Iranian Journal of Horticultural Science
Year:2016 | Volume:46 | Issue:4|Papers Count:15

A few information about the combined effects of different environmental stress on turfgrass physiology and growth is available. Also, a separate study of environmental factors on plant cannot be a suitable model for natural conditions. This study was conducted to investigate the interactive effects of different levels of shade (0, 50, and 70%) and water treatments (well-watered and non-irrigated) on visual quality and root characteristics of wheatgrass (Agropyron deserturum L.) and tall fescue (Festuca arundinacea Schreb. ‘Forager’) in a factorial arrangement based on a completely randomized design. Under different levels of shade (50 and 70%), the negative effects of drought stress on the rate of dehydration, visual quality, ion leakage and the mortality rate of surface and deep roots was reduced. According to the ornamental performance, tall fescue had better performance than the wheatgrass under drought stress conditions and full sunlight, but wheatgrass was more successful than tall fescue under drought stress and 70% shade level. Under moderate shade (50%) and drought stress, tall fescue spent more time to dehydrate than wheatgrass. It can be concluded that in water stress conditions, shading could be useful to cope with drought stress, which needs to be further investigated.

This experiment was conducted to study the effect of plastic mulch on the growth and some physiological characteristics of two strawberry cultivars (Paros and Queen elisa) under drought stress. A factorial experiment was performed based on randomized complete block design with four treatments, including mulch, without mulch, normal irrigation (control) and deficit irrigation (-10 bar) with three replications. Some vegetative and physiological parameters in first year and yield of second year were measured. Results showed that leaf relative water content and stomatal conductance reduced by drought stress in both cultivars. Using of mulch increased leaf relative water content, cell membrane stability index and stomatal conductance in both cultivars compared with drought stress conditions. Drought stress reduced cell membrane stability index in Queen Eliza. However, Parus had higher cell membrane stability index than Queen elisa under drought conditions. Proline and total soluble carbohydrates significantly increased in both cultivars under drought stress compared to control. The amount of total soluble carbohydrates increased in Parus under drought conditions even with using mulch. Root to shoot dry weight ratio was increased under drought stress. Reduction of total dry matter was obtained by decline in leaf and petiole dry matter. However, application of mulch had significant effect on increasing of root dry weight, volume and length under drought stress. Yield of next year increased by mulch application under drought stress compared to non-mulch application. Results showed that using plastic mulch improved growth characteristics of strawberry under drought stress and helped to lower reduction of next year yield.

In order to evaluate the effects of sodium bicarbonate of irrigation water on the physiology and growth characteristics of walnut genotypes, a factorial experiment was performed with two factors including bicarbonate at 3 levels (0, 20 and 40 mM) and walnut genotypes (including local genotype A and wild genotypes B and C), based on completely random design. In this study, the effect of bicarbonate on various traits such as growth, photosynthetic parameters, osmotic adjustment compounds and nutrient elements of each genotype were examined. Results showed that bicarbonate affected all traits, and the differences among the three genotypes were clearly obvious. Irrespective of genotype, iron concentration decreased in shoots of all plants. The lowest reduction (15.17%) of iron concentration of shoots at 40 mM bicarbonate was related to the genotype A. The lowest chlorophyll percentage was observed in genotype A when exposed to bicarbonate, as compared with control. Results showed that walnut belongs to the group of horticultural crops that are highly sensitive to bicarbonate existance in irrigation water. So that, the growth of plants began to reduce from 20 mM treatment. According to the results of this study, genotype A had the highest tolerance to bicarbonate and had better growth in these conditions. Although, there was no significant difference between genotype B and C. Therefore, genotype A can be introduced as a tolerant genotype to bicarbonate existence in irrigation water and can be used in walnut breeding programs.

