ایوب ملا احمد نالوسی

Effect of different temperature treatments on the biochemical compounds and growth parameters of Hyacinthus orientalis cv. Blue jacket bulbs were evaluated under different temperature (5, 10, 15 and 20 °C). After four weeks, biochemical traits such as carbohydrate solution, protein, triglyceride, peroxidase and amylase during storage were measured. After the storage period they were planted in pots and some physiological traits during season growth were examined. Storing at 5 and 10 °C showed the highest carbohydrate solution, protein and triglyceride content and highest enzyme activities were observed in 15 and 20 °C treatments. Moreover, during the growing season the plant treated with 5 and 10 °C showed higher growth rate and earlier flowering time. Overall, according to the results, to achieve high quality and rapid flowering, storage temperature of 5 or 10 °C are recommended in hyacinth bulbs before planting.

Aloe vera is one of the most popular ornamental plants that is widely used in production of medicines and cosmetics. To investigate the effect of different ratios of peat and perlite on quantitative and qualitative characteristics of Aloe vera, a split-plot experiment, arranged as completely randomized design, with five substrates (peat, peat and perlite (1:3 v/v), peat and perlite (1:1 v/v), peat and perlite (3:1 v/v) and perlite, (main plots)) at five different times (sub-plots) was conducted. Results showed that adding perlite to peat substrate increased the growth rate and quantitative and qualitative indices of A. vera. Maximum amount of antioxidants, total phenols, aloin and dry weight of plants were observed in peat and perlite substrate (3:1 v/v). But, maximum number of leaves, plant height, number of shoots, root weight, leaf weight, total weight, gel weight and dry weight of leaves were observed in plants grown in peat and perlite substrate (1:1 v/v). Based on these results, the peat and perlite substrate (1:1 and 3:1 v/v) could be recommended to increase quantitative and qualitative indices of Aloe vera.

In the modern world, unbridled urbanization, industrialization, increased use of motor vehicles and a lack of cultural development in line with those changes are eroding air quality in major population centers. By developing modern industrialization and urbanization, nowadays using the modern equipment is increasing and indoor air quality is affected by chemicals which applied in such equipment. Scientists found that indoor air could be 5 to 7 times more polluted than outside. As people spend more and more time in the homes or in offices quality improvement of indoor air became one of the most important concerns of modern societies. Here, the main question is that how can we make indoor air healthier for people? According to many studies, one of the most efficient and cost-effective ways is taking advantage of ornamental plants for absorbing and removing air pollutants. Overall, for reduction of indoor air pollution using at least one ornamental plants such as Acer campestre, Cymbidium sinense, Spathiphyllum wallisii, Rhododendron simsii, Aloe barbadensis, Euphorbia pulcherrima, Hedera helix, Epipremnum aureum, Chrysanthemum spp, Dracaena fragrans, Pachiraaquatica, Gerbera daisy, Hemer ocallisfulva, Nephrolepis exaltatabostoniensis. Schefflera arboricola, Ficus elastic, Ficus benjamina Codiaeum variegatum Chlorophytum comosum, Chamaedora seifizii, Howea forsteriana, Zamioculcas zamiifolia, Phoenix roebelenii and Syngonium podophyllum per 9 m2 at home or offices are strongly recommended.

Drought stress is a main limiting factor of turfgrass growth in arid and semi-arid regions. Therefore، in this study، the physiological and biochemical changes in two turfgrass species Agrostis stolonifera and Festuca arundinacea schreb during drought stress (70-75 centibar) in a 40-day period and recovery were investigated. Control plants during drought stress were regularly irrigated at soil field capacity (20-25 centibar). The results showed that leaf relative water content and leaf chlorophyll content with long-term stress decreased. Electrolyte leakage and proline during drought stress significantly increased and in recovery stage، the level of electrolyte leakage and proline reached to the control. The activity of peroxidase and superoxide dismutase in two turfgrass significantly increased after 30 days and then significantly reduced. In F. arundinacea schreb the activity of ascorbat peroxidase after 20 days significantly increased and then significantly reduced. Also، in F. arundinacea schreb species the activity of catalase increased during drought stress and in recovery stage the activity of catalase reduced. In studied species during drought stress and recovery stage، the activity of ascorbat peroxidase and catalase significantly increased compared to the control. These results suggested that the resistant species F. arundinacea schreb، under drought stress had a low level of electrolyte leakage، higher level of relative water content and chlorophyll destruction was less than A. stolonifera.

