فهرست مطالب

Plant Physiology - Volume:1 Issue: 2, winter 2011

Iranian Journal of Plant Physiology
Volume:1 Issue: 2, winter 2011

  • تاریخ انتشار: 1389/06/30
  • تعداد عناوین: 9
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  • Aneela Fatima, Shaista Jabeen Khan* Page 61

    Gelling agent plays an important role in the in vitro growth of Stevia rebaudiana. Agar solidified MS medium fortified with 1.5 mg/l BA + 0.5 mg/l Kin was found the best concentration for shoot induction from apical meristem and nodal explants, while gelrite solidified MS medium containing the same concentrations of hormones produced weak plants. Healthy and profuse growth of regenerated shoots along with roots were observed when shoots were again subcultered in agar solidified MS medium with 0.1 mg/l IBA, whereas gelrite solidified medium with 0.1 mg/L IBA again produced 1‐2 average number of shoots and roots. The medium became liquid in case of gelrite medium during the growth period and the pH of the medium was also changed. Gelling effect was further confirmed by transferring the shoots from gelrite solidified medium to agar solidified medium with the same hormones concentration. Shoots resumed normal growth and proliferation after they were transferred to agar medium. This effect may be due to the change in concentration of the cations (Ca, Mg).

    Keywords: Stevia rebaudiana, micropropagation, gelling agents, artificial sweetener
  • Nabat Sedghi Ghartavol*, Gholamreza Bakhshi Khaniki, Farrokh Karimi Page 69
    In this study for the purpose of evaluating the somaclonal variation during repetitious subcultures of tobacco (Nicotiana tabacum cv. chopogh), we cultured the leaf and stem explants of tobacco plants in a medium containing 4 mg/l 2,4‐dichlorophenoxyacetic acid and 0.5 mg/l kinetin. After the growth of calluses, they were sub‐cultured in the same medium. After the fourth subculture, calluses were transferred to regeneration MS medium containing hormone concentrations 4mg/l kinetin, 1 mg/l zeatine. After regeneration of seedlings, total genomic DNA was extracted from the primary and regenerated plant. Somaclonal variation of the samples was analyzed using 20 Random RAPD Primer. The electrophoresis pattern of 3 Random Primers including OPC‐09, OPR‐12, OPA‐10 indicated the polymorphism in amplified DNA band. This polymorphism resulted from production of somaclonal variation during subcultures of tobacco callus.
    Keywords: RAPD‐PCR, somaclonal variation, tobacco callus
  • Bahareh Allahverdi Mamaghani, Mahlagha Ghorbanli*, Mohammad Hassan Assareh, Abbas Ghamari Zare Page 85
    An in vitro propagation protocol has been developed for three superior Damask rose accessions using axillary buds of mature 5 years-old plants. Effects of culture medium and plant genotype were evaluated using a split plot design based on a completely randomized design with three replications. Surface sterilization was carried out with 0.1% HgCl2 for five minutes. The appropriate seasons for collecting explants were summer and autumn. Endogenous contamination was eliminated by cefotaxim antibiotic. Shoot growth rate and shoot index showed better performances on MS than on WPM medium. Thidiauzuron (TDZ) in combination with 6-benzylaminopurine (BAP) induced significantly higher number of shoots per explants than the most optimum BAP treatment alone. The highest level of shoot multiplication rate (5.9) was recorded at a combination of 5 mgl-1 BAP and 0.1 mgl-1 TDZ. Type and concentration of auxins did not have significant effects on shoot multiplication and shoot length. Between various cytokinins, BAP was more effective than kinetin on shoot multiplication. There was no consistent response by both shoot multiplication rate and genotype to different concentrations on growth regulators. Two accessions were rooted on the medium supplement with 0.1 and 0.2 mgl-1 naphtalene acetic acid respectively.
    Keywords: micropropagation, multiplication rate, culture medium, Plant Growth Regulators (PGR), Rosa damascena Mill
  • Alireza Houshmandfar*, Farhang Moraghebi Page 95
    In order to study heavy metal tolerance at different clover (Trifolium resupinatum L.) plant growth stages, a pot experiment contaminated by cadmium, copper, nickel, or zinc at 500 mg/l was conducted in three replications. Applied seven days after germination, all heavy metals except zinc had lethal effects on the clover seedlings. Furthermore, when they were applied 14 days after germination, nickel still had a lethal effect on the seedling, and cadmium and copper killed more than half of the plant population. While approximately 90% of the plants exposed to cadmium, copper and zinc were able to grow without apparent negative effects, 21 days after germination nickel still showed lethal effects. In this study, the concentration of heavy metals in shoot dry tissues were 940 mg/kg for cadmium, 781 mg/kg for copper and 670 mg/kg for zinc. These results suggest that the tolerance of clover to cadmium, copper and zinc positively correlates with the age of the plant.
