Journal of

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Accessing to the data that could increase our knowledge associated with the response of seed to moisture content and temperature, is very important on exact time of planting decisions making. In this study Hydro-thermal-time modeling of Platycladus orientalis germination, one of the most planted trees in Iran forests, by applying 5 levels of water stress (0.-0.5, -1, -1.5, -2 MPa) and temperature treatments (10, 15, 20, 25, 30 ° C) was performed. The results showed that the optimum temperature (To) for germination is 23.12° C and basic temperature (Tb) for germination is 8.18 ° C. Meanwhile amount of the hydrotime constant (θH) for this species is 0.45. The outcomes indicated that the reduction in water potential and temperature germination is linearly reduced. Interaction of temperature and water potential factors affected significantly on time and percent germination value. A Hydro-thermal-time model was introduced for Platycladus orientalis L. in which its constant value was 105.1 MPa°C.d.

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Judas tree belongs to valuable species in Zagros forests. Nowadays, due to the special beauty of this species, it has received substantial attention in afforestation. In this regard, the improvement of seed germination is a suitable way to improve the quantity and quality of producing seedlings in nurseries and the establishment of forest plantation. In this study, the seed germination characteristics and seedling survival of Cercis griffithii in different soil treatments have been surveyed in the nursery of Aivan County in Ilam province. The experiment was set up as a randomized complete design with four treatments each contained 120 pots. Three seeds in plastic pots were sown in nursery soil (Control Control soil- cattle manure (5:1), Control soil- Litter (5:1) and Control soil- Cattle manure- Litter (5:1:1). According to the one-way ANOVA results, significant differences were observed between soil treatments in terms of germination rate, maximum, mean daily germination and germination energy, while there were no significant differences in other germination characteristics between soil treatments. The highest germination rate, maximum, mean daily germination and germination energy were observed in the treatment of Control soil- Cattle manure- Litter. In terms of time, seedling survival decreased from September to March. The results showed that there is a significant correlation between mean daily germination and different soil composition. In general, it can be concluded that germination and survival of Cercis griffithii can be improved using organic compounds in the nursery.

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Salinity is one of environmental stresses in the world and especially in arid lands and desert that reduces production of plants and it is important to choose salt-resistant plants in all life stages, especially germination. The aim of this study was to investigate the effect of seed source (provenance (on germination and morphological traits of Amygdalus elaegnifolia saplings undersalt stress. The experiment was carried out as factorial in completely randomized design  withthree replicates. Seed source (FereydonShahr, Kazeron and Semirom) and salinity treatment withfour levels (0, 1.5, 3 and 5 dSm^-1) using NaCl were considered as first and  second factors, respectively. The measured variables were germination percentage, germination rate, vigor index, shoot length, radicle length, shoot wet weight, radicle wet weight, shoot dry weight, radicle dry weight, total leaf number, and radicle length/shoot length. The results of analysis of variance and mean comparison showed that salinity made significant differences in most of the investigated traits of Amygdalus elaegnifolia. In the control treatment of salinity, significant differences were found among the studied seed sources but the effect of seed sources was not significant in the other levels of salinity. In general, Fereydunshahr was the best of all studied provenances in non-saline conditions (control treatment).