m. shoor

 Since the beginning of the industrial revolution, the indiscriminate consumption of fossil fuels has led to a dramatic increase in the concentration of atmospheric carbon dioxide. Over the past few decades, the concentration of atmospheric carbon dioxide has increased from 280 to 370 ppm and is expected to increase by about 1.8 ppm each year. Carbon dioxide, such as light, appropriate temperature, water and nutrients, is one of the essential nutrients needed by plants, which is currently less than required by plants. In general, plants need to absorb water from the soil and carbon dioxide from the atmosphere and use it in photosynthesis, which This is done by absorbing carbon dioxide through the through the pores. In general, stomatal properties have a major influence on the response of plants to carbon dioxide treatment. Leaf  morphology, including stomatal density, may have a significant effect on the response of plants to carbon dioxide. There seems to be a great deal of variation among plant species in terms of how stomata density changes with increasing CO2 concentration. The opening and closing of the stomata through carbon dioxide absorption, regulates the amount of water wasted when adverse environmental conditions. In fact, increasing carbon dioxide in plants reduces stomatal conductance and transpiration, increases water use efficiency, photosynthesis rate and higher light utilization efficiency. 

 This study was conducted as a split plot experiment based on a completely randomized design with three replications in the research greenhouse of Ferdowsi University of Mashhad. Treatments included three concentrations of carbon dioxide (380 ppm as control, 700 and 1050 ppm) as the main plot and two species of ornamental ficus (Benjamin and Elastic) as sub plots. At first, cuttings were rooted in boxes containing washed sand infused with carbendazim for 8 weeks. After rooting, the cuttings were transferred to culture media containing appropriate soil mixture and exposed to different concentrations of carbon dioxide for 16 weeks. Were affected. Mean daily temperature of 25 and mean night temperature of 18 °C and 65% humidity were considered equal for all treatments. Then, after the treatments, Stomatal traits were measured.

 The results showed that high concentrations of carbon dioxide can affect the anatomical traits of Ficus ornamental species. In this study, the results obtained from the analysis of variance of the studied traits showed that the effect of different concentrations of carbon dioxide was not significant only for the stomatal index, but for other traits studied in this study. The main effect of carbon dioxide concentration was significant at 1% probability level.The results showed that the traits of stomata diameter in plant species and different concentrations of carbon dioxide were significant at 5 and 1% probability levels, respectively. Also with increasing the concentration of carbon dioxide the diameter of the stomatal decreased so that the highest stomatal diameter was related to the concentration of 380 ppm and the lowest to the concentration of 1050 ppm. In fact, increasing the concentration of carbon dioxide from the level of 380 to 1050 ppm led to a decrease of 19.91 percent in the diameter of the stomatal. Increasing the concentration of carbon dioxide in the environment of plants, initially increases the slope of the concentration of carbon dioxide between the surrounding air and the chamber under their stomata, and then more carbon dioxide through the pores leads to a decrease in the slope due to the abundance of carbon dioxide in the chamber below the stomata, This action reduces the diameter of the stomatal. As the concentration of carbon dioxide increased the stomatal cell density and stomatal area. Among the high concentrations of carbon dioxide the concentration of 700 ppm affected most of the traits, including stomatal diameter, stomatal area, epidermal cell density, stomach length and stomach width. though there was no significant difference between high concentrations of carbon dioxide (700 and 1050 ppm). According to the results of this study, it seems that anatomical traits are influenced by environmental factors and are not recognized as a hereditary factor. Among the species, the elastica species showed the most reaction to carbon dioxideal. 

 In general, clarifying the stomatal response to carbon dioxide concentration is important for understanding the stomatal physiology and gas exchange between vegetation and the In general, stomatal properties have a major influence on the response of plants to carbon dioxide treatment. Carbon dioxide at appropriate concentrations can increase growth and also affect the stomach properties to allow the plant to adapt to environmental conditions.