    Keywords: Clover plant, growth stages, tolerance, heavy metals
  • Mahlagha Ghorbanli, Mozhgan Farzamisepehr *, Lale Jahani, Najme Jafari Page 100
    Littoral environment is a natural developed ecosystem with high vulnerability, which is susceptible to water pollution and climate changes. Despite the existence of difficult conditions on the littoral zones some plants are still able to overcome such conditions and maintain their permanence via interaction of mechanisms. The littoral zone ecosystems are affected by many factors such as the littoral zone raining, heavy winds, sea waves, water and soil pollution, and sea water pH as the most significant factors. In this work, the effects of these factors on Tounefortia sibirica L. and Xanthium strumarium L. were studied. Tounefortia sibirica L. and Xanthium strumarium L. The present study on these two sand growing plants indicated that, they underwent ecological and morphological changes in order to protect their lives. Tuberous and succulent stems and leaves in the morphlogical structure, increase of osmoliticaly active compounds such as proline, soluble sugars, and protein are physiological functions increasing tolerance and adaptation of these plants to stressor factors. Xanthium strumarium has very deep roots with balloon shape trichomes in its leaves. Physiological study indicated the highest rate of soluble sugars and protein in the shoots and roots. Moreover, the rate of proline in the T. sibirica''s shoots and roots was higher than those in X. strumarium. Leaves and stems of T. sibirica are covered with trichome. T. sibirica contains the rhizome structure making the plant able to regenerate via rhizome in high salty conditions. Results of physiological study revealed the highest proline accumulation in the T. sibirica’s shoots and roots. According to the physiological study, the highest proline content was observed in the T. sibirica’s shoots and roots. On the other hand, the rate of soluble sugars and protein in T. sibirica were less thanthos in X. strumarium.
    Keywords: anatomical characters, proline, protein, soluble sugars, Tounefortia sibirica, Xanthium strumarium
  • Seied Ahmad Sadat Noori, Hamideh Khalaj, Mohammad Reza Labbafi* Page 108
    For examining and producing salt tolerant wheat genotype based on morpho-physiological characteristics, a factorial experiment was set out in a green-house in a completely randomized design with three replications. The treatments included four saline solutions (0, 150, 200 and 250 mM NaCl) and 8 wheat genotypes: 3 hybrids (Cajema × Sette Cerros, Cajema × HO2 and Cajema × Lermaroja), 4 parents (Sette Cerros, HO2, Lermaroja, Cajema) and Axona as a control. Data for Na+, K+ and Cl- concentrations and Na/K ratio in the first leaf below the flag leaf yield and 1000 grain yield were measured. Based on analysis of variance, salinity had positive significant effect on Na+, Cl- concentrations and Na/K ratio. As salinity levels increased, yield and 1000 grain weight and K+ concentration declined. Based on Na/K ratio, the best physiological characteristic for recognizing sensitive and tolerant genotypes, Cajema was the most tolerant genotype. Hybrids produced in this study weren’t good for salinity condition and the hybrids didn’t show more feature than their parents.
    Keywords: salinity, wheat, grain yield, sodium, Na, K ratio
  • Mozhgan Farzami Sepeher, * Mahlagha Ghorbanli Page 118
    Freshly harvested seeds of Rhubarb exhibited a high degree of dormancy when germination has been studied in different temperatures in distilled water. In the present paper, different treatments including moist - chilling, immersing in NaOCl, acid scarification, surgical procedure, and treatment by CaCl2 and KNO3 were performed to determine the most effective method for removing dormancy in Rhubarb (Rheum ribes L.). When seed coats (pericarp + testa) were completely removed, the root and hypocotyls of excised embryo from dormant seeds did not elongate. This indicates that dormancy is imposed by the embryo and those inhibitors in seed embryo may be responsible for the dormancy. Germination was observed only in CaCl2 and KNO3 treatments. Optimum temperature for germination was 10 °C and dormancy was partially removed when seeds were germinated in different concentrations of CaCl2. Moreover, CaCl2 solutions promoted germination more than KNO3.
    Keywords: Rhubarb, dormancy, KNO3, CaCl2, germination
  • Fatima Shahhosseini* Page 125