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Effect of different levels of salinity stress on seed germination and early growth of fenugreek (Trigonella foenum-greacum) seedling
Azam Roumani, Seyed Mohammadreza Ehteshami,
Volume 1, Issue 1 ((Spring and Summer) 2014)
Abstract
In order to study the effect of different levels of salinity stress on germination indices and early growth of Trigonella foenum-greacum L., an experiment was conducted in agronomy laboratory of Faculty of Agricultural at the University of Guilan in 2012. The experiment was arranged base on completely randomized design with four replications. The used treatments were different levels of salinity stress due to NaCl (0, -0.2, -0.4, -0.6, -0.8, -1, -1.2, -1.4, -1.6 and -1.8 MPa). Results showed, by increasing of salinity levels, decreased germination percentage, germination speed, germination energy, germination rate index, water percentage of seedling tissue, seedling length, the dry and fresh weight of seedling and vigor index significantly. However, the levels of salinity (-0.2 and -0.4 MPa) increased the dry and fresh weight of seedling in comparing with control by growth stimulation. Moreover, germination rate reduction had increased trend in comparing with control. Results indicated that there was a positive significant correlation between percent of germination and other germination indices except for germination rate. Generally, the results showed fenugreek seed can tolerate salinity amount until -1.2 MPa (38.9 ds/m) in germination time.

Effect of Drought Stress at Reproductive Stage on Seed Germination Characteristics of Local and Improved Rice (Oryza sativa) Genotypes
Seyedeh Arhameh Fallah-Shamsi, Hemmatollah Pirdashti, Aliakbar Ebadi, Masoud Esfahani, Mahmood Raeini,
Volume 4, Issue 1 ((Spring and Summer) 2017)
Abstract
In order to study drought stress effect at the reproductive stage on seed germination characteristics of seven rice genotypes, an experiment was carried out at Sari Agricultural Sciences and Natural Resources University in 2014. This study was conducted on drought-stressed seeds and seeds grown under normal conditions. The results of orthogonal mean comparison among non-stressed seeds showed that local genotypes had a lower germination index, germination rate, water percentage of seedling tissue, shoot length and root dry weight than the improved genotypes. Among stressed seeds, however, local genotypes had a higher germination index and germination rates than those of improved genotypes. Comparison of non-stressed seeds of susceptible and tolerant genotypes indicated that susceptible genotypes had a higher germination index, germination rate and germination percentage than tolerant genotypes. On the other hand, the comparison of the stressed seeds of susceptible and tolerant genotypes revealed that drought stress increased the time to 10, 50, 90 and 95% germination, water percentage of seedling tissue and plantlet length in susceptible genotypes, which were higher than those of tolerant genotypes. In conclusion, it seems that drought stress at reproductive stage has a significant effect on germination characteristics of the plant’s following generation. However, their responses are different, depending on the level tolerance of the genotype to stress and genetic origin.

Highlights: 
1-  Drought stress at reproductive stage has a significant effect on germination characteristics of the following generation of the rice plant.
2-  Among stressed seeds, local genotypes have a higher germination index and germination rates than those of the improved genotypes.
3-  Drought stress increases the time of germination in susceptible genotypes, which is higher than that in the tolerant genotypes.

Effect of Different Levels of Temperature and Drought Stress on Germination Characteristics of Roman Nettle (Urtica pilulifera)
Zakia Ibrahim Quchi, Gholamreza Mohsenabadi , Hamed Hassanpour ,
Volume 4, Issue 2 ((Autumn & Winter) 2018)
Abstract

In order to investigate the effect of different levels of temperature and drought stress on seed germination parameters of nettle roman (Urtica pilulifera L.), an experiment was conducted as factorial in a completely randomized design with three replications at the Department of Agronomy, College of Agriculture, University of Guilan, in 2014. Treatments included different temperature levels (5, 10, 15, 20 and 25 °C) and drought stress levels (0 (control), -2, -4,-6 and -8 bars). The results showed that treatments and their interactions had a significant effect on germination percentage (GP), germination rate (GR), root length and root dry weight. The highest GP (88%), GR (1.8 seed/day) and root dry weight (0.06 g) were obtained as the result of the interaction between the temperature of 25°C and no-stress condition. In this study, with an increase in drought stress and a decrease in temperature, GP, GR, root dry weight, root length and shoot length decreased. The impact of drought stress on GR and GP was lower at 20°C, compared with the temperature of 25°C. A decrease in water potential from -4 to -6 bars at 20°C caused a reduction of 50% and 30% in GP and GR, respectively. However, these reductions at 25°C were 75% and 70%, respectively. According to the results, it could be stated that the significant reduction threshold of seed germination parameters was -2 bars.

 
Highlights:

  1. The germination characteristics of Roman nettle were studied under drought stress and temperature.
  2. In drought stress of -4 bars, germination percentage and germination rate decreased significantly.

