جستجوی مقالات مرتبط با کلیدواژه « هدایت الکتریکی » در نشریات گروه « زراعت »

Quinoa, Chenopodium quinoa Willd, plays a strategic role in establishing food security under changing climatic conditions due to its nutritional value, genetic diversity, and high adaptability under stressful conditions and different environments. The purpose of this research was to evaluate the germination and biochemical characteristics of 12 quinoa genotypes adapted to the climatic conditions of Iran. This experiment was conducted in the form of the randomized complete blocks design with three replications in the Laboratory of Seed Physiology and Biotechnology, Faculty of Agricultural Sciences, Guilan University. In this experiment, the characteristics of germination percentage, germination rate, germination uniformity, D10, D50, D90, radicle fresh and dry, shoot and seedling weight, radicle, shoot, and seedling length, electrical conductivity of seed solution, malondialdehyde content, alpha-amylase enzyme activity and saponin content were investigated. The analysis of the data's variance demonstrated significant differences between genotypes in all studied traits. Q26 Genotype showed high values in germination percentage (91.33%), germination rate, radicle, shoot and seedling length, seedling fresh weight, alpha-amylase enzyme activity (0.234 micromoles released glucose per one gram of seed weight) and saponin content. Q26 genotype had the worst, and Q2 and Q12 genotypes had the best performance in terms of germination uniformity, electrical conductivity of seed solution and malondialdehyde content, respectively. Among the studied genotypes, the Q26 genotype demonstrated better results in comparison with other genotypes. It seems that this genotype may have better conditions for planting in the climatic conditions of Iran

IntroductionThe seed is the most important input of the agricultural section, which provides the reproduction, survival and extension of the plant. Therefore, identifying the factors affecting seed production and its quality at the production and harvesting stages is very important. Previous reports show that the use of soil modifier compounds such as biochar, arbuscular mycorrhizal fungus (AMF), and silicon foliar application can improve the germination indices of produced seeds under environmental stressess conditions, especially salinity stress. So far, the experiments conducted to investigate the effect of biochar, mycorrhizal fungus and silicon foliar application on plant growth and salinity stress tolerance have mostly been about the individual applications of each of these soil modifiers, and there is little evidence of their synergistic effects, especially for plants grown under saline soil conditions. The objective of this experiment was to investigate the synergistic effects of biochar, arbuscular mycorrhizal fungus and silicon foliar application on improving the quality of mother class seeds of maize variety under saline soil conditions. Materials and methodsThis study was conducted as a factorial experiment in a randomized complete block design with three replications in a research field with an electrical conductivity of 6.01 dS.m-1, in Fasa city, Fars province, in 2020. The first factor was three varieties of maize, including early- maturity variety 370, mid-maturity variety 604, and late-maturity variety 704, and the second factor was soil modifier compounds in eight levels, including no-application of modifier compounds as control, biochar, AMF, silicon foliar application, biochar + AMF, biochar + silicon, AMF + silicon and biochar + AMF + silicon. The measured traits included the concentration of sodium and potassium, activity of alpha and beta amylase enzymes, and seed germination and seedling growth indices. Statistical analyzes including analysis of variance and comparison of means were performed with Duncan's multiple range test at the 5% probability level using SAS software ver. 9.1. Research findingsThe results of this experiment showed that sodium concentration of seedling in cultivar 704 was reduced by 31% in the combined treatment of biochar + mycorrhizal fungus + silicon foliar application compared to the control treatment. The use of soil modifier treatments alone and in combination caused a decrease in the ratio of sodium to potassium, electrical conductivity of seeds as well as an increase in potassium concentration. An increase of 57% and 25% of alpha and beta amylase enzymes was observed in the combined treatment of biochar + mycorrhizal fungus + silicon foliar application compared to the control treatment. Also, application of soil modifier resources alone at a lower level could cause a significant increase in germination percentage. Seedling dry weight in the combined treatment of biochar + mycorrhizal fungus + silicon foliar application showed an increase of 15% and 10% in varieties 604 and 370, respectively. On the other hand, the highest seed germination and 1000-grain weight in the studied corn varieties were also observed in the combined treatments of biochar + mycorrhizal fungus + silicon foliar application. ConclusionIn total, the results of this experiment showed the positive effect of soil modifier sources in improving of germination characteristics and seedling growth indices of corn varieties. Based on these results, the combined application of biochar + mycorrhizal fungus + silicon foliar application is recommended to improve the quality of seed production in corn varieties under salt stress conditions.