The Turfgrass industry in saline soil is expanding, making it important to use salinity-tolerant turfgrasses. In this experiment, the effect of salinity stress on some biochemical content in salt-sensitive and salt-tolerant tall fescue was evaluated. The Sanandaj and Daran populations with commercial tall fescue (TF) were evaluated as salt-tolerant tall fescues and the Sanajan population was used as salt-sensitive TF. Five salinity levels of irrigation water (0, 45, 90, 135, and 180 mM NaCl) were applied to turfgrasses to identify the tolerance mechanisms in tolerant tall fescue under salinity stress. Results showed that salinity affected all turfgrasses in proline, chlorophyll, 1-1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, as well as sodium and potassium in their shoots. Sanajan population in 90, 135, and 180 mM salinity had the lowest chlorophyll content among all turfgrasses. Salt stress leads to an increase in the activity of proline compared to the control at the first stage (for evaluating osmotic stress) of measurement. In the second stage (to evaluate ionic stress), at concentrations of 135 and 180 mM NaCl, maximum proline was recorded in Daran and Sanandaj populations, respectively. The interaction effect of salinity and TF was significant for DPPH activity. The Na+/ K+ ratio in the Sanajan population was the highest at all salinity levels. In conclusion, the growth and antioxidant capacity of Festuca arundinaceae populations differ in their response to NaCl treatments. In salt-tolerant TF, proline and antioxidant activity increased with increasing NaCl. These may be a mechanism to protect tolerant TF in salt stress, leading to lower accumulated Na+ in tolerant TF, high K+ uptake, and high chlorophyll content. Based on these results, proline content, DPPH radical scavenging activity, chlorophyll contents, and potassium content could use to distinguish tolerant TF from sensitive TF.

 Unbalanced and frequent use of chemical fertilizers and pesticides results in the degradation of soil physicochemical properties, loss of soil-born organisms, reduction of quality of produced crops and reduction of yield plant. Nowadays, due to environmental considerations of chemical fertilizers, use of organic acids for quantitative and qualitative improvement of crops has been increased. Humic materials are natural organic compounds that contain 50 to 90% of organic matters of peat, wood coal and rotten material, as well as non-living organic matters of aquatic and terrestrial ecosystems. Humic compounds indirectly increase soil fertility by providing micro- and macro-elements for root, improving soil structure, increasing medium permeability to water and air, increasing soil microbial population and beneficial microorganisms, increasing cation exchange capacity and the ability to buffer pH of medium or nutrient solution, and providing some special substances for plant roots such as nucleic acids and acetamides.

 In order to investigate the influence of humic and fulvic acids on some growth characteristics in ornamental plant of Scindapsus spp., an experiment was conducted based on a completely randomized design with three replications at greenhouse in Ferdowsi University of Mashhad during 2014-2015. The first factor was humic acid in four levels of 0, 0.2, 0.5, 1 g/l, and the second factor was fulvic acid in four levels of 0, 0.2, 0.5, 1 g/l. Cuttings were taken from the plant in late March. Two weeks after transferring the rooted cuttings to pot, the treatments were applied on plants via fertigation. The traits measured in the experiment included plant height, mean number of nodes, internode length, leaf number, leaf length, leaf width, leaf area, root length, root fresh weight, leaf fresh weight, shoot fresh weight, aerial organ fresh weight, root volume, aerial organ volume, root dry weight, leaf dry weight, shoot dry weight, aerial organ dry weight, fresh and dry weights ratios of aerial organ to fresh weight. Statistical analysis of data was performed by 8-JMP software. LSD test was used to compare the means of the data.

 Based on the results obtained, the combined use of humic acid and fulvic acid had a significant effect on height, fresh and dry weights of leaf, shoot, aerial organ and root, number of node and leaf and volume of aerial organ, fresh and dry weights of root, length and volume of root and the ratio of fresh and dry weights of aerial organ to root. Thus, combined use of humic acid and fulvic acid caused an increase in all the measured traits compared to the control treatment. Furthermore, an increase was observed in the length, width, and area of leaf, and internode length as the result of application of humic substances when compared to the control treatment. Organic fertilizers increase plant growth by improving soil conditions and increasing availability of plant to nutrients. Humic compounds cause changes in the specific distribution of cytokinins, polyamines and ATP by affecting the activity of root H+-ATPase and the distribution of root nitrate in the stem, thus affecting the growth of the plant stem. Humic materials increase plant growth by using different mechanisms such as hormonal effects, direct effect on plant cell metabolism, increase of cell division, chelating power and nutrient uptake, increase of soil ventilation and enhancement of plant photosynthesis by increasing Rubisco enzyme activity. Increasing nitrogen uptake leads to the increase in the growth of shoots and aerial organs. It also increases the number of branches in plants and increases the production of dry matter by increasing the production of photosynthetic materials.

 In general, according to the results of this experiment, it can be concluded that application of humic substances (humic acid and fulvic acid) together, improved the growth characteristics of the plant and led to the better growth of the plant; therefore, these materials can be a good alternative to plant growth-stimulating chemical fertilizers.

