolla Caroliniana and then application of Azolla extract as an organic fertilizer. This research was conducted in the two studies at the Soil-Plant Interaction Research Center of Isfahan University of Technology. The Azolla culture media treatments showed significant effect (p < 0.05) on Azolla iron and zinc concentration. In the both Azolla species, addition of 20% of sulfur and phosphorus to the culture media significantly increased concentrations of nitrogen and acidic, alkaline, polar, aromatic and aliphatic amino acids. In the second study, Johnson and half Johnson media contained 5% and 10% Azolla extract showed highest fruit yield (i.e., fresh and dry weights) and concentrations of iron, zinc and nitrogen in the fruit, shoot and root of bell pepper, in which some of them were significant (p < 0.05). In total, our results showed that Azolla culture media composition may change quality and quantity of the Azolla extract and application of the extract may led to biofortification of bell pepper significantly.

The use of plant hormones has been introduced as a simple and suitable strategy to reduce the adverse effect of heavy metals in plants. To investigate the effect of salicylic acid (SA) in reducing lead (Pb) stress in tomato (Lycopersicon esculentum L.), a factorial experiment was conducted based on completely randomized design with three replications in the greenhouse of Razi University. Factors included soil Pb contamination at three levels (0, 150 and 300 mg kg-1 soil as Pb(NO3)2) and SA at three levels (0, 250 and 500 μM). Results showed that the highest proline content (23.4 mmol g-1) and Pb concentration (4.26 mg kg-1) were obtained in 300 mg kg-1 of Pb and 0 μM SA, which shows an increase of 303 and 387%, respectively, compared to the control (without Pb and SA). Also, the highest amount of soluble sugars (0.48 mg kg-1), plant height (43.5 cm), root length (18.3 cm/plant), shoot dry weight (7.48 g/plant), and leaf area (263.1 cm2/plant) were found in the treatment of 500 μM SA and 0 mg kg-1 Pb. In general, the results showed that the application of SA, as a plant hormone, is a simple and convenient method to reduce the adverse effects of Pb stress in tomato.

One of the research requirements in agriculture is to find a new and practical method for sustainable production that brings the highest efficiency and the least harm to humans and the environment. In order to investigate the effect of different levels of carbon dioxide and ethanol foliar spraying on the physiological and biochemical characteristics of basil (Ocimum basilicm cv. Keshkeni luvelou), a factorial pot experiment based on a completely randomized design with three replications was conducted in the research greenhouse of the Department of Horticultural Sciences and Landscape of Ferdowsi University Mashhad in 2018. The factors included ethanol spraying at 4 levels (0, 10, 20, and 30% v/v) and carbon dioxide at 3 levels (380, 700, and 1050 µmol mol−1). The results showed that the highest relative water content (RWC) of leaf, photosynthesis rate, transpiration rate, stomatal conductance, and leaf protein were observed in the treatment of 20% v/v ethanol foliar application with the application of 700 µmol mol−1 of carbon dioxide, as they increased by 45%, 295%, 684%, 83%, and 328% compared to the control, respectively. Fresh and dry biomasses of shoot parts increased significantly with increasing carbon dioxide concentration and ethanol spraying. Thus, the highest fresh and dry biomasses of shoot parts were obtained in foliar spraying of 30% v/v of ethanol and 700 µmol mol−1 of carbon dioxide which increased by 176% and 76%, respectively, compared to the control. The highest activity of polyphenol oxidase and guaiacol peroxidase, stomatal resistance, and electrolyte leakage were related to spraying 30% v/v of ethanol with an application of 1050 µmol mol−1 of carbon dioxide which showed an increase of 2%, 4%, 65%, and 76%, respectively, compared to the control. Overall, the results showed that foliar spraying of 20 and 30% v/v of ethanol along with the application of 700 µmol mol−1 carbon dioxide had the greatest effect in increasing photosynthesis and finally the fresh and dry biomasses of basil.