نشریه علوم و تحقیقات بذر ایران
سال هشتم شماره 2 (تابستان 1400)

This experiment was conducted to evaluation of warehouse temperature effects on two cultivars of onion (Alba and Texas early grano؟) with different initial standard germination. In these, study three levels of initial standard germination including 1- 70-75% 2- 80-85% and 3- 90-95% of two onion cultivars including: Alba (long day) and Texas early grano؟ (short day) were selected. Seeds stored in tow conditions including  5 ºc and 60% relative humidity  and 25 ºc and 30% relative humidity. The study carried out as a factorial experiment based on a completely randomized design in four replications.  After storage period, germination %, normal seedling%, mean time to germination (MTG), rate and percentage of emergence seedlings catalase and peroxidase activities were measured. Factors were initial standard germination levels in three levels, warehouse temperatures in two levels and cultivars in two levels. Results showed that interaction of temperature  initial standard germination  cultivar had significant effect on germination, MTG, percentage and rate of seedling emergence. In addition, interaction of initial standard germination  cultivar and interaction of temperature  initial standard germination on normal seedling were significant. Mean comparisons showed that germination percentage of Texas early grano Cultivar with 90-95% initial standard germination when stored at 5 ºc warehouse temperature was higher than 25 ºc warehouse temperature significantly. Generally, in all three levels germination, normal seedling percentage was decreased with increasing of warehouse temperature. The highest MTG belonged to Texas early grano in both warehouse temperatures (5 and 25 º c) with 70-75%, initial standard germination. The lowest one belonged to Alba cultivar with 90-95% initial standard germination and Texas early grano with 80-85% initial standard germination when stored at 5ºc. In Texas early grano, seeds with 90-95% initial standard germination and 5ºc temperature warehouse had higher establishment than 25 ºc. Based on the results, storage conditions can affect germination and seedling emergence by affecting enzymatic activity.

Seed-borne fungi can reduce reduce the quality and quantity of crop by affecting seed health.  The aim of this study were to evaluate the germination and vigor indices of native fennel seed populations, isolate and identify the seed-borne fungi and then pathogenicity, aggressiveness, and activity of cell wall degrading enzymes (CWDEs) produced by these isolates were investigated. In order to identify of seed-borne fungi of fennel seed populations from some fields in provinces of Golestan, Zanjan, Kurdistan and Hamedan were sampled according to the International Rules for Seed Testing (ISTA). After isolation and purification, fungal isolates were identified based on morphological and molecular characteristics. Then the enzyme activity of cellulase, xylanase, pectinase and lipase as the main virulence factors secreted by isolates were evaluated. Also, pathogenicity potential and the aggressiveness of isolates were evaluated by pathogenicity test on seedlings. A total of 33 isolates were identified based on morphological and molecular characteristics that belonging to species, Alternaria alternate and Fusarium oxysporum. The results of the standard germination test showed that there was a significant difference among the native seed populations studied in the germination and vigor indices. Seed infected by seed-borne fungi significantly affects germination and vigor indices and reduces seed quality. The results showed that the lowest in the germination and vigor indices were observed by the seed population of Golestan, followed by the seed populations of Hamedan, Zanjan and Kurdistan. The results of pathogenicity test showed that about 85% of the isolates were pathogenic and weakly pathogenic and 15% were non-pathogenic isolates. Also, different levels of pathogenicity and aggressiveness were observed for various isolates of Alternaria and Fusarium species. Analyzing the activity of CWDEs produced by isolates revealed that cellulase and xylanase activities were more than important than pectinase and lipase activities for the pathogenicity of isolates and enzyme activities affects levels of pathogenicity and aggressiveness of isolates. Therefore, these findings suggested that activity levels of cellulase and xylanase are correlated with variation in pathogenicity and aggressiveness of seed-borne fungal isolates on seeding. This is the first report on identify the seed-borne fungi of Iranian native fennel seed populations, together with the investigation of the relationship among the levels of pathogenicity, aggressiveness and the activity of CWDEs produced by isolates.

In order to investigate the genetic variation of seed physiological development in 14 ecotypes of Iranian cumin and one Indian genotype, an experiment was conducted in a completely randomized block design with four replications in the research farm of callege of Aburaihan, University of Tehran. Results analysis of variance showed that ecotypes had significant difference at 5% probability level for characteristics of wet and dry weight of seed at before harvest time and harvest time, seed moisture content before harvest time, maximum germination percentage and rate to 10% of germination, that it indicates the diversity among the 15 ecotypes for these characteristics. Ecotypes did not have significantly different at the 5% level for seed length and embryo size, also the ratio of embryo length to seed length. Factors investigated for germination test included 15 ecotypes and temperatures at three levels (10, 15 and 20 °C). The effect of temperature on germination percentage and rate to 10, 30 and 50% of germination was significant at 5% level and the most percentage and the rate of germination of ecotypes occurred at temperature of 15 °C. Also, the interaction between temperature and ecotype was not significant at 5% level. Among the ecotypes, the "Kooh-banan" ecotype had the highest value for most of the studied characteristics. Therefore, this ecotype is recognized as the best ecotype for characteristics related to germination and it can be used in breeding and farming programs. "Chat" and "Hydarabad" ecotypes had the lowest values for most characteristics.

