نشریه فیزیولوژی محیطی گیاهی
پیاپی 47 (پاییز 1396)

Salt stress is one of the factors limiting plant growth and a major obnstacles for nutrient uptake in plants. A factorial experiment with pots in the open air was implemented based on a completely randomized design with three replications to evaluate the effect of foliar application of iron (Fe: Sequestrene 138 at a concentration of 5 per thousand), boron (B: Boric acid at a concentration of 5 per thousand), and selenium (Se: Sodium selenite at a concentration of 2 per thousand) under NaCl salinity on root growth characteristics and the photosynthetic pigmentscontent of Stevia plant. The experiment factors included different levels of sodium chloride (0, 3, 6, and 9 dS m-1) and spraying composition at eight levels (no spraying, Fe, B, Se, Fe Se, Fe B, Se B, and Fe Se B). Results showed that salinity caused significant reduction in root dry weight, volume, length, diameter and density of root, percentage of dry weight to soil volume ratio, and chlorophyll a, b, and total. Among the various combinations of spraying, combined application of Fe, B, and Se had the highest mean dry weight, volume, length, area, and density of the root. The highest significant mean chlorophyll b and total chlorophyll contents were observed in spraying solution containing Fe at the non-stress level, and the combination of Fe and Se at 3 dS m-1 level of salinity. In general, decrease in root growth and leaf chlorophyll content (especially chlorophyll a) occurred under salt stress and generally, these factors led to the loss of plant growth at higher salinity levels (6 and 9 dS m-1). In order to reduce the negative effects of salinity stress, especially at lower levels (3 and 6 dS m-1), using Fe and Se elements are recommended to increase the chlorophyll content of the plant and improve root growth.

In order to investigate the effects of biological, chemical, and integrated fertilizers on growth, yield, and yield components of sunflowers, an experiment was conducted in a randomized complete block design with three replications at the Agricultural Research Station of Zabol University in the growing season 2014-15. The experiment consisted of 13 treatments including NPK, biophosphorus, biophosphorus 25% NPK, biophosphorus 50% NPK, biophosphorus 100% NPK, nitroxin, nitroxin 25% NPK, nitroxin 50% NPK, nitroxin 100% NPK, biophosphorus nitroxin, biophosphorus nitroxin 25% NPK, biophosphorus nitroxin 50%NPK and biophosphorus nitroxin 100%NPK. The results showed that the effect of different treatments of chemical, biological, and integrated fertilizers were significant on most of the studied traits except the number of leaves, flowering date, and the number of florets per head. The highest mean in most of the studied traits belonged to the nitroxin biophosphorus 100% NPK treatment which was not significantly different from the nitroxin biophosphorus 50% NPK integrated treatment. The results of this study showed that combined application of nitroxin biophosphorus 50% NPK in comparison with the integrated treatment of nitroxin biophosphorus 100% NPK in addition to reducing 50% of chemical fertilizers application can also produce optimal yield. According to the obtained results, the application of 50% of the recommended amount of chemical fertilizers in combination with the nitroxin and biophosphorus biofertilizers can be recommended for obtaining the maximum quality and quantity yield of sunflower.

In order to study the effect of height and habitat on some biochemical features of Sambucus ebulus, an experiment was carried out in three cities in Golestan (Ramiyan, Tuskestan-Gorgan and Minoodasht), three height levels (elevations above 1400 m, 700-600 m, and below 300 m), and on leaves, flowers and fruit with three replications in 2015. Total phenols, total flavonoids, and antioxidant activity were measured. The results showed significant effects of heights, region, and organs on biochemical features of the plants so that the interaction of effects of the region and height on the total phenol content and antioxidant activity and the interaction of effects of the region and organ on the total phenol content and on the antioxidant activity, and the interaction of effects of the height and organ on the total phenol content and flavonoids were significant. Also, the interaction of effects of the region, height, and organs was significant on total phenol content and total flavonoids and antioxidant activities. Maximum and minimum total phenol contents were recorded in the leaves of the plants in low height of Tuskestan and in the flowers of plants at average height of Minoodasht, respectively. Also, the highest flavonoid contents were recorded in the flowers at low heights of Minoodasht while the lowest flavonoid content was observed in fruits of the plants at low heights of Tuskestan. The findings also suggest that the maximum antioxidant activity was observed in fruit of the plants at medium elevation in Tuskestan while the minimum content was recorded in leaves of the plants at medium height in Tuskestan. Overall, it can be conclude that total phenol and flavonoids decreased with an increase in the height and the highest quality was obtained from the plants grown at low heights.

This experiment was carried out in order to evaluate interaction effect of irrigation and zinc foliar application on physiological enrichment indices of two hybrids of sweet corn as the split plot factorial in the form of randomized complete block design with three replications in the experimental field of Faculty of Agriculture, Islamic Azad University of Arak in 2014 and 2015. All furrow irrigation (control, I1) and every other furrow irrigation (I2), and alternative every other furrow irrigation (I3) as the main plot and solution spraying levels including Zn 1 (No injection Zn), Zn 2 (Drop Zn) and Zn 3 (Fast Zn) were the subplots. Also, sweet corn (Zea mays var saccharata) varieties (sweet and ultra-sweet) were considered as the subplots. Parameters under investigation included plant height, seed yield, one thousand seed weight, harvest index, seed Zn content and leaf proline content. Interaction effects of the treatments increased plant height by 33%, grain yield by 27%, one thousand seed weight by 21%, and harvest index by 13%. The highest amount of cannable grain yield was observed in periodic irrigation, zinc fast in Challenger hybrid while the lowest amount was recorded in every other furrow irrigation treatment without zinc and Chase Hybrid. The highest level of grain zinc content was observed in the alternative irrigation zinc fast treatment in the Challenger hybrid while the lowest level was recorded in every other furrow irrigation without zinc in Chase hybrid which showed significant difference at p≤0.01. The highest interaction of effects was observed in the alternative irrigation treatment, zinc fast, and Challenger cultivar with average harvest index and lowest was observed in every other furrow irrigation, drop Zinc, and Challenger cultivar. According to the results of this study, in low irrigation conditions, application of alternative irrigation pattern and Zinc-fast foliar application in Challenger cultivar is recommended.

