نشریه رستنیها
سال یازدهم شماره 1 (پیاپی 38، بهار و تابستان 1389)

Arasbaran protected area is located in NW Iran, is one of nine designated Biosphere Reserves in Iran. According to the literatures and the current study, 1067 plant taxa are identified in the area. Eighteen plant taxa of the area are endemic to Iran. Hemicryptophytes (42.5 %) are the most frequent life forms in the reserve followed by therophytes (25.8 %), cryptophytes (18.8 %), phanerophytes (8.1 %) and chamaephytes (4.8 %). Remarkable number of Irano-Turanian and Euro-Sibirian species characterizes the phytogeography of the area. Due to transitional climate of this area, two or pluriregional elements are frequent. Threatened categories for plant species were based on their frequencies from 284 phytosociological releve's collected in the area. A preliminary ordination analysis (AFC) on total releve's data indicates the separation of five main habitats or vegetation formation in the area, i.e. lowland vegetation, primary woodlands, secondary woodlands, grassland mixed with dwarf shrubs and relatively pure grasslands.

In order to obtain an optimum management of natural resources, determination of variables that control plant presence and distribution is needed. In the present research, the relationship between some character plants of drylands and some soil and environmental variables were investigated. After primary survey and selection of main plant species, sampling was done in each vegetation type within 3-4 transects (200 m length) by randomized-systematic method. Dominant species included Tamarix ramosissima, Salsola kali, Phragmites australis and Ephedra distachya. Vegetation sampling was done in 200 plots and soil sampling was done from two depth 0-20 and 20-60 cm in 38 plots. SHAZAM 10 package was used to find the logical relationship between plant species and environmental variables. The statistical pattern for this research was based on qualitative function. Therefore, logic function was evaluated. Results show that for T. ramosissima, potassium in the first depth and available water in the second depth; for S. kali, available water in the second depth; for P. australis, pH in the first depth and organic matter in the second depth, and for E. distachya, saturated moisture in the first depth and available water in the second depth have the most important role in plant presence and absence probability.

Four species of wood inhabiting cup fungi belonging to order Helotiales are reported for the first time in Iran. Species are described and illustrated with photographs and drawings. Three genera Arachnopeziza, Hymenoscyphus and Lachnum are new records for Iran.

Stomata play a key role in the control of plant water relations and photosynthesis. A rapid non-destructive method to study the stomatal behaviour in aerial parts of plants is important for researchers in plant sciences and agricultural fields. Stomata close in response to drought stress. Stomatal closure causes lower availability of CO2 inside the leaf and thus a decrease in the rate of carboxylation. Thus, a measurement of relative quantum yied for electron transport by photosystem II (ΦPSII) under a non-photorespiratory condition may be used to detect the closure of stomata. In this research we aimed to study the relationship between ΦPSII and stomatal closing behaviour in Tradescantia virginiana under water stress and rehydration using a chlorophyll fluorescence imaging system. Results showed that in leaves from well-watered plants and in an atmosphere of 2% O2 and normal CO2, ΦPSII was high (0.69) before excision, but 2 h dessication after excision ΦPSII decreased significantly (0.33), and with the transition to high CO2 ΦPSII almost completely recovered to the value of the control images (0.66). Moreover, ΦPSII increased significantly from 0.27 to 0.64 during rehydration of the dessicated leaves. Direct measurement of stomatal aperture in control and dessicated plants (7 and 1 µm, respectively) confirmed the high correlation between ΦPSII under low O2 concentration and stomatal closure as well as the effectiveness of chlorophyll fluorescence imaging system in the study of stomatal behaviour. Therefore, this new non-destructive method could be used to study stomatal closing behaviour and patchiness in different parts of a leaf.

Variations in fruits morphology of Tilia spp. were studied along longitudinal and altitudinal range. Ten populations of Tilia spp. from Golestan, Mazandaran and Gilan Provinces (N. Iran) were selected. After biometrical measurements and Scanning Electron Microscopic (SEM), Cluster Analysis divided the population into seven groups. Discriminat Analysis showed that among all traits studied, size of rib, thickness, density of down and fruits colour traits have outstanding role in separation of groups. In first and second groups, fruits have smooth surface and tiny shell, but group two due to globose fruit without visible rib is different from group one. Surface dense tomentose with light brown colour is differentiating characters of third group. Prominent ribs are related to groups four and five but density of down surface in fifth group is much greater than the forth group. Distinguishable character of the sixth group is woody shell velutinous with less prominent ribs. Only one tree form Dalir population (Valley of Chalous) due to its completely different form (cup form) made seventh group. From view point of SEM, third group with having simple trichome differed with first, second, forth, sixth and seventh groups that have stellate trichome. Trees in the fifth group are varied in this trait, some trees have stellate trichome and some others have simple trichome. In conclusion, this research reports two new forms of the genus Tilia in the north of Iran and it can be stated that the presence of other species from this genus in the north of Iran is possible.

