جستجوی مقالات مرتبط با کلیدواژه « seed dormancy » در نشریات گروه « جنگلداری »

Caucasian whortleberry seed germination faces with problem due seed dormancy. This research was conducted to investigate stratification and gibberellic acid treatments on Caucasian whortleberry seed germination. For this purpose, Caucasian whortleberry ripe seeds were collected from the forest area of Fandoglo (Soha forest). For this purpose, ripe seeds of Caucasian whortleberry were collected from the forest area of Fandoglo (Soha forest) and then treated with stratification treatment (0, 1,2,3,4 and 5 month) at 4°C followed by gibberellic acid (0, 75 and 150 mg/l) for 24 hours. The germination test was performed through a factorial experiment with two factors of stratification and gibberellic acid Caucasian whortleberry seed germination faces with problem due seed dormancy. This research was conducted to investigate stratification and gibberellic acid treatments on Caucasian whortleberry seed germination. For this purpose, Caucasian whortleberry ripe seeds were collected from the forest area of Fandoglo (Soha forest). For this purpose, ripe seeds of Caucasian whortleberry were collected from the forest area of Fandoglo (Soha forest) and then treated with stratification treatment (0, 1,2,3,4 and 5 month) at 4°C followed by gibberellic acid (0, 75 and 150 mg/l) for 24 hours. The germination test was performed through a factorial experiment with two factors of stratification and gibberellic acid in completely randomized design with three replications in the seed laboratory of Ardabil Alaroq Agricultural and Natural Resources Research Station. The results showed

Information regarding germination and dormancy of Parrotia persica seeds is very limited and there are no reports on cardinal temperatures and type of dormancy of this tree species. Thus, the purpose of this study was to determination of type of dormancy and cardinal temperature of seeds of P. persica and to identify the best way(s) to overcome seed dormancy in P. persica. In order to investigate the dormancy in P. persica, a factorial experiment was conducted based on a completely randomized design with four replications at the seed technology laboratory of Aburaihan Campus, University of Tehran, Iran, during 2018. In order to investigate the effect of after-ripening on breaking dormancy and germination, seeds were treated with four different treatments (control or distilled water, 100 mg gibberellin, melatonin at 50 and 100 µM concentrations).  After collecting seeds, the germination test was carried out at different temperatures (5, 10, 20 and 30°C), and the percentage and seed germination rate were recorded until 26 days. The result of this experiment showed that, fresh seeds had conditional dormancy and germinated in a narrow range of temperature conditions. The lower and upper temperature limits for fresh seeds were 5 and 20°C, respectively. The application of after-ripening and gibberellic treatments resulted in increasing germination percentage and temperature range. Among treatments, after-ripened seeds and those treated with gibberellic had the highest germination percentage while control and 50 mg melatonin had the lowest.

Persian honey locust(Gleditsia caspica Desf.) is an endemic tree in the northern forests of Iran and southeastern Azerbaijan, which has low seed germination because of water impermeability of seed. In this research, effects of hot water at 70 °C and 100 °C (5, 10, 15 and 20 minutes), dry heat at 60 °C, 80 °C and 100°C (15, 30 and 60 minutes) and sulphuric acid treatment at two concentrations of 70% and 98% (at immersions of 5, 20, 40 and 60 minutes) were studied on the characteristics of seed germination of this species. Experiment was carried out based on completely randomized design in three replicates. No germination was observed in the seeds treated with hot water (100 °C), dry heat and control, while the seeds treated with semi-hot water (70 °C), sulphuric acids of 70% (60 minutes) and 98% (20 and 40 minutes) obtained 20, 84 and 100 percent of germination, respectively. In general, hot water, warm water and dry heat are not good treatments for seed germination of Persian honey locust seed. It suggests that for seed dormancy breaking as well as seedling production of Persian honey locust,sulfuric acid 98% (with immersion of 20 or 40 m.) to be used.

