فصلنامه زیست شناسی گیاهی ایران
سال یازدهم شماره 2 (پیاپی 40، تابستان 1398)

Increase in secondary metabolites content has been attracting interest recently due to their huge economic importance. For example, Artemisia aucheria, which produces artemisinin, has both medicinal and economical importance. The aim of this study was to investigate the effect of single or combination UV radiation as well as sampling time on biochemical-physiological properties of A. aucheria on the increase in secondary metabolites, especially artemisinin. Therefore, a completely randomized factorial design including 7 radiation (no UV, UV-A, UV-B, UV-C, UV- (A + B), UV- (A + C) and UV- (B + C)) and Two different sampling times ( 2 and 24 hours after treatment) was carried out in three replicates. The results indicated that the content of chlorophyll a, b and total chlorophyll decreased in response to all UV radiation conditions except for UV-A. Moreover, the highest decrease of photosynthetic pigments was observed in the UV-(B+C). In addition, the concentration of photosynthetic pigments was reduced through time. In contrast, the content of carotenoids in plants treated with UV-A was increased. Moreover, total flavonoid content was increased about 50% in response to UV-(A+C). Further, the delay in sampling was shown to be associated with an increase in the concentration of flavonoid. Generally, all types of UV radiation, except for UV-C, increased the concentration of artemisinin and most of the other essential oils in both sampling times. Although the highest concentration of artemisinin was observed in the plants treated with UV-(B+C), the usage of UV-B, UV-(A+B) and UV-(A+C) radiation is suggested for increasing the artemisinin content in the short time

Mycorrhizal fungi cause plants to withstand environmental stresses. This research was carried out in order to investigate the effects of mycorrhizal fungus (Glomus versiforme) on tomato plants to ameliorate the salinity stress. This completely randomized experiment includes salinity (0, 4 and 8 dS m-1) and mycorrhizal (0 and 5% w/w) treatments in the research greenhouse of Urmia University in 2017. Morphological, physiological and biochemical characteristics such as plant height, root volume, proline and malone dialdehyde content, catalase activity, electrolytes leakage and content of soluble sugars were evaluated. Plant height and root volume in symbiont plants were more than the control, significantly. Increased catalase activity and content of proline and soluble sugars in inoculated plants indicates reduction in stress damage due to salinity. Also, electrolytes leakage and malone dialdehyde content in symbiont plants under salinity stress was less than the control. These positive effects of mycorrhizal symbiosis could be due to physiological impacts such as cell turgor control and osmolytes production and also due to morphological characteristics including root development and following ameliorating effects against salinity stress.

In order to evaluate the freezing tolerance of olive cultivars (native and foreign), a factorial experiment based on completely randomized design with three replications was carried out under controlled conditions. The investigated factors included cultivar (Zard, Roghani, Koroneiki, Mission), temperature (-18, -20 °C) and frost duration (24 and 48 hours). In addition, the effects of double and triple interactions among cultivar were significant for these two physiological traits. By applying freezing temperatures for 24 and 48 hours, the results showed that the electrolyte leakage percentage and the amount of free proline increased and decreased respectively with decreasing temperature in all studied cultivars; however, the changes of proline were more regular than the electrolyte leakage. So that at -18 °C, the highest and lowest percentage of electrolyte leakage was related to Koroneiki and Roghani cultivars, respectively and at -20 °C, the following descending order was obtained for the percentage of electrolyte leakage: Koroneiki > Mission- Roghani> Zard. However, in similar conditions, the highest and lowest amount of proline belonged to Zard and Koroneiki cultivars respectively. The proline capability to discriminate the studied cultivars was higher. So, based on the results obtained, cultivar Zard may be suggested as the preferable and superior cultivar for cultivation in areas under freezing stress.

