نشریه روابط خاک و گیاه
پیاپی 48 (زمستان 1400)

The study was conducted in a factorial experiment based on a randomized complete block design with two factors and three replications. In this experiment, pothos cultivar at three levels of ‘Golden’, ‘Manjula’, and ‘Marble’ and the substrate at five levels of garden soil, garden soil + Azolla compost, garden soil + leaf mold + rice bran, garden soil + perlite, garden soil + leaf mold + rice bran + perlite + Azolla compost were evaluated. Traits including plant height, leaf number, leaf area, shoot fresh and dry weights, content of chlorophyll, carotenoid, anthocyanin, leaf nitrogen (N), potassium (K), and phosphorus (P) were measured. It was found that the Golden pothos plants had the highest chlorophyll, carotenoid, and anthocyanin contents, but the highest leaf N and P contents were observed in the Manjula pothos. The results as to the simple effect of the substrate on the recorded traits revealed that the plants grown in ‘garden soil + leaf mold + rice bran + perlite + Azolla compost’ had the highest growth rate, plant height, leaf number and fresh and dry weights. Concerning the interaction effect of cultivar × substrate, the highest leaf number and shoot fresh weight were obtained from Manjula pothos × ‘garden soil + leaf mold + rice bran + perlite + Azolla compost’, the highest leaf area from marble pothos × ‘garden soil + leaf mold + rice bran’, the highest total chlorophyll from Golden pothos × ‘garden soil + Azolla compost’, and the highest chlorophyll b content from Marble pothos × ‘garden soil + perlite’.

The present study was aimed to evaluate the effect of organic fertilizers of folic acid and amino acids (glycine and glutamic acid) on the plant resistance to stress and yield of cucumber under deficit irrigation conditions. The study was carried out as a factorial in randomized complete blocks with 3 replications. The first factor was fertilization at four levels as control, 200 mg/l folic acid, amino acid glycine and glutamic acid (6 liters per ha), and folic acid + amino acids (glycine and glutamic acid). The second factor was irrigation interval (3, 5 and 7 days). The results showed that an increase in irrigation interval caused a significant reduction in plant dry and fresh weights, internode length, root and shoot lengths, stomatal conductance and chlorophyll contents. Furthermore, combined use of folic acid and amino acid and 7 day irrigation interval increased root length, internode length, leaf area, chlorophyll a and relative leaf water content by 159, 46.9, 84.7, 138 and 36%, respectively, when compared with the control at the same irrigation interval. In addition, a 70% increase in plant fresh weight and 84% increase in fruit weight were observed in irrigation interval of five days and combined treatment of amino acid and folic acid. In general, it can be concluded that the combined application of amino acids and folic acid improved the morphophysiological characteristics of cucumber under deficit irrigation conditions, while it was not effective in improving yield and fruit production with the seven-day irrigation interval.

Hydrogen peroxide plays an important role in the response of plants to environmental signals. This experiment aimed to find the effect of hydrogen peroxide at four levels (0, 20, 40, and 80 μL L-1) on the quantitative and qualitative characteristics of two tomato cultivars including "Newton" and "Cherry Santella” grown in the hydroponics. The experiment was conducted as a factorial based on randomized complete block design with eight treatments and three replications. The results showed that the application of hydrogen peroxide significantly increased the vegetative characteristics and qualitative characteristics of tomato such as number of leaves, dry weight of leaves, fresh and dry weights of root, root volume, firmness and fruit juice pH. Maximum fresh weight of fruits was achieved at 80 μL L-1 concentration with a 58% higher than that of the control. Furthermore, hydrogen peroxide increased fruit shelf life by 35% in "Cherry Santella" cultivar compared to control. The highest number of leaves, fresh and dry weights and root volume were observed at 80 μL L-1.  Fruit firmness and shelf life were increased at 40 μL L-1 concentration. These findings suggest that the concentrations of 40 μL L-1 can be used for tomato production in hydroponics.

Silicate (Si) has potential effects on crops under different stresses. It can affect biochemical and physiological parameters and reduce drought stress destructive effects. This study aimed to investigate the effects of Si on morphological and biochemical traits under drought stress in two rice cultivars of Local Tarom and Shiroodi. The experiment was organized in completely randomized blocks in a factorial design. Silica treatments included potassium silicate, calcium silicate and a combination of the two at the rates of 0 and 350 kg/ha. Drought stress at the time of cluster emergence and stress during redistribution and water scarcity (soil matric potential of -0.05 MPa) with three replications. Under the conditions of water shortage, stem and seed silica, stem cellulose, and lignin were increased. After silicon treatment, some morphological characteristics such as plant height, harvest index, and grain yield. After the application of silica, leaf blast disease decreased (34%) compared to control. Water stress conditions showed adverse effects on fertile tillers, number of tillers per plant, number of panicles and number of seeds per panicle. The two rice cultivars significantly differed in plant height, panicle length, number of effective tillers, number of panicles per plant, flag leaf chlorophyll, harvest index, the Uptake of copper, manganese, nitrogen, and biochemical traits. The combined effect of water stress on the two cultivars studied did not significantly differ, and therefore, both could be suggested for cultivation under water stress conditions. The results showed the potential effect of silica in alleviating water stress impact, and thus silica treatment may be recommended to increase drought stress tolerance in rice plants.