In the course of a survey during growing seasons of 2002-04, various fields and pastures in 23 Iranian provinces were sampled. Some 1200 isolates of Fusarium from root, crown, stem and spike of various plants belonging to the family Poaceae were recovered using Nash-Snyder selective medium and purified on potato dextrose agar (PDA). Based on morphological characters, 35 Fusarium species were identified using PDA, SNA, KCl+WA and CLA media. Sporulation was encouraged using near UV light and darkness of 12h at 22-25˚ C. Among the species identified, Fusarium verticillioides and F. nygamai recovered from wheat, maize, rice and sugarcane had higher frequencies of 13.5 and 9%, respectively. Fusarium graminum and F. poae isolated from wheat, barley, rice, aegilops and oat had the lowest frequencies of 0.17 and 0.083%, respectively. F. heterosporum, F. pallidoroseum, F. pseudonygamai and F. sacchari from Poaceae are new taxa to the mycoflora of Iran.

In order to determine morphological characteristics of Fusarium species associated with root and stem of maize in Kermanshah province, during two growing seasons of 2006-2008, 110 samples, mostly from diseased plants were collected from different geographic regions of the province. The collecting localities were Gilan Gharb, Sarpol Zohab, Qasr Shirin, Sonqor, Kangavar, Bisotun, Ravansar, Kermanshah, Paveh and Sahneh. About 1100 Fusarium isolates were collected and 29 species were identified.

By studying the type specimens and field works from locus classicus, it became clear that the two species of Silene eremicana and S. goniocaula which are considered as conspecific in the Flora Iranica are distinct species. Silene commelinifolia var. isophylla is considered as a synonym of S. eremicana. The numbers of herbarium specimens (voucher) are emended and the descriptions of each species are completed. The chromosome number of S. eremicana, 2n=4x=48 is reported for the first time. The karyotype of each species is presented.

Seed dormancy of wild mustard (Sinapis arvensis) could be changed through seed storing. The seeds were collected from four regions: Fars, West Azarbaijan, Khuzestan and Mazandaran provinces. They were stored at three different temperatures (-18, +3 and 22-25°C) for 3, 6, 9, 12 and 15 months. They were then put under suitable condition for germination. Mean germination time for seeds was measured during 6, 12 and 18 months storage. The results showed that the dormancy level and germination speed of seeds showed some differences after different time periods of storage. Also large differences in percentage of germination were found among populations. The results suggest that the most effective factor on seed germination is environmental maternal conditions at seed production stage. Because of the secondary dormancy, the storage temperature is not suitable to promote seed germination. Despite the increased germination speed of seeds at room temperature, the amount of this increase was not similar in all populations. It was contrary to the seeds from Mazandaran Province where the seed germination speed was reduced. According to the results, the secondary dormancy, which causes low germination and high contamination of soil with the seeds, is considered an important factor in management of wild mustard weeds.

In this investigation, the effect of zinc excess and its interaction with ascorbic acid on some growth parameters (root and shoot, fresh and dry weight, leaf blade area and length of root and stem), proline content, soluble sugars and starch plant were studied on canola. Experimental plants were treated with different concentrations of zinc sulfate ie. 0.7 (control), 50, 100, 250, 500 and 700 mM) and one set with the same zinc concentrations (except control) mixed with 1M of ascorbic acid in Hougland nutrient solution for two weeks. Results indicated that any increase in zinc content leads to considerable decrease in starch level, leaf blade area, stem and root length, but proline and soluble sugars increased significantly in shoot and roots of rape seed. In higher concentrations of zinc sulfate in the presence of 1M ascorbic acid, the above-mentioned effects of zinc sulfate excess on growth parameters were considerably blocked. In the presence of 700 mM of zinc sulfate, chlorosis and necrosis were occurred on the leaves of rape seed, but at the copresence of 1 mM of ascorbic acid, mentioned symptoms was disappeared. It means that at the presence of ascorbic acid the plant could tolerate the toxicity of zinc sulfate excess. In the other word, ascorbic acid could considerably reduce the toxicity of high concentrations of zinc and induce poison durability.

