فهرست مطالب

Plant Physiology - Volume:5 Issue: 3, Spring 2015

Iranian Journal of Plant Physiology
Volume:5 Issue: 3, Spring 2015

  • تاریخ انتشار: 1394/04/18
  • تعداد عناوین: 8
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  • Taher Barzegar, Mojtaba Delshad, Abdol K. Kashi, Caroline Mauve, Jaleh Ghashghaie Pages 1353-1359
    Soluble sugar accumulation pattern and contents were studied in two Iranian melon cultivars, ‘Suski Sabz’ and ‘Jalali Zard’ (Cucumis melo L. Inodorous). Sucrose, glucose and fructose contents were determined in different mesocarp tissues of developing fruits during days after pollination (DAP). They were characterised by enhanced accumulation of glucose and fructose during early fruit developmental stages with almost no sucrose detectable. A sharp increase in sucrose occurred from DAP 30 and 40 in ‘Jalali Zard’ and ‘Suski Sabz’, respectively. Then, both glucose and fructose showed a steady decrease with fruit maturation. In mature fruits of both cultivars, an obvious gradient of sucrose accumulation was detected, ascending from pedicel to middle and umbilicus part of mesocarp. Also both cultivars could be considered as high sucrose accumulators. The present results might be useful for future studies on improvement of melon fruit quality.
    Keywords: Soluble sugars, Mesocarp, Days after pollination, Iranian melons
  • Zahra Mohammadzade, Forouzandeh Soltani* Pages 1361-1371
    A biotic stresses can directly or indirectly affect the physiological status of an organism by altering its metabolism, growth, and development. In order to study the effect of drought stress on Citrullus colocynthis samples a factorial experiment was conducted in Horticultural science Department of University of Tehran in 2013. The first factor was two accessions of Citrullus colocynthis (Yazd and Khorasgan) and the second factor was water deficit induced by different osmotic potential levels 0 (the control), -0.4 MPa (slight), -0.8 MPa (moderate) and -1.2 MPa (severe (using polyethylene glycol. The results indicated that fresh and dry weight of seedlings and leaf area decreased in both accessions as osmotic potential increased. Khorasgan samples showed higher net photosynthetic rate than Yazd accession in all osmotic condition. Total phenolic content, antioxidant capacity and proline content of leaves varied between two accessions which Yazd accession represented higher value at different osmotic condition. The present data suggest a relation between proline and total phenolic content and water stress also well-developed antioxidant defense mechanism activated during water stress. Based on this study Yazd accession was more tolerant to drought stress and could use in breeding or grafting program to improve Citrullus species growth under water deficit condition.
    Keywords: Accession, Citrullus colocynthis, Osmolyte, Polyethylene glycol, Water deficit
  • Nobar Hajihosseinlo*, Siavash Hosseini Sarghein, Rashid Jamei Pages 1373-1381
    It emerged recently that there is an inter-relationship between drought and Ultraviolet-B (UV-B) radiation in plant responses, in that both stresses provoke an oxidative burst. The objective of the present investigation was to study the effect of drought stress, UV-B radiation and the combined effects of UV-B and drought stresses on two cultivars of gourd seedling. The gourd plants were grown with diurnal regime of 16h light and 8h dark and temperature of 22/26°C (night/day). The relative humidity 60% and average of photosynthetically active radiation was 150 μmol.m-2.s-1. Treatments was started 25 days after planting. Then, 25-days-old seedlings were divided in to four groups. The control and three groups subjected to stress conditions: UV-B radiation, drought stress conditions, UV-B radiation and drought stresses combined. The results of measurement on compounds which absorbs UV including flavonoids, anthocyanins, phenol and antioxidant enzymes activity including catalase, guaiacol peroxidase showed that these parameters increased when plant irradiated with UV-B, drought stress and their combination. Biochemical parameters indicate that with this experiment situation UV-B stress has stronger stress effectors than drought on the growth of seedling of both cultivars. The present results suggested that, under soil drought conditions, enhanced UV-B radiation had not let to greater decrease gourd biochemical markers. The results suggested that co-stresses of supplementary UV-B radiation and drought synergistically functioned and one of them could alleviate the inhibitory effects of another under the condition of arid and semiarid loessial soils.
    Keywords: Gourd, Ultraviolet radiation, Drought stress, Antioxidant enzymes
  • Elham Harati*, Bahareh Kashefi, Mohammad Matinizadeh Pages 1383-1391
    Salicylic acid (SA) is a naturally occurring plant hormone that has positive effects on growth and tolerance to biotic and abiotic stresses, especially salinity in plants. To evaluate the effects of SA and salt stress on some morphological and physiological traits and quantitative activities of antioxidant enzymes on thyme (Thymus vulgaris), was conducted a factorial pot experiment based on completely randomized design with four levels of SA (0t 150, 300 and 400 ppm) and four levels of salinity stress (0, 50, 100 and 150 mM, induced by NaCl) and three replicates. The results showed that salinity increased soluble sugars, quantitative activities of peroxidase and fresh weight and decreased stem height, leaf area and protein content. Interaction effects between salt stress and SA treatments resulted to greater leaf area, fresh weight, protein content and quantitative activities of catalase and peroxidase, significantly. Based the results of this study, leaf sparing of SA, improve physiological traits and alleviate salt stress effects through influencing physiological processes as increasing of antioxidant activity enzymes and soluble sugars content in Thymus vulgaris.
    Keywords: Antioxidant enzymes, Thymeus vulgaris, salt stress, growth regulators, vegetative traits
  • Hamid Reza Eisvand *, Nasim Fathi, Darioush Goudarzi Pages 1393-1402
