مجله پژوهشهای گیاهی (زیست شناسی ایران)
سال بیست و ششم شماره 4 (زمستان 1392)

Physiological characteristics commonly employed for selection of tolerant and sensitive plant genotypes to environmental stresses are mainly time consuming and expensive. Since، development of alternative accurate and time–saving assay methods is inevitable. Owing to above mentioned facts، two durum wheat cultivars; Egypt 449 (tolerant) and Turky506 (sensitive) were cultured under aeroponic conditions for the evaluation of their chlorophyll a fluorescence parameters under salinity conditions. During 4-5 leafy stage، wheat seedlings were exposed to 200 mM salinity stress for 10 days. Chlorophyll a fluorescence was assayed in both salinity treated and control plants. In Turky506، OJIP-test curve area coverage، evaluation factor for quinones pool volume and photosystem II initial efficiency were significantly reduced under salinity conditions compared to control. Moreover، study of the parameters related to energy flow towards the reaction center showed that in Turky506، due to reduced ratio of active reaction center to cross section under salinity condition، parameters of energy absorption in reaction center، energy trapping ratio related to reaction center and electron flow toward reaction center were increased under salinity situations. However، blocked flow of electron transport toward reaction center in Turky506 led to increased energy waste in reaction center due to salinity. On the other hand، indexes such as energy trapping to energy absorption، electron transmission rate to trapped energy and electron transmission rate to absorptive energy rate in Turky506 were significantly reached under salinity conductions. Although، performance index under salinity was declined in both cultivars، but، the studied traits revealed than Turky506 was sensitive to salinity and also، had low efficiency. Overall، it is worthy of note that، study of the chlorophyll a fluorescence may be a validate physiological index for selection of wheat cultivars in response to salinity.

The relationship between ecological species groups and some of indicator environmental factors were studied in Golzar Izeh area. Random- systematic sampling method was applied. 40 plots with an area 1200 square of meter were taken for trees and shrubs species and in each plot، 3 transects were settled for herbs. Soil sampling was performed from 0 to 20cm. Measured data were analyzed by PCA ordination and TWINSPAN classification. The results of classification were shown that the plant communities، can divided to three ecological groups. The results of ordination which coincided to classification outcome، were revealed that the most important environmental factors which are shown significant correlation with three ecological groups included: pH، cover percentage of rock، percentage of litter and CaCO3 in terms of percent.

Accelerated aging test is the most important tests used to evaluate the physiological potential of seeds of various species and provide the information of their compatibility degree. In this investigation the impact of seed deterioration (accelerated aging test) on germination and seedling growth indices was conducted in three cultivars of canola; SLM، Elite and Zarfam. The accelerated aging test was carried out at three different temperatures: 30، 40 and 50 °C with four duration periods of 24، 72، 120 and 144 hr and a 100% relative humidity in factorial experiment that laid out in randomized complete block design with three replications. The results showed that accelerated seed aging and cultivar، temperature and duration period interactions have significant effect on germination percentage (GP)، Index (GI) and rate (GR)، D50 and seed vigor (SV). All germination indices (GP، GI، GR، D50 and SV) and seedling growth included length and weight of root and shoot and allometric coefficient decreased in three cultivars with increasing in seed aging temperature and duration period. Results indicated that Zarfam cultivar has maximum rate of germination and seedling growth indices rather than two other cultivars. This good quality will continued in accelerated seed aging. So that Zarfam، Elayt and SLM germination percentage under 40 °C and 144 h accelerated seed aging declined from 80 percent to 64 and 29 percent respectively. Zarfam and SLM were having highest and lowest seed quality and resistance to storage conditions، respectively under long period of storage in hot and humid weather.

One of the sections of Astragalus L. (Fabaceae family) is Incani DC. In the recent research were studied morphological and anatomical characters on 5 species of this section in Boroujerd. The collected species contain: A. curvirostris Boiss.، A. cyclophyllos Beck، A. kabutarlanensis Dehshiri & Maassoumi، A. latifolius Lam.، A. supervisus (Kuntze) Sheld. For anatomical study the cross section of peduncles، rachis، leaflet، pulvinulo and epidermis of leaflet were prepared by hand-operated and stained by double staining with morphological studies showed that characters such as number of leaflet in each leaf، number of flower، standard length، legume length and legume shape were different and resolving in study species and in anatomical study anatomy structure of peduncles، rachis، leaflet، stomatal Index and hair Index can use as a useful tool in the identification and classification species of this section.

