مجله علوم و فنون باغبانی ایران
سال پانزدهم شماره 1 (بهار 1393)

In a greenhouse experiment, the effects of salinity was studied on endogenous levels of two hormones; jasmonic acid (JA) and abscisic acid (ABA), some growth parameters and proline content. Strawberry (Fragaria ananassa Duch.) plants of two cultivars, ‘Queen Elisa’ and ‘Kurdistan’ were exposed to four levels of NaCl (0, 5, 10 and 20 mM) for four months. The experimental design was a complete randomized design with 3 replications and 3 plants per replicates. The highest concentration of ABA was recorded under the maximum level of salt stress (20 mM) for both cultivars. The highest level of JA was detected in ‘Kurdistan’ when 20 mM of NaCl was used. In total endogenous concentrations of ABA and JA were higher in ‘Kurdistan’ leaves compared to ‘Queen Elisa’. A rising trend in proline content was observed by increasing salinity level. Salinity stress lowered leaf relative water content (LRWC) in both cultivars. A close relation between JA, ABA and proline accumulation and relative water content reduction was observed in this experiment. Root, crown and shoot fresh and dry weight were decreased by salt treatment but both ABA and JA accumulation could not ameliorate the inhibitory effects of salt on growth. Possibly higher levels of both ABA and JA content, for ‘Kurdistan’ in the saline conditions, is related to stronger protective mechanism against salt stress compared to ‘Kurdistan’.

In this experiment, the effects of mulch application on of soil moisture conservation and water use efficiency and also their effects on yield and yield component of almond were investigated. Experiment was conducted under irrigation condition (drip irrigation) in a randomized complete block design (RCBD) with three replications and four trees per each plot in two years in Eghlid area. Treatments consisted of 1- No mulch application as farmer traditional condition (ctrl.), 2- Inorganic Pamis (volcanic mulch) with 2 cm thickness, 3- Organic shredded wood mulch, 4- Glycyrrhiza root waste mulch, 5- Wheat straw mulch, each of them under tree canopy and full coverage treatment with 10 cm thickness. The experiment was carried out on 108 uniform almond trees. The results showed that different treatments had significant effects on improving the soil water percentage in 0-40 cm depth from soil surface and soil moisture depletion. Mulch application improved vegetative and reproductive traits such as number of current season growth branches, bud burst time, flower intensity, fruit dimensions, kernel weight, blankness and twin percentage. Straw mulch treatment was the best and in comparison with the control treatment it was increased the pure profitability by 138.5% followed by shredded wood, Glycyrrhiza root waste and inorganic Pamis mulch under tree canopy.

Fritillar iaimperialis is one of the most beautiful ornamental plants all over the world and is propagated by bulbs and seeds. Uncontrolled harvesting of this plant from its natural habitats resulted to exposure it to endanger. Due to the limitations of conventional methods of propagation, therefore using a tissue culture technique may be a suitable and alternative technique for large- scale propagation of this species. In this study, bulb scale explants were cultured on MS medium and Gamborg medium (B5) and different explants of sexual embryos, eggs, ovaries, leaves and stems were cultured only on MS medium. Results showed that among the different explants only bulb scale and embryo explants produced bulblets during subcultures. Also the highest number of bulblets was produced from scale explants in concentrations of 5 mg l-1 NAA and 3 mg l-1 BAP. Due to the stronger shoot and root induction and also the greater number of bulblet production via scale culture than embryos, the scale explants is recommended for micropropagation of Fritillar iaimperialis.

Genetic diversity is an important mean for breeding program. In this study, 70 accessions of hazelnut from two areas of Guilan (Eshkevarat) and Ardabil (Fandoghloo) were selected and tested with 15 pair primers of microsatellite markers. DNA was extracted from young leaves and then amplified with 15 pair primers by PCR method. Results showed 53 polymorphic alleles at the 15 SSR loci with average of 3.5 in each locus. The most alleles were observed in CAC-B029b with 7 alleles. Average observed and expected heterozygosity was 0.46 and 0.44, respectively. Mean polymorphic information content was calculated 0.48 and the highest PIC was related to CAC-B029b with 0.77. Cluster analysis using UPGMA method Jaccard’s similarity ratio divided the samples in to seven main groups. Results also detected microsatellite markers in this study showed a high level of genetic diversity among genotypes.

