فصلنامه گیاه و زیست بوم
پیاپی 9 (بهار 1386)

Upon the conducted samplings through 1997-2006 in different regions of Iran including:Fars, Isfahan, Tehran, Semnan, Guilan, Mazandaran, and Golestan provinces, 214 speciesof host plants belong to 127 genera, and 58 families for Iranian whiteflies (Homoptera:Aleyrodidae) were ldentified. The most number of whiteflie's host plants were determinedin the families Leguminosae (21 species), Malvaceae (18 species), Solanaceae (14 species),Compositae (13 species), Rosaceae (14 species), Rutaceae (8 species), Euphorbiaceae (8species), Oleaceae (8 species), and Brassicaceae (7 species), respectively. On the basis ofconducted studies in different seasons, and different regions of the sampled provinces,many host plants including: Eucalyptus camaldulensis (Myrtaceae), Myrtus communis(Myrtaceae), Vitex pseudo - negundo (Verbenaceae), Malva parviflora (Malvaceae),Ziziphus lotus (Rhamnaceae) and Ricinus communis (Euphorbiaceae) were determined asimportant shelters for hibernation and survival of aleyrodids, because of evergreen andhaving the abundant foliages through year. Therefore, identification of important whiteflie's host plants in winter and early of spring, and planning for reduction or elimination of them from around the fields, can be accounted as fundamental process in Integrated Pest Management (IPM) of aleyrodids.

The Removal of Phenanthrene from polluted soils as a function of time and concentration is investigated. The results were based on a 16 week period and a greenhouse study for determining the removal rate of Phenanthrene by a grass, Sorghum vulgare Pers sudanense, in soils containing 10,15,20 ppm Phenanthrene. Variations in pollutant concentration was investigated by HPLC in different times. It was indicated that after five weeks of plant growth and developing its root system, there was a significant difference for planted soils versus unplanted control soils (p<0.05). The elimination rate in planted treatment was 20% more than unplanted controls.

In order to study the effect of delayed irrigation in primary stages of growth on yield andyield components of Corn, an experiment was conducted in agricultural research center ofKhorasan (Torogh). This research was done in 3 separated experiments in randomizedcomplete block with 5 replications. Each block was an indicator of a water stress treatment. Varieties consisted of single cross hybrids of 704, 647, 604 and 301. Date of planting was 23rd Ordibehesht for all experiments (I4). In experiment (I), irrigation started from the beginning of the planting, according to the plant needs (50% allowable water depletion) uptothe end of plant growth, and in experiment (2) and (3) first irrigation was done in 70% and 90% of allowable water depletion. Results showed that the varieties had significant differences in their morphology and physiology. Stress up to 70% allowable water depletion (1,2) resulted to decreasing attributes such as plant height, ear height, number of total and also upper leaves, number of seed row per ear and increasing stem diameter, ear length, ear diameter, wood diameter, number of seed per row, weight of 1000 seed, seed depth and harvest index in most varieties. Also yields of varieties 704, 647, 604 and 301 were 11.959, 11.745, 12.09 and 10.201 ton per hectare compared to control having the averages of 11.473, 11.489, 11.971 and 10.033 ton per hectare improved significantly.Stress intensity up to 90% allowable water depletion (3) resulted to increasedcharacters like as stem diameter, number of seed row and decreased other characters in the most varieties compared to control. Yields of varieties under this treatment decreased. This decrease was significant just in varieties 704 and 301. Based on results, it will be possible to delay second irrigation up to 70% allowable water depletion. In case of water limitation, variety 647 can be used for its better yield with regard to the others and dont have significant difference with control. In this case the second irrigation up to 90% allowable water depletion will be delayed. Also it seems that the variety 647 has more resistance to water stress than the others.

Using chemical weed control methods play an important role in the reduction of herbicide use as well as environmental protection. nowadays Appropriate land preparation, specially puddling has been known as one of the best factors for weed control in rice fields. plowing in late winter and then in one or two weeks beforetrans planting in spring, is the current method of plowing in Guilan province. Number of puddlings and type of equipment used, depends on conditions and farming system in different sites in Guilan province.since the Kind of equipment and number of secondary tillage's affect weed density, an experiment was conducted in 2005. The treatments included: Conventional method with once and twice puddling, the second puddling after a 10 day interval puddling, method once or twice, with a rotivator as well as puddling once or twice, with cone- puddler. These trials were conducted in rice fields in Taki Tazeabad village with 3 replications. Main noxious weeds were: Echinochloa crus-gali, Cyperus rotundus and Alisma plantagoaquatica. The results indicated that, number of tillage and kind of equipment affected weed population and density. The best treatment was conventional method with two puddlings which reduced weed density 2.1 times in comparison with the worst treatment that is, cone puddler with once puddling.