Drought stress can have many effects on the agronomic and physiological characteristics of plants. Corn is used in human and animal nutrition. It has 60-72% starch and 8-11% protein (Darrah et al., 2019). The high water requirement of corn is one of the most important effective factors in preventing the development of its cultivated area. Therefore, It is very important to introduce new corn hybrids that tolerate drought (Corcoles et al., 2019: Rudnick et al., 2017). Selenium is an essential and rare element, which has many effects on human health and physiological characteristics of plants (Rayman, 2017). The research results have shown that the use of selenium fertilizers is a suitable solution to increase the tolerance of plants to environmental stresses such as drought stress. This research was conducted to investigate the effect of selenium spraying on the electrical conductivity of cell sap in corn cultivars under drought stress conditions.

This experiment was conducted in 2011 in the twice split-plot arrangement of treatment in a randomized complete block design with three replications in a training-research farm. Payam Noor University of Central Province (Arak city) was implemented. Drought stress (I0= Control irrigation, I1= Irrigation about 80% plant requirement water, I2= Irrigation about 60% of plant requirement water, were assigned in the main plots, maize cultivars (V1= KSC 500, V2= KSC 520, V3= KSC 700) in sub plots and foliar treatment of selenium in two levels (Se0= Control, Se1= 20 g ha-1) in sub-sub plots. In this study characteristics such as: ear height, panicule length, number of ear m-2, stem height, forage yield and un-stability of cell membrane were assessed.

The results showed that the effect of water stress treatment on the traits of stem height (5%), forage yield and cell membrane instability (1%) was significant. Also, the difference of maize cultivars was significant in terms of the number of ear m-2, forage yield and cell membrane instability. The highest and lowest values of cell membrane instability with an average of 1759 and 1456 µs cm-1, respectively, belonged to the irrigation treatment based on 60% of the water requirement of the plant and the control irrigation treatment. Among the maize cultivars, the highest and lowest values of cell membrane instability with an average of 1675 and 1587 µs cm-1, belonged to KSC 700 and KSC 500, respectively. Selenium consumption had a positive effect on reducing the amount of cell membrane instability, so that the average cell membrane instability in the treatment without selenium consumption decreased from 1687 to 1601 µs cm-1, in the treatment with selenium consumption.

The results of this research showed that by changing the irrigation regime from normal conditions to irrigation based on 60% of water requirement of maize, forage yield decreased by 23.35%. The response of maize cultivars was also different in terms of forage yield, so that cultivar KSC 700 was superior to the other two cultivars. The use of 20 (g ha-1 of selenium) increased the forage yield by 64.4%.

Guar (Cyamopsis tetragonoloba L.) is an annual, dicotyledonous plant of the legume family, also known as cluster beans. This plant can tolerate salinity and drought stress well. Optimal planting date and plant density are factors affecting the quality and quantity of crops. The distribution of plants in the field influences the absorption and productivity of environmental factors affecting the growth and intra- and inter- competition and eventually is one of the factors determining the quantity and quality of yield. Different planting dates set off different conditions in terms of temperature day length, relative humidity, solar radiation, ripening and harvest time and thus, affect the quantitative and qualitative characteristics of seeds. The purpose of this experiment is to evaluate the quality and also to evaluate some of the germination characteristics of Guar seeds at different dates and planting densities under the climatic conditions of Guilan.

This experiment was conducted in the spring and summer of 2017 in the research farm of Rasht Rice Research Institute located in Gil Pardehsar village at Sangar as a factorial based on a randomized complete block design with three replications. Experimental treatments included four planting dates (12 May, 26 May, 9 June and 23 June) and three plant densities (20, 40 and 60 plants. m-2). Seed harvesting was done as the pods in 75% of the plants in each plot turned brown and traits such as germination percentage, germination rate, root and shoot length and fresh and dry weight of roots and shoots, longitudinal index of seedling vigor, 1000- grain weight, electrical conductivity and alpha-amylase activity were investigated.

The results of the present study showed that guar seeds had the highest quality on 26 May and a density of 40 plants.m-2. Due to favorable climatic conditions during the period of seed filling, germination rate, germination percentage, seedling vigor index, root length and 1000- grain weight was high on 26 May. The amount of these traits decreased with delay in planting. The amount of electrical conductivity in 23 June date of planting treatment showed the highest value. The highest level of alpha-amylase activity was observed on 9 June.