Glycine betaine (GB) is an important compatible solute that acts as a substitute for water molecules release protein and membrane protection and also acts as active oxygen scavengers. In some plants، accumulation of this compound causes resistance to various stresses such as low temperature. In this experiment، the effect of exogenous application of GB and low temperature stress was investigated on Mexican lime in factorial experiment based on complete randomized design with three replications. Glycine betaine was applied at five levels (0، 2. 5، 5، 7. 5 and 100 mM) and also plants were subjected to five temperature treatments (2، 0، -2، -4 and -6°C). Results showed that spraying by 7. 5 and 10 mM GB as compared to other concentrations apart from the temperature at 2°C significantly increased the activity of peroxidase (POD) during the stress. Also، 10 mM of GB increased the total protein during the low temperatures in leaf tissues significantly. However، different concentrations of GB had not any clear effact on other characteristics such as lipid peroxidation (MDA)، ion leakage (EC)، total antioxidant capacity (DPPH sc%) and superoxide dismutase (SOD). It seemed that GB had protected the proteins such as peroxidase. In this study SOD content did not change during treatments that may depended on the low duration of stress. In addition، GB without antioxidant role in Mexican lime، could not protect the membrane from proxidation.

Water deficit is a major limiting factor for turfgrass growth in arid and semi-arid regions. Thus, in this study the drought tolerance of two turfgrass species, creeping bentgrass (Agrostis stolonifera var. „Palustris‟) and tall fescue (Festuca arundinacea schreb var. „Ky 31‟) was investigated by sodium nitroprusside (material that release nitric oxide (NO)). A facrtorial experiment was carried out in completely randomized design with three replications. Three factors including; two turfgrass species, four levels of nitric oxide and four levels of drought stress. The results showed that drought stress and NO treatment had not significant effect on shoot length of both grass species. Drought stress significantly increased electrolyte leakage, but NO treatment reduced electrolyte leakage in drought stress conditions. In both turfgrass species, leaf relative water content decreased with increasing soil suction, but NO treatment maintained the leaf relative water content higher than untreated plants. In tall fescue NO significantly reduced peroxidase activity during drought stress when compared to the untreated plants, but in creeping bentgrass NO significantly increased activity of this enzyme. In both turfgrass species, superoxide dismutase activity of leaves decreased with increasing soil suction, however, different concentrations of NO significant increased the activity of this enzyme when compared to control. Finally, it appears that the nitric oxide by supresing free oxygen radicals and increasing antioxidant enzymes activity decreased electrolyte leakage and increased leaf relative water content, and as a result decreased drought stress damage in the turfgrasses.

Drought stress is one of the most important limiting factors for plant growth and productivity. Synthesis of glycine betaine in some plants has improved the tolerance to environmental stress. In this study, the effects of glycine betaine (0, 2.5, 5, 7.5, 10 mM) and four levels watering (100% FC, 75% FC, 50% FC, and 25% FC) were investigated on two-year old Mexican lime seedlings during two months. Following treatments, lipid peroxidation, electrolyte leakage, total protein, antioxidant capacity, peroxidase and superoxide dismutase activity were evaluated. Results showed that 7.5 and 10 mM treatments of glycine betaine prevented reduction of peroxidase activity during drought stress. In addition, 10 mM treatment of glycine betaine prevented significant loss of total protein. However, glycine betaine had no effects on some traits such as lipid peroxidation, electrolyte leakage, antioxidant capacity and superoxide dismutase activity. However, 50% FC level, increased antioxidant capacity. Content of malondialdehyde was added by low watering. This study shows that, glycine betaine at different concentrations could not enhance antioxidant capacity in seedlings while has protected proteins and may antioxidant enzymes such as peroxidase. This compatible solute has probably affected drought resistance through protection of some enzymes, substitution for water release and osmoregulation.