نشریه فیزیولوژی محیطی گیاهی
پیاپی 61 (بهار 1400)

Identification of genes related to stresses tolerance and mechanisms of tolerance is an important factor for developing tolerant plants. For this purpose, an experiment was conducted based on completely random design with three replications with 99 rice genotypes under flooding and drought stress at Gonbad Kavous University in 2018. To apply drought stress, irrigation was stopped at the three-leaf stage. According to the humidity curve, the stress level of 2% by weight moisture was estimated to be -0.55 MPa. Significant differences were detected between traits in both conditions. The result of association analysis of molecular and phenotype studies under flooding condition revealed that among the alleles, the RM129A allele with stem fresh weight and root length, the RM129G allele with root fresh weight and the width of the largest leaf, the RM129B allele with root dry weight and the length of the largest leaf, the RM1029I allele with stem dry weight and the length of the largest leaf, and under the drought condition, the RM1029G allele with stem dry weight, root volume, and the number of roots were maximally associated with the relevant traits under study. RM1029 was recognized as one of the most important primers at the seedling stage. The results of this research can be used to increase drought tolerance in rice varieties.

The aim of this study was to investigate interaction of sodium chloride with chromium on vegetative, and physiological traits, uptake, and accumulation of sodium and chromium in roots and shoots of portulaca oleracea. In a completely randomized design with 3 replications, 4 salinity levels (0, 4, 8, 12 dsm-1) using sodium chloride every 4 days through irrigation water and five levels of chromium (0, 7, 14, 21, 28 mgkg-1 of dry soil weight) were applied in a pot experiment. Different levels of chromium treatment were prepared before sowing the seeds by adding potassium dichromate to the soil. The amounts of root chromium and shoots were measured by the atomic absorption spectrometry. Sodium contents of roots and shoots, root and stem length, root diameter and surface, greenness index, transfer factor, and bioaccumulation were measured after 60 days of cultivation. Results showed that an increase in different salinity level was associated with a significant increase in sodium and chromium content of roots, shoots and bioaccumulation factor. The highest amount of chromium, sodium, and bioaccumulation factor were observed at salinity levels of 12 dsm-1 and 28 mgkg-1. The interaction between salinity and chromium was significant. With an increase in the salinity level, the amount of plant root transfer factor showed an increasing trend and with increasing chromium, the transfer factor decreased. Root length, diameter, and surface as well as stem length and greenery index showed a significant decrease in plants treated with chromium and salinity. The combined effect of high levels of chromium and salinity led to a further reduction in the concentration and accumulation of minerals compared to each stress alone. Although salinity and chromium reduced the growth of portulaca oleracea, it seems that accumulation of significant amounts of sodium and chromium in the roots, prevents their excessive transfer to the shoots and further reduction in plant growth.

The study of use of nutrients and the optimal balance between nutrients and concentrations of absorbable compounds has always attracted the attention of researchers in biological and agricultural sciences. In this research, effects of four levels of Nitrogen sources (100 % urea, nano-chelate nitrogen, 100% Panaromix biologic fertilizer, and 50% urea + 50 % Panaromix biologic fertilizer) along with three levels of Zinc sources (control or without application of Zn, zinc sulfate, and nano-chelate zinc) and interaction effects of hese sources were investigated on physiology and yield of wheat. The study was carried out by split-plot method based on completely randomized blocks design with 3 replications and 12 treatments in a private farm located in the north of Jelin, a city located 3 Km east of Gorgan, during the 2017-2018 crop year. Results showed that the traits under study were affected by the sources of nitrogen supply and the interaction effects of sources of the two elements but there was no significant difference under treatment with sources of zinc supply. In Nitrogen supply sources, the maximum leaf area and number, shoot length, chlorophyll b and chlorophyll (a+b) content, and nitrate reductase activity as well as biological and grain yield was related to 100% urea and 50% urea + 50% biologic fertilizer. In combined treatments with the interaction effects, the highest amount of proline was related to 100% biological fertilizer + nano-chelate zinc and in the treatments that were associated with increased proline, there was no increase in the soluble sugars and glycine betaine contents. The highest level of NR activity, chlorophyll a, and total chlorophyll (a+b) content, and also the highest level of grain performance and biological yield were observed in 100% urea + Zinc sulfate fertilizer treatment. The results showed that high yield of wheat in this treatment was a function of plant physiological behavior, showing a positive interaction between nitrogen and zinc.