In general, it can be concluded that the best planting date and plant density of guar seeds in Guilan province with the highest quality of seeds and germination is on 26 May and 40 plants.m-2.

Pulses are among the best sources of plant protein and important components of crop rotation, which in recent years, have been considered one of the major options for plant research. Seed storage is one of the important traits in legume breeding. Storage temperature, seed moisture content, and storage duration are the most important factors affecting seed quality during storage. Inappropriate storage conditions lead to deterioration and reduction of seed quality during storage, which is severely affected by the environmental conditions of storage.

This research was conducted at the Seed Technology Laboratory, Faculty of Agriculture, Yasouj University in 2014 as a three-way factorial based on the completely randomized design with 5 replications of 20 seeds. Seeds with moisture content at 5 levels (6, 10, 14, 18, and 22%) and storage temperature at 4 levels (15, 25, 35 and 45 °C) were stored for 9 months (0, 30, 60, 90, 120, 150, 180, 210, 240 and 270 days). After sampling at the end of each month, a standard seed germination test was done using the pleated paper method in a germinator at 25 °C for 10 days. Also, an electrical conductivity test of the electrolytes leaked from the seeds incubated for 24h in water at 20 ˚C was done with 4 replicates. Some germination attributes and electrical conductivity of the electrolytes leaked from the seeds were measured according to standard methods.

According to the results, interaction effects of storage temperature, seed moisture content, and storage duration on germination indices and electrical conductivity of bean seeds were significant (P<0.1). The germination trend during storage at 15 °C and seed moisture content of 6% decreased from 94% to 81% after 270 days of storage, so that germination decreased to 35% under similar moisture content after 270 days of storage as temperature increased from 15 to 45 °C. As the storage time passed, electrical conductivity increased and this increase was more pronounced at higher temperatures. Viability constants were calculated 9 months after storage using the seed viability equation, in which KE, CH, CW, and CQ were calculated -5.39697, 0.03201, 2.13041, and 0.000017, respectively.

The results showed that the electrical conductivity of the leaked material increased with increasing storage temperature and seed moisture content, which led to lower viability of seeds. At 15 °C and 6% seed moisture content provided better conditions for seed survival during the 9-month storage time compared with all other temperatures and moistures and had the lowest rate of deterioration. The results showed that with increasing seed temperature and moisture so that they had to lowest electrical conductivity of the leaked material from seeds and deterioration rate.

Drought is the most severe abiotic stress factor limiting plant growth and crop production. Drought stress decreases the yield of many crops by inhibits plant photosynthesis and photosystem II efficiency. Mycorrhiza application is a strategy that can improve plant performance under stress environments and, consequently enhance plant growth through different mechanisms. The mechanisms used by mycorrhiza to enhance the water relations of host plants are not amply clear, however, this may occur by increasing water absorption by external hyphae, regulation of stomatal apparatus, increase in activity of antioxidant enzymes and absorption of nutrients particularly phosphorus. Also, vermicompost can directly increase plant production through increasing available plant nutrients and indirectly promote soil quality by improving soil structure and stimulating microbial activities, relative to conventional chemical fertilization. Silicon is an essential micronutrient for biological systems and plays a crucial physiological role in photosynthetic rate and chlorophyll content. Therefore, the aim of this study was to evaluate the effects of mycorrhiza, vermicompost and silicon on some physiological and agronomic traits of triticale under different intensities drought stress.

an experiment as factorial was conducted based on randomized complete block design with three replications in a research greenhouse of faculty of Agriculture and Natural Resources, University of Mohaghegh Ardabil during 2020. The experimental factors were included irrigation in three levels (normal irrigation as control; moderate water limitation or irrigation withholding at 50% of heading stage; severe water limitation or irrigation withholding at 50% of poddind stage), application of organic and bio fertilizers (no application of bio fertilizers as control, application of vermicompost, Mycorrhiza application, both application vermicompost and Mycorrhiza), foliar application of Nano Silicon (foliar application with water as control and foliar application of 2 g.L-1).

