Iranian Journal of Plant Physiology
Volume:6 Issue: 3, Spring 2016

Seed priming is a technique which is potentially able to promote rapid and more uniform seed germination and plant growth as well. In this regards, the presowing effects of seed priming treatments were investigated on some physiological viz. seed germination, germination rate, radicle elongation, shoot elongation, radicle dry weight, shoot dry weight and vigor index. Seeds were subjected to two seed priming methods , hormo priming, and halopriming. A lso , untreated seeds were used as control. Halopriming with - 0.5 MPa of KNO 3 and KCl and hormopriming with 100 mg/L of SA at 15 C were used for 24 h in a factorial experiment with completely randomized design under laboratory co nditions. The results showed that hormopriming (100 mg/L of SA) im proved the germination rate (no significant difference with KNo3 and KCl), germination percentage, radicle elongation, plumule elongation , radicle dry weight, plumule dry weight , and vigor index under cadmium stress (30 mg/L) at 56.35, 11.9, 30.65, 30.33, 65.21, 71.42 , and 46.16%, respectively. In all cadmium concentrations, the maximum of all germination parameters w ere related to the seeds primed with SA solution. While in primed seed by KNO 3 and KCl treatments, expos ure to 20 and 30 mg/L Cd decreased radicle length as compared to the control. Also, exposure to 30 mg/L Cd, KNO 3 solution showed lower plumule length than control. The amount of reduction in radicle length in primed seeds with KNO 3 solution and KCl solution was 11.88% and 6.18% , respectively, in 30 mg/L Cd. However , in all cadmium concentrations, germination percentage and rate were enhanced by KNO 3 and KCl solubles.

Cadmium is a non - essential element that induce s various toxic responses in plants when accumulated above the threshold level. The aim of the present research was to study the effect of cadmium on growth factors, concentration of cadmium in the rhizomes and leaves, and quality and quantity of essential oils in the leaves of Mentha piperita L. The experiment was carried out in a completely randomized design with three replications. Rhizomes with uniform weight were planted in pots 30 × 50 × 35 cm. After foliation of all rhizomes , plants were irrigated every other day, for 2 months by different concentrations of CdCl2 (0, 100, 500 , and 1000 μM). Results dem onstrated that the minimum stem length and fresh and dry weight of leaves were achieved in the plants treated with CdCl 2 (500 μ M). With increasing the cadmium in treatments, the amount of cadmium in the rhizomes and leaves were also increased. In treatment of CdCl 2 (1000 μM) the accumulation of cadmium in the leaves was more than the rhizomes. There were not significant differences in the essential oils conte nts between treatments. Analysis of the c hemical composition of essential oils indicated that the main constituents of all treated plants were 1, 8 Cineole, Dihydrocarvon, Pulegone , and Carvone. Limonene oxide was observed only in the leaves of control plants.

This study was conducted to find the effects of fruit ripening and extraction method on the quantity and quality of the Koroneiki olive oil. The oil samples extracted in six ripening stages were used for further quality analysis. Quality assessment of the oil was conducted according to the standard methods and the composition of fatty acids was measured by gas chromatography. The results showed that there were some significant differences in the percentage of oil among different fruit tissues and harvesting times. In all tissues, the percentage of oil in dry matter increased significantly from 12 Oct to 4 Jan. The mesocarp and seed had significantly higher percentages of oil compared to endocarp. The extraction method and harvesting time had some significant influences on peroxide value. Furthermore, the extraction method showed a significant effect on the refractive index, but not on the other quality traits studied. The oil extracted using soxhlet had higher peroxide value, but lower refractive index compar ed to the oil extracted by centrifugation. The harvesting time showed some significant effects on the percentage of free fatty acids, K232 value, K270 value and the amounts of total chlorophylls and total carotenoids. There were a higher percentage of free fatty acids in the oil samples produced in later harvesting times. The oil extracted on 1 Mar showed the highest percentage of free fatty acids. On the other hand, the oil samples obtained from earlier harvesting times had higher values of K232 and K270 a nd higher amounts of total chlorophylls and carotenoids. The results showed an increase in the percentage of oleic acid and linoleic acid during the harvesting times; while, there was a slight decrease in the percentages of other fatty acids studied.

