جستجوی مقالات مرتبط با کلیدواژه « shoot » در نشریات گروه « جنگلداری »

Abarkooh cypress (Cupressus sempervirens L. var. horizontalis (Mill) Gord) is one of the oldest trees in the world. Because of its prolonged life, the plant has tolerate many adverse environmental conditions, so if this valuable treasure is propagated, it can produce a large plant population with the ability to withstand extreme environmental conditions. Tissue culture is one of the best methods for protection and propagation of in danger and rare plants such as this plant. This study was conducted to determine the best culture media and concentration of BA in micropropagation of Abarkooh cypress plant. In this research, different culture media such as Murashige & Skoog (MS) and modified MS contained ½ MS, ¾ MS, MS without ammonium nitrate, MS with ½ nitrogen, source MS with modified vitamin-1 and 2 group by three concentrations of BA (0, 0.1 and 1 mg/l) in establishment phase and five concentrations (0, 1, 1.5, 2 and 5 mg/l) in proliferation phase were used. Experiments were performed in factorial and completely randomized design with five replications. In establishment phase the highest length and number of shoots as well as the lowest percentage of browning were obtained in ½ MS culture medium. All culture media except MS with ½ nitrogen source, maintained greening degree. By increasing the BA concentration in establishment stage, length of shoots significantly, increased. However, the highest length of shoots was obtained in culture media supplemented by 1 mg/l BA. In all media with modified nitrogen source or without it, length and number of new shoots significantly decreased in compare other culture media. In proliferation phase, the highest number and length of shoots were obtained in ½ MS culture medium supplemented by 2 mg/l BA and the highest greening degree was recorded in cultured explants ½ MS and ¾ MS culture media. According to the results, by increasing BA concentration in proliferation stage, length and number of shoots significantly increased, but greening degree significantly decreased. Generally, proliferation rate, length and number of shoots greatly depended on nutrition of explants and kind of culture medium. According to the results of this study, ½ MS culture medium supplemented by 1 mg/l BA in establishment stage and 2 mg/l BA in proliferation stage, is recommended. Generally, proliferation rate, length and number of shoots greatly depended on nutrition of explants and kind of culture medium. According to the results of this study, ½ MS culture medium supplemented by 1 mg/l BA in establishment stage and 2 mg/l BA in proliferation stage, is recommended.

This study was conducted to protect the genetic properties and propagation of 4000-year-old Abarkooh horizontal cypress (Cupressus semprvirens L. var. horizontalis (Mill.) Gord.) by tissue culture technique. In the first experiment, the effect of preparation time of explant (four seasons), medium culture (MS and WPM) and concentrations of BA (0, 0.1 and 1 mg/l) on proliferation of horizontal cypress explants was investigated. In second and third experiments the effect of culture media (MS and WPM), concentrations of BA (0, 0.1, 0.5 and 1 mg/l) was studied alone or in combination with 0.01 mg/l IBA and type of explant (primary or secondary shoots) in a factorial experiment and completely randomized design with three replications. In first experiment, the maximum shoots number was obtained from spring and summer explants that were cultured in MS and WPM culture media, respectively. In second experiment, the maximum number and length of shoots was obtained in WPM culture medium and secondary shoots. The highest length of shoots was found in first shoots cultured in WPM medium containing 0.1 and 0.5 mg/l BA, followed by primary shoots cultured in MS medium culture without BA. In the third experiment, the maximum number of shoots (3) was observed in secondary shoots by using WPM medium containing 0 mg/l BA 0.01 mg/l IBA. Conclusively the best time of preparing explant, type of culture media and explant were found to be spring, WPM medium and secondary shoots, respectively.