In order to study water deficit tolerance in Thymus daenensis subsp. daenensis ecotypes, seeds of eight ecotypes were collected from different locations. Seedling are produced in greenhouse, and then transferred to field as an experiment of split plot design based on RCBD with three replicates. Three irrigation treatments (normal irrigation, prevention of irrigation at the start of flowering and at the vegetative stages) were considered as main plots. Sub plots were formed by the ecotypes. Plants were harvested at the full bloom stage and measured for dry matter, essential oil percentage and tolerance indices. Generally, results showed that sever stress led to reduction of dry matter yield. The ecotypes under different level of irrigation showed different responses for essential oil content. High correlation observed between dry matter yields and tolerance indices. Based on the results, GMP, STI, MP and HAM were the best indices for selecting the most tolerant and the best ecotypes. According to these indexes, the ecotypes of arak, khan- e- miran bala and khan- e -miran paien were appropriate options for future studies. Totally, this plant showed high tolerance to water deficit stress and may be a good choice for culturing in water deficit conditions.

Variety creation in ornamental plants is always considered by the breeders. To achieve this goal, controlled crosses were performed among various cyclamen genotypes with different flower color, shape and leaf pattern. The results showed that crossing is effective for creating varieties with new flower characteristics in cyclamen. 15 genotypes with different flower color and shape were obtained, but white leaf patterns in more progenies were similar to the feature of their parents. In comparison to self-pollination, cross-pollination had a great influence in increasing growth rate and also in reducing required time for flowering. In general, progenies resulted from crossing compared to those from self-pollination, flowered two months earlier. Mean flower number in these progenies was averagely 1.7 times higher than that of their parents. In terms of growth rate, the progenies from cross-pollination had either more or less growth rather than parents. In conclusion, it is of worth to consider cross pollination as an effective way to create varieties with high growth rate and proper floral view in cyclamen.

Puffing is a physiological disorder in some citrus cultivars which splits pulp from peel and reduces marketing, increases rind damage and reduces shelf life of fruit. To investigate possibility of decreasing puffing, an experiment was performed in randomized complete block design with 11 treatments: 1. control, 2. mono ammonium phosphate, 3. calcium chloride, 4. potassium nitrate, 5. mono ammonium phosphate + potassium nitrate, 6. mono ammonium phosphate + GA3, 7. 2,4-D, 8. Potassium nitrate + 2,4-D, 9. Potassium nitrate + GA3, 10. Potassium nitrate + 2,4-D and 11. 2,4-D + GA3 and 4 replications with mature trees of Satsuma mandarin on sour orange rootstock. Results showed that all treatments caused to increase fruit peel density compared to control. The best treatments in increasing peel density were compound treatments: 8, 10 and 11 and nutritional treatment: mono ammonium phosphate (treatment 2). Also, treatment 2 produced the highest fruit size. The heavier and larger fruits were more puffy. Leaf copper and phosphorus concentration had a respectively positive and negative correlation with puffy fruits number. According to this experiment, it is recommended that at fruit colour break time, phosphorus foliar application should be done, while, the use of copper compound should be reduced as much as possible.

To determine the effects of biofertilizers, nitrogen and azocompost on oil yield and essential oil content of dragonhead (Dracocephalum moldavica L.), a field experiment was conducted as factorial in a randomized complete blocks design with 20 treatments and 3 replications. This study was performed at two locations during 2009-2010 on field in Tarbiat Modares University, and at the Khoy Agricultural Research Center. Treatments were consisted of two genotypes (landrace and SZK-1 cultivars), two seed inoculation (either (B1) with or without (B2) bacterial inoculation with Azotobacter + Azosprillum + pseudomonas) and five fertilization regimes (152 kg urea per hectare, F2: 114 kg urea per hectare + 85.3 tones azocompost per hectare, F3: 76 kg urea per hectare + 77.7 tones azocompost per hectare, F4: 38 kg urea per hectare + 55.11 tons azocompost per hectare and F5: 55.15 tons azocompost per hectare). F3 treatment had the highest geraniol and zhenya when genotypes were inoculated with bacterial in both regions and genotypes. Integrated treatment with 50% urea + 50% azocompost with or without bacterial inoculation in land race population, improved performance of yield and essential oil components by reducing the amount of chemical nitrogen, which could be a substitute to chemical fertilizers.