The results showed that 81 days after planting, both application of vermicompost with Mycorrhiza and nano silicon foliar application under normal irrigation conditions, increased maximum fluorescence (43.93%), variable fluorescence (97.41%), quantum yield (37.05%), chlorophyll index (60.62%), nitrogen index (42.75%) and relative water content of flag leaf (84.27%) in comparison with no application of organic and bio fertilizers and nano silicon under irrigation withholding in podding stage. no application of organic and bio fertilizers and nano silicon under full irrigation increased electrical conductivity and minimum fluorescence of flag leaf. Also, both application of vermicompost with Mycorrhiza and nano silicon foliar application under normal irrigation conditions, increased grain yield (59.52%) in comparison with no application of organic and bio fertilizers and nano silicon under irrigation withholding in podding stage.

It seems that the application of organic and bio fertilizers and nano silicon can increase the grain yield of triticale under water limitation due to improve chlorophyll fluorescence and some physiological traits.

An appropriate planting date of the mother plant can improve the germination and growth of the seeds resultant from these plants. This experiment was conducted as a split-plot design with three replicates during 2016-2017 and 2017-2018. The main factors included three planting dates (October 11, November 10, and December 10 as the early, usual, and delayed). The secondary factors were wheat cultivars (Zare and Heidari with winter growth habit, Pishgam and Alvand with the mid-growth habit, and Pishtaz and Sirvan with spring growth habit). The results of the standard germination test related to the seeds resulting from this research indicated that the highest thousand kernel weight and alpha-amylase activity with winter growth habit were obtained on October 11 planting date. On the other hand, the delay in sowing due to the increase in electrical conductivity reduced the germination rate and percentage, especially in the cultivars with winter growth type. It seems that the activity of enzymes involved in seed germination, including the activity of the alpha-amylase enzyme, could be affected by delays in planting in winter cultivars through increasing the electrical conductivity. Winter cold on the planting date of October 11 in the cultivars with spring growth type caused the production of weaker seedlings. However, the dry weight of seedlings in cultivars with spring and intermediate growth type was greater than the winter cultivars on December 10. In general, the delayed planting significantly reduced germination rate and percentage, especially in cultivars with winter growth habits. Therefore, it is recommended to use intermediate and spring cultivars in delayed cultivation.

In order to study the effects of accelerated aging on quantitative and qualitative characteristics germination of Malva neglecta, Portulaca oleracea and Amaranthus retroflexus experiments a completely randomized factorial design were conducted in the research laboratory of the college of agriculture, University of Tarbiat Modarres during 2018. Treatments were accelerated aging, respectively, at five levels (0, 24, 48, 72 and 96 hours Placing seeds in an environment with a relative humidity of 100% and a temperature of 45 degrees Celsius) Were considered as the first factor and weed species as the second factor. The results showed that all traits were influenced by the interaction of factors. In optimum conditions (without accelerated aging) Portulaca oleracea and Amaranthus retroflexus highest percentage germination and seedling emergence. But, the results about the antioxidant enzyme activity and protein concentration was different in three weed species, so that the highest catalase activity was obtained in the Malva neglecta and Amaranthus retroflexus under 24 hours Seed aging treated and 72 and 96 hours seed aging treated on Portulaca oleracea. Overall the results of this study showed that, it was concluded that seed quality of weeds Species was seriously decreased under the aging conditions.

Increasing of soil temperature by using plastic mulch is a non-chemical method to control the weed. It has attracted a lot of attention in the last two decades. This study was conducted in the city Fasa in 2018. This study was done as a factorial experiment based on completely randomized design with two factors and three replications. The first factor was the kind of weed, that were Amaranthus retroflexus, Chenoodium album and Avena fatua , the second factor was the time period of plastic mulch, that were 4 levels of control, in which plastic mulch were 15, 30 and 45 days. The results showed that the percentage, germination speed and seed vigor will decrease with higher plastic mulch levels 45 days of plastic mulch caused a reduction of 23.53 percentage in germination speed comparing to the treatment which had control. The percentage, germination speed and seed vigor showed a positive and significant correlation with the activity of Alpha Amylase and a negative and significant correlation with electrical conduction of the seeds. 45 days of plastic mulch increased the period before the 50 percent level of germination and uniformity of germination increased 33.61 and 33.56 respectively comparing to the treatment control. Plastic mulch treatment for 45 days caused a 45.83 percentage decrease in the dry weight of the seedling comparing to the treatment control. On the other hand, a 45 day plastic mulch treatment caused a 33.16 percentage reduction in the activity of Alpha Amylase enzyme comparing to the treatment control. Electrical conduction of seeds showed a negative and significant correlation with the activity of Alpha Amylase enzyme. The result of this study showed that the negative effect of plastic mulch treatment was more on Avena fatua weeds.