Cumin (Cuminum cyminum) is one of the important medicinal and aromatic plantswith low yield but high economical value. In this research, the effect of chemic and organic manure on yield, one thousand seed weight and quantity of essential oil in Khorasan cultivar of cumin were investigated. A field experiment conducted during winter 1384 and spring 1385 in Shahr-e-Rey unitof Islamic Azad University. The System of treatment included three levels of chemical fertilizers, N. P. K (b1,b2, b3) and two levels organic fertilizers (a1,a2) or a mixture of different ratios of chemical fertilizer and of organic manures with control group. The experimental design was a factorial in randomized complete blocks design with 3 replications. Duncan comparative test was used for the means comparation. The results showed that control plants had the most yield and one thousand seed weight, it also indicated that the use of manure couldnt increase the cumin product. The least of thousand seed weight related to plants treated with a2b2 and a2b3 however these plants had the most essential oil.percentage

Cuminum cyminum is one of the most important aromatic and medicinal plants.Despite of its low yield it has highly economic value. In this study the effect ofchemical and organic fertilizer on yield, weight of 1000 grain and amount ofessential oil of Cuminum cyminum variety of Isfahan had boon done. This studywas carried out in winter and spring (2007) in research farm of Shar-e Rey branch,Azad University. Treatments consisted of three levels of chemical fertilizer of N.P.K(including a1, a2 and a3) and two levels of organic fertilizer (including b1 and b2).Controls did not receive any kind of fertilizers. a1, a2 and a3 chemical fertilizertreatments composed of N=20 P=16 K=20, N=40 P=32 K=40 and N=80 P=64 K=80kg/ha, respectively. b1 and b2 organic fertilizer treatments composed of 10 and 20ton/ha, respectively. Experiment was carried out in a factorial plot with randomizedcomplete blocks with three replicates. Data was analyzed with Dunkan method.Results showed that a2 and a1 had the best effect on yield and weight of 1000 grain,respectively. Plants treated with b2 had the most essential oil. Controls had the leastyield, weight of 1000 grain and essential oil. It can be concluded that, fertilizersincreased the yield of Cuminum cyminum.

Peppermint with scientific name of Mentha. piperita from Lamiaceae family is one of themedicinal and aromatic plants that its essential oil is used widely in medicinal, food,cosmetic and health industries. Peppermint cultivated in different regions of Iran. Thisresearch was aimed to investigate the identification and selection of suitable cultivationregion and the effect of climate on essential oil and menthol content of peppermint in three different regions in Kermanshah.At suitable time, shoot of peppermint harvested and dried, then volatile oil was extractedby stream distillation method. Volatile oil was analyzed by G.C and G.C/MS methods toidentify and deter mine the menthol percent and another component. Result showed thechange of amount essential oil and menthol contents. Change of menthol was in range14 41-39 95 and essential oil was in range 2 26-3.41. This variation showed that essential oil and menthol content varied on different climatic condition. climatic condition affectod the qualityd and quantity essential oil in plant. Main components in three samples werementhol, menthone, pulegone, menthyl acetate and 1,8 cineole. Number of componentsvaried in range 38-56. Karoacrol component was not in any samples of Kermanshah.This research showed that the sample of Sahneh has the highest quantity but the highestquality belongs to sample of Kermanshah. Sample of Ghilan_gharb has the lowest ofessential oil and the highest of menthone content that it is by reason of warmer climate.

The volatile constituents of the leaf and berry of Juniperus excelsa, isolated bysteam distillation, were analyzed by GC-MS. Leaf and berry samples of juniper werecollected in summer from trees growing wild in Iran. Results indicated that the total oil (yield: 0.6% in leaves and 1.85 in berries) was consisted of almost 22 constituents including -Pinene, -elemene, trans-verbenol, verbenone, methyl carvacrol and -elemene. Comparison of volatile fresh and dried leaf and berry oil indicated that the drying affects some of the constituents,however the others do not. but others not. Analysis of fresh and dry leaf and berry oils with GC and GC-MS indicated that, -pinen as the most important constituent of leaf and berry oil was decreased after the drying, as it was decreased form 44 % in fresh leaves to 19.8 % in dried ones, and from 83.7 % in fresh berries to 75.8 % in dried ones. Whereas the amount of the other constituents in leaf and berry oil was increased after drying.