    Low soil temperature is one of the reasons for poor germination and establishment of maize. The aim of this study was to evaluate the possibility of improving the seedling emergence and performance of maize under low temperature stress. A pot experiment was conducted on Zea maize (single cross 704) at 14 ºC as cold stress and seed treatments were priming with 200, 300 and 400ppm of GA3; 100, 200 and 300ppm of salicylic acid (SA) and ascorbic acid (AA) with a hydro priming treatment and non-primed seed. Results showed that priming with SA 100ppm and AA 100ppm could strongly improve the emergence percentage and rate. SA100ppm and AA 100ppm improved root dry weight better than other treatments. The CAT activity in root was not affected by priming treatments but POD activity increased only by GA3 300ppm. In leaf, CAT and POD activity increased by priming with GA3, SA and AA. There was a negative correlation between CAT activity in root and seedling emergence percentage. There was no correlation between CAT activity in leaf and CAT in root. Meanwhile POD activity in leaf and root was positively correlated.
    Keywords: chilling, emergence, maize, phytohormone, seedling
  • Hamid Ahani *, Hamid Jalilvand, Jamil Vaezi, Seyed Ehsan Sadati Pages 1403-1410
    We studied the response of Elaeagnus rhamnoides (Sea Buckthorn) to drought stress in a nursery. Photosynthesis and chlorophyll content under drought were change rather modest. Growth and physiological differences in response to drought were compared between four Sea Buckthorn seedlings treatments inhabited in the Qazvin provenance origin seeds in Mashhad city of Iran. The experimental design included four water regimes (100% of field capacity) and three blocks. Our experiments were under semi-controlled environmental conditions for four growing season. Four-month-old seedlings were examined with four different water regimes corresponding to 2, 4, 8, 12, day's duration. At the end of watering regimes, Chlorophyll content and Photosynthetic of leaves was measured using SPAD, CCI (Chlorophyll Concentration Index) and A (Photosynthetic rate) by several devices. The A was positively correlated with SPAD and DS (Dry Stem) but negatively correlated with the CCI and DR (Dry Root) in all of treatments except 12 day irrigation. CCI was positively correlated with DR, in 2day treatment, with SPAD and DR in 8day with all of traits in 4day and 12 day but negatively correlated with others. There were significant negative correlations between SPAD with DR in first watering regime and DS in third watering regime. Between DR and DS were significant positive correlations only in 12day treatment but significant negatively correlated in 2day and 8day watering regime measured. We concluded SPAD and A were tolerated efficiently between 4day and 8day, then we can irrigate seedlings more than 4day and less than 8day treatment. Different watering treatments employ different strategy for physiological and morphological responses of this plant.
    Keywords: CCI, SPAD, Hippophae, Iran, Biomass, Water stress
  • Ferdous Fendereski, Mahlagha Ghorbanli *, Arian Sateei Pages 1411-1423
    Copper is one of the heavy metal in plant that causes toxicity at high concentration via producing reactive oxygen species. Nitric oxide can protect cells from oxidative stress produce by reactive oxygen species. Effect of different concentrations of copper (1000, 1500 and 2000 μM) and interaction with nitric oxide (100 and 150 μM) were studied on growth parameters (shoot and root length) and some physiological factors (chlorophyll a, chlorophyll b, soluble carbohydrate), antioxidant enzymes (catalase, peroxidase and ascorbate peroxidase) in Portulaca oleracea L. For this purpose, an experiment was done in complete block random design with three replications under pot condition. Our result showed that nitric oxide treatment increased shoot and root length, shoot and root fresh weight as well as chlorophyll a and b content under copper stress. Therefore, in stressed plants treated with nitric oxide growth parameter improved and damage to pigments decreased. Copper stress did not affect soluble carbohydrate and increased antioxidant enzyme activity but nitric oxide increased soluble carbohydrate content and decreased antioxidant enzyme activity with exception of catalase and peroxidase. Pre-treatment with nitric oxide had protective role under copper treatment stress with interaction with ROS and photosynthetic pigments.
    Keywords: copper toxicity, Nitric oxide, Portulaca oleracea L
  • Ghader Habibi*, Somaie Sarvary Pages 1425-1433
    Plant metabolism and productivity is influenced adversely by salinity. Exogenous selenium (Se), applied as sodium selenate in biofortification programmes, has been found effective in alleviating the salt induced damage in plants. The study was conducted in order to determine the effects of exogenous Se supply (10 μM) on the resistance of lemon balm (Melissa officinalis L.) plants to salt stress (40 mM NaCl). Plant growth was negatively affected by salinity and dry mass production as well as chlorophyll a and b accumulation severely reduced. Selenium significantly improved the growth rate and increased the photosynthetic pigments and total amino acid contents in lemon balm plants subjected to salt stress. Salinity stress caused great membrane damage, as assessed by lipid peroxidation, but Se application significantly reduced the membrane damage because of an efficient scavenging by peroxidases (POD) and glutathione peroxidase (GSH-Px). Compared with the non-selenium treatment, application of Se increased the activity of phenylalanine ammonia-lyase (PAL) under salinity. As a result, the physiological and biochemical parameters measured in this study indicated that the salinity had adverse effects on growth of lemon balm plants, but the data also showed that presence of exogenous Se in nutrient solution could alleviate seedling damage under high levels of NaCl in the medium.
    Keywords: Lemon balm, lipid peroxidation, photosynthetic pigments, medium, sodium selenate, salinity