 Storage potential is an important characteristic for onion. Annually, a large quantity of worldwide onion production deteriorated during storage. The storage ability of onion is influenced by various endo- and exogenous factors including cultivar and storage conditions specially, temperature. Based on literature, there is considerable genetic variation for onion storability in onion germplasms from different origins. Rivera Martínez et al. (2005) evaluated the storability of 18 local and 4 commercial onion cultivars in Spain. Their results showed that there was significant variation for storability among different onion cultivars, and interstingly the local cultivars had more storability than commercial ones. Onion storage could also affected by environmental conditions such as temperature. Benkeblia et al. (2000) studied the effects of various temperatures on respiratory parameters of onion. Their finding showed onion respiration were raised by increasing temperature. Likewise, the positive effect of higher temperature on enhancing the growth of sprouts and elevating transpiration has been reported (Miedema, 1998; Yoo et al., 1997). Although, Afghanistan is considered to be one of the origins of onion (Brewster, 1994) there are no reports on estimating the storability of Afghan local cultivars under different temperature conditions. So this research has been conducted to study the effects of various temperatures on storability of native onion cultivars of Afghanistan.

 In this research, the plant materials consisted of 10 onion cultivars consisting eight local varieties “Hanaaie Harat”, “Zard-e-Harat”, “Ghermrz-e-Harat”, “Mazar-e-Sharif”, “Kabul”, “Sar-e-Pul”, “Ghonduz” and “Balkhaab” originated from Afghanistan, an Iranian cultivar (“Ghermez-e-Azarshahr”), and a commercial cultivar “Sweet Grano”. The cultivars were stored at two different temperature regimes (5 ºC and ambient temperature), during six-time intervals of 20 days. The average temperature of ambient storage was 13 °C ranging from 8-18 °C. The experiment lasted from November 6th, 2011 to March 5th, 2012. This research was performed in a completely randomized design based on split factorial design, with three replications. For each replication, 50 healthy non-sprouted bulbs were packaged in plastic nets. Storage potential related characteristics such as sprouting percentage, weight loss percentage, sprout length, and sprout weight/bulb weight ratio in 20 days intervals were measured. All data were subjected to analysis of variance (ANOVA) using SAS statistical software. Mean comparisons were calculated at 5% probability level using LSD when the F-value was significant (Fisher’s protected LSD).

 The results showed that there were significant differences among cultivars for storage characteristics (weight loss percentage, sprouting percentage, length of sprouts and sprout weight/bulb weight ratio). “Ghonduz” and “Ghermrz-e-Harat” local cultivars had the most and least storage ability, 50% of bulb sprouting after 105 and 35 days, respectively. Rivera Martínez et al. (2005) and Ramin (1999) also reported Spanish and Iranian local cultivars had more storability compared to commercial cultivars. In 5 °C, weight loss of onion bulbs followed a linear model during storage period. But, in ambient storage, it was higher at the beginning and the end of storage period, showing the adverse effects of high temperatures on bulbs weight loss during storage. The interaction between cultivar and time was also significant. It showed onion weight loss differs in various intervals.  It could be attributed to the genetic variation and morphological difference such as number and thickness of dry scales of onion bulbs. In ambient storage condition, onion sprouting percentage showed a sharp increase in early storage intervals and became stable in the late intervals. Under 5 °C treatment, it raised as a linear model with very slow slope. It seems that weight loss and sprouting of onion bulbs in ambient storage is dependent on temperature and relative humidity of environment. This finding is in agreement with previous reports (Baninasab and Rahemi, 2006; Forudi, 2005). The sprout length and the ratio of sprout weight to bulb weight was lower in 5 ºC than ambient temperature. Abdalla and Mann (1963) and Yoo et al. (1997) also reported that smaller sprouts were observed in lower temperatures. 

 In this experiment, the effects of temperature on storability of some local cultivars of onion originated from Afghanistan were studied in different intervals. It was found that the storage potential of onion bulbs could be influenced by genetic factors and environment conditions such as temperature. Findings of this research showed that sprouting percentage, weight loss percentage and onion sprout growth were less under 5 °C treatment than ambient temperature. Therefore, it was concluded that storing onion bulbs in low temperature conditions can reduce the onion spoilage and improve their storage life. Additionally, cultivars showed highly significant variations for all characteristics related to storage ability. Our findings showed that some local cultivars are more storable than commercial cultivars. Among the cultivars, “Ghonduz” cultivar has more storage potent as compared to all studied cultivars. Our results confirmed that local cultivars can be a good source of desirable genes related to storability. Subsequently, they can exploited to broaden the genetic base of breeding matreials.