In order to study the effect of bio-fertilizers and putrescine on biomass, nodulation, and some morphological and biochemical traits of vetch(vicia villosa)under rainfed conditions, a factorial experiment has been conducted based on randomized complete block design with three replications in research farm of University of Mohaghegh Ardabili within 2018-2019. The studied factors include bio-fertilizers(withoutbio-fertilizersas control, application of Rhizobium  (Rhizobium legominuzarum), Mycorrhiza (Glomus mosseae), both application of Mycorrhiza and Rhizobium, Rhizobium and Azotobacter (Azotobacter chrocoocom strain 5), Mycorrhiza and Azotobacter, Rhizobium with Mycorrhiza,and Azotobacter) as well as foliar application of putrescine in three levels (foliar application with water as the control, application of 0.5 and 1 mM putrescine). Results show that both application of Azotobacter with Mycorrhiza and Rhizobium and foliar application of 1 mM putrescine increase root weight, leaf share from total biomass, soluble sugars of leaf and stem, and total biomass by 133.33%, 4.5%, 31.94%, 41.82%, and 56.94%, respectively, in comparison with no application of bio-fertilizers and putrescine. Also, application of Azotobacter with Mycorrhiza and Rhizobium and foliar application of 1 mM putrescine decrease electrical conductivity and malondialdehyde by 99% and 125.39%, respectively, in comparison with no application of bio-fertilizers and putrescine. It seems that application of bio-fertilizers and foliar application of putrescine can boost total biomass of vica villosa under rainfed condition as it improves both biochemical and morphological traits.

To investigate the effect of integrated nitrogen fertilizers (manure and urea) resources and mycorrhiza under water deficit stress on soil chemical properties and biological yield of Purslane, an experiment was conducted in Qom during 2015-2016 growing seasons. Treatments were arranged as a factorial split plot in a randomized complete block design with three replications. A factorial combination of two levels of irrigation (Irrigation at 50% and 70% of available water) and two treatments of mycorrhizal (inoculated and non-inoculated) were assigned as the main plots. The subplots consisted of six different sole and integrated combinations of fertilizers consisting of manure (sheep and chicken) and urea fertilizer (control, without fertilizers, 100% manure, 75% manure+25% urea, 50% manure+50% urea, 25% manure + 75% urea, and 100% urea). Results showed that water deficit stress increased oil content and decreased the electrical conductivity, total nitrogen, phosphorous, potassium of soil, mycorrhiza colonization (30.3% and 15.3 %( and biological yield (21.3% and 17.7 %( of purslane in first and second year, respectively. Also, manure in combination with urea fertilizer and mycorrhiza increased the biological yield (50% Manure+50% urea) and oil content (25% Manure+75% urea) in purslane leaf and reduced the consumption of urea fertilizer by modifying the negative effects of water deficit stress and increasing the availability of nutrients. Decomposition of halophyte purslane plant residues in soil increased the electrical conductivity and potassium content of the soil. Due to the key role of potassium in fertility and osmotic regulation of soil, it could produce acceptable biological yield in water stress conditions.

This research conducted in order to study on effect of seed moisture content and storage duration on some germination and vigor traits of 3 wheat cultivars at Mazandaran province as split split plot based on complete randomized design by 4 replications. Treatment were Morvarid, Milan and N8019 cultivars seeds which by 10, 12, 14 and 16 percent seed moisture content harvested and for 2, 3 and 4 month after harvest stored. By standard germination test, final germination and normal seedlings percent, mean germination time, seedling length and dry weight and seedling length and weight vigor indices (respectively seedling dry weight and length multiplication in final germination percent) determined and electro conductivity measured. Results revealed that, harvested seeds at 10 percent moisture content stored for 2 month, Milan and N8019 cultivars seeds stored for 4 month and Milan cultivar seeds harvested at 12 percent moisture content had the most final germination percent, 98 percent. Morvarid and Milan cultivars seeds harvested at 10 percent moisture content and stored 2 month and N8019 cultivar seeds harvested at 12 percent moisture content and stored 2 month had the most normal seedlings percent, 98 percent. The lowest mean germination time, 1.210 day, belonged to Milan cultivar seeds harvested at 10 percent moisture content and 2 month stored. Based on this research results, optimum seed moisture content at harvest for Morvarid cultivar was 10 percent and for Milan and N8019 were 12 percent and suitable seed storage duration was 3 months for Morvarid cultivar and for Milan and N8019 were 2 months.