In the identification process of weed materials available in "IRAN" herbarium, a specimen belonging to the genus Lactuca (Asteraceae) had the following characteristics: Plant annual, many stemmed from base; stem erect-slightly procumbent, slender, glabrous, whitish and leafy. Basal leaves dried; stem leaves ca. 7 × 0.5 cm, glabrous, linear-lanceolate, entire at margin, sessile, auriculate, auricles small, forming a hastate leaf base. Inflorescence spike-like; heads in the axils of reduced leaves, shortly pedicelate, solitary or in clusters of 2-3; involucres narrow, ca. 12 mm long; florets turning purplish when dry. Achenes ca. 4 × 1 mm, light brown, flattened, inversely ovate, many-ribbed, in upper part provided with short hairs, with filiform 3-3.5 mm long beak; pappus white, deciduous (Fig. 1). The above-mentioned specimen was already identified as Lactuca saligna L. This species which is known as willow-leaf lettuce and narrow-leaved wild lettuce was described from Germany and is distributed in Europe, Mediterranean region, Caucasia and N. Africa. Lactuca saligna has reported in all Floras of western neighboring countries of Iran. In the Flora Iranica area, this species is reported only from Iraq (Rechinger 1977). Lactuca saligna has been reported by Parsa (1943) from four localities in Iran. Many of Parsa's specimens are found in Herbaria of Vienna (W), Berlin (B) & Kew (K), but as none of these specimens are listed in Flora Iranica (which was published 34 yrs after Parsa's Flore de lIran), it seems that Parsa's specimens did not exist at the mentioned herbaria. By visiting Herbarium of Pharmacy Faculty of Tehran University (THE), we could only find one specimen determined as L. saligna, mounted on two sheets with Nos: 10834 & 10835 (1169), both collected from Lowra, 2000 m, 20 Jun. 1955, M. Sotoodeh. More studies revealed that, the said specimen was Lactuca orientalis Boiss. (= Scariola orientalis (Boiss.) Sojak. In the Flora of former Soviet Union (Kirpichnikov 1964), L. altaica and L. saligna considered as distinct species, the proportion of achene's beak to achene's body is their only difference. But, only L. altaica is reported from Iran (Kurdestan), without citing any locality. It is noticeable that L. altaica is presently considered as a synonym of L. saligna, reported only from N. Iran, but without substantiating by a specimen citation (Heller & Heyn 1993). Checking different references shows that reporting of L. saligna from some parts of Iran was mostly on the basis of one specimen without citing the exact locality and there is no specimen of this species in any Iranian herbarium. Furthermore, none specimen of this species has been reported in Flora Iranica. The only specimen of this species which is presently available in "IRAN" herbarium (54460-IRAN) has been collected as a weed without a note on its collecting locality.

After heavy rainfalls in late Apr. of 2010 in Tehran, an epizootic occurred amongst hoverflies (Eupeodes corollae Fabricius) population in green spaces of Iranian Research Institute of Plant Protection, caused by an entomopathogenic fungus. Infected flies fixed to the upper parts of whitetop (Lepidium draba L.) and small tumbleweed mustard (Sisymbrium loeslii L.) plants with their proboscis and clasped legs, their head went downwards and their wings spread latero-dorsally (Fig. 1, a, b). The fungus produced conidiophores, which ruptured the host cuticle at the intersegmental membranes, resulting in cream-coloured mycelial bands on the abdomen or in a complete cover of the dorsal abdomen. They forcibley discharged around primary conidia, many of them landed on wings and on the surface of the cadaver. Lactophenol Aceto Orcein (LPAO) was used as a mounting medium for slides prepared directly from dead insects. Studied slides showed unbranched conidiophores terminally enlarged up to a diameter of 19.2-25.6 (19-28) m and contained 16-24 (13-29) nuclei with a diameter of 4-5.6 (3.5-7) m (Fig. 1, c-e). Primary conidia were companulate and measured 27.5-33.5  23-27.4 (21-37  20-30) m (L/D=1.13-1.30), containing 13-23 nuclei with a diameter of 2.5-4 (2.5-5) m. They had a distinct apical point, a flat to slightly rounded papilla and the projected ones were surrounded by a halo which was the residual of ruptured outer wall of primary conidium (Fig. 1. f-h). They produced secondary conidia which were homogenous in shape, measuring 21.2-26.  17-21.3 (20-29  16-25) m (L/D= 1.15-1.32). They contained 11-23 nuclei, with no apical point or sorrounding halo (Fig. 1, i-k). Hence no rhizoids and cystidia were observed. Based on these data the fungus was identified Entomophthora syrphi Giard (Keller 2002). E. syrphi has been reported from Europe on smaller syrphids (e.g. Melanostoma spp. and Platycherius spp.); Eupeodes corollae and larger syrphids were supposed to be the host of another species, Entomophthora grandis Keller, which has few differences from E. syrphi with larger conidia, less pronounced apical point on primary conidia and more nuclei per conidia. As species of Entomophthora have a narrow host range, it seems that molecular evidences or further morphological features are needed for recognition of these two species. This fungus was reported by Ghazavi & Baniameri (2008).

In a project on the Flora of Iran (Trib.: Ranunculeae), many herbarium specimens of the genus Ranunculus were studied. The results of this study are a new record and suggestion of a synonym for the Flora of Iran, specimens of which are preserved in the herbarium of Research Institute of Forest & Rangelands (TARI).