In order to evaluate the effect of organic and biological fertilizers on quantitative and qualitative characteristics of Melissa officinalis L. a factorial experiment was conducted in a completely randomized design with 4 replications in the form of open air pot conditions in Sari, in 2015. The factors examined included Mycorrhizal fungi (Glomus mosseae) (0 and10% of the pot volume), vermicompost (0 and 10% the pot volume), and compost tea (0 and 1.5 liter). Some characteristics such as number of flower, nitrogen, phosphorous, and potassium contents of aerial parts. Results showed that application of organic and mycorrhizal fertilizers had a significant impact on all measured characteristics and increased the number of flowers and fresh weight when compared with those of the control group so that the highest nitrogen concentration and the stem diameter were obtained from the combined mycorrhizal symbiosis, compost tea, and vermicomposting treatment. The triple interaction effects showed that the absence of vermicompost with compost tea, and mycorrhizal symbiosis treatments increased the fresh weight compared to the control. Results also indicated that using vermicomposting, compost tea, and mycorrhizal symbiosis through the availability of nutrients increased the yield and improved qualitative and quantitative characteristics of Melissa officinalis L..

This research aimed to study the genetic diversity of trees in Chahar Bagh habitat in Golestan province using peroxidase and esterase enzymes in both slope directions. To investigate the genetic diversity of Juniperus polycarpos species, 48 trees from both the East and the West slope direction of Chahar Bagh habitat were selected. Scales samples were sampled at the same height from the ground to the tree canopy. After extraction of the samples, qualitative study of the enzyme was carried out using Polyacrylamide gel electrophoresis (PAGE). Cluster analysis of the qualitative data showed the diversity of the intra population in the East and the West in 5 and 6 Groups respectively and the inter population variation in six groups. Quality of peroxidase and esterase activity scales showed that the mean observed number of alleles, mean effective number of alleles, mean gene diversity (Ney), mean Shannon Information Index, percentage of polymorphism and mean polymorphic information content (PIC) in the slope direction of the East were more than that oof the West. Comparison of genetic diversity of inter population and intra populations genetic diversity of Juniperus polycarpos species suggested that the inter and intra population genetic diversity are almost the same. The findings of this study highlight the need for conservation and utilization of effective methods to improve the genetic diversity of this species.

Heavy metals are the most important bioenvironmental pollutants that are found in all industrial communities. The phytoremediation technique is applied to refine the land and reclaim contaminated soil from heavy metals. In order to evaluate the phytoremediation potential of Marigold plant against lead and cadmium heavy metals and their influence on growth, yield, and other characteristics of this plant, a pot experiment was carried out in a completely randomized design in a factorial layout with six replications at Research Field Municipal Parks and Green Spaces of Shahrekord during spring and summer of 2016. Treatments included different levels of cadmium (0, 5, 25, and 50 mg.kg-1 in dry soil) and lead (0, 40, 100, and 250 mg.kg-1 in dry soil). Results showed that different levels of lead and cadmium significantly affected morpho-physiological characteristics. Shoot and root dry and fresh weights and lead and cadmium accumulation in plant soil differed significantly. With an increase in heavy metal concentrations, shoot and root dry and fresh weights significantly decreased compared to the control plants. By adding cadmium concentration, the amount of cadmium in plant and available cadmium in soil increased and therefore translocated to aerial parts of plants along with the more lead. Results of this research showed that Marigold is a super accumulator plant that can accumulate cadmium and lead particularly in its aerial parts. The tolerance threshold in this plant was observed in the treatment containing combination of cadmium (up to 5 mg.kg-1) and lead (up to 250 mg.kg-1) of dry soil after which a decreasing trend was observed in most of the characteristics under study. It seems that negative effects of these heavy metals particularly cadmium is due to their effect on photosynthesis.

Soil salinity is a serious environmental problem that has negative effect on plants’ growth and production. On the other hand, salicylic acid plays an essential role in preventing oxidative damage in plants by detoxifying superoxide radicals produced as a result of salinity. In this research the effect of different concentrations of salicylic acid, sodium chloride, and interaction effects of both factors were studied on morphological and biochemical parameters in sunflower (Helianthus annuus L.) plants. NaCl concentrations of 0, 25, 50, 75, and 100 mM and salicylic acid concentrations of 0, 0.5, 1, and 1.5 mM were used in the form of a factorial experiment in a complete randomized design (CRD). Results showed that salinity caused significant decrease in shoot and root length, fresh and dry weights, chlorophylls, and carotenoid of plants while in salicylic acid pre-treated plants, this reduction has been moderated. On the other hand, increasing the amount of anthocyanin, chlorophylls, and carotenoid indicated the role of salicylic acid in increasing the tolerance of this plant to sodium chloride stress. These findings suggest that salicylic acid application increases plant tolerance to sodium chloride stress.