Turfgrasses, as one of the important components of urban landscapes, have played a vital role in this regard. However, the main problems of turfgrass development are the cost of turfgrass seeds, maintenance costs such as moving, as well as the high water requirement in arid and semi-arid regions. Thus, the reduction of lawn culture in the landscape is one of the decision has taken in parks and green spaces organization of Tehran, Isfahan and even Mashhad. For over ten years, researchers have been looking for alternatives to conventional grass lawns to reduce the high cost of maintenance especially irrigation cost in urban landscapes. According to many researches, one of the potential ground cover alternatives that might be used instead of turfgrass is White Clover. Clover (Trifolium spp.) from Fabaceae family is a genus of about 300 species.

The aim of this experiment was to compare three common turfgrasses with two clover varieties as turf replacement to reduce landscape maintenance cost specially moving cost. So, some growth and qualitative factors of clover lawn: Trifolium repens var. Calway and Trifolium repens var. Pipolina (micro clover) and three turfgrasses of Festuca arundinacea L. and Lolium perenne L. and commercial sport turf mixture (from NAk-Nederland Ltd.) were compared together. This research was conducted in randomized complete block design with three replications in the research field of the Department of Horticultural Science and Landscape Engineering‚ Faculty of Agricultural‚ Ferdowsi University of Mashhad‚ Mashhad‚ Iran, during 2016 and 2017. The site (59º 38′ E and 36º 16 ′ N; elevation 989 m) is located in an arid and semi- arid region with mean annual rainfall 233.8 mm and long term averages of maximum and minimum temperature are 22.5 ºC and 9.3 ºC‚ respectively. Turfgrass plots were established by directly sowing the seeds in April, 2016. The planting rate of the seedling considering their pure live seeds (PLS) were 45 g.m-2 for Lolium perenne, 34 g.m-2 for Festuca arundinacea, 6.5 g.m-2 for Trifolium repens, 5.5 g.m-2 for micro clover and 39 g.m-2 for commercial mixture of sport turf. The plots were 1 m2 (1m×1m) in size and were prepared after plowing and leveling the soil. The seeds were hand sown and covered with a thin layer of leaf compost and sand.

According to the results in the first evaluation of emergence percentage, Lolium perenne had the highest emergence percentage. After 36 days from culture, all plants had 92-98 % coverage which did not have any significant difference among grasses with clover lawns. In terms of density, uniformity and weed density, there was no significant difference between the studied plants. In the other hands, white clover showed the best quality after clipping in both years. At the point of growth index, which have done in this experiment by measuring height and dry weight of clipping, grass lawns had the higher growth index in compered to clover lawn in both years. Festuca arundinacea and Lolium perenne had the highest growth index and white and micro clover had the lowest growth. Also, with air warming, Festuca arundinacea became dominated plant in height and clipping dry weight. In July, Festuca arundinacea produced the highest clipping dry weight by 40 gr.m-2, Lolium perenne (19.52), commercial sport turf (15.68), white clover (6.24) and micro clover (0.36) gr.m-2.

One of the problems of landscape is reduction of maintenance costs such as mowing. So, the low growth of white and micro clover is a positive factor in reduction of the moving costs than turfgrasses. Also, the coverage and proper density of clover lawns are similar to grass lawns and did not have a significant difference with them. The character of low growth can be effective in reduction of irrigation costs in white and micro clover, which requires more research and examination in future. This is a positive point in the white clover and micro clover that do not need to move or cut every months. Almost, clover moving is recommended for removing their flower. Therefore, it is recommended to use white and micro clover as a replacement with less maintenance costs in landscape. Finally, the results of cultivation of grass and clover as monoculture in this study can be used to produce clover-grass mixtures suitable for the climate of our country (arid and semi-arid regions), instead of importing turf mixtures from European countries.

The Hollyhock (Alcea rosea) is a summer flowering biennial plant that is native to China and belongs to the Malvaceae family. It is one of the most valuable ornamental plants, whose 36 species are cultivated in Iran. It is an increasing garden escape, especially in urban areas, and is usually found at foot of walls, in ruderal areas, and in cracks of pavements and old walls. Also, it is sometimes seen on riverbanks (for instance on dikes of the river Maas), dumps or road- and railway banks. Alcea rosea has been used as an herbal plant in folk medicine for treatment of different diseases such as common cold and cough. This plant is antiphlogistic, astringent, demulcent, diuretic and expectorant. Drought is the most significant environmental stress in agriculture worldwide, and improving yield under drought is a major goal of plant breeding. Seed germination and early seedling growth are potentially the most critical stages for water stress. When subjected to drought stress, plant metabolism is interrupted or inhibited by increasing reactive oxygen species (ROS) and lipid peroxidation, resulting in reduced germination, weaker root and shoot growth and even mortality. Plants have evolved oxygen-scavenging systems consisting of non-enzyme antioxidant metabolites, such as proline and various antioxidant enzymes including superoxide dismutase, peroxidase and catalase.