Aquatic plants have positive and negative effects on the human and other organisms. They affect ecological progresses of water environment and provide ecological niche for different taxonomical groupes like bacteria، epiphytes and others as well. We decided to investigate them in part of north of Iran. In this investigation، at the first specimens were collected from sampling sites، e. g. stagnant water stops and irrigated farms in different seasons. Then they were identified and after that، they were devided to three groups (helophytes، hygrophytes and euhydrophytes)، acording to their habitat and water requirements. The results revealed the existence of 135 aquatic plant species that 83 species were hygrophytic، 23 species were helophytic and 29 species were euhydrophytic. Llife forms of helophytes and hygrophytes include 21. 69% helophytes، 33. 96% threophytes، 20. 75% hemicryptophytes، 16. 03% geophytes and 7. 54% phanerophytes. Growth forms of euhydrophytic plants include 17. 24% Lemnid، 13. 8% Magnopotamid، 6. 9% Nymphaeid، agnonymphaeid، Myriophyllid، Elodeid، Batrachiid and Parvopotamid as well as 3. 45% Peplid، Ceratophyllid، Hydrocharid، Parvonymphaeid، Ricciellid، Salviniid، Charid and Magnozosterid.

The purpose of this study is determination of best altitude range for forestation of Quercus libani Oliv in Kurdistan province and dendrochronology of this species. For this purpose، twelve disks as a random sampling used from pulled trees on three elevation classes (1400-1600m، 1600-1800m، 1800-2000m) in Marivan forest. ANOVA results showed that diameter growth on these elevation ranges have significant difference (p<0. 05). The average annual increment diameter on first class (1400-1600m) measured about 2. 2mm، second class (1600-1800m) 2. 6mm and third class (1800-2000m) 1. 8mm. Also، results showed that second class site has a better growth condition than other sites. Thus in three sites، average of annual diameter increment in Quercus libani Oliv indicated a direct relationship with precipitation of the last 17 years.

In order to ecologically investigate Rhus coriraria L. species and recognize its existing sites in west of Iran، boundaries of these species were located on the topographic map and 8 plots with areas of 100 square meters were implemented. Soil samples were collected from 0-10 and 10-20cm depth. Using analysis Kolmogorov-Smirnov، Levene and T-test were also used to compare that with and without Sumac covering with regard to biodiversity indices. The results showed Organic matter and Potassium in depth of 0-10 cm at Sumac covered area was greater than those at adjacent (without Sumac covering) area. Sumac covered area had greater values of Organic matter، nitrogen، calcium and clay percent in depth of 10-20 cm in comparison to adjacent area. In addition، the comparison of soil ingredients in different depths of the two areas showed that Electric conductance in depth of 0-10 cm and Nitrogen content in depth of 10-20 cm of sumac covering area was greater than those of adjacent area. Based on the results of this study، it can be concluded that Rhus coriraria L species in regions with soil types of high amounts of N، C-O، K، Ca and Clay and located in steep lands with north directions. Therefore، in order to plant this species and enrichment of this species in its natural habitat and other dry and semi-dry regions requirements of this species must be considered.

Lead is one of the hazardous heavy metals environmental pollutants. According to the environmental protection agency (EPA)، Pb is the most common heavy metal contaminant in the environment. The current study was undertaken to determine the effects of Pb toxicity in leaves of Hypericum perforatum L. Plants divided to 2 groups that first group treated by contaminant soils with 75، 150، 300، 600، 800، 1000، 1500 mgkg Pb in soil and second group treated by foliar spray with 0. 724، 1. 44 and 2. 9 mM Pb. This experiment was conducted under greenhouse condition. Results indicated that most of structural changes in soil pollution have been happened in epiderm، mesophyll، collanchyma and vascular bundles tissues. In foliar spray also epiderm، mesophyll، collanchyma and vascular bundles and secretory cavities have been changed.

Zygophyllum atriplicoides، a perennial shrub in the family Zygophylaceae، is one of the important halophytes in Iran. In this research، seeds of this species were collected from the salt zones near Isfahan City. Experiment was carried out in order to determine the salinity-alleviating effect of germination promoting compounds (GPCs) on its seed germination as factorial with completely randomized design with 4 replications. GPCs were including: nitrate (20 mM)، Thiourea (10 mM)، Ethephon (10 mM)، GA3 (3 mM) and water as control and salinity concentrations were 0، 40، 80 and 120 mM NaCl. In water treatment (0 mM NaCl) only 50% of seeds germinated and germination decreased with an increase in salinity to 40، 80 mM، and at 120 mM NaCl، seed germinated was less than 3%. Also salinity decreased capacity، velocity and synchronization index of germination. All GPCs significantly enhanced germination in control treatment (0 mM NaCl). Nitrate and thiourea increased 30-40 % seed germination than water treatment، but in 80، 120 mM did not have significant promotive effect on germination than water treatment. At 40 mM NaCl، Ethephon and GA3 application significantly promoted germination at all salinity levels. In 0، 40، 80 and 120 mM NaCl، Ethephon and GA3 promoted germination 92، 68، 51، 25 % and 100، 97، 86، 75 % respectively. Therefore، GA3 better than other chemicals، alleviated the inhibitory effects of all salinity levels on the germination of Z. atriplicoides and increased capacity، velocity and synchronization index of germination. In sum، our data suggests that innate dormancy of Zygophyllum atriplicoides seeds is non-deep physiologic type and salt-induced dormancy، is caused probably because of distortion of seed hormonal balance and exogenous GA3 application compensated this hormonal un-balance and led to dormancy breaking and germination of Zygophyllum atriplicoid seeds.