In order to identify the best sowing depth and seed cover of Quercus brantii Lindl., a trial was conducted at Kamfirouz Oak Experimental Station in Fars province of Iran at two year period, using Factorial statistical method and experimental design of Randomized Complete Blocks at four replicates. The first factor was depth of seed sowing at six levels (0.0, 2.5, 5.0, 7.5 and 12.5 cm) and the second factor was seed cover at three levels (ordinary forest soil or control treatment, mixture of ordinary soil and 20% manure, and mixture of ordinary soil and 50% manure). The measured characteristics of established oak seedlings consisted of: survival, root and shoot length and shoot and root wet and dry weight. Data analysis was performed, using Variance Analysis and Duncan test and applying SAS software. The results showed that effects of year, seed cover and sowing depth on survival were significant (p< 0.01). Average seedling survival at first and second year of trial was 32.7 and 40.5 %, respectively. Increased amount of manure in seed cover material increased survival significantly and it increased from 33.8 % in ordinary soil to 40.7 % in soil and 50 % manure mixture. Greatest percentage of survival at 2.5, 5.5 and 7.5 cm sowing depth was 47.7, 49.3 and 51.6 cm, respectively, whereas the lowest rate (10.1 %) belonged to zero sowing depth. Overall, the highest rate of shoot length, root length, shoot dry weight and root dry weight were 11.8 cm, 80.3 cm, 4.8 g and 3.4 g, respectively.

Almond is one of the major shrub species with high ecological extent in Iran. Impact of climate change and drought stress on forest ecosystems، as well as the unsuitable conditions of Zagros forest ecosystem and importance of planting shrub species at such ecosystems، have brought the attentions to use the wild almond species in forest plantation programs. Awareness of the impact of habitat factors on tolerance to environmental stresses will guarantee success of most of the forest rehabilitation programs. For this reason، seeds of four wild almonds، including Amygdalus arabica، A. scoparia، A. haussknechtii and A. eleagnifolia، were collected from three altitude levels، including: 1600-1800، 1800-2000 and more than 2000 m. above sea level at Karebas site; (Chaharmahal and Bakhtiari province)، west of Iran. After cold stratification، the seeds were sown in nylon bags. Two months later، the seedlings were treated by four levels of drought stress (control، -0. 4، -0. 8 and -1. 2 MPa) induced by application of Polyethylene Glycol 6000 in irrigation water، using the factorial experiment under the completely randomized design with three replications (five seedlings per each replicate). Results showed that drought stress significantly reduced seedlings growth characteristics، including total height، shoot height and shoot wet and dry weight، except root wet weight which was increased. Furthermore it increased seedling''s nitrogen and calcium content، while the minimum levels belonged to control treatment. In addition، the seedlings from the lowest (1600-1800 m. a. s. l.) and the highest (above 2000 m a. s. l.) altitude origin، provided the highest and the lowest growth values، respectively. Overall، Amygdalus arabica showed the highest resistance to drought levels among the other species، due to its greatest growth values at these hard circumstances.

Pinus brutia is one of the most important species respect to low ecological needs and tolerance against winter drought and summer heat. This species is used in degraded ecosystems and dry and semidry shrub lands in Iran. It is an important species for urban green space as well. This experiment was performed as complete randomized and factorial design with three treatments, sowing date (autumn and winter), irrigation periods (every 2 and 4 days) and weed mechanical control (every 7 and 14 days) with four replications and 15 vases (per replications) in Zaghe nursery in Khorramabad city. At the end of the first growing season, measurements included biomass and vitality rate. Results showed that the effect of treatments on amount of biomass was significant. The maximum of biomass was showed in winter sowing, every 2-days irrigation and every 7-days weeding. Effect of irrigation on shoot/root ratio was significant and maximum rate concluded in every 4-days irrigation but conversely effect of sowing date and weed control and composition of treatments were not significant. Effect of treatments including, sowing date, weed control and composition of treatments on vitality rate were significant. Maximum vitality achieved at autumn sowing with every 2-days irrigation and 7-days weeding. Based on the results, for decreasing of nursery costs, the duration of irrigation can be extended and winter sowing can be replaced by autumn.