In order to examine the effect of drought stress on germination indexes, various antioxidant enzyme changes and non-enzyme antioxidant metabolites in Alcea rosea, an experiment was conducted in complete randomized design with three replications. The drought stress treatment was conducted in five levels with osmotic pressures 0, -2, -4, -6, and -8 bar and with using PEG (Poly Ethylene Glycol 6000) on two ecotypes of Alcea rosea (ecotype 1= Mashhad and ecotype 2= Tehran). The seeds are at first sterilized with hypo chloride sodium for two minutes and then washed superficially three times with distilled water. 25 seeds were transferred to a glass petri dish with 10 cm diameter, and for the duration of the experiment, 5 ml solution with different levels was added to each petri dish. After 14 days at 25±1 ºC temperature, the number of geminated seeds in each day was counted and recorded. In the first part of the experiment, after the end of the germination period, the following growth parameters were measured: germination percentage, germination rate, root and shoot length, and the fresh weight of seedling. In the second part, the activity of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT), malondialdehyde content, lipid peroxidation in terms of malondialdehyde (MDA) content, and proline index were measured.

The ecotype, drought treatments and their interaction had significant effects on growth parameters (germination percentage, germination rate, radicle and plumule length, and seedling fresh weight), as well as physiological and biochemical parameters (SOD, POD, CAT, MDA and proline). The highest germination parameters were recorded at Mashhad ecotype. Germination percentage and germination rate were severely affected by drought. Maximum percentage of germination (36) was recorded at control group followed by 32.1 at -2 bar and -4 bar PEG treatments in ecotype 1. Germination percentage in two ecotypes further declined to 33% at -8 bar compared to the control treatment. In both ecotypes, plants had the highest germination rate in control media (zero osmotic potential) but germination rate decreased significantly by decreasing water potential. Germination rate of control seeds of ecotype 1 was 11.7, while that of ecotype 2 was 8. 3. Germination rate in two ecotypes further declined to 56% and 38 %, at -8 bar compared to the control treatment, respectively. Ecotype 2 displayed a significant reduction in radicle and plumule length compared to the ecotype 1. Generally, the radicle and plumule length decreased significantly in relation to the drought stress caused by PEG. Ecotype 2 in -8 bar PEG treatment had the highest (41 and 32%) decrease in radicle and plumule length compared to the control temperature. In two ecotypes (Mashhad and Tehran) of Alcea rosea, increasing PEG concentrations resulted in a decrease in fresh and dry weights. Water absorption is the first germination stage. Due to the probable resistance of the ecotype one, water absorption rate is higher, and as a result, the percentage and rate of germination have increased. Ecotype 1 exhibited higher leaf SOD activities in response to -2 bar compared to -8 bar, but the SOD activities in ecotype 2 showed a general increase trend with increases in the PEG concentration. Drought stress resulted in lower antioxidant enzyme activities (POD) in leaves of both ecotypes compared to that observed at the control treatment, but the activity of CAT increased with the increase of drought stress. In both ecotypes, exposure to -8 bar resulted in significantly higher leaf MDA activities. Plants exhibited higher proline in response to -8 bar treatment compared to the control. By increasing the PEG concentration from control to -8 bar, proline content increased about 90 percent. In this experiment, drought stress reduced the rate and germination percentage and delayed subsequent plant deployment. When plants are subjected to drought stress, their metabolism is interrupted or inhibited by increasing reactive oxygen species (ROS) and lipid peroxidation, resulting in reduced germination, weaker root and shoot growth and even mortality. The recent experiment showed that the activity of two superoxide dismutase and peroxidase enzymes decreased with increasing drought stress, and the activity of the catalase enzyme increased; this is in agreement with the results reported by other studies. On one hand, the increase in the activity of the catalase enzyme indicates that it is perhaps the most important enzyme involved under drought condition, which increased over the course of 14 days. On the other hand, limiting the activity of enzymes and increasing the amount of proline showed that increasing the resistance to drought stress in the plant depends on the accumulation of contaminating substances such as proline.