Winter cold is a significant damaging factor in fruit trees specially stone fruits. Relative resistance of 20 local and introduced sweet cherries (Prunus avium) to winter cold in artificial cold condition and its association with electrical conductivity and a number of morphological traits including trunk diameter, shoot diameter, anthocyanine and lenticels frequencies was studied in year 2011. In February, dormant shoots and buds were collected and treated in a freezer with temperatures decreasing from 4 OC to -24 OC and increasing from -24 OC to 4 OC. Then, cold damage was determined based on percentage of discoloration from green to brown. Results showed variability of shoot and bud cold tolerance among different genotypes/cultivars. Cold damage to buds was higher than shoots and they showed significantly positive correlation. In both organs, Albaloogilas Daneshkadeh was rated as the most resistant and Meshkinshahr as the most susceptible genotypes. According to the observed responses to the low temperature treatment, the germplasm was divided in three relative susceptibility groups including highly susceptible (10%), relatively susceptible (15%) and relatively resistant (75%) and no genotype was completely resistant. Accordingly, it is concluded that most genotypes/cultivars studied were relatively tolerant to winter cold. A correlation existed between cold damage and shoot diameter, indicating that this species is more cold-susceptible at the seedling stage. Considering low correlation between cold damage and lenticel numbers/anthocyanin pigment intensity, these traits are not appropriate criteria for winter cold tolerance selection in cherry.

Commercial production of seed potato tuber by means of traditional and conventional methods resulted in the spread of bacterial and fungal disease. In contrast, high cost of nutritional supply is one of the problems in the some methods such as aeroponic. Hence in order to study seed tuber potato production in aeroponic condition using substances with natural origim, an experiment was conducted with eight treatments as completely randomized design with three replications. The treatments were 1- Otazo nutritional solution, 2 and 3- Tea vermicompost solution with 1:5 and 1:10 ratio, 4- Vermi wash solution, 5 and 6- Liquid poultry manure with 2 and 6:1000 ratio, 7 and 8- Mixed solution as mixed of cow manure with fruits and plants waste with 2 and 6:1000 ratio. Among the tested organic nutritional solutions, the vemi wash and tea vermicompost be able to substitute for Otazo chemical solution due to their satisfactory function. Whereas nutritional elements absorbtion was interrupted in pH of higher than 7.3 and EC over than 2 dS/m, therefore, the most important reason for low yield in liquid poultry manure and mixed solutions were their pH (7.9 and 7.6 respectively) and EC about 3. According to the role of phosphorous in carbohydrates transfer from leaves to tubers, the more tuber yield can attributed to more phosphorous contents in vermi wash and tea vermicompost solutions compared with liquid poultry manure and mixed solutions.

In order to investigation effect of different irrigation regimes on seed germination characters in some of promising rapeseed lines, two separate split plot experimental based on CRD and RCBD design at laboratory and environmental condition, respectively, during 2015-16 cropping seasons were performed. At each experiment, different levels of irrigation––control, cut-off irrigation at the flowering stage, and cut-off irrigation at the pod formation stage––and 18 promising lines were considered as main and sub-plots, respectively. Results of analysis of variance obtained from laboratory showed that cultivar and irrigation regimes effects were significant on all of the measured characters. However, at environmental condition, only irrigation regimes, line, and their interaction effects were significant. Correlation coefficients among different characters indicated that, germination percentage under laboratory significantly correlated with final emergence percentage and final mean emerging, while correlation among electrical conductivity with some of characters such as germination percentage, daily germination and seedling dry weight was negative. Overall, our findings revealed that KS7 has desirable status than other lines. Hence, the use of this promising line for future experiments and assessing its grain yield and other related traits is recommended.