In order to survey the effect of silver nano-silver particles and weight of corm on physiological and morphological features of Crocus Sativus under climatic conditions in the area of Systan, an experiment was carried out based on a factorial randomized complete base-blocks design with three repetitions using two different weights of Crocus Sativus corm (more and less than 8 g) and two different concentrations of nano-silver treatment (zero and 50 ppm) in Dadi village located in Teymourabad district of Hamoun province during two consecutive years 2014-2016. Findings indicated that the treatment with nano-silver particles (AgNPs) had a significant effect on the morphological and physiological properties during the both study years and increased all traits under study as compared with the control. Moreover, the treatment including corm weight more than 8 g had significant effects on all properties under study during these two years. The results of analysis of the quantitative traits and color in saffron, which was done by HPLC method, showed that flavonoids, flavor, and odor of saffron in the sample soaked in the Ag Nanoparticles' solution remarkably increased in comparison with the control. Comparisons also indicated that the samples weighing more than 8 grams had a more significant increasing rate of the traits compared with the lighter samples. The results of the present study also showed that under hot and dry conditions and if the saffron corms with optimal size are exposed to suitable concentrations of Ag nanoparticle solution, increased qualitative and quantitative traits is observed, and this can even lead to improved economical properties in the plant.

In order to study the effects of supplementary irrigation and application of mycorrhiza and azetobacter on grain filling components, chlorophyll content, and grain yield of rain fed barley (Var. Sahand), a factorial experiment was conducted based on a randomized complete block design with three replications in the village of Khalkhoran Viand, Ardabil province during 2017. Factors of the experiment included irrigation levels (no irrigation as rain fed, supplementary irrigation at 50% heading, and booting stages) and biofertilizers application at four levels (without biofertilizers as control, application of mycorrhizal fungi, application of azetobacter, and combined application of mycorrhiza and azetobacter). Results showed that the highest chlorophyll a (1.76 mg/g FW), chlorophyll b (0.88 mg/g FW), carotenoid (0.83 mg/g FW), chlorophyll total contents (2.64 mg/g FW), maximum fluorescence (1433.2), variable fluorescence (1281.3), quantum yield (0.847), grain filling period (32.06 days), and maximum grain weight (58.3 mg) were obtained under supplementary irrigation treatment at boot stage with both application of mycorrhiza and azetobacter while the minimum levels of these traits were obtained under rain fed condition without application of biofertilizers. Moreover, the highest grain filling rate (1.9 mg/day) was obtained under rain fed condition and no application of biofertilizers while the lowest rate was obtained under supplementary irrigation at boot stage with application of mycorrhiza. Supplementary irrigation at boot stage and combined application of mycorrhiza and azetobacter increased grain yield by 29.87% in comparison with no application of biofertilizers under rain fed condition. Based on the results, it seems that application of biofertilizers and supplementary irrigation can increase grain yield of rain fed barley through improving chlorophyll content and grain filling components.