Due to the higher resistance of the ecotype 1 and increase in water absorption, the percentage and rate of germination were increased. If water absorption is disturbed by the seed, the germination activity is slowly applied and the later growth of the roots will decrease the germination rate. Therefore, it seems that Mashhad ecotype with increase of catalase and proline has the highest drought tolerance compared to the other ecotype at germination stage. There was a significant correlation between germination percentage with SOD and POD.

Climate change is expected to have impacts on ecosystems worldwide. During the last 50 years, the greatest warming trends have been observed in winter months and significant increases in both the occurrence and duration of winter warming have already been reported. In general, predicted future climate change scenarios will result in less than optimal cold acclimation conditions, leading to decreases in freezing tolerance and predisposition of plants to winter injury. Nonetheless, it is not clear whether water stress induced during cold hardening is of high importance in inducing freezing tolerance in plants or it is an integral part of typical cold hardening process. Since rapid and effective assessment of plant cold tolerance is important for researchers and also field trials have no regular process and have high error, different kinds of artificial freeze tests such as survival percentage test and regrowth after imposing stress have been developed.

In order to evaluate the effect of drought stress on plant freezing tolerance of viola, a factorial experiment was conducted based on completely randomized design with three replications in faculty of Agriculture, Ferdowsi University of Mashhad. Experimental factors include three water treatments (80% FC, 60 % FC and 40% FC) and 10 temperature levels (Control, from zero to -24 with 3 °C intervals). Pansy seeds sown in a nursery in the summer of 2015 and after reaching the five-leaf stage in the fall plants were transferred to the pots. After the potted plants spend cold acclimation in nature conditions, plants were subjected to water stress including control (80% FC), 60% and 40% FC for two weeks. After drought stress, whole plants were sampled for freezing tolerance assessment and they were transferred to the freezer thermos-gradient. After applying the stress, electrolyte leakage, lethal temperature 50 according to the electrolyte leakage percentage (LT50el) were measured. One months later, survival percentage, lethal temperature 50% of plant according to the survival percentage (LT50su), leaf area, number of flower and bud, dry weight (dry weight of vegetative, reproductive, root and total) and reduced dry matter temperature 50 (RDMT50) were evaluated.

Electrolyte leakage percentage (EL %) and survival (%) were significantly (p ≤ 0.01) affected by irrigation treatments in the freezing conditions. By lowering the temperature from 20 to -24 °C, the EL% significantly increased in three irrigation treatments and it increased in 80% FC compared to 60% (by 16%) at -24°C. plants under 60% FC treatment exhibited higher baseline freezing tolerance (LT50 of −18.4 °C) compared to 80% FC (LT50 of −11.8 °C).Treated plants (except 80% FC) were able to tolerate lowering the temperature to -21°C. Lowering the temperature to -24°C caused the total mortality. According to the LT50su index, 60% FC treatment was less than compared to other treatments. Leaf area significantly increased by 16%, respectively, when plants were under water deficit (60% FC) compared to 80% FC at 0 °C. The maximum number of flower were seen in 60% FC at – 3 °C and the maximum number of bud were observed at 0 °C. The results showed that dry weight was significantly (p ≤ 0.01) increased by drought stress in the freezing conditions. Plants under 60% FC at 0 °C had the highest increase (55, 62 and 64%, respectively) dry weight of vegetative, reproductive and total growth, respectively compared to control. By lowering the temperature to -18 °C in 80% FC vegetative, reproductive and root growth decreased (36, 38 and 42%, respectively) compared to control plants. RDMT50 significantly affected by drought stress. There were significantly correlation between EL with LT50el and RDMT50 (r =0.25* and r = 0.72**, respectively). In total, plants under 60% FC showed highest freezing tolerance compared to the other treatments.

In the current study, we found that the greatest gain in freezing tolerance was associated with cold and that the effect of drought stress on freezing tolerance varied with temperature. Drought stress resulted in an improvement in freezing tolerance of viola (lower LT50). Among the different parameters evaluated, 60% FC treatment at 0 °C most consistently induced increases in survival percentage, reproductive and vegetative growth which suggested a synergistic effect between drought exposure and low temperature. Higher dry weight of viola plants may contribute to better plant overwintering capacity. In addition, future research should explore the effect of repeated mild drought events on freezing tolerance of acclimated plants, by using strategies such as wilt-based irrigation scheduling, partial root zone drying, and deficit irrigation.