Salinity tolerant of 24 lentil genotypes was investigated in a split-plot based on a randomized complete blocks design with three replications. Salinity levels (0.5, 12, and 16 dS m-1) were arranged as the main plot and lentil genotypes as the subplot. Results indicated that salinity levels of 12 and 16 dS m-1 reduced the survival percentage of all genotypes compared to control. MLC57, MLC73, MLC94, MLC104, and MLC108 genotypes were not able to tolerate the 16 dS m-1 salinity level. Morphological traits were affected by salinity stress as plant height, number of branches per plant, dry weight, and leaf survival percentage in most genotypes were decreased. Compared to control, the lowest reductions of plant height, number of branches per plant, plant dry weight, and leaf survival percentage were observed at salinity level of 16 dS m-1 in MLC13, MLC120, MLC4, and MLC12 genotypes, respectively. Also the lowest increase in Na+ (5.5 times) and the highest increase in Ca2+ (4 times) were observed at salinity level of 16 dS m-1, in MLC108 and MLC78, respectively. In other words, these genotypes were able to reduce the adverse effects of increased NaCl in higher salinity levels. Principal component analysis (PCA) showed that all genotypes of the first group (MLC6, MLC12, MLC26, MLC117, MLC120, and MLC178) were superior for most traits as compared to the total mean. Generally, it could be concluded that this group of genotypes has a better survival percentage and growth characteristics in salinity conditions, which may be used to select salinity tolerant lentil genotypes in subsequent studies.

Regarding the scarcity of water resources in Iran, management of planting dates and irrigation is necessary for wheat production. The goal of this study was to determine the effect of two planting dates of November (PD1) and February (PD2) and two irrigation regimes: traditional (T) and supplementary (W) on wheat yield and irrigation water productivity in the east of Isfahan. Field experiments were carried out during two consecutive seasons’ autumn and winter in the crop year of 2016-2017 in a clay loam soil. The results showed that planting date significantly affected wheat yield and water productivity (P < 0.01). Yield in PD1 was 11.5% higher than PD2, while water productivity in PD1 was 9.0% lower than PD2. Supplementary irrigation in clustering period had a significant effect on wheat grain yield. Comparison of crop evapotranspiration (ETc) calculated by FAO-Penman-Monteith method with that of applied irrigation water showed that the later in TPD1 and TPD2 treatments were, respectively, 40.0 and 19.9% more than the ETc. In traditional irrigation management (T), lack of coordinations between the supplied water and the timely water requirement based on ETc led to high water losses due to deep percolation and runoff. Supplementary irrigation regime on both planting dates significantly increased yield, with no positive effect on water productivity. We concluded that due to supply-oriented water management in the east of Isfahan, farmers use irrigation water more than what is needed for wheat yield production leading to less yield and much low water productivity than the potentials realizable in the region.

This research was performed to determine the effect of inoculation of two species of arbuscular mycorrhizal fungi (AMF) on soil available water (SAW) and glomalin concentration under drought and salinity stresses according to a factorial based on completely randomized design with three replications. Treatments included two plant species Atriplex canescens and Haloxylon ammodendron with inoculation of two fungal species Glomus geosporum and Glomus mosseae plus two levels of salinity stress at 7 and 14 dS m-1, and two levels of drought stress including maximum allowable depletion (MAD) of 50 and 80%. After one year of treatments, plant available water (PAW), least limiting water range (LLWR), integral water capacity (IWC), total and easily extractable glomalin concentration and soil organic carbon (SOC) content were measured. Results indicated a significant increase in SOC, glomalin concentration, PAW, LLWR, and IWC by increasing the salinity level in treatments inoculated with G. mosseae and G. geosporum. The highest percentages of increase in PAW (147%), LLWR (140%) and IWC (85%) as compared with control were observed under combined salinity and low drought treatment (14 dS cm-1 + MAD of 50%) in A. canescens inoculated by G. geosporum. The highest concentrations of total glomalin and easily extractable glomalin were observed in both plant species under salinity of 14 dS m-1 and severe drought treatment (MAD of 80%) with the inoculation by G. geosporum and G. mosseae. Overall the results of this research indicated a reduction in negative consequences of drought and salinity stresses in the soil under cultivation of A. canescens and H. ammodendron, with application of mycorrhizal fungi.