جستجوی مقالات مرتبط با کلیدواژه « ویژگی های فیزیولوژیک » در نشریات گروه « باغبانی »

Environmental stress in plants, particularly due to heavy metal presence, poses a significant challenge to their growth. Manganese, an essential micronutrient, can become detrimental when accumulated in soil and plants. To assess the impact of silicon on linseed (Linum usitatissimum L.) under manganese stress, a factorial experiment was conducted. Linseed plants were grown in hydroponic culture with four different manganese levels (2, 250, 500 and 1000 μM) along with five silicon treatment levels (0, 0.5, 1, 1.5 and 2 mM). Results revealed that increasing manganese stress levels led to a rise in proline, soluble sugars content, and manganese in the root and shoot, accompanied by a decrease in other studied traits. Notably, the application of 2 mM silicon consistently yielded the highest values across all manganese levels for the examined traits. Silicon application enhanced proline and soluble sugars content in leaves, consequently increasing plant photosynthetic capacity and leading to greater root and shoot dry weights under various silicon levels. The use of silicon significantly ameliorated the harmful effects of manganese in linseed under manganese stress conditions. Therefore, 2 mM silicon is recommended as a beneficial solution in areas contaminated with manganese, which can lead to the reduction of this heavy metal in the root and shoot of plants.

Polianthes is one of the most important cut flowers in Iran and the world, and increasing its quality and quantity is one of the most important issues. In this study, to evaluate the effects of foliar application of salicylic acid and thiamine in two cultivation systems on biochemical characteristics of tuberose, a factorial experiment, based on completely randomized design with 3 replications, was conducted in the greenhouse of Gorgan University of Agricultural Sciences and Natural Resources. Treatments consisted of salicylic acid (concentrations of 0, 50, 100, 150 and 200 mg/L) and thiamine (100 and 150 mg/L) in two soilless and soil culture systems. Results showed that the treatments had significant effects on biochemical characteristics. In this experiment, the highest amount of catalase enzyme was 1.69 μmol peroxide per minute per mg and 1.175 μmol/g fresh weight per minute peroxidase was related to 50 and 100 mg/L salicylic acid treatments, respectively, and the lowest amount was observed in control treatment (0.87 and 0.56) respectively. Therefore, it seems that salicylic acid and thiamine can increase the photosynthetic pigmentation and activities of antioxidant enzymes of tuberose flowers. Also, the highest amount of concrete (8.49%) was reported in 200 mg/L salicylic acid treatment and its lowest value (4.47%) was reported in control treatment. Based on the results of this research, the soilless system was in all physiological characteristics at a higher level than the soil system. So that the amount of chlorophyll a, b, total and reduced sugar in soilless substrate was 0.16, 0.41, 0.57 and 0.11 mg per gram of fresh weight, respectively. Concrete and protein content were 0.07% and 0.33%, respectively, which were the highest in comparison to the soil culture system.

Using of Regulated Deficit Irrigation (RDI) and improved water holding of soil are very important in irrigation of fruit trees. For this purpose, the effects of both RDI and super-absorbent (SA) were studied on the vegetative growth, yield and amount of marketable fruit and some quality characteristics of Japanese plum (Prunus salicina cv. ‘Santarosa’). The trees were exposed to three RDI levels including 100% ETc, 75% ETc, 50% ETc and four super-absorbent levels of zero, 100, 200, and 300 grams/tree at the pit hardening stage. In RDI, the difference of vegetative growth compared to control trees was significant and the SA treatments could not compensate for the decrease of vegetative growth. The amount of yield was not affected under the influence of 75% ETc, but at the 50% ETc level, it decreased significantly. The yield of control, 75% ETc and 50% ETc treatments were 47, 46.15 and 35.50 kg/tree respectively. However, comparing between control and other levels of RDI showed that the amount of marketable fruit increased in 75% Etc. In addition, the irrigation levels were not effective on soluble solid content (SSC), titrable acidity (TA), SSC/TA and the magnesium (Mg) concentration. While, the concentration of fruit calcium increased considerably under RDI and the highest amount of Ca was observed at 50% Etc. The quality characteristics such as total phenol, firmness and antioxidant potential of fruits increased by lower irrigation than the control fruits. In this study, the interaction effects of RDI and SA treatments were significant only for total phenol trait.