Humic acid and fulvic acid are natural and organic materials, which are derived from various sources such as soil organic matter (humus), soil, peat, oxidized lignite and coal. In order to evaluate the effect of humic substances on physiological characteristics of two ornamental plants of granium (Plargonium spp.) and scindapsus (Scindapsus spp.), an experiment was conducted as 4×4 factorial, based on completely randomized design with three replications, in Research Greenhouse of Ferdowsi University of Mashhad during 2014-2015. The first factor was four levels of humic acid (0, 0.2, 0.5 and 1 g/L) and the second factor was fulvic acid at four levels (0, 0.2, 0.5 and 1 g/L). Results showed that the use of humic acid and fulvic acid caused an improvement in most measured physiological traits in geranium and scindapsus. In granium plant, application of humic acid at low concentration could improve plant growth characteristics. The content of chlorophyll and stomatal conductance in granium increased by humic acid application (0.2 and 0.5 g/L) as fertigation compared to control treatment. Combined application of humic acid and fulvic acid in this plant, also improved soluble sugar content of the plant and reduced the electrolyte leakage as compared to control. In scindapsus, using humic acid at the highest concentration, solely or in combination with fulvic acid, resulted in the improvement of growth traits, so that the combination of humic acid and fulvic acid resulted in increased soluble sugar and SPAD index in this plant. Moreover, chlorophyll content of the plant was increased by the application of humic acid (1 g/L) as fertigation in comparison with the control treatment. These compounds increase plants’ growth by improving their growth conditions. According to the results of this study, application of humic acid and fulvic acid as organic fertilizers is recommended for improving growth in geranium and scindapsus ornamental plants.

The present study was carried out to investigate biochemical, morphological, and physiological processes involved in the adaptive processes of cut roses grown in arching and high-rack culture systems under water deficit condition. Rose plants ‘Club-Nika’ were subjected to three water regimes [control (100% of irrigation needs), moderate water stress (75%), and severe water stress (50%)] factorially combined with two training systems defined as arching and high-rack systems. Water deficit significantly reduced morphological and qualitative traits as well as water relations of cut roses. Water deficit significantly reduced Net CO2 assimilation rate (PN), transpiration rate (E), and stomatal conductance (gs), whereas it did not affect Water Use Efficiency (WUEi) and intercellular CO2 concentration (Ci). Surprisingly, water deficit did not affect chlorophyll content [chl a, chl b and total chl (a + b)] and proline accumulation of leaves. Considering the lack of change in intercellular CO2 concentration, it seems likely that both stomatal closure and metabolic impairment limit photosynthetic CO2 assimilation under water deficit. Regardless of irrigation regimes, rose plants trained with high-rack culture system showed a superiority for most of the qualitative and quantitative attributes compared to those trained with arching system. The high-rack system resulted in 60% higher extra-quality stems (> 60 cm) compared with the plants trained with arching. It can be concluded that cut roses respond to water deficit through adaptive changes in physiological and morphological levels to reduce water loss without any negative impact at biochemical level.

Creating water-conserving turfgrasses using superabsorbents in soil is a challenge especially in arid environments because their related soil and plant’s behavior is still less known. This research investigated soil moisture content and physiological characteristics of Lolium perenne L. ‘Chadegan’ (perennial ryegrass) and Festuca arundinacea (tall fescue), in the absence (control treatment) or presence of four superabsorbent types. The superabsorbents were Zeolite (zero and 10% wt), Bentonite (zero and 6%wt), Aquasorb (zero and 6 g/m2) and Boloorab (zero and 50 g/m2). The experiment was factorial based on a randomized complete block design with four replications. A one-month stop on irrigation occurred after the first five-month full irrigation regime to simulate drought stress conditions. The results showed tall fescue had higher leaf relative water content, lower relative electrolyte leakage and lower relative saturation deficit than that in perennial ryegrass after applying the drought stress. However, tall fescue had higher chlorophyll content than this factor in the ryegrass. Aquasorb and then Bentonite were able to improve the fresh weight and dry weight in roots and shoots under drought stress conditions compared to the control treatment. Using Aquasorb was associated with better physiological characters in the turfgrasses and higher water content in the soil. Overall, under drought stress conditions, planting tall fescue in a soil containing Aquazorb promised a better quality turfgrass for urban green spaces.