Wild pistachio seeds have a hard coat and deep physiological dormancy, which declines their germination success. In this study, the effect of seed priming with carbon nanotubes was studied on two species of wild pistachio (Pistacia atlantica and P. Khinjuk) and was then compared with common treatments. For this purpose, seeds of each species were primed for four hours in solutions containing 0, 10, 25, 50, 75 and 100 mg / L of carbon nanotubes. In addition, some of the seeds were also treated by the common acid concentrations (65%, 5 and 10 min) and cold treatments (4 °C for one month), followed by an analysis of their germination characteristics. According to the results, carbon nanotubes affected the germination characteristics of the both species. The highest germination rate of P. khinjuk occurred under 75 mg/l and for P. atlantica at 10 mg / l. for P. atlantica, whereas the lowest germination was observed in acid (5%) and control treatments. Although cold treatment showed higher germination (18.33%) compared to control and acid-treated seeds, it was less than carbon nanotube treatments. For P. khinjuk, the lowest germination was also observed for acid treatment (11.67%). The seed germination rate and percentage of both species at concentrations of 100 mg/L were lower than those at concentrations of 10 and 75 mg/l, thus the use of lower concentrations of the nanomaterial economically is recommended.

A comprehensive study on breaking dormancy of mountain ash(Sorbus luristanica Bornm.) endemic species is still lacking. Here, the high efficient potentials of multiwall carbon nanotubes were used to break seed dormancy and improve seed germination in mountain ash. First, the seeds were primed with different concentrations of the nano-material including 0, 75, 150, 250, 350 and 500 mg l-1 during 24 hours. Then warm (two weeks) and cold (three or four months) stratifications were performed. The results showed that the seeds require cold stratification for at least 3 months. After the cold stratification period, the seeds were transferred to petri dishes in germinator. Daily seed germinations were recorded during 22 days. Eventually seed germination parameters such as seed germination percent, germination speed as well as mean germination time were calculated and compared. To understand the effects of nano-materials on the seedlings from different treatments, the subsequent growth of seeds was studied. The results revealed that all germination parameters were improved by 350 mg l-1 treatment. The microscopic seed observations showed that the nano-priming treatments led to seed endocarp abrasion and increased oxygen and moisture infiltration into seeds. Increasing root height growth was associated with the most considerable effects of treatments. Conclusively, it seems that increase in seedling moisture is one of the functional mechanisms of the MWCNT.

Germination of hazelnut seed faces with problems due to hard pericarp and dormancy period. The present study aimed to overcome these problems and improve the germination traits. For this purpose, hazelnut riped seeds were collected from three areas in Makesh in Aqh-Evlar, Fandoglou, and Makidi in Arasbaran, northwestern Iran. The seeds with pericarp and without pericarp were cold stratified in moist sand and kept in the refrigerator (5 ±1 °C) for 3 and 4 months and then grown in room conditions (20-22 °C) in order to record the seed germination daily. The experiment was done based on factorial in a completely randomized design with three replicates of 20 seeds. The highest germination (51.66 %), germination speed (2.86 per day), germination evenness (4.28 per day), germination energy (45.33%), root length (11.55 cm), shoot length (10.35 cm) and seed vigor index (112.84) belonged to without pericarp seeds of Makesh exposed to four months cold stratification. The seeds with pericarp of the three ecotypes, stratified particularly at four months, indicated the satisfactory germination percentage (≈ 40%) and seed vigor index (≈ 70). Although, germination of seeds without pericarp had better ability, however, in case of using the seeds with pericarp for the propagation of hazelnut in the nursery or for seed direct sowing in the deforested areas, the seeds of cold stratified (if possible four months) are recommended.

This research aims at finding the best treatment for seed dormancy breaking, improvement of germination and vegetative characteristics of Acer monspessulanum sub turcomanicum. Seeds were collected from Siah Marz Kouh, 18 kilometers from south east of Gorgan city, Golestan province and were treated under cold stratification for 2, 4 and 6 months as well as gibberllic acid (250 and 500 ppm), fungicide (Dyphno Conazol) and pesticide (Imida Cloride). Germination characteristics including germination percent, germination capacity, germination energy, germination value, germination speed, vigor index and vegetative characteristics including root length, shoot length and plant biomass were also measured. Results showed that the seeds need six-month stratification for seed dormancy breaking. Gibberellic acid at 250 ppm concentration increases the germination characteristics after this period. Four-month stratification had no effect even for seeds treated with gibberellic acid that is usually applied to shorten the stratification period.

