فصلنامه زیست شناسی گیاهی ایران
سال پنجم شماره 3 (پیاپی 17، پاییز 1392)

In this research، the effect of etylendiamintetraacetic acid (EDTA) on chromium accumulation and growth of Raphanus sativus L. was studied. 10-day old seedlings were cultured in hydroponic conditions containing different concentrations of chromium (1، 2، 4 and6 mg/L) and EDTA (1 and 3mg/L) for 4 weeks. After harvesting، growth parameters، amount of chromium in shoot and root and also prolin in shoot were measured. The results of this study showed shoot and root length، leaf area and root area، root/shoot ratio significantly increased at 6 mg/lit cr by using of EDTA، compared to chromium alone. Measurement of prolin showed that the amount of prolin in shoot was significantly decreased compared to chromium، at 6 mg/lit cr and 1 and 3 mg/L EDTA. According to the results of this research، appropriate concentration of EDTA decreased stress of chromium، so that not only did not have any negative effect on plant growth it enhanced the growth of the plant.

Elicitors are compound with biotic or abiotic origin which induce defence responses including secondary metabolite production. Elicitors may activate new genes which induce enzymes and finally produce different biosynthesis pathways and secondary metabolites. Linum album is one of endemic species in Iran and has lignans like podophyllotoxin (PTOX). In this study، we investigated the effect of fungal extracts of Fusarium graminearum، Rhizoctonia solani، Rhizopus stolonifer، Trichoderma viride and Sclerontinia sclerotiarum on cell growth and lignans production and phenylpropanoid compounds in cell suspension cultures of L. album. Various fungal extracts uniquely induced lignan production، so that F. graminearum extract induced the highest increase of PTOX [141 μg g-1 dry weight (DW)] which was 6-fold greater than the untreated control، while R. stolonifer extract enhanced the accumulation of lariciresinol up to 365 μg g-1DW، which was 7-fold greater than the control. In addition، fungal elicitors increased the total phenol، flavonoid، flavonol and lignin. To study the mechanism of fungal elicitors action، phenylalanine ammonio-lyase (PAL) and cinnamyl alcohol dehydrogenase (CAD) activity were investigated. The activity of PAL and CAD enzymes involved in the first steps of the phenylpropanoids biosynthesis was activated by fungal elicioes، reaching a peak at 3 days after treatment.

In Rosa hybrida، after removing head of the stem، the lateral buds become free from apical dominance and start to form new branches. In each branch، leaves arrange in an age dependent manner. Four leaf samples were numbered from apex to base، exhibiting young to mature leaf stages. During maturation، physiological and biochemical changes occurred. Decrease of reactive oxygen species contents، led to reduction of membrane lipid peroxidation and ultimately increased the stability of cell membranes. Increasing total soluble protein contents were accompanied by decreasing of free amino acids and soluble carbohydrates contents. Results demonstrated differences in synthesis and degradation of proteins between young and mature leaves.

Glycyrrhiza glabra L. is a perennial herbaceous plant، belonging to the family Fabaceae and subfamily Papilionoideae. Comparative floral ontogeny is important for better understanding of floral evolution within the subfamilies of Fabaceae. The aim of this study was to present a complete ontogenetic pathway of G. glabra، as a member of tribe Galegeae and to compare it with other studied species of the Papilionoideae. For this purpose، flower buds of different ages were collected and then fixed in FAA. After a fixation period of 24 h، the samples were rinsed and after dissection the samples were dehydrated in sequential ethanol concentrations of 70% and then 95%. The samples were stained with 0. 5% nigrosin black in ethanol. The more remarkable features of flower ontogeny were the abaxial-adaxial unidirectional initiation of organs primordia within each floral whorl، high overlap in the time of initiation of whorls and early carpel primordium initiation. The overlapping in time of organ initiation and precocious inception of carpel were advanced characters that were previously reported in the members of inverted repeat lacking clade (IRLC) of Papilionoideae. However، lacking common primordium was the character that distinguished G. glabra from other studied species of IRLC.