Meadow saffron (Colchicum) is a non-domesticated medicinal plant, rich in isoquinoline alkaloids. These alkaloids are used in medicines mainly for their anti-gout and myorelaxant properties. Meadow saffron has an unusual biology that does not favor cultivation. Flowers of Meadow saffron appear in September and fruits mature in June. The corms enter dormancy phase in winter (January to March) and after fruiting in summer (June to September). Each year, a mother corm produces one daughter corm, or sometimes two daughter corms. The uptake of mineral element in plant is a complex process that governed by numerous factors influencing each other. nitrogen, phosphorus, and potassium application can significantly increase the yield and improve the quality of plants. Meadow saffron need more consider in fertilization managements in comparison with other crops because it has shallow roots than other crops and exposes to more problems in uptake of immobile nutrients in the soil. The object of this study was to determine the effect of different fertilizers and mother corm weight on yield characters of Colchicum kotschyi Boiss.

This experiment was conducted as factorial layout based on a randomized complete block design with three replications at Research Station, Ferdowsi University of Mashhad, Iran, in two years, 2012- 2013 and 2013-2014. The Corms of Colchicum kotschyi Boiss. were harvested from natural site of Binalood Mountains during their summer dormancy. The mother corm weight was considered as a factor in the experiment, because of the variation between the collected corms. In order to evaluate fertilizers effect, soil analysis was conducted. So, the experimental factors were: mother corm weight (less than 40 g and more than 40 g), cow manure (0 and 50 t.ha-1), urea (0 and 50 kg.ha-1) and superphosphate (0 and 25 kg.ha-1). Before planting, cow manure and superphosphate were well mixed with soil and urea was added to soil during emergence of leaves. Planting date was 28th August 2012. Planting depth was 12-15 cm and the space between plants was 25 cm. During flowering, flower number was recorded. Plants were harvested when the color of leaves and capsules were changed from yellow to brown, and characteristics such as corm yield, seed yield, biological yield, 1000-seed weight, capsule number, capsule dry weight, seed number, seed dry weight, corm and seed HI were measured. Data analysis was done by SAS Ver. 9. Mean comparisons were done by LSD test at 5% probability.

At the first year of experiment, most of transplanted corms did not flower due to transplanting. Therefore, just the results of the second year were presented here. The results showed that mother corm weight had significant effect on the yield (p≤0.05). The weight of daughter corms was increased by increasing mother corm weight, because of more supply of nutrients. The weight of the corm is basically determined by the amount of total food stored in the corm by the plant through the process of photosynthesis. The initial plant growth and its vigor are determined by the amount of food supplied to the growing plant by the corm. The results showed that seed yield characters were affected by the cultivated corm weight. The most flowers per area unit, capsule number per plant, seed number and dry weight per plant were belonged to heavier cultivated corms. The effect of corm weight on corm HI was not significant (p≤0.05), but smaller corms had more seed HI than bigger corms (p≤0.05). The effect of cow manure on most characters was significant (p≤0.05). Corm yield and corm HI increased in cow manure treatment in comparison with control. Organic fertilizers cause improvement of soil structure, better development of roots, regulation of soil temperature and useful microorganisms, supply of nutrients for plant and supports plant in nutrient absorption. Capsule number, capsule dry weight and seed number per plant were not influenced by cow manure. The number of capsules per plant and the number of seeds per capsule were determined during fertilization. The only parameter that can vary during capsule development was the thousand-seed weight. The results showed that seed dry weight per plant, 1000-seed weight, seed yield and seed HI were decreased in cow manure treatment in comparison with control. It seems that cow manure has more effect on vegetative growth and decrease proportion of seed compared to corm in whole plant weight. Meanwhile, the competition between corm and seed for photosynthetic materials may decrease seed dry weight. The effect of superphosphate was significant on some studied characters. Superphosphate utilization was increased corm yield and biological yield compared to control. Many researchers reported that phosphorus that was effective in leaf photosynthesis and carbon metabolism in plants. Phosphorus increased seed dry weight per plant, seed yield and 1000-seed weight. Phosphorus is a very important nutrient in plant nutrition and is more effective in the formation of flower, fruit and seed. Many researches have shown that phosphorus promote reproductive growth.

The results showed that colchicum could have a good response to treatments especially cow manure and superphosphate. It seems that more levels of fertilizers especially urea could improve quantitative and qualitative yield of plant.

Nowruzak (Salvia leriifolia) of Lamiaceae family has a good capability for domestication in Khorasan’s natural habitats. In order to investigate the effect of sowing design and depth in seedling emergence and permanence, a split plot experiment based on a randomized complete block design was performed with three replications. Results indicated sowing design in all three parameters, sowing depth in number of days for emerging were significantly differents