حمیدرضا محمددوست

Urban landscapes are considered as one of the main elements of beauty in cities. In order to investigate the effect of different herbicides on the control of dandelion in the lawn, an experiment was conducted in the greenhouse and natural landscape of University of Mohaghegh Ardabili in 2021. For this purpose, first, in the screening test, nine broad-leaved and dual-purpose herbicides were tested at 0.25, 0.5 x , 1 x and 2 x recommended dose with a control (no herbicide application) in the greenhouse environment on dandelion seedlings. After the statistical analysis of the data from this stage, six herbicides bromoxynil, U46, Otello, Dylan, Atlantis and Total were selected and tested at 0.5, 1 and 2 of recommended dose with the control in natural conditions. It was used in three replications in the landscape infected with dandelions in plots of 1 square meter (1x1). In natural condition, applied of bromoxynil and U46 reduced dandelion dry weight by more than 50% compared to control, which had significantly different with other treatments (except Total). In this case, level of visual scoring on lawn was less than 20% in U46, Bromoxynil, Dylan, Atlantis and Total herbicides and had no significant difference between them. Application of 2x recommended dose of bromoxynil, U46 and Atlantis herbicides had the lowest density of dandelion, which was 37, 50 and 37% less compared with control (dose 0), respectively.

The 2019 novel coronavirus is another type of known coronaviruses; SARS-CoV-1 and MERS-CoV. The World Health Organization (WHO) has named the virus SARS-CoV-2 and its disease as coronavirus disease 2019 (abbreviated COVID-19). The first case of COVID-19 was reported in December 2019 in Wuhan, China. The epidemiological studies have shown that the disease is transmitted from animal to human, and the spread of the disease from person to person is rapidly expanding. Currently, the most important factor in preventing and controlling the spread of the disease is proper recognition, health care, and control measures. Given the importance of early detection and timely treatment of the disease, the use of nanoscale materials for the production of sensors and drug delivery system can be of great assistance to the researchers. In this context, we aimed to explain the effects of the prevalence of the disease worldwide and consider the different aspects of SARS-CoV-2.

Borage is one of the important medicinal plants with unequal and poor seed germination as a result of deterioration during storage. With attention to abundance of salty water and soils in country, this research was contacted to study of the effect of priming and deterioration of seed on germination, growth and biochemistry characteristic of borage under salinity stress. The experimental treatments were salinity stress, seed priming and deterioration duration (0, 8 and 14 hours). The results showed that percentage and rate of germination, seedling dry weight and length and weight were decreased with increasing of salinity stress levels and duration of deterioration. Seedlings dry weight loss was about 75% to 78% under salinity stress. Activity of peroxidase and catalase enzymes and proline content in seedling were increased under salinity stress, and this increase in seedlings from primed seeds was significantly higher than those of control seeds. Seed priming significantly increased the seed germination, growth and prolin content of seedling in both salinity stress and deterioration conditions. Seed priming caused a 1.6 and 2.5- fold increase in the catalase activity of seedlings derived from undeteriorated and deteriorated (14 hours) seeds, respectively. Generally, seed priming with ascorbic acid was reduced the negative effects of salinity stress and deterioration through increasing seed vigor and improving the biochemical properties of seedlings, and led to improve the seed germination and seedling growth under favorable and unfavorable conditions.

Cyerus rotundus is a perennial weed of the Cyperaceae family spread throughout the tropical and subtropical parts of the world. It is a C4 and fast-growing plant that replicates rapidly through the extensive underground system and tuber. This weed causes damage to more than 92 countries and 50 crop species. In this regard, it is considered as the most damaging weed in the world. The amount of damage varies depending on the crop. One of the most important characteristics of purple nutsedge is the production of the tuber. According to available studies, burial depth of tuber plays an important role in the emergence of the onset of the competition period. Among the physical properties of the soil, soil texture plays an important role on plant growth characteristics, development of underground organs, especially in tuber plants and the amount of water penetration and maintenance. So, given the importance of accurately recognizing the biology and the ability to reproduce of nutsedge in its management, this research is also intended to study the effect of burial depths and the soil texture on the growth of purple nutsedge.