In this study، plant morphology and palynology of 40 populations belonging to 17 species from 3 sections of the genus Onobrychis، namely Afghanichae، Heliobrychis and Lophobrychis، were investigated. In morphological study، 59 quantitative and qualitative characters comprising vegetative and reproductive structures were investigated and 3 groups were distinguished. In spite of the comparatively homogenous morphological features including، 3-colpate and reticulate ornamentation، a considerable variation was observed in the quantitative morphological characters of the pollen grains. However، among the studied pollen morphological characters، equatorial and polar diameters were more significant than others and based on these data، the members of the studied sections could be divided into 3 groups. This confirmed the results obtained from morphological survey.

Salicylic acid is a common plant-produced phenolic compound and sited as a plant hormone. The work reported in this paper investigated the effects of different concentration of exogenous application of salicylic acid on flavonoids، anthocyanin، apigenin and carbohydrates in hydroponically- grown Matricaria chamomilla L. (german chamomile) during 4 days. Although 0. 125 mM salicylic acid applications produced prominent results، higher salicylic acid dose had a toxic effect. Indeed، salicylic acid treatments effectively promoted the production of a wide range of plant secondary metabolites. Generally، 0. 125 mM salicylic acid increased flavonoids، anthocyanin، apigenin and soluble sugars compared to the control. Salicylic acid was also shown to inhibit seed germination.

Certain chemical and biological parameters of the plants including secondary metabolite accumulation are affected during the establishment of arbuscular mycorrhizal symbiosis. Since، secondary metabolites are important from many aspects like food and pharmaceutical industries and also plant defense system، many studies are focused on the effects of fungal inoculation on different growth parameters and secondary production in plants. In this study، after simultaneous inoculation of licorice seeds with two fungal species Glomus mosseae and G. intraradices effects of inoculation on growth parameters and secondary production in 6-mounths old samples were assessed. Percentage of colonization، plant growth parameters، phosphorus and zinc، amount of glycyrrhizin، the total phenolic compounds and total flavonoids were measured. Results showed that length of roots and stems were increased as well as the number of leaflets، fresh and dry weights of seedlings، as compared to the control plants. Amount of phosphorus and zinc were also increased in inoculated samples compared to the controls. Significant increases were also observed in secondary compounds of roots of the 6-mounths old plants (phenolic compounds، total flavonoids and glycyrrhizin) compared to the control samples. Results showed that simultaneous inoculation of licorice seeds with mycorrhizal arbuscular fungi G. mosseae and G. intraradices played an important role in increasing quantitative plant growth parameters and improving qualitative characteristics of medicinal plant licorice.

Dunaliella is a dominant unicellular Eukaryote alga genus in the Urmia Lake. Recently، the density of this genus has been vastly decreased owning to Urmia Lake intense desiccation. This study investigated the species diversity of Dunaliella in Urmia Lake stations. Species determination was based upon Polymerase Chain Reaction (PCR) method using the combinations of 18srDNA gene primers. The sampling and subsequent isolation of the Dunaliella species from the Urmia Lake stations revealed that in spite of the Urmia Lake intense crisis and severe density decrease of the algae، at least 4 species of Dunaliella namely D. bardawil، D. parva، D. salina and D. tertiolecta existed in the studied stations of the Urmia Lake.

In this study، signal peptide sequences of Lillum longiflorum anther-specific protein LIM14 and ATCPrecA، a protein with the origin of A. thaliana that had the characteristics of chloroplast signal sequence were independently fused to the N terminus of the green fluorescent protein (GFP) and β-glucoronidase (GUS) genes and subsequently transferred to potato (Solanum tuberosum cv. Kardal) as an important starch storage plant by Agrobacterium-mediated transformation. Fluorescence microscopy and GUS staining showed that the recombinant LIM14-GFP fusion protein was targeted to the amyloplast and chloroplast of transgenic potato plants. Quantitative assay of GUS showed that the level of expression in the enriched amyloplast fragment of signal peptide included plants is higher than the GUS control transformed plants. ATCPrecA is a protein with the origin of Arabidopsis thaliana that had the characteristics of chloroplast signal sequence in N-terminus. To study the function of the transit peptide of ATCPrecA، full length cDNA was fused to the N-terminus of the GFP to make recombinant protein. ATCPrecA-GFP was transferred to potato by Agrobacterium-mediated transformation and transiently expressed in onion (Allium cepa L.) epidermal cells via microprojectile bombardment. According to the results of this research، we concluded that the transit sequence of both LIM14 and ATCPrecA were functional and were capable of directing recombinant proteins into plastids.