Tomato is one of the most important vegetable in Iran, not only because of its economics importance, but also for the nutritional value of its fruit, mainly due to the fact that they are an excellent source of natural colors and antioxidant compounds. Water quality and fruit maturity stage has a significant effect on tomato fruit quality. In the present research, we studied the response of tomato grown at different salinity levels, as well as the changes that take place during different maturity stages, in order to improve the management and harvesting of tomato and obtain fruit of a higher nutritional value. In this study, to evaluate the effect ofsalinity and fruit ripening stage on physical, biochemical properties and shelf life of tomato fruits in hydroponics system, an experiment was carried out as factorial based on randomized complete block design with three replications at Moghan College of Agriculture and Natural Resources, during 2015. Fruits from plants grown under three saline treatments (2, 4 and 8 dS m-1) were harvested at three ripening states (mature green, purple and red colors). The nutrient solution was prepared based on full strength of Hoagland's solution containing: 5.6 mM Ca (NO3)2, 4 mM KNO3, 1 mM KH2PO4. Characteristics such as fruit fresh and dry weight, total soluble solid, firmness, flavor index, titratable acidity, soluble protein, ascorbate peroxidase activity and shelf life were measured. The results showed that total soluble solids, juice electrical conductivity and dry matter percentage of fruits significantly increased with increasing salinity in the nutrient solution and progressed the ripening stage, but fruit water content decreased by 9%. The highest weight (147.7 g) and volume of fruits (153 cm3) were obtained in plants grown under 2 dS m-1 salinity and fruits harvested at the purple stage. Titratable acidity increased with increasing of salinity in the nutrient solution, but its content decreased at the red color stage. Firm fruit with greater shelf life was observed under 2 dS m-1 salinity and at the mature green stage. Soluble protein content in fruit was increased by increasing salinity levels in the nutrient solution, especially at the ripening stage. The application of 4 dS m-1 salinity at mature green stage increased ascorbate peroxidase activity up to 62.5% compared to 8 dS m-1 salinity and red color fruits. These results suggest that the improvement in fruit quality induced by the salinity is achieved by some biochemical changes and the reduction of fruit water content. Increasing of salinity in the nutrient solution can be useful for improving fruit quality, especially, when fruit is harvested at the red stage. However, with increasing salinity in the nutrient solution up to 4 dS m-1 and fruit harvest in the red color stage fruits with better quality and more suitable weight can be produced.

In tolerance to coldness researches, scholars are looking for exams which in addition to having easiness, velocity and enough validity, be repetitive as well and mean while the feasibility of controlling the thermal conditions be in it. Using different kinds of freezing exams in controlled and artificial conditions have been suggested. Hence, damage evaluation via measuring the electrolyte leakage and determining the Lethal Temperature 50 According to the Electrolyte Leakage percentage (LT50el) is considered as a suitable and direct method for evaluating the amount of coldness damages by the researchers.
In order to evaluate freezing tolerance of fenugreek a factorial experiment in 2013-2014 year based on completely randomized design with three replications was conducted under controlled conditions in faculty of agriculture, Ferdowsi University of Mashhad. The investigated factors include sowing date in four levels (September 13, October 14, March 5, and April 3), ecotype in 10 levels (Azari, Ardestan, Long foot, Short foot, Shiraz, Shirvan, Mashhad, Neyshabur, Hamedan and Hendi) and freezing temperature in seven levels (control, 0, -3, -6, -9, -12, -15 0C). The potted plants grew and cold acclimation in outside conditions then the plants which were implanted in September and October, and the plants which were implanted in March and April , were transferred to the freezer thermo gradient to apply the cold temperature in the middle of December and in the middle of May respectively. After freezing, Percentage Electrolyte leakage (%EL) and Lethal Temperature 50 According to the Electrolyte Leakage percentage (LT50el) was determined. Survival percentage of them after freezing and 28 days growth was measured in the greenhouse.
Although in the all sowing dates the electrolyte leakage was constant up to the temperature of -6 0C and by more reduction in temperature, it had an increasing trend, but the leakage increase velocity in the sowing dates in the first decade of March war more than other dates. As in this sowing date by reducing the temperature from zero to -15 0C, the percentages of electrolyte leakage increased about 71 percent. In some ecotypes such as Shiraz and Hamedan by causing delay in sowing date from July to April the percentage of electrolyte leakage was increased. Although the electrolyte leakage percentage in all ecotypes in the second sowing date of fall and spring was reduced in compare to the first sowing date, the lowest and the highest reduction resulted from delay in sowing date belonged to Hamedan and Ardestan respectively. Although by temperature reduction the percentage of electrolyte leakage was increased in the all ecotypes, but this increase was more intense in the Hendi ecotype than other ones. In this ecotype by reducing the temperature from zero to -15 0C, the electrolyte leakage percentage increased 73 percent whereas in Neyshabur ecotype this increase was 53 percent. The percentage of electrolyte leakage from the Trigonella foenum-graecum ecotypes in each sowing date increased by temperature reduction. In the majority of ecotypes this increasing trend was witnessed from the -6 0C. In the all ecotypes, the October 14 sowing date in the majority of the studied temperatures had lower leakage percentage than other sowing date. According to the LT50el index, the sowing date of the first decade of October in ecotypes was lower in compare to other dates. In other words, earlier sowing date of ecotypes probably leads to increase in plants sensitivity to coldness. The highest and lowest tolerance to freezing, according to this index, belonged to Neyshabur and Azeri ecotypes respectively. Between Lethal Temperature 50 According to the Electrolyte Leakage percentage (LT50el) and survival (r=-0.536*) negative and significant correlation was witnessed which indicates that using this index in evaluating the damage of freezing tolerance in Trigonella foenum-graecum is possible.
Generally in this study in all of the ecotypes, reducing the temperature led to increase in the percentage of electrolyte leakage. This leakage increase slope in the majority of ecotypes began from -6 0C and in -15 0C was maximized. Delay in autumnal and spring sowing dates by affecting the plant growth stage cause increase in plants tolerance to freezing. In other words, the plants which were in advanced vegetative level in the exerting time of freezing temperatures had lower tolerance to freezing. Among the studied ecotypes, however, the Neyshabur and Azeri ecotypes had the highest and the lowest tolerance to freezing respectively considering the leakage amount and LT50el. Therefore, it seems that the sowing date of October is suitable for sowing Neyshabur, Mashhad, Shirvan and Short foot ecotypes which had lower leakage percentage and more suitable LT50el in compare with other ecotypes. However, more researches in evaluating the plant’s tolerance to freezing in real winter conditions and determining correlation relationships between the results in controlled situations and farm will be useful.