This research was conducted to investigate the effects of peppermint (Mentha piperita) essence treatment (2000 mg L - 1) and cola soft drink treatment separately and in combination with each other on the vase life and some physiological characteristics of gerbera ( Gerbera jamesonii ) cut flowers with factorial arrangement in a completely randomized design with 3 replications. Distilled water used as control. The results sh owed that all treatments significantly increased the vase life, solution absorption, petal carotenoids, flower dia meter, relative fresh weight , and petal total soluble solids in comparison with control. The highest and the lowest vase life were obtained in the peppermint essence plus cola soft drink treatment (250 ml L - 1 ) with 20.33 days and in the control with 9 days, respectively. The highest amount s of carotenoid, flower diameter, relative fresh weight , and total soluble solids w ere obtained in the peppermint essence plus cola soft drink treatment (250 ml L - 1 ). The highest amount s of solution absorption w ere obtained in flowers treated with cola soft drink (250 ml L - 1 ). In general, the results indicated that the peppermint essence a s a safe and natural antimicrobial compound and the cola soft drink as a common drink having sugary and acid materials with easy access and being affordable could be used in gerbera cut flower preservative solution.

Citrus genus is known as one of the world's major economic agricultural products . In the current research, a method is reported for a rtificial seed production technology by shoot tips in Citrus sinensis. var. Thamson navel . Alginate is one of the most efficient gelling agents in the production of capsule coating in artificial seeding technique. In the current research, impa ct of different constituents of a lginate matrix was investigated on a rtificial seed germination. In order to produce artificial seed s , shoot tips of Thamson navel were coated by three a lginate coating including SA 1 containing liquid MS and BA and NAA hormo nes, SA 2 with liquid MS without hormone , and SA3 with distilled water.Alginate coating with BA and NAA hormones was usedas control environment. The artificial seeds were then stored in the refrigerator (4 °C). Following passing storage period, seeds were placed in MS solid medium with BAP (10 mgl-1) and NAA (1 mgl-1) forconversion to seedlings. Using distilled water instead of MS medium for the preparation of a lginate coating significantly reduced the percentage of conversion in to seedlings.

High use of synthetic pesticides has detriment al effects on the environment. A n a lternative option is application of natural pesticide compounds. The aim of this study was to evaluate the possibility of replacing Vitavax with savory essential oil to inhibit physiological damages to wheat ( Triticum aestivum L.) seed s caused by Fusarium oxysprum. A pot experiment was carried out on wheat seed s as fact orial on the bas is of completely randomized design with three replications. Factors were fungal infection ( Fusarium oxysprum infection and non - infection), and fungicide (control, savory essential oil at 10 and 20 ppm and Vitavax 2 g per kg). Fusarium infec tion decreased seed physiological quality. Using savory essential oil could not inhibit fungal infection in seeds and seedling but Vitavax could. In addition, the savory essential oil decreased somewhat germination percent age and its inhibitory effect on g ermination increased with concentration. Although there are some reports about anti - fungal effects of savory essential oil under in vitro conditions, such effect was not ob served under this pot experiment. This may be due to application of low concentration in this experiment; however high concentration will kill the seeds.

Aeroponic culture is an alternative method for optimizing growth of different plants in controlled conditions. Aeroponic systems are an efficient tool for the root studies and improving medicinal root production. In order to study the feasibility of valerian ( Valeriana officinalis L.) production in aeroponic system s and assessing the effects of different NAA concentration s(0, 0.1, 0.3, and 0.5 mg/l) on some morpho-physiological traits of valerian, the current study was conducted based on a completely randomized design. The results indicated that the effects of the production system were significant for plant height, root length, number of leaves, volume of root s,and dry weight of the shoot and root. Application of NAA hormone hada significant effect on all of the studied traits and by increasing NAA concentration, leaf number, root length and volume, plant height, dry weight of root and shoot, root/shoot ratio, rela tive water content ,and photosynthetic pigments increased significantly.

One of the important abiotic stre sses that negatively affect cereals such as wheat is heavy metals. Soil pollution with heavy metals has become one of the major environmental concerns resulting from the industrial development and use of fertilizers containing heavy metals. One way to counteract the negative effects of heavy metals in plants which produce reactive oxygen species is the activation of antioxidant sy stems in plant cells. In order to study the physiological traits involved in resistan ce to these stresses, a factorial experiment was conducted in a completely randomized design with three replications. The first factor was wheat cultivars including Gonbad (tolerant to Fusarium) and Tajan (susceptible to Fusarium). Th e second factor was spraying heavy metals (mercuric chloride at concentrations of 5, 10, 15 , and 20 μM, cadmium chloride at concentrations of 0.25 and 0.5 mM and control) and the third factor was sampling times after treatments ( after 8 and 16 hours ) . The results showed that the total protein and soluble sugar contents increased with cadmium and mercuric chloride treatments. Furthermore, with increasing concentration of mercuric chloride, the catalase, peroxidase , and polyphenol oxidase activities decreased while the activities of these enzymes increased with increasing concentration of cadmium chloride. Thus, this study showed that spraying of cadmium and merc uric chloride at micro - and nano - molar concentrations can stimulate and strengthen plant antioxidant system and make plants more tolerant to heavy metals stresses.