Cercis siliquastrum is compatible to soil types and has resistance to climate changes. Therefore the study of its germination and growth condition can lead us to correct use for semi-arid lands in Iran. In this research the effect of different treatment on Cercis siliquastrum germination and growth indices was investigated and the most effective treatment was distinguished. Thus, five frequencies and five treatments as control (full light), shadow (50% light), seed size, cultivation depth and sulfuric acid (level 0-5) was done on this species in water, soil and plant laboratory of agricultural science and natural resources university of Sari. Data was analyzed as factorial test and random method by analysis of variance and mean comparison in SPSS 16 and MSTATC Softwares. The independent and reciprocal effect of the parameters was obtained too. The result showed that the independent effect of light and the reciprocal effect of depth and acid were effect on collar width. But, resultant of all parameters such as light, depth, seed size and acid were effect on vegetative characteristics as leaf number and plant height.

Smoke-tree(Cotinus coggygria Scop.)is one of the endemic valuable shrub species of Iran which has only distributed in the Arasbaran Forests. Natural regeneration of this specie is mostly asexual with the shape of root-sucker, and its sexual reproduction is rarely possible. Considering the importance of this specie as well as difficult germination of the seeds naturally, an effort was made through the present study, for the first time in Iran, to examine the effects of several treatments on the improvement of seed germination of this specie, and to introduce the best treatment. In order to break the physical and physiological dormancies, the seeds were soaked in 98% concentration sulphuric acid for 5 and 50 minutes and cold stratified at 4°c for 30 and 60 days. In addition, both of the mentioned treatments, soaking in 98% concentration sulphuric acid for 5, 20 and 50 minutes with cold stratified at 4°C for 60 days, were simultaneously utilized to break both physical and physiological dormancies. The experimental design was completely randomized design (CRD) with three replications in which 30 seeds were planted per replicate. The results of analysis of variance showed that the selected treatments had significant effects (p < 0.01) on all the traits including germination rate, germination speed, and seed vigor index. Furthermore, comparison of the means resulted by the Duncan tests revealed that the best results were obtained by simultaneously application of both the treatments of soaking in 98% concentration sulphuric acid for 20 minutes and cold stratification at 4°C for 60 days. Totally, the results of this study demonstrated the positive effects of the selected treatments on breaking the seed dormancies of this shrub, and the results may be considered in reforestation programs.

Crataegus from Rosaceae family is a tree that has medical and ornamental applications. Seeds of this genus have germination problem and may not germinate for 2 to 3 years. There are limited information about germination of different species. Therefore, study on germination of three native species of Iran, Crataegus aminii, C. persica and C. babakhanloui is conducted and the most effective treatment was determined. To evaluate the germination and breaking seed dormancy of three species, an experiment was carried out as a completely randomized design with four treatments and three replications. Seeds were imposed under physical stimulator treatment, including, scarification and warmth followed by cold stratification. Results indicated that in all treatments, scarification is effective for permeability to water of seed coat and breakage of seed dormancy. Germination rate in treatment 4 (impose to running water for 24h, then 3 month warmth, followed by 4.5 month cold stratification) had the highest rate. The highest percentage of germination and vigor were in treatment 3 (sowing the seeds outdoors at the beginning of summer). The number of the seeds that have embryo in each fruit is determined. More than 80% of fruits have only one embryo.

The best time of seed collection of Tilia in nurseries is at the end of September and the first of October. In this study, the effect of collection time on seed germination was investigated. Seeds were collected at the first of September, end of September and end of October with three weeks intervals. Because of their hard pericarps, seeds of Linden exhibit double dormancy and thus require both scarification and stratification (moist-prechilling) because of their impermeable seed coat and dormant embryo, respectively. Since the effectiveness of hydrogen peroxide (H2O2), of Tilia seeds were already investigated, in this study the seeds were immersed in concentrated hydrogen peroxide 1% for 40 minute, including stratification in river sand for 7 month, approximately. Stratification continued until emergence of radical. Then the seed were removed and counted. Results showed that the best time of seed collection is the first of September when the pericarp is semi-hard.