Quantification of the Best Harvest Time of Guar (Cyamopsis tetragonoloba) Seed with High Quality in Golestan Province
Mahsa Nazer, Seyed Mohammadreza Ehteshami, Masoumeh Salehi, Ali Kafighasemi,
Volume 6, Issue 1 ((Spring and Summer) 2019)
Abstract

Extended Abstract
Introduction: Guar (Cyamopsis tetragonolob) which belongs to fabaceae and leguminosae families is self-pollinating and is indigenous to India and Pakistan. This plant is suitable for growth in dry, damp and sandy soils, and can tolerate saline and relatively alkaline soils. Determining the best time for harvesting seeds and its timing with maximum quality is one of the important issues in the field of seed production management. The changes in the physiological quality of seeds occur during development until seed treatment. The use of high-quality seeds plays an important role in the final yield of crops. The purpose of this study was to determine the most suitable time for harvesting seeds because seed moisture content at harvest time is one of the most important factors affecting seed quality.
Materials and Methods: This research was carried out in July 2013 at Iraqi Research Station in Gorgan, Golestan, Iran in a split-plot design with four replications. The treatments consisted of the time of harvesting the seeds from the mother's base in six stages (with different moisture content) and harvesting places (upper, middle, and bottom pods) so that, starting from the podding, every 7 days, the seeds were removed from the base. The mother was harvested and such traits as germination rate, germination percentage, seedling vigor, seed moisture content, and alpha-amylase activity were calculated. In this research, a logistic model was used to study the changes in germination percentage, germination rate, seedling vigor index and straw index during seed dressing on Guar.
Results: The results of this study showed that the hypothesis that seed reaches its maximum quality at the end of the period of seed filling is confirmed, suggesting that with a moisture content of 30 and 14% in late seed filling period, Guar seeds have the highest quality. In general, the results of the present study confirm that the stages of development and management of Guar seeds on maternal basis have an impact on its quality. In the early stages of growth (humidity 85, 80 and 62 percent), due to prematurity and lack of essential seed structures, the qualitative traits of germination percentage, germination rate, seedling vigor, and strawberry index were low, and with the evolution of essential structures and reduced seed moisture content (58, 30 and 14%), the quality traits increased.
Conclusions: In general, it can be concluded that the best timing for harvesting Guar seeds with the highest quality in Golestan province is when seed moisture reaches 14% or 100 days after planting, and the pods formed at the bottom are the ones with the highest quality.
 
 
Highlights:
  1. To investigate the qualitative indices of Guar seed on the mother plant during seed filling period
  2. To determine the best harvest time and its adaptation with the highest quality of Guar seed

Germination Characteristics and Enzyme Activity of Mung Bean (Vigna radiata) in Response to Methyl Jasmonate and Salinity Treatments
Majid Ghanbari, Ali Mokhtassi-Bidgoli, Kamran Mansour Ghanaei-Pashaki, Soheil Karamniya,
Volume 7, Issue 1 ((Spring and Summer) 2020)
Abstract


Extended abstract
Introduction: Legumes are the most important source of plant protein and Mung bean has a high nutritional value for humans, as it produces seeds containing high protein percentage. The major problem of salinity in seed germination of higher plants is due to excessive amounts of sodium chloride, osmotic pressure, disruption of nutrient uptake and transport, and direct effects of ionic toxicity on the membrane and enzymatic systems that in turn reduce germination. External use of methyl jasmonate can modulate the effects of various stresses, such as salinity and drought, by increasing the antioxidant activity of the seed. Therefore, the purpose of this research was to evaluate the effect of methyl jasmonate and salinity stress on germination and enzymatic properties of Mung bean.
Material and Method: This study was conducted as factorial based on a completely randomized design with three replications during 2015-16 at the laboratory of Department of Agronomy, Tarbiat Modares University. The experimental treatments included four methyl jasmonate solution (0, 50, 100 and 150 mM) and four salinity stress levels (0, 2, 4 and 6 dS/m salinity from NaCl). Petri dishes were placed in a germinator at 25 ° C and in full darkness for 14 days. In this experiment, germination rate and percentage, time to reach 50% germination, alpha and beta amylase, catalase and peroxidase were measured.
Results: The results of the experiment showed that the lowest rate of slope and final germination percentage were obtained in 50 and 100 mM solutions of methyl jasmonate. In terms of T50, an increase of 4.7 days was observed per one dS/m increase in salinity stress and the lowest T50 was estimated at a methyl jasmonate solution concentration of 78.68 mM. In terms of the activity of germination enzymes, reduction of 0.031 μmol/ml/min per 1 dS.m increase in salinity stress and the highest amount of α-amylase were estimated 72.6 μmol/ml/min at a methyl jasmonate solution concentration of 73.33 mM. Also, the lowest activity of β-amylase enzyme was 0.79 μmol/ml/min at a concentration of 5.6 dS/m salinity stress and the highest activity of β-amylase enzyme was estimated to be 1.7 μmol/ml/min at a methyl jasmonate solution concentration of 86.67 mM. The highest activity of catalase (25.7 ∆A/mg protein/min) was observed at 14.72 dS/m salinity stress and the lowest activity of catalase enzyme (8.9 ∆A/mg protein/min) was estimated at 5.88 mM methyl jasmonate solution. The highest activity of peroxidase enzyme (22.06 ∆A/mg protein/min) was at 24.3 dS/m salinity stress and the lowest activity of the enzyme peroxidase (2.5 ∆A/ mg protein/min) was determined at a methyl jasmonate solution concentration of 266.66 mM.
Conclusions: In general, pre-treatment of methyl jasmonate can reduce the germination time, increase the rate of germination and reduce the oxidative stress in salt stress conditions by improving the activity of germination enzymes, increasing the activity of enzymes, increasing the activity of hydrolyzing enzymes and increasing the easy availability of seedlings to nutrients during germination.

 
Highlights:
1- Germination rate and percentage and morpho-physiological changes of Mung bean seed as affected by methyl jasmonate were investigated.
2- The role of alpha and beta amylase germination enzymes in accelerating the production of Mungbean seedlings under saline conditions were estimated.
3- Methyl jasmonate- induced catalase and peroxidase enzymes activity in resistance to salinity stress were estimated.

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