Water Hyacinth, Eichhornia crassipes is one of the world’s worst weeds. It originates from Amazonia and be invader to other areas in the worldwide. It has recently been detected in several natural areas of northern part of Iran such as Anzali Wetland. Here, distribution of Water Hyacinth was studied in Anzali Wetland during 2015-2018. Also some biological characteristic including; evapotranspirative water losses, surveillance against salinity gradients and nutrient effect on biomass production of root and green parts were investigated. Water Hyacinth infestation was observed from 7 to 84 points of Anzali Wetland with 100 to 1000 m2 in different years. The distribution of Water Hyacinth was limited in summer of 2017 because of a prolonged temperatures below freezing winter. The seed was germinated in study area after two years. The water losses were estimated up to 2.5 times more from Water Hyacinth compared to open water. While the mortality of Water Hyacinth was observed in salinities more than 5.2 g.l-1, the leaves was increased in salinities lower than 1 g.l-1. The biomass of root was more than biomass of green part in areas with lower nutrient while it was versus in regions with high nitrogen level. Water Hyacinth has a high risk threat in the most water bodies in northern Iran because of the favorite climate situation and high eutriphication level. A multidisciplinary approach should be designed in the fight against Water Hyacinth in Anzali Wetland that awareness raising among local communities and the stakeholders is the most important.

Strawberry belongs to the genus Fragaria and family Rosaceae. Now days, the species Chiloensis, Virginia, and hybrid between them, namely, Ananasae, are cultivated. This perennial herb has a small genome that is prone to the transfer of Fragaria ananasae cultivated strawberry genes and other important economic plants from the Rosaceae family. Present study was conducted to study and compare the complete chloroplast sequence of Fragaria vesca, analyses of its genome structure, gene content and organization, repeated sequences, codon usage and comparison with two cultivated octaploid sequenced Fragaria species (F.chiloensis and F.virginiana). F.vesca chloroplast (cp) genome is 155691 bp in length with conserved quadripartite structure. Single copy region of cp genome is separated by the two inverted regions. The large single copy region is 85561 bp, and the small single copy region is 20204 bp whereas the inverted repeat is 24963 bp each. The plastidic genome has 130 single genes and 18 duplicated genes located in inverted repeats. The singletons encode 85 proteins, 8 ribosomal RNA genes and 37 transfer RNA genes. Amongst all plastidic genes only 18 genes appeared to have 1-2 introns and when compared with DNA of two cultivated octaploeids, rps18 was the only duplicated gene in F.vesca and rps 12, rpl 2 and trn I-GAU are genes which are located in inverted repeats. Despite the high level of conservation in chloroplast SSRs, these are useful in analysis of genetic diversity due to their greater efficiency as opposed to genomic SSRs.

In order to evaluate the effects of chitosan spraying and irrigation interval on physiological characteristics and antioxidant enzymes common mallow, a factorial experiment in a completely randomized design with three replications was conducted in 2015 at the Faculty of Agriculture, University of Zabol. The experimental treatments included irrigation interval (Irrigation interval 7 day, Irrigation interval 11 day and irrigation interval 15 day) and foliar chitosan spray (0, 0.5 and 1 mg.l-1). The results of interaction showed that spraying with 1 mg. l -1 chitosan during irrigation increased 27 and 7 % respectively, chlorophyll a and the relative content of leaf water and on the other hand spraying with 1 mg. l -1 chitosan during 15 day irrigation cause increased in total phenol content (79 %),proline (68 %) and Activity of antioxidant enzymes peroxidase (51 %), ascorbate peroxidase (72 %), guaiacol peroxidase (70 %), superoxide dismutase (54 %) and catalase (80 %) relative to the control. The results of correlation showed that proline had significant and positive correlation with RWC, but showed a negative correlation with photosynthetic pigments. Also there was a significant positive correlation between enzyme and non-enzymatic antioxidants.. The results of this study showed that chitisan spraying at the rate of 1 mg. l -1 reduced the lipid peroxidation, through increasing the antioxidant defense system activities of the plant and prevent the relative water content of the leaf through retