نشریه علوم باغبانی
سال بیست و سوم شماره 1 (پیاپی 5، بهار و تابستان 1388)

Many uses of landscape and important roll of ground covers aspect turfgrasses caused extensive of this plant in the cities. This study focuses on shoot responses and tolerance of native and commercial turf grasses under drought stress in a factorial experiment based on unbalanced completely random design on the year 2006. The specious that we used in this experiment included (i) commercial tall fescue (Festuca arundinacea) (ii) commercial perennial ryegrass (Lolium perenne) (iii) native tall fescue population (Festuca arundinacea). The drought stress levels included (i) 50%FC (ii) 25% FC (iii) recovery from drought stress and 3 groups of pots that was always in the field capacity condition. The results of this study showed that dry weight decreased 26.4% in 25% FC traits in compare with control traits under severe drought stress. Decreased in leaf wide, leaf total area, leaf total length and increase in leaf diameter caused decrease in evaportanspiration under drought stress in festuca genus. Parameter of quality change (TQ) and decrease in total chlorophyll content was minimum in native tall fescue and maximum in commercial ryegrass, from perfect irrigation to sever drought stress. Shoot dry weight, leaf width, total leaf area and total leaf length, visual quality and leaf total chlorophyll content increased 18.2%, 103.3%, 74.4%, 28.8%, 64.1%, 40.8% respectively, and mean leaf diameter decreased 53.2% in compare with sever drought stress condition after 14 days rewatering.

In order to study the effect of elements in early splitting and the effect of phenolic compounds and Gallic acid in control of aflatoxin, an experiment was conducted in Rafsanjan pistachio research station. At harvest, from the trees of 3 pistachio’s varieties(Ahmadaghaii, Kalehghuchi, Ohadi) 15 clusters in each variety collected as randomized and phenolic compounds and Gallic acid in hulls were determined. From all varieties, many fruits of each type such as early split, cracked and true fruits collected and their hulls examined for macro and micro elements. These experiments were performed in 1385 according to complete randomized design and results analyzed in 3 replications by Duncan test with SAS and Sigma plot soft wares. Highest rate of Nitrogen (2.15%) in the intact fruit hulls and lowest rates was in early split and cracked fruit hulls (1.94 & 1.97%). Highest rate of Mg (0.13%) was in the intact fruit hulls and lowest rates were in early split pistachio hulls (10%). Maximum rates of phenolic compound determined in the fruit hulls of Ohadi variety (1398mg/100gr) and the minimum rates measured in the fruit hulls of Ahmadaghaii 1131 mg/100g. Results showed that increase rates of phenolic compound caused to reduction or prevention of aflatoxin in the pistachio’s fruits.

Shiitake mushroom [Lentinulus edodes(Berk) Singer/Pegler] has the third production class among the most important edible mushrooms. For a long time this mushroom has draw attention due to its unique flavor and taste and also therapeutic properties. The research conducted to optimizing the environmental conditions for shiitake production. In the first experiment the effect of four medium types in solid form, three medium pH (4.5, 5.5 and 6.5) and two temperatures regimes (25 and 27 oC) were evaluated on mycelium radial growth of the mushroom. In second experiment the effect of medium types and pH was evaluated on mycelium yield in liquid form at 25 oC. The experimental design in both media was factorial on the basis of completely randomized design with 4 replications.The obtained results of the first experiment showed that medium type, pH and temperature significantly affect mycelium growth rate at p≤0.01. Interaction between medium×pH, temperature×medium and pH×temperature also was significant at p≤0.01. The highest growth rate (8.548mm/day) was detected on 1 and 2 “hand making” media and the lowest one (6.201mm/day) was observed on 3 hand making media. The higher temperature (27 0C) cause the lower the mycelium growth rate. Increasing the medium pH from 4.5 to 6.5 also decreased mycelium growth rate and the highest growth rate was observed at pH=4.5. In second experiment (liquid medium), medium type and pH also affect mycelium yield significantly (p≤0.05). The highest mycelium yield was belong to hand making media and on the contrary with first experiment, the best mycelium yield was obtained on pH=5.5.

Field experiment was carried out at the Ferdowsi University research field, Mashhad, Iran during 2006-2007, to determine how much effective the N-fertilization is, to find out the most suitable plant density which could be used in chamomile (Matricaria chamomilla L. Asteraceae) to increase the yield of anthodium flowers and content of essential oil. The experimental design was as two factor factorial completely randomized block design having four plant densities (D1=20pl/m2, D2=25pl/m2, D3=40pl/m2 and D4=50pl/m2) as first factor and three levels of Urea™ fertilizer (%46) (N0=0g/m2, N1=10g/m2 and N2=20g/m2) as second factor, replicated thrice. During the flowering period, growth indexes such as plant height, anthodia diameter, dry flower yield, essential oil content and chamazolene were measured. The results indicate that plant density and urea do not have a significant effect on morphological characters. Plant density had significant effect on dry flower yield and essential oil yield. So, maximum yield of dry flower and oil were obtained at 50 pl/m2. In the other hand, the increasing of Urea up to 20g/m2 caused dry flower yield, essential oil content and yield and chamazolene content to be increased significantly. The significant interaction between plant density and Urea levels had been recorded in the case of yield of dry flower and essential oil of Bodegold.

An experiment was conducted to study growth analysis and evaluation of change in simple non- structural carbohydrates (sucrose, glucose and fructose) during bulb formation of Ghermez Azarshahr, Zargan, Safid naishaboor and Safid Qom cultivars in randomized complete block design containing three replications. Seeds were sown in nursery in early February and seedlings were transplanted in early May. During initiation of bulbing carbohydrates accumulated in leaf bases. Before and after bulb formation (about 20 days after bulb formation) the most simple non-structural carbohydrates content was found in Safid Qom cultivar. The maximum and minimum increasing percent of simple non- structural carbohydrates components belong to glucose and sucrose respectively. The results of growth analysis indicated that the period of slow growth had been about 75 days after emergence (for all studied cultivars) and then the period of rapid growth of leaf has begun. The bulb growth rate of Zargan cultivar during the most parts of bulb development stage was higher than other culitivars, due to this reason and earliest date of bulbing, yield of mentioned cultivar was higher as compared with other cultivars. A high significant positive correlation (r = 48%) was found between relative growth rate and net assimilation rate at 1% level. Zargan cultivar produced the highest total and marketable yield, so that mentioned cultivar is recommended for Karaj region.

To evaluate the influence of nitrogen rate and split application method on tuber yield and other quantitative characteristics of different potato cultivars, a 2-yr experiment was conducted at Khorasan Razavi Agricultural and Natural Resources Research Center. Experimental treatments consisted of four nitrogen rates (0, 90, 180 and 270 kg N ha-1) with two split applications (emergence and hilling stages) or three split applications (planting, emergence and hilling stages) and six potato cultivars (Fontane, Kuras, Agria, Miriam, Cosmos and Picasso) that were arranged in a randomized complete block split-split plot design. Shoot dry weight, average stem length, tuber number per plant, total tuber yield, marketable tuber yield

The variation of leaf number and area on fruit weight, fruit number and plant yield in relation with environment temperature in three cucumber cultivars (Green Gold and Dharwad native of India and a new cultivars namely Super Dominus) in experimental field of Gorgan university were studied in 2007. In this study, the first flowers after formation of 4.99, 17.74 and 28.5 leaves in Green Gold, Dharwad and Super Dominus appeared, respectively. This obtained results showed that after planting with increase of daily time, leaf number, leaf area and dry weight (g) increased as well. Then with progress of plant growth the amount of heat unit which is required for completing of a leaf, one cm2 leaf area and one gram dry weight decreased. This trend continued till the end of harvesting that was lowest. The results showed that essential heat for fruit set in Super Dominus, Dharwad and Green Gold were 470.5, 485 and 593.25 degree days, respectively. A negative correlation (-0.86) were observed between the number of fruits per plant and their weight. In this research between time of first harvest and fruit number negative correlation (-0.93) observed but the correlation (p)

Soilless culture of greenhouse vegetables has been a fast developing section in Iran during recent years. Most growers use hydroponics systems with artificial substrates. Some of the used substrates have low water retention which results in wasting a great deal of solution. On the other hand, low vigor of cucumber root in water and fertilizer absorption, especially in low media temperatures causes decrease of absorption and yield as well as appearing deficiency symptoms. In this research we studied effect of hydrogel amendment and Cucurbita pepo. Rootstock on hydroponicaly cultured greenhouse cucumber. Results showed that incorporating hydrogel into media could improve perlit physical properties and increased it’s water holding capacity. This condition could also decrease leaching fraction and increase yield and water/ fertilizer use efficiency. Furthermore, grafted plants grown in non-amendment substrates had higher yield and water/ fertilizer use efficiency compared to non grafted ones.

Chilling injury of vegetative and generative buds, bark and wood during fall and winter seasons are mainly limiting factors for productivity of fruits. Selecting and expanding cultivars for more yield and quality without attention to the rate of their frost resistance are impossible. In this research, the rate of relative resistance of some peach and nectarine cultivars at a sudden downfall of temperature was analyzed in vivo weather conditions during the 2008 winter season in Mashhad. The meteorology station of the studied area (Golmakan station) registered -22°C for the minimum temperature of this year on 13th January, which was a little different from the weather of Mashhad. This test is performed as factorials in the form of a randomized complete block design with three replications. Relative ionic leakage is used on reproductive and vegetative buds, annual and biennial wood in peach cultivars (J.H.Hale, Elberta, Redhaven, Mashhad Sorkhosepfide and Mashhad Ghermez) and nectarine cultivars (Indipendens, Qiuota, Nectared 6 and Stargold). Between studied peach and nectarine cultivars, Mashhad Sorkhosephid and Mashhad Ghermez cultivars, which are cultivars native to Iran, were the most resistant reproductive buds that did not have a significant difference in comparison with other peach and nectarine cultivars with the exclusion of Indipendense cultivar. The most sensitive reproductive buds were nectarine Indipendense cultivar and the most resistant vegetative buds were Mashhad Sorkhosephid and Redhaven in peach cultivars and Nectared 6 and Qiuta cultivars in nectarine cultivars. The relative ionic leakage of annual wood in peach cultivars was more than nectarine cultivars. But the relative ionic leakage between peach cultivars was not significant and Nectared 6 cultivar did not have any difference compared to peach cultivars. The "Sorkhosephid" peach cultivar of Mashhad had more solution carbohydrates in generative buds and annual wood (93.33 and 136.50 mg/lit, respectively) than other studied cultivars. Results of sugar rate followed relative ionic leakage and visual observations and showed increasing sugar and decreasing ionic leakage in organ caused lower their susceptibility to cold.

Silicon (Si) is considered one of the beneficial elements for plant, however recent studies show that Si plays an important role in plant resistance to environmental stresses, like salinity. An experiment was conducted to study the effect of Si and NaCl salinity on the growth, yield and fruit quality of strawberry (Fragaria × ananassa Duch) cv “selva” was grown hydroponically in the controlled environment glasshouse. Three levels of NaCl (0, 20, 40 mM) and three levels of Si (0, 1, 2 mM) was factorially combined in a completely randomized design with four replicates. The yield characteristics and fruit quality were measured during the experimental period. At the end of the experiment, plants were cut and vegetative characteristics such as number, fresh and dry weights and leaf area were measured. In addition, leaf relative water content and chlorophyll index were measured. The results showed that salinity reduced the vegetative characteristics, increasing the Si in the saline conditions, increased the number, fresh and dry weights and leaf area of the strawberry plants. The yield characteristics was reduced in the saline conditions, however applying Si reduced the adverse effects of salinity on the yield components. Both salinity and Si had no effect on the chlorophyll index. Leaf relative water content was reduced in salt stress, but silicon treatment largely improved relative water content of leaf. Both salinity and Si treatments increased acidity of fruit, but other quality characteristics were not affected by the treatments. The results reported here indicated that application of Si is recommend under salinity stress in strawberry.