Journal of Plant Biological Sciences
Year:2010 | Volume:2 | Issue:1 (SEQUENCE 3)|Papers Count:7

The effects of activated charcoal and different combinations of plant growth regulators for micropropagation of using nodal culture were investigated. Adding activated charcoal improved growth and root system of plantlets; on the other hand, on the bottom of explants, no callus was formed. The best response was observed on medium containing 2 mg/l BAP and 0.5 mg/l IBA, with respect to the number of buds per explant and percentage of rooting. The explants grown on the medium containing IBA 0.5 mg/l were rooted. 70-90% of transferred plantlets to the greenhouse were survived and grown.

Mushrooms, in addition to their nutritional values, are currently considered as useful tools for biological of agricultural wastes to useful food products. In the button mushroom (Agaricus bisporus), there are several enzymes which catalyze lignin compounds of the compost during the mycelia growth and the fructification phases. Manganese Peroxidase (MnP), as one of the most important lignin-degrading enzymes, plays a key role in degradation of lignin compounds in the button mushroom. To achieve a high yield of MnP in the A. bisporus, the gene encoding MnP was isolated, characterized and cloned. The total RNA was extracted from the mycelium growing on the liquid compost extract medium, followed by construction of its cDNA by reverse transcriptase. The PCR products were then inserted into the pTZ57R/T cloning vector, and transferred into E. coli (the DH5α strain). Finally, the plasmid was extracted from the transgenic bacteria, followed by enzymatic digestion and nucleotide sequencing. The BLAST analysis revealed two different nucleotides (657 and 850) between the cloned fragment (generated in this research) and the mnp1 (available in the gene bank of NCBI). The difference in the nucleotide positions of 657 and 850 subsequently changed Isoleucine to Valine and Serin to Alanine, respectively.

Zinc plays an important role in many structural and biochemical functions in plants. However, excess amount of this element as heavy metal is one of the limiting factors for plants. Spearmints were grown in green house at nutrient solution containing different concentration of zinc until the flowering stage. The essential oils from fresh spearmint samples were isolated by water distillation (clevenger) and analyzed by gas chromatograph-mass spectrophotometer (GC-Mass). In this research, results indicated that, monoterpenes were major parts of essential oils in M. spicata and low percent of these compounds were sesquiterpenes. In comparative investigation, content of oxygenate monoterpenes decreased with employing zinc in nutrient solution but, hydrocarbonate monoterpene contents of essence were increased. Total monoterpene contents of essence increased significantly by zinc treatment. However, with increasing Zn concentration, sesquiterpene contents such as hydocarbonates and oxygenates reduced gradually. It was concluded that, total oxygenate monoterpenes were more affected by Zn treatment and its reduction was remarkable. This could be due to bioenergetical changes in plant cells in response to heavy metal stress.

An experiment (under controlled condition) was implemented applying randomized complete block design in three replications and eight spraying compound treatments at the agricultural experiment center of Tehran located in Varamin region, in order to investigate the effects of zinc and auxin (IBA) foliar on some anti-oxidant activity, consisting of catalase, super oxide dismutase, peroxidase, poly phenol oxidase and auxin oxidase. Results showed that, of various compounds of zinc (Zinc Sulphate and Zn EDTA) and auxin foliar application were increased level of anti-oxidant enzymatic activities, so it seems that foliar application of zinc and auxin enhance corn tolerance against drought stress via promoting of root growth.

Formation of brownish yellow pigments in damaged fruits and vegetables by tyrosinase enzyme is one of the main causes of their quality loss. Tyrosinase is a metaloprotein and is used in researches, regarding food, pharmacology and cosmetics. Peanut is one of the most important strategic agricultural products of northern Iran. In a general survey from the local farmers and producers, it was found that many of older peanuts lose their market and are reduced in quality and price when the new crop product is entered into the market. Considering the experience and the experties within our group on tyrosinase extraction and characterization, the aim of this research was focused on peanut tyrosinase. Peanut was grounded in liquid nitrogen, followed by precipitation by ammonium sulphate and dialysis. Electrophoresis showed the presence of two possible isozymes. Enzyme activity was determined during various stages of purification. Some important physical properties of the enzymes were also measured. It was shown that the optimum pH for peanut tyrosinase was 5.2 and that optimum temperature was 40oC. Kinetics studies determined the Michaelis-Menton constants, i.e. Km=257.5 mmol and Vmax= 0.00421 mmol/min. The ultimate goal of this research was to investigate the possibility of replacing peanut tyrosinase for mushroom tyrosinase in various industrial and research applications.

Most Solanaceae plants produce a range of biologically important alkaloids including nicotine and tropane alkaloids, such as hyoscyamine (atropine) and scopolamine. These alkaloids are used for their medicinal properties. Atropa belladonna is a medicinally important herbaceous plant that produces high amount of tropane alkaloids in roots. In this research, Atropa belladonna explants were obtained from sterilized seedlings in the modified Murashige and Skoog (MS) solid medium. The seeds were collected from Vaz and Garmestan regions of Mazandaran Province, Iran. Explants were cultured for four weeks on a modified MS solid medium, containing different concentrations of salicylic acid (0, 0.01, 0.1 and 1 mM). In addition, hairy roots of Atropa belladonna that was established by transformation with Agrobacterium rhizogenes, were cultured in MS medium for two weeks. Then the production of two tropane alkaloids, atropine and scopolamine, in different parts of neoformed plants were assayed by HPLC method. Generally, tropan alkaloids content in hairy roots was considerably higher compared to those contents in plants. Although Garmestan population was better than Vaz group, the amount of atropine in hairy roots was influenced by salicylic acid as high as 5 to 35 times of produced atropine in different parts of plants. The scopolamine content in the hairy roots was 2-30 times higher than in plant organs. In conclusion, it is suggested that, hairy root lines can be used as a replacement of plants in further studies and for tropane alkaloids production in economical and commercial scales.

Five species of Papaver L. genus, belonging to the Papaveraceae family, namely Papaver dubium L., Papaver orientale L., Papaver fugax Poir. (with two subspecies), Papaver glaucum Boiss & Hausskn. and Papaver gaubae Cullen. & Rech. were collected from rangelands across Ardabil province. Several karyotypic characteristics such as long arm, short arm and satellite length were studied then, total length of the chromosomes, long arm to short arm and others characteristics were estimated. Result showed that, there were two types of basic chromosomes numbers, x=4 and x=7. This is the first record of basic chromosome numbers of x=4 observed on Papaver glaucum Boiss & Hausskn. and Papaver gaubae Cullen. & Rech.. The species Papaver fugax Poir. var. fugax Cullen. contained B-chromosome. From evolution point of view, Papaver fugax Poir. var. platydiscus Cullen. was considered as the most asymmetric and thus the most evolved species. The range of total chromosome length was 23.57±0.81 to 7.53±0.64 µm. Analysis of variance showed highly significant differences between the studied species for all of the traits at (a= 0.01). Based on these characteristics, cluster analysis classified the species in four distinct groups.