This study was conducted in greenhouse condition to investigate the growth, morphological and physiological changes and some antioxidant enzyme activities of one-year-old seedlings of Alnus subcordata C. A. Mey. inoculated with Rhizophagus irregularis mycorrhizal fungi under water deficit stress in a period of 70 days. The experiment was carried out at two inoculation levels (control or non-inoculated seedlings and inoculated with R. irregularismycorrhizal fungi) and with two levels of irrigation including irrigation at field capacity (control treatment) and irrigation at 30% of field capacity (water deficit treatment) in a completely randomized design with four treatments and 10 replications. Results revealed that morphological and physiological characteristics of A. subcordata seedlings significantly decreased under water deficit stress at 99% level while all enzymatic activities significantly increased. Although the morphological characteristics such as height and diameter growth, root length, leaf area, and leaf, stem, root, and total biomass significantly increased by 20-30% in R. irregularis mycorrhiza treatment of the irrigation control plants, these features increased by 55, 40, 46, 47, 37, 35, 50 and 37%, respectively when the plants under water deficit treatment were added R. irregularis mycorrhiza compared to non-mycorrhiza water deficit treatment. The meancomparisonresults indicated that the photosynthesis rate, stomatal conductance, transpiration, and leaf water potential reduced by 57, 54, 53, and 65%, respectively under water deficit regime whereas addition of R. irregularis mycorrhizal fungi in soil alleviated the effects of water deficit. Also, under water deficit condition, activities of catalase, peroxidase, superoxide dismutase, and ascorbate peroxidase significantly increased in comparison with field capacity irrigated seedlings while treatment of soil with mycorrhiza mitigated the destructive effects of water deficit. In general, the present study showed that inoculation of R. irregularis mycorrhizal fungi can alleviate physiological indexes and antioxidant enzyme and consequently leading to an increased tolerance of A. subcordata seedlings during the first year.

Since the quantity and quality of the active ingredients of medicinal plants are dependent on the genetic and environmental factors, this research was carried out in 2018 to investigate the effects of climatic changes and phenological stages on the quantity and quality of essential oils in Salvia syriaca L to introduce the most suitable phenological stage and region. The experimental design was randomized complete design in a factorial layout with 2 factors of phenological stages (vegetative, beginning of flowering, and full flowering stages) and regions (Shahrekord, Kouhrang, and Lordegan) with three replications. The essential oil content was determined by distilling tissues in Clevenger type apparatus. All the essential oil samples were injected into a GC–MS apparatus to determine their components. Results showed a significant effect of phenological stages and regions on the components of essential oils. The highest levels of essential oil compounds included Cis- Thujone (23.9-31.4%), Camphor (16.4-19.7%), Trans- Thujone (8.8-11.5%), and 1, 8-Cineole (8.43-12.1%). The results showed significant effects of phenological stages and regions on essential oil content and composition. The highest contents of essential oil were obtained from Kouhrang region and at beginning of flowering stage. The highest contents of volatile components such as α/β-Pinene (monoterpene hydrocarbons) and Caryophyllene (sesquiterpene hydrocarbons) were obtained at the beginning of flowering stage. In addition, the amounts of volatile components and monoterpene hydrocarbons such as α/β-Pinene and Limonene of essential oils decreased from Kouhrang (temperate climate) to Lordegan (tropical climate) while the percentage of sesquiterpene hydrocarbons such as Caryophyllene in the oils increased. To obtain more aromatic components of this plant, it is recommended to harvest plants in temperate climate and at the beginning of flowering stage.

In order to study the morphological traits and yield of maize 704 SC under the influence of spraying with growth regulators and drought stress conditions in Isfahan, an experiment was conducted for two years based on the split plot design with 3 replications. The main treatment included drought stress at three levels of control (irrigation based on 100% water requirement of corn), mild stress (based on 85% of the plant's water requirement), and severe stress (based on 70% of the plant's water requirement). The second treatment included spraying with distilled water as control, abscisic acid (100 mM), gibberellin (100 ppm), salicylic acid (5 mM), and Nano-zinc (2 gl-1 water). The results of this experiment showed that the effect of year on biological yield, crude protein, and forage yield were significant. Also, the effect of drought stress and spraying on leaf area index, chlorophyll index, biological yield, crude protein, and forage yield were significant. Also, the effect of drought stress and spraying on leaf area index, chlorophyll index, biological yield, crude protein and forage yield were significant. The highest forage yield (90.44 t ha-1) was obtained under the complete irrigation with salicylic acid treatment. Salicylic acid treatment resulted in higher forage yield under the complete irrigation conditions. Salicylic acid treatment also reduced the damage of mild and severe stress treatments by 27 and 9%, respectively. According to the results of the experiment and CGR, using salicylic acid treatment during three foliar application periods at eight-leaf, before tassel emergence, and at the milky stage was able to reduce drought stress and is recommended for conditions similar to the present experiment.