At the time of harvest and postharvest, some parameters like tissue firmness, tissue color and fresh weight are altered which affect the visual quality of fruit as well as intensifying the physiological disorders. This study was performed with the aim of determining the effect of calcium spraying time and sources on some quantitative, qualitative and postharvest characteristics of ‘Elberta’ peach cultivar. In this experiment, CaCl2 (0.5 and 1%),Ca(NO3 2 (0.5 and 1%) and Calcium Chelate (0.1 and 0.2%) were sprayed once, 50 days after full bloom (pit hardening stage) and three times spraying starting at 50 days after full bloom with two-week intervals. Experiment was performed as randomized completely block design with 11 treatments and five replications. After harvest, peach fruits were stored at 4ºC and 90±2% relative humidity. The results showed that both concentrations of CaCl2 (0.5 and 1%) as three times spraying increased the fruit firmness (at harvest and postharvest stages) and reduced the tissue browning (25%) and water loss (11%) in comparison to the control after two weeks of cold storage. It is concluded that repeated calcium spraying, may result in improving the growth parameters as well as the postharvest characteristics of peach fruit.

Storage conditions influence quality of gladious corms thereby affecting quality of flowers. In the present study, the effects of pre-storage curing and different temperature conditions on morphological, anatomical and physiological characteristics of corms and flowers of two cultivars were studied. Application of pre-storage curing plus one or two month cold treatment at 5°C accelerated morphological, anatomical and physiological changes in corms. These corms had less starch and more soluble sugars at the end of storage period comparing to the corms stored at the other conditions. These changes in corms with two months cold treatment at 5°C were significant. The corms stored during whole storage period at 13 and 5°C showed high level of starch and low level of soluble sugars. The observations of both cultivars followed the same trend.

Growth and potential of mineral uptake by tow citrus rootstocks [sour orange (Citrus aurantium L.) and trifoliate orange (Poncirus trifoliate Raf.)] was investigated under in vitro salt stress. A factorial experiment in a completely randomized design was conducted in tissue culture laboratory of University of Zanjan. First, explants (nucellar seedling obtained from seeds) of both rootstocks were proliferated on Murashige and Skoog (MS) solid medium containing 8.9 μM benzyladenine (BA) and 0.5 μM naphthaline acetic acid (NAA). After proliferation, nucellar seedlings were subcultured to same proliferation culture medium with different concentrations 0, 50, 100, 150 and 200 mM sodium chloride (NaCl) as salinity treatment. At the end of experiment (6th week), growth parameters (dry weight, shoot length and shoot number), concentrations of macro and microelements, sodium and chlorineions in plant tissues (as uptake index) were measured. There were significant differences between two rootstocks in control and other treatments on growth parameters, mineral uptake, sodium and chlorine ions. At 200 mM sodium chloride, explants grown of trifoliate orange were stopped after three weeks and gradually at 5th week were necrotic. The highest and lowest dry weight and concentration of mineral (uptake index) were observed in the control and of 200 mM concentration of sodium chloride, respectively, while copper uptake was not affected by salinity stress. In comparison with trifoliate orange, sour orange was more capable rootstock for nitrogen and phosphorous uptake under salinity stress. Also, accumulation of sodium and chloride ions in sour orange tissue was significantly lower than trifoliate orange. Based on the obtained results, it is concluded that sour orange rootstock is more tolerant to NaCl salinity than trifoliate orange.

Graden or bedding plants are suitable for landscape design purposes. Marigold (Tagetes spp.) is currently a popular landscape bedding and garden plant due to its color range and moderate tolerance to drought. Therefore, increasing flower number, flower diameter, and some other parameter related to bedding plants performance such as flowering period are veryimportant. Thus, a CRD -based factorial experiment was conducted to assess the effects of foliar application of some substances on growth, flowering and some biochemical characteristics of marigold. The seeds were sown in pots at the beginning of season. Foliar spray (4 times) was applied at 6-leaf stage and with 10 day intervials using thiamine, ascorbic acid and gibberellic acid (GA3) solely or in combination at 100 and 0 mg-1 with 5 replications. The results indicated the highest fresh and dry weight of shoot and root, the highest stem height, root length, stem diameter and flower diameter (0.87, 1, 1.5 and 1.62 fold, respectively), the highest photosynthetic pigments and reduced sugars were found in the combined treatment of these mentioned chemical, compared to control. Furthermore, parameters such as the average number of lateral shoots, chlorophyll index and flower number were considerably increased compared to control. A synergistic effect was also found when vitamins and GA3 were used simultaneously.