Almond trees have been grown in Iran for many years. Despite almond has been classified as salt semi-tolerant plant, poor quality of irrigation water in association with salt has reduced the yields of almond over recent years. Salicylic acid (SA) is responsible for inducing tolerance to a number of biotic and abiotic stresses. Thas, an experiment was conducted to study the effect of SA on salinity stress alleviation of bitter almond seedling. The experiment was set up as factorial experiment in completely randomized design with two factors including NaCl concentration (0, 40 or 80 mM) and SA at three levels (0, 0.5 or 1 mM). The results showed that salt stress decreased some vegetative growth parameters and relative water content and increased ion leakage and leaf proline content in almond seedlings. Application of SA improved vegetative growth parameters, decreased proline concentration, increased water relative content and leaf chlorophyll index. Improved stress indexes in SA- treated seedlings showed that applied of SA ameliorated the adverse effects of injury caused by salt stress.

Mint is an important medicinal herb that is cultivated in different parts of the world. In order to investigate the effects of salinity stress on morphological characteristics of spearmint (Mentha spicata L.), an experiment was conducted in 2013, based on complete randomized design, under hydroponic conditions, at Research Greenhouse of Faculty of Agriculture, Ferdowsi University of Mashhad, Iran. Treatments were five salinity levels (0, 30, 60, 90 and 120 mM of sodium chloride) with four replications. Growth medium was 2:1 cocopeat to perlite, and complete nutrients solution was used. Supplying plants’ nutrients was twice a week along the irrigation water application. When plants’ height was 30 cm, salinity treatments were applied and were continued till full flowering. At the end of the experiment, morphologic traits including plant height, number of main stems, number of lateral branches, leaf area, specific leaf weight, stem diameter, number of nodes, fourth internode length, and spike length were measured. Results showed that salinity stress had significant effects on leaf area, fresh and dry weights of leaf, stem and root, plant height, number of lateral branches, number of nodes, fourth internode length, and spike length. The highest leaf area, leaf dry weight, plant height and number of lateral branches were observed in control treatment. The lowest leaf area and leaf dry weight were obtained in salinity level of 120 mM, and the lowest plant height and number of lateral branches were observed in salinity levels of 90 mM and 120 mM. Salinity had no significant effect on fresh weight of shoot to root ratio, fresh weight of leaf to root ratio, specific weight of leaves, number of main stems and stem diameter. According to the results, it appears that spearmint is sensitive to salinity stress and it cant tolerate salinity levels higher than 30 mM sodium chloride.

In drought stress conditions، besides the inhibition of water uptake، the plant nutrients availability and uptake are also limited. Proper nutrition is known as a management procedure for plant production under different environmental-stress conditions. Generally، the combined effects of drought and deficiency of potassium and zinc on plant water content and some physiological parameters reduce yield quantity and quality. This investigation was conducted to assess the interactive effect of different levels of potassium as KNO3 (0. 6، 3 and 6 mM) and zinc as ZnSO4 (0، 1 and 2 μM)، under drought stress conditions induced with PEG 6000 (0، 55 and 110 g/L PEG 6000) on some water status indices and physiological parameters of tomato in hydroponic culture. The results showed that interaction of drought، potassium and zinc on shoot and root dry weight، leaf chlorophyll and proline content and percentage of root ion leakage was significant. Both potassium and zinc improved water status of the plants; however the effect of zinc on leaf water potential was not significant. Drought stress increased the chlorophyll content and decreased the sulfhydryl groups. Application of a high level of potassium in the nutrient solution increased root ion leakage.