In order to evaluate the effects of soil texture and burial depth on purple nutsedge vegetative characteristics, a trial was conducted at Kerman Natural Resources and Agricultural Research Center, using factorial statistical method and experimental design of randomized complete blocks at three replications. The first factor was burial depth at five levels (2, 12, 22, 32 and 42 cm) and second factor was soil texture at three levels (sandy loam, silty loam and clay loam). The traits of emergence percentage, the time of emergence, the number of produced tubers and dry weight of the underground organs were measured at 130 days after planting. For this purpose, the pots and dumps were emptied, then the underground organs were separated and placed in paper envelopes and finally, paper envelopes were placed in oven with temperature of 75°C for 72 hours. Data were analyzed using SAS v. 9.1 software. Figures are also plotted by Sigmaplot v. 12 and Excel v. 2013.
Results and Discussion The results showed that emergence time, germination percentage, underground organ dry weight and tuber numbers were affected by depth of planting and soil texture. Emergence of C. rotundus was faster in sandy soil and at a lower depth, so that the tubers grew in the sandy loam soil at a depth of 2 cm 7/7 days after planting (the shortest time), and silty loam and clay loam were ranked next lowest. Understanding ecology of germination and weed emergence plays an important role in their management. With increasing depth of sowing, the percentage of germination in the tested soil texture decreased. So that the maximum amount of germination (85%) was obtained at 2 cm depth of sandy loam soil and the lowest germination percentage was observed at depths > 32 cm in silty loam and clay loam soils and the depth of 42 cm of sandy loam soil encountered with no germination and emergence of seedling. According to the results, the underground organ dry weight of C. rotundus in the textures and depths of the soil was quite different. In sandy loam, the highest underground dry weight was obtained at the 2 cm depth and the lowest was at 42 cm depth (0) of sandy loam. The highest underground dry weight of the tuber (63.6 g) was observed at 12 cm depth and the lowest (0) was obtained at 32 and 42 cm depths. The results showed the highest tubers number was observed at 2 cm depth of sandy loam soil and the lowest was obtained at 42 cm depth of sandy loamy and 32 cm and 42 cm depth of sandy loamy. The number of tubers decreased with increasing planting depth in all three texture types. The highest percentage of tuber production in heavy textures (silty loam and clay loam) was formed in layers of 2 to 12 cm of the soil.

The results showed that with increasing depth in all three types of soil texture, all the growth characteristics of purple nutsedge significantly reduced. More than 80% of the distribution and dispresal of underground organs was formed at a depth of 2 to 12 cm. The percentage of emergence decreased by 100 % at 32 and 42 cm depths of clay loam and silty loam. It seems that, the lack of emergence at the high soil depth is due to disruption of gas exchanges and lack of light. Given the importance of tubers in reproduction of this plant, this should be considered in management strategies. The deep plowing by delaying the emergence and growth and decreasing the production of reproductive organs (rhizome and tuber) of purple nutsedge can be considered as a management option. This weed has high emergence ability in the sandy loam soils due to high permeability and porosity.

Wheat is one of the most important and strategic products and is the most valuable food for the people of the world, especially the Third World countries. Wheat farms in arid and semiarid regions in rainfed conditions are generally exposed to drought stress at the germination, emergence and the late stages of the growing season. The effects of PEG simulated osmotic stress on morphological traits, such as root and stem length, fresh and dry weight of root and stem have been studied in a large number of previous studies. This research was conducted to investigate the effect of osmotic stress on morphological characteristics of advanced durum wheat lines and to classify the studied lines in terms of osmotic stress tolerance and to identify the susceptible and tolerant lines. In order to study the effect of osmotic stress in durum wheat lines, 83 lines were evaluated at two levels including zero (control) and -4 bar osmotic potential. The experiment was done in tow condition based on completely randomized design with four replications. Polyethylene glycol 6000 was used to create -4 bar osmotic potential. The lines were cultivated in plastic pots with 10 cm diameter and 50 cm height that filled with sand. Irrigation of all pots until germination of seeds was done by normal water. After germination stage, control pots irrigated with Hogland solution and under stress pots irrigated with Hogland solution contain PEG6000. The Measurement of morphological traits included root and shoot length, fresh and dry weight of root and shoot, root volume and root area was done one month after applying stress and Ti and SIIG indices were calculated based on these traits. After calculating the Ti index for the studied lines and obtaining the highest and lowest tolerance index for each trait, they were used to calculate the distance of each line from the positive ideal genotype (d +) and the ideal negative genotype (-d). In addition to using the SIIG index in this analysis, the grouping of the studied lines was done using cluster analysis using Ward method. This grouping was performed by applying the average of the lines for Ti index and the results of cluster analysis were compared with the results of the SIIG index. Statistical analysis of data was done using SPSS16 software and comparison of averages was done with Duncan's test at a probability level of 1%. The results of variance analysis of Ti showed that the lines had a significant difference in all traits at 1% probability level. Based on the results of the comparison of the average of durum wheat lines in terms of the Ti indices calculated from the traits, in most traits, the lines 9, 26, 34, 40 and 53 the lines had the highest value of Ti index and the lines 22, 29, 51, 77 and 79 were the lines with the lowest value of Ti index. The high level of this index on each line indicates the high tolerance of these lines to osmotic stress. The results of line rating using SIIG method showed that lines 9, 16, 24, 25, 26, 34, 35, 38, 53 and 64 had the highest SIIG in comparison with other lines and these lines were identified as the most tolerated ones to osmotic stress. Lines 22, 29, 30, 51, 52, 61, 73, 77, 79 and 82 were ten lines with the least amount of SIIG and were the most sensitive lines to osmotic stress. Based on the indices of Ti, lines 34, 9, 53, 26, 40, 16, 64, 7 have a high average and lines 29, 77, 22, 30, 51, 13, 79 have the low average of the traits . According to the SIIG index, the lines 34.9, 53, 26, 16, 64, 38, 25, 35, 24 were in the high average group and the lines 61, 52, 51, 30, 82, 73, 79, 77, 29, 22 were in the low average group. These results were also obtained in cluster analysis, and the results of this grouping were highly consistent with the results of the lines' ranking using the SIIG index. This shows that the SIIG index helps the researcher to sum up the results of different indices. In general, it can be presented that in this study, the lines 9, 34, 53, 26, 16, 64, 38, 25, 35, 24 were tolerant lines and the lines 61, 52, 51, 30, 82, 73, 79, 77, 29, 22 were susceptible ones to osmotic stress.

To evaluate the effect of different levels of nitrogen fertilizer and rimsulfuron herbicide interactions on weeds density and biomass and potato yield, a field study was conducted as a factorial experiment on the randomized complete block design with 3 replications in South Kerman Agriculture and Natural Resources Research and Education Center, Jiroft. The treatments included rimsulfuron 25%DF application at five levels (0, 30, 40, 50 and 60 g ha-1) and nitrogen fertilizer as urea 46 at 4 levels (0, 90, 180 and 270 kg ha-1). Weed densities was measured 30 days after spraying and weed biomass and potato yield were measured at the end of the growing season. The results showed that rimsulfuron and nitrogen fertilizer had significant effects on density and biomass of all weeds (Digera muricata (L.) Mart., Echinochloa colonum L., Chenopodium murale L., Malva parviflora L. and Portulaca oleracea L.). weed density and biomass decreased significantly, when rimsulfuron increased. In the absence of rimsulfuron, using the nitrogen increased weed density and dry weight. However, application of nitrogen fertilizer and imsulfuron decreased weeds density and biomass. Application of 50 and 60 g ha-1 rimsulfuron plus 180 kg ha-1 nitrogen was the best treatment for reducing the density and biomass of weeds and increasing yield of potato by 91 (35.9 T ha-1) and 92% (36.38 T ha-1), compared to the control treatment, respectively.

In order to study tolerance of durum wheat (Triticum durum) lines to drought stress and also evaluating stress tolerance indices, an experiment based on randomized complete block design with four replications was conducted under two rain fed and supplementary irrigation conditions at Gachsaran station during 2011-2012 cropping season using 20 durum wheat lines. Results of combined analysis of variance for seed yield showed significant differences (p≤0.01) between lines and interaction between lines and environment. The yield based indices were calculated in rain fed and supplementary irrigation conditions. With considering of significant positive correlation between grain yield in the rain fed condition (YS) with geometric mean productivity index (GMP), mean productivity index (MP), stress tolerance index (STI), yield index (YI), drought response index (DRI), drought resistance index (DI), harmonic mean (HM) and modified stress tolerance index (K1STI), these indices were suitable criteria for identification of drought tolerant lines. Also, tolerance index (TOL), yield stability index (YSI), stress susceptibility index (SSI), relative drought index (RDI), abiotic tolerance index (ATI), stress susceptibility percentage index (SSPI) and stress non-stress production index (SNPI) didn’t have important role in the differentiation of lines. Grouping of lines using cluster analysis method showed that the lines 3 and 13 had high yield and were tolerant rain fed condition and the lines 7 and 18 were sensitive to rain fed condition. The results from grouping of lines using three dimensional graphs based on yield in rain fed and supplementary irrigated condition and STI index were same as cluster analysis.

Environmental stresses are the most important factors that reduce plant growth in stages of development. The presence of aluminum in acidic soils as an environmental stress has an impact on different parts of the plant and reduces root growth, water absorption and nutrients and increases susceptibility to drought. In order to evaluate the effect of aluminum stress levels on wheat at germination stage, an experiment was conducted as factorial based on completely randomized design with three replications. The root and shoot characters of four wheat cultivars (Arta, Gascozen, Moghan3, Mihan) at seedling stage were studied at eight stress levels (control, 0.5, 1, 1.5, 2, 2.5, 5 and 10 mM Al
3
). The root and shoot fresh weight, root and shoot length, root volume and area, root number and Root/Shoot ratio were measured. Results showed that stress level had significant effects on all studied traits. Also, wheat cultivars were significantly different for number, volume, weight and area of root and also shoot length. Interaction between cultivars and stress levels was significant for root number. The Mogha3 variety had higher root number at 2.5 mM Al
3
stress level. In all of varieties, the root number increased by increasing of Al
3
concentration. Comparison of means showed that Al
3
stress caused significant reduction in all studied traits except root number. The Moghan3 variety had higher means for studied traits as compare with other varieties.