Glycine betaine and proline are two osmolytes that are accumulated in plants in response to environmental stress. To investigate the effect of these compounds on photosynthesis parameters, fruit yield and quality of grape under drought stress, a factorial experiment based on randomized complete block design with four replications was performed on four ownrooted grape cultivars (‘Khushnav’, ‘Peykani’, ‘Perlette’ and ‘Flame Seedless’) at Takestan National Grape Collection Station. Stressed vines were irrigated by 70% of the required water. Grapevines were sprayed at four growth stages (before flowering, flowering, sour cluster and veraison) with proline (10 mM) and glycine betaine (15 mM). Proline and glycine betaine application increased stomatal conductance, net photosynthesis and fruit yield under drought conditions, in comparison with control. However, fresh edible quality of fruit was not desirable due to lower TSS and higher TA. Among the four studied cultivars, ‘Khushnav’ and ‘Peykani’ had the highest ripening index (TSS/TA), but the amount of fruit yield was similar in four cultivars.

Spinach (Spinacea oleracea L.) is one of the most important vegetables of Chenopodiaceae. Excessive nitrogen fertilizers application increases plant nitrateaccumulation. A complete randomized block design greenhouse experiment was carried out to study the effects of nitrogen levels on growth, nitrate accumulation and nitrate reductase in ‘New persian’ variety of spinach in Gorgan University of Agricultural Sciences and Natural Resources. Treatments included 0, 100, 200, 300, 400 and 500 kg ha-1 urea. Measured traits included leaf number, leaf area, leaf dry weight, protein, nitrate content, chlorophyll a, b and nitrate reductase gene expression. Results showed that leaf number, leaf area, leaf dry weight and leaf protein content increased as urea level increased up to 300 kg ha-1 but there was no significant increase when urea increased to 400 and 500 kg ha-1. Chlorophyll content (a, b) and nitrate formation increased when more urea were used. Nitrate level was greater in petiol than leaf blade. Urea fertilizer up to 200 kg ha-1 increased nitrate reductase transcript significantly but at higher levels, the gene expression showed lower activity and caused higher accumulation of nitrate in the leaves.

In this study, the salt tolerance of ten cultivars of kentucky bluegrass (Poa pratensis L.) was studied using NaCl (0.3, 1.5, 3, 4.5, 6 and 7.5 dS m-1) in a factorial experiment based on a completely randomized design with three replications. Shoot and root dry weights, leaf water content (LWC) and turfgrass quality was reduced as the salinity level increased. Meanwhile the leaf necrosis was increased under salt conditions. ‘Ampellia’ and ‘Harmony’ produced the highest shoot and root dry weights where as, the ‘Banf’ and ‘Nutop’ produced the lowest. ‘Ampellia’ and ‘Park’ had the maximum LWC while ‘Banf’ had the minimum one. The highest turfgrass quality was recorded in ‘Ampellia’ and ‘Harmony’, while the lowest quality was found in ‘Banf’ and ‘Merion’. ‘Ampellia’ showed the least leaf necrosis followed by ‘Harmony’ whereas ‘Banf’ and ‘Crusade’ showed the highest one. Based on overall measured parameters in this study, ‘Ampellia’ was the most salt tolerant cultivar followed by ‘Harmony’, ‘Park’ and ‘Nutop’, respectively. Also, the results showed a wide variation in salt tolerance among cultivars that can be selected for salt conditions.

Most of the pomegranate orchards have been established in areas with high concentrations of bicarbonate in irrigation water that leads to the loss or impairment of availability of some mineral nutrients to plants and affects growth and fruit yield. In present study, the effects of different concentrations of irrigation water sodium bicarbonate (,, 10 and 15 mM) on some growth, biochemical and ecophysiological characteristics of pomegranate, was studied using a factorial experiment based on randomized complete design with three replications on ‘Gorj-e-Dadashi’, ‘Zagh-e-Yazdi’ and ‘Ghermez-e-Ali Aghai’. Results showed that cultivars response was different, so that at 15 mM sodium bicarbonate, the lowest chlorophyll a and total chlorophyll and lowest growth parameters (fresh and dry root weight, dry shoot weight) were observed in ‘Ghermez-e-Ali Aghai’ and ‘Zagh-e Yazdi’ respectively. In ‘Gorj-e-Dadashi’ only phenol concentration of upper leaves significantly decreased and the other measured characteristics were not affected by sodium bicarbonate. Based on our results ‘Gorj-e-Dadashi’ was identified as relative tolerant cultivar to sodium bicarbonate and both ‘Zagh-e-Yazdi’ and ‘Ghermez-e-Ali Aghai’ were relatively sensitive.