Aeroponic is a new technology for potato minituber production. In order to recognition of the suitable nutrient solution and potato variety for minituber production in aeroponics in comparison with classic hydroponics, a factorial experiment was carried out with three factors of culture systems (aeroponics and hydroponics), nutrient solutions (Chang et al., 2008; APCoAB and commercial nutrient solution of Esfahan), and three cultivars of potato (Marfana, Santana and Morn). Leaf number, leaf area, stolon length, shoot and roots dry mass, photosynthetical pigments content, photochemical quantum yield of PS II photochemistry (Fv/Fm), photosynthetical performance index (PI) were investigated. Results showed that plants growing in aeroponics exhibited a considerable increase in growth and physiological parameters regardless of cultivar and nutrient solution, compared to classic hydroponic system. It might be due to the better nutrient availability and aeration of roots in this system. Also, root and shoot dry mass of plants and photosynthetic pigment contents were higher in aeroponic than classic hydroponic grown plants. In addition, plants nourished with Esfahan economical nutrient solution had higher vegetative growth compared to Chang et al. (2008) and APCoAB nutrient solution, which was due to the higher N in this solution.

In this investigation, the effect of different treatments on breaking of seed dormancy of almond species and peach seeds include Prunus scoparia Spach, P. haussknechtii Bornm, P. communis L. and P. persica L. was studied to determine their seed germination percentages. First, mature seeds, without endocarp were treated with two percent TMTD® (tetramethylthiuram disulphide) fungicide solution for 30 min, then were tested by hydrogen peroxide ( 0%, 0.5% and 1%), GA3 (250 and 500 mgl-1) for 24 hours and stored at 7oC for 1–10 weeks. Number of germinated seeds, germination percent (GP), mean germination time (MGT) and mean germination rate (MGR) were recorded for each species. Results showed significant difference between species according to their germination time. Prunus communis L. required the least time to break seed dormancy and germinated faster among tested species while P. persica L. required the highest period of time. Also, different concentrations of hydrogen peroxide and gibberellic acid had significant effect on breaking seed dormancy of studied species. After five weeks of stratification, seed germination percentages were 68% in Prunus scoparia (0.5% H2O2), 60% in P. communis (500 ppm GA3), 42% in P. haussknechtii (500 ppm GA3) and 34% in P. persica (250 ppm GA3) while control seeds failed to germinate.

To investigate effect of calcium and growth medium on Lilium (Asiatic Hybrid Lilium bulbs “Tresor” cultivar) and nutrients uptake, a factorial experiment based on completely randomized design was conducted by three levels of calcium in nutrient solution (2, 4 and 6 mM*) and five growth media (100% Perlite, 70% Perlite + 30% Cocopeat, 50% Perlite + 50% Cocopeat, 30% Perlite + 70% Cocopeat, 100% Cocopeat) with three replicates. The attributes measureing in this experiment were height of the plant, stem diameter, length of flower stalk, number of buds, flower diagonal diameter, time taken to blossom, weight of the dried plant and postharvest vase life. Results showed that the height, stem and flower diameter, flowering stem height and bud number increased in combined bed of coccopeat and peat proportional to increment of coccopeat proportion. At the same concentration of calcium, the mixture of 70% coccopeat and 30% perlite increased flower longevity, but in net coccopeat and perlite, increasing of calcium led to increase in flower longevity.

In this experiment, effects of three polyamines (putrescine, spermidine and spermine) on postharvest life of plum fruit cv. ‘Shablon’ were studied. Fruit was dipped in solution of polyamines with 1 and 2 mM and distilled water (control) for 5 min in a cold storage at 1.5±0.5°C and 80-85% RH. Experiment was conducted in a factorial with a complete randomized design with 7 treatments and 6 storage time with three replications. Fruit firmness, titratable acidity and pH, soluble solids and weight loss were evaluated once a week. Also, the rate of ethylene production was determined in three weeks, and polygalacturonase enzyme activity was measured at the first and last of storage life. Polyamines reduced ethylene production significantly and was maintained the fruit firmness. The most effective treatment in maintaining the firmness was 2 mM spermine. Also, this treatment was effective in preventing of ethylene production with 2 mM putrescine and 1 mM spermidine. No difference was found between the three polyamines in prevention of polygalacturonase enzyme activity. Polyamine treatments were prevented fruit weight loss significantly during storage.