Global warming and climate change are very important issues of the last century, which have been considered by scientists in various fields of science. The Hyrcanian forest is one of the oldest and most historic habitats of the world's deciduous trees. Beech trees are one of the valuable industrial species with a lifespan of 200 to 300 years. The science of tree chronology can show past weather events. The diameter of the annual growth rings of the trees forms a time series. With this method, a time series of 202 (1816-2017) years was obtained from the diameter of the growth rings of beech trees.Researchers are always thinking about the future. This study uses time series of growth rings of forest beech trees and analyzes it.And the use of modeling based on the Box-Jenkins method with emphasis on ARIMA models were examined. The results showed, Time series with ARIMA model (1,1,1) had the best fit, at the 95% level, it is significant and the trend forecast has a negative and decreasing slope. Climatic factor of annual precipitation in the regional station and neighboring stations with a decreasing and negative trend The average minimum, middle and maximum average temperatures are increasing. Climate change is reducing growth for Hyrcanian forest trees. It was registered as the second natural heritage of Iran in UNESCO. It will pose a threat to plant and animal communities.

Arctium lappa is an important medical plant with seed dormancy problem. A study was carried out to investigate the effects of seed dormancy breaking treatments on Arctium lappa germination. Treatments were arranged in a completely randomized design (CRD) with five replication. The highest germination percentage was recorded in seeds treated with GA3 (500 ppm) +  H2SO4 75% (86%), GA3 (500 ppm) + hot water 70 0C (87%) and GA3 (500 ppm) + hot water 90 0C (84%). Seed scarification with hot water were better than H2SO4 because H2SO4  increased  abnormal seedling percentage. Highest abnormal seedling showed in H2SO4 75%, GA3 (500 ppm) + H2SO4 75% and KNO3 (1%) +  H2SO4 75 % treatments (11.7%, 11.3% and 10.9% respectively). Seed treatment with KNO3 and GA3 increas α- amylase activity and Auxin concentration in Arctium lappa seedlings and decreased Abscisic Acid content in seedlings. The maximum seedling vigor index obtaines in seeds treated with GA3 (500 ppm) + hot water 70 0C . Results indicated Arctium lappa seeds scarification with hot water 70 0C (10 min) followed by socking in GA3 (500 ppm) for 12 hour was most effective treatment for seed dormancy breaking and improved seedling growth.

To evaluate the effect of sodium nitroprusside on some physiological and germination indices of black cumin (Nigella sativa) under salinity stress, an experiment was conducted in a factorial arrangement based on completely randomized design with three replications at research laboratory of Agricultural Faculty, Shahid Bahonar University of Kerman. Treatments included sodium nitroprusside at three levels (0, 50 and 100 μmol) as the first factor and three levels of salinity stress (0, 50 and 100 mmol) as the second factor. The results showed that increasing salinity stress caused the reduction of all traits of germination index (germination percentage and rate, seed vigor index, root and shoot length, fresh and dry weight of root, stem and seedling and leaf relative water content), while 100 μmol salinity level caused an increasing of 52.2% in proline content as compared to control. Application of sodium nitroprusside increased all traits (except proline, which had no significant effect on this trait). Seeds which were primed with 100 μmol sodium nitroprusside caused an increment of 54.2, 47.7, 63.6, 20.2 % in germination rate and percentage, seed vigor index and relative water content compared with non-treated seeds at the highest level of salinity stress, respectively. Finally, the application of this plant growth regulator in this experiment enhanced germination indices and relative water content of black cumin seedling.

Plant access to micronutrients helps to plant growth and the human need for these elements by eating vegetative food. In order to investigate the effects of foliar spraying of zinc sulfate (0, 2 and 4 g.l-1 of zinc sulfate), iron sulfate (0, 3 and 6 g.l-1 of iron sulfate) and seed osmopriming (control and polyethylene glycol 6000 (-2 bar)) an experiment was carried out in factorial based on a randomized complete block design with three replications at the research farm of Agricultural Sciences and Natural Resources University of Khuzestan (spring, 2017). The results showed that seed priming had a negative effect on most traits including seedling emergence percentage, seedling emergence rate (SER) and mean emergence time (MET). It was also observed that the highest grain yield, protein yield, and harvest index were obtained from triple interactions effects of non-priming × non-application of zinc sulfate × application of iron sulfate (3 g.l-1), no priming × non-application of zinc sulfate × non-application of iron sulfate, non-priming × non-application of zinc sulfate × application of iron sulfate (6 g.l-1) respectively. The general results showed that the application of iron and zinc in low concentrations can be somewhat improved bean plant growth traits. But seed priming had little effect on the growth traits of this plant.