Cichory (Cichorium intybus) roots contain medicinally important compounds such as phenols (mainly cichoric acid)، Flavonoids and inulin. Here، we obtained and established 11 different hairy root lines of chichory by inoculation of plant sterile leaf explants with the soil bacterium Agrobacterium rhizogenes، A4 strain. Phenolic compounds، total flavonoids and carbohydrates were determined by spectrophotometer، and chicoric acid was determined by HPLC. The highest growth rates were observed in A، H، J and I root lines. Total phenol and flavonoid contents had no significant difference between the obtained root lines but cichoric acid in J and then in F lines were more than the other lines. The highest levels of carbohydrates were observed in D، G، J and I root lines. According to the results، The J root line was the best one for growth rate، cichoric acid and carbohydrate production.

Lolium composed of 8 species in the world has 6 species native to Iran. In this research 108 quantitative and qualitative anatomical features of leaf cross sections and dorsal epidermis of 20 accessions from 5 species of this genus in Iran were evaluated. Statistical analysis was performed by use of SPSS 17. Cluster analysis by WARD method and ordination based on Principal component analysis and Factor analysis were done to evaluate the species relationships. Our results indicated that qualitative characters as subsidiaries cell shape، leaf margins at cross section، mid rib position in coastal region and quantitative features as stomata length، leaf thickness in mid rib and bulliform cells width has the most important role as diagnostic characters in inter-specific variation. Based on statistical results and diagnostic characters an identification key is provided for Lolium elements in Iran.

Interaction between soil and its effect on plant roots is the key factor in success of a plant species in tolerance and remediation of hydrocarbon pollutant. The root exudates are the link between plants and microbes that leads to the rhizosphere effects. The result of this interaction results is degradation of petroleum hydrocarbons. Aim of the current study was consideration of growth، changes and reaction of the plants root in the oil-contaminated soils. The effect of oil-contaminated soils on root length، protein concentration، rhizosphere microbial population and damaged of the root tissues in the anatomical studies on Zea mays، Helianthus annus and Avena sativa were investigated. As a result Z. mays and A. sativa roots length significantly decreased in contaminated condition while H. annus root length increased in contaminated soils. In all of the plants roots protein concentration was higher in compared with uncontaminated plants. The anaerobic microbial population in the contaminated soil increased in the presence of H. annus and Z. mays root system whereas A. sativa caused enhancement of the aerobic microbial population in rhizosphere. Anatomical studies were indicative vulnerability and rupture of the root parenchyma tissue in the contaminated Z. mays.

The Saral region is located in Kurdistan province in Iran. Farhadabad sub catchment is a part of Saral rangelands with 3312 hectares area. Its geographical position is 46º 44´ N to 46º 47´and 35º 31´ E to 35º 37´. Flora of these rangelands includes 275 plant species which belong to 39 families and 172 genera. The largest families are Asteraceae (33 species)، Papilionaceae (30 species)، Apiaceae (28 species). The most important genera are Astragalus (14 species)، Centaurea (9 species) and Salvia (6 species) respectively. The main life form of plant species includes hemichryptophytes 57. 09%، Therophytes 20% and Bulbygeophytes 10. 18%. Investigation on chorology of plant species showed that 72 persent of species belong to Irano_Touranian region and other species can be found in other regions too. The number of endemic plants of Iran are 49 species (17. 81%)، and the number of endangered species are 34 in Saral region.

Collection research design established with 64 clones of poplar at climatic condition of poplar research station in 1983. They are planted in distance 5 meter in row. This design find out after two nation design as collection of different poplar clones and selection nursery establishment. Factors of phenomena like open catkin، flowers، capsule of seeds and leaves falling were studied every year. Results showed that Populus chopita was sooner than the other clones and P. e. 94/57 was late for catkin appearance. Physiological activities start with appearance leaves that P. e. 488 clone was sooner and P. agresgrandis was latest of them. Seed dispersal was started in P. e. 488 clone sooner and P. e. costanzo was late. Amount of diameter growth in P. e. triplo clone with diameter average 24/73 cm and P. e. riminii clone with15/81cm were most and least respectively. Height growth in P. e. 45/51 and P. e. agresgrandis with 28. 65 and 14. 4 m were most and least respectively.

The seeds of Hyoscyamus genus of Solanaceae family has various ornamental structure on seed coat wall. Thus 11 species of Hyoscyamus seed of herbarium samples were collected and evaluated. This has been shown useful taxonomic characteres. Various structure in morphology of seed coat walls was observed. Seed shapes were categorized in three distinct group that include: I - Lens shape. II- Pyramide shape. III- Triangular shap. Has hair or not، depth of sinuate and wall thickness were the other factors that promotes differentiation of species from each other.