This study was conducted to evaluate the effect of water stress on the growth and mineral concentrations in the leaves and roots of four pistachio seedling rootstocks including Pistacia vera ‘Badami-Riz-Zarand’, ‘Ghazvini’, ‘Sarakhs’ and P. mutica. Irrigation treatments were 100% ETc (control), 65% ETc (medium stress) and 30% ETc (severe stress) applying for 75 days on four months old pistachio seedlings. At the end of experiment, biomass and nutrient contents in the leaves and roots were determined. The obtained results indicated that water stress had significant effects on biomass and mineral composition of the leaves and roots of studied rootstocks. In the case of shoot, root and leaf dry weight, the rootstocks P. mutica and P. vera cv. `Badami-Riz-Zarand’ showed lower reduction under water stress. P. mutica showed greatest contents of P and Mn in the leaves and P, K and Ca in the roots under water stress. P. vera ‘Badami-Riz-Zarand’ also showed highest contents of Mg in the leaves and roots under water stress, whereas, `Ghazvini’ showed highest contents of N, K, Cu in the leaves and Fe, Cu, Zn in the root under water stress. Pistacia vera L. ‘Sarakhs’ also showed highest contents of Fe in the leaves and N, Mn in the root under water stress. Based on the obtained results, it was concluded that water stress had negative effects on pistachio seedling rootstocks and P. mutica and P. vera ‘Badami-Riz-Zarand’ showed more resistance than the other genotypes.

Silicon has useful effects on growth and yield of many plants. The aim of the present study is to investigate the impact of nano silicon oxide on proliferation and improvement of some growth traits of apple, cultivar Gala. Thus, an experiment was designed based on completely randomized design (CRD) with five levels of nano silicon oxide concentrations (0, 25, 50, 100 & 200 ppm) in five replications. The means were compared with Duncan s Multiple Range Test. Results showed that nano silicon increased fresh and dry weight, length of shoots, number of shoots, and chlorophyll index, in which the highest amount of was observed at 100 ppm silicon oxide. According to the result of this investigation; 100 ppm silicon oxide can be added to MS medium to improve in vitro growth and proliferation rate of cultivar Gala apple explants.

Because of the harmful effects of the chemicals on human health and environment, the use of these compounds is recently restricted and it is necessary to use the safe compounds in postharvest technology of fruits and vegetables. In this study, the effect of salicylic acid (SA; at concentrations of 0, 1, and 2 mMol L-1) and Aloe vera gel (at concentrations of 25 and 33 %1) application on postharvest life and quality of grape cv. Gizel uzum was studied during storage at 0±0.5C with 90-95% RH for 45 and 90 days in Urmia university lab during October 2011. Experiment was based on completely randomized design with six replications fruit and each replicate contained fresh grapes. Quality characteristics, including pH, total acidity, vitamin c, antioxidant property, catalase activity, and percent weight loss were evaluated. Treatments of 33% Aloe vera gel and 2 mM salicylic acid could significantly maintain antioxidant activity by increasing catalase activity and had significant effect on organic acids, and vitamin c level, percentage of weight loss and the amount of fruit juice pH.

In present study two species of Pleurotus with different morphological characteristics were collected from Guilan forest and then cultured on MEA medium. Spawn was prepared on wheat grains and finally all strains were cultivated on rice straw. Identification of species was performed by PCR, microscopic and macroscopic characters. Results revealed that our local strains are known as Pleurotus ostreatus and Pleurotus pulmonarius. Minimum days required for pinhead formation were observed in P. florida (14.8 days). The highest protein and nitrogen content was found in P. florida (26.24 and 9.77%). In other characteristics, there were no any significant differences between strains.