نشریه فیزیولوژی محیطی گیاهی
پیاپی 59 (پاییز 1399)

In order to investigate the effect of gibberellin hormone and drought stress on corn, an experiment was conducted as split plots based on a randomized complete block design with three replications. Treatments included moisture stress at three levels of normal irrigation (I0=60), medium stress (I1=90), and severe stress (I2=120) mm evaporation from class A evaporation pan as main factor and a sub factor of gibberellin hormone spraying at four levels non-consumption (G0=0), (G1=15ppm), (G2=20ppm), and (G3=25ppm). Results showed that the highest and lowest grain yields were observed in 60 mm evaporation from evaporation pan with 20 ppm gibberellin acid and 120 mm evaporation from the evaporation pan without using gibberellin acid as 9658.2 and 5797.3 kg/h, respectively. Also, under all levels of drought stress, gibberellin acid application increased grain yield of corn. The interaction of hormones and irrigation had a significant effect on starch, proline, alpha amylase, beta amylase, and protease. Drought stress increased proline concentration in corn leaf. Gibberellin hormone had no significant effect on proline concentration in corn leaf under drought stress conditions, but under prolonged drought stress, proline concentration increased. The application of 20 and 25 ppm gibberellin under moderate dehydration (90 mm evaporation from evaporation pan) increased leaf proline concentrations by 36% and 50%, respectively, compared with control treatment (no gibberellin consumption). Under severe drought stress conditions (120 mm evaporation from the evaporation pan), proline concentrations with 20 and 25 ppm gibberellin were 32% and 21% higher than gibberellin consumption, respectively. Overall, the results showed that gibberellin acid, through positive effects on increasing and improving the yield components, can ultimately increase corn grain yield.

In order to investigate the effect of frost stress on Phyla lanceolata as a cover plant under the influence of some organic mulches, this experiment was conducted as a factorial experiment based on completely randomized design with four replications at Ferdowsi University of Mashhad. Five levels of freezing temperature (0, -5, -10, -15, and -20 °C) and three types of mulch (manure, leaf needle, and bran) were treated in the experiment. For evaluation of frost tolerance temperatures, some traits such as electrolyte leakage percentage, soluble carbohydrate content, leaf proline content, leaf number, leaf area, and plant dry weight were considered. Results showed that the simple and interaction effects of mulch and temperature on the measured morphological traits, electrolyte leakage, relative water content, spade and photosynthetic pigment content (chlorophyll a, b and total) were significant. All of the organic mulches used in the study increased shoot and root dry weight so that by applying three mulch of bran, leaf needle, and animal manure, shoot dry weight from 2.15 g under non-mulch conditions reached to 2.72, 3.13, and 3.19 g/plant, respectively and root dry weight from 1.50 g reached 1.90, 2.23, and 2.29 g /plant, respectively. The highest electrolyte leakage (80%) was at -20 °C and in plants treated with bran mulch and the highest relative water content (55%) was at 0 °C and in plants treated with needle mulch treatment. Also, total chlorophyll content was 0.11 mg higher than that in control treatment. In general, among the mulches used, animal manure mulch had the greatest effect on mitigating the effects of frost on morphological and biochemical traits of the plant.

Rice (Oryza sativa L.) is one of the crops which is the main source of food for more than a third of the world's population. Limiting factors such as environmental stress require increasing the yield of agricultural products per unit area. Soil salinity is one of the most important factors reducing the productivity of crops throughout the world. Induced mutation is widely used as an effective tool for improving the yield, quality, and resistance to biotic and abiotic stresses in product modification. In order to screen salt-tolerant superior mutant lines of rice, 10 mutant lines (M5) derived from three Iranian local varieties (Tarom, Anbarbo, and Hasani) were assessed during two generations (M6 and M7) at saline field (EC of soil was 6-8 ds/m). The experiment was conducted based on a randomized complete block design with three replications. Three salt-tolerant superior mutant lines (13-3, 32-18 and 22-1) were selected in comparison with their parents (control). Physiological parameters of superior mutant lines (high stomatal conductivity, Fv/Fm, and total chlorophyll) were biochemical (lower Na+/K+ ratio, high proline accumulation, less membrane damage). These superior mutant lines will be introduced as new salt-tolerant rice varieties and sources of plant germplasm.

Goldenrain-tree (Koelreuteria paniculata Laxm.) is a woody perennial ornamental tree, mainly used for landscape purposes. The aim of this study was investigation salt tolerance of this plant and the effect of cow manure and vermicompost on plant growth and increasing the salt tolerance of two-year plants. In a factorial experiment and completely randomized design (CRD), three levels of organic amendments (soil, 80% v/v soil + 20% v/v vermicompost, and 80% v/v soil + 20% v/v cow manure) and three levels of salinity (1, 4, and 7 dS.m-1) with three replications per treatments in greenhouse were applied. In this experiment, media without organic amendment was were considered as control and stress duration was three months. Results showed that increasing soil salinity levels progressively decreased the number of shoots and fresh and dry weights of roots, shoots, and whole plant while it increased activity of peroxidase and sodium and chloride uptake. Vermicompost treatment increased fresh and dry weights of shoots, roots, and whole plant, peroxidase, sodium, potassium, and chloride uptake more than control and cow manure. The highest fresh and dry weights of shoots, roots, and whole plant as well as sodium potassium and chloride uptake were obtained in salinity level of 4 ds/m and under vermicompost treatment. Generally, application of vermicompost increased growth characteristics and salt tolerance of goldenrain tree better than cow manure.

This study was conducted to evaluate 18 different native and foreign sugar beet cultivars in terms of some important quantitative and qualitative traits under optimal and limited irrigation conditions in 2017 crop season in as a strip split plot design (normal and stress conditions) as main plots and cultivar factor as sub plots based on RCB design with six replications. The results of combined ANOVA of the obtained data showed that the interaction effect of the environment × cultivar was significant on sugar yield, white sugar yield, alkalinity coefficient, molasses sugar (p≤0.05), and root potassium content (p≤0.01) traits while it had no effect on other traits. Based on the obtained results from ANOVA, the effect of cultivar was not significant on α-amino nitrogen trait while it was significant on other assessed traits under normal condition. Also, under stress condition, the cultivar effect was significant at p≤0.01 on all of the assessed traits. In terms of root yield trait, Merak and Dorthea foreign cultivars had the highest value with 86.5 and 70.4 t ha-1 and Sharif native cultivar had the lowest value with 14.3 and 17.2 t ha-1 under normal and stress conditions, respectively. Under normal and stress conditions, the mean sugar contents were calculated 19.88 and 20.15%, respectively. Although the difference was not significant, the increase in sugar content (about 1.34%) under stress condition was as expected. Given that the decreasing and increasing effects of water deficit stress on most measured traits were not significant, it can be found that sugar beet crop has a good tolerance threshold for water deficit and, surely the finding should always be considered by beet farmers in West Azarbaijan province, especially in the current situation in which there are attempts to revive the drying Urmia lake.

Stachys lavandulifolia is a medicinal plant growing in different parts of Iran. Its flower and leaf infusions are used for treating diseases related to stomach and also as sedative for insomnia and stress. This research was carried out based on a completely randomized design with three replications to investigate the essential oil contents of leaf and flower obtained from four different sites (Shahrud, Ghuchan, Nyshabur, and Mashhad). Ethnopharmacological data were obtained from local people and the plant samples were collected from their habitas during flowering stage in spring 2014. Essential oils of the sample leaves and flowers were distilled using a Clevenger apparatus to determine essential oil percent and yield in each site. Furthermore, the essential oil components were determined with a GC/MS tool. Results of ethnopharmacological study showed that this plant has different local names in the sites under study but its general application was for reducing stress. The highest essential oil yield and percent and also dry weight were obtained from Mashhad. Also, the highest numbers of essential oil components of Stachys lavandulifolia flower (n=72) and leaf (n=82) were extracted from Nyshabur and Ghuchan, respectively with a maximum essential oil weights of 92.692 and 96.818, respectively. The highest values of major components including betapinene, betaphellandrane, and caryophyllene were obtained from Shahroud and the highest values of spathulenol and alfathujene were obtained from Ghuchan and Mashhad, respectively and these components were higher in leaves than in flowers. The highest quality of the essential oils was obtained from plants grown in Mashhad and Ghuchan habitats.

Environmental factors are the most important factors affecting morphological traits and expression of chemical synthesizing genes. Wild primrose has compounds such as calicillin, benzabolol, quinolone, thymol and is traditionally used to treat gastrointestinal and infectious wounds. This study was conducted to evaluate the effect of differences in elevation level in Mazandaran province (Azni area with a height of 1035 meters and the Kasoot area with a height of 481 meters) on the quantitative and qualitative characteristics of wild primrose. The studied phytochemical traits included total phenol content, total flavonoid, antioxidant capacity of samples using DPPH as well as chlorophyll a, chlorophyll b, and total chlorophyll content. Also, morphological traits including leaf length, leaf width, root length, pedicel length, petiole length, and number of leaf were measured at the site of plant growth. Results showed that with increasing altitude in Azni site, leaf area, leaf width, petiole length, and pedicel length decreased compared to Kasoot region. But the plants in Azni region had longer roots and more leaves. On the other hand, the plants in Azni had higher leaf and flower flavonoid contents and their total phenol contents were more than those in Kasoot area. But considering the antioxidants and photosynthetic pigments, plants in Kasoot had significantly higher contents. In general, morphological traits decreased with increasing altitude while biochemical properties such as phenol and flavonoids increased.

Soil fertility is an effective factor on quantity and quality of crops and medicinal plants. In order to investigate the effect of vermicompost and humic acid on quantitative and qualitative traits of savory(satureia hortensis L.), an experiment was conducted as factorial based on completely randomized design in Payame Noor University of Sabzevar under natural condition. Treatments were vermicompost in three levels (0, 25, and 50 percent in volume) and humic acid in four levels (0, 250, 500, and 750 mg.l-1). In this study, plant height, root length, branch number as well as leaf, root, and shoot dry weights and essential oil percentage and yield were measured. Results indicated that vermicompost affected stem height, branch number per m2, dry weight of leaf, stem, and root, and leaf to stem ratio significantly while this treatment did not have a significant effect on essential oil percentage and yield of savory. The highest stem height and dry weight of leaf, stem, and root were observed in 50% vermicompost. The effect of humic acid was also significant on stem and leaf dry weight and leaf to stem ratio, statistically. In general, results showed that both organic fertilizers had synergistic effect as the highest dry weight of leaf, stem, and root and also essential oil yield were obtained under vermicompost 50% and humic acid 750 mg.l-1 treatment.