Dr Behrooz Eesmaielpour, Msc Akram Rahbari, Phd Student Hamideh Fatemi,
Volume 8, Issue 30 (vol. 8, no. 30 2019)
Abstract
Silicon is one of the beneficial elements for plants, recent studies have shown that this element plays a very important role in plant resistance to environmental stresses, including heavy metal stress. To evaluate the effect of silicon foliar spraying on increasing tolerance to lead contamination in dill (Anethum graveolens L) a factorial experiment based on completely randomized design with four replications was conducted in research greenhouse of Mohaghegh Ardabili University at 2015-2016. Experimental factors included soil contamination by lead (0, 400, 600 and 1000 mg/kg soil) from (Pb(NO3)2 source and silicon( From Na₂SiO₃5H2o source) levels 1 mM and control (spraying with water). During this experiment traits such as plant height, plant dry weight, leaf number, lateral branch number, root dry weight, electrolyte leakage, leaf relative water content, photosynthetic pigments, proline, total carbohydrates and catalase and peroxidase enzymes activity, concentration of lead and calcium concentration in the plant's shoot were measured. The results showed that lead stress had a significant reduction effect on the measured growth parameters of the plat. The highest root dry weight, stem diameter, leaf relative water content was obtained in control plants which treated with spraying by 1 mM silicon. The highest value for proline and carbohydrates production, catalase and peroxidase enzymes activity were obtained by combination of spraying with 1 mM of silicon at under 1000 ppm lead contamination. In general the results of this study showed that the foliar application of silicon can be advised for improving growth of dill plants under lead contamination stress conditions.
Raheleh Rahbarian , Zahra Talebzade,
Volume 13, Issue 64 (VOL. 13, NO. 64 2025)
Abstract
Mercury is one of the toxic and heavy metals that causes pollution in agricultural fields. Mercury aggregation disturbs cellular behaviors and stops plant growth. In order to examine the effects of mercury on wheat growth indexes, a study with 4 commercial genotypes of Iran, Sirvan, Sivand, Parsi and Sepahan in various levels of this element (0, 30, 70, 100 mg/kg soil) was conducted. This experiment has been conducted in a random factorial design with 3 replications and indices including CO2 assimilation rate (A), transpiration rate (E), stomatal conductance (gs), water use efficiency (WUE), PSII photochemical efficiency (FV/FM), photosynthesis quantum yield (Y), electron transfer rate (ETR), intra-leaf CO2 concentration (Ci), chlorophyll a, chlorophyll b, total chlorophyll, chlorophyll a/b, chlorophyll stability index and carotenoids were measured after 60 days. The result indicated that all measured parameters except carotenoid were decreased as mercury concentration increased. In 100 mg/kg stress level, Sirvan genotype had the highest transpiration rate, chlorophyll a, b, total chlorophyll, carotenoid, PSII efficiency and Ci as compared to other investigated genotypes. Also, Sepahan genotype showed the highest increase in chlorophyll stability index, stomatal conductance, ETR and quantum yield of photosynthesis at a stress level of 100 mg/kg as compared with control plants. Parsi genotype had the lowest transpiration rate, stomatal conductance, PSII efficiency, ETR and Ci at a stress level of 100 mg/kg as compared to other investigated genotypes. Based on these results, Parsi genotypes can be introduced as sensitive genotypes, and Sivand and Sirvan genotypes can be introduced as tolerant genotypes to mercury treatment.