Seed deterioration is a natural phenomenon that occurs in all seeds and leads to gradual decline of seed viability during storage. However, the rate of seeds age depends upon their physiological status, genetic constitution and storage conditions. The lipid peroxidation through the production of free radical plays an important role in the loss of seed viability during seed storage.
Material and In order to investigate the effect of deterioration on germination indices and enzymes activity of the flax oil seed, a factorial experiment was conducted based on a Completely Randomized Design with four replications in the seed laboratory of Yasouj University in 2015. The factors included 4 levels of temperature (15, 25, 35 and 45oC) and moisture content (5, 9, 13 and 17%). With relation intended seed moisture, Hampton and Teckrony (1995) was calculated. After determining the moisture content of the seeds in envelopes of aluminum foil was placed, then the amount of water the need added and to ensure that the packaging and moisture exchange with the outside world for 24 hours at 15 °C were identical to the seed moisture and then for 6 months in storage conditions at temperatures of 15, 25, 35 and 45oC were kept.
Analysis of variance showed that the single effects including temperature and seed moisture content experimental treatments for traits including germination percentage, germination rate, seedling vigor index (weight), activity enzymes antioxidant catalase, superoxide dismutase and ascorbate peroxidase, soluble proteins, electrical conductivity and oil percentage were significant (P≤0.01). Also, the interaction temperature and seed moisture content of all treatments except for enzyme, activity of superoxide dismutase and ascorbate peroxidase were significant (P≤0.01) but were significant (P≤0.05) for the activity of superoxide dismutase and ascorbate peroxidase. The results showed that with increasing temperature and moisture content, all the physiological and biochemical traits, except for electrical conductivity, decreased. The decrease in germination was also associated with a decrease in the activity of antioxidant catalase, superoxide dismutase and ascorbate peroxidase and as a result the antioxidant system was not sufficient to protect seeds against free radical damage. With the increase in reactive oxygen species, lipids peroxidation increased, probably due to the destruction of cell membranes, increased electrical conductivity seed the negative correlation between the electrical conductivity and the activity of the enzymes antioxidant indicator of the issue.
Thus, oil flax seed deterioration was closely related to decrease in the activities of free radical detoxifying enzymes and increased lipid peroxidation. In general, the best flax seed storage condition is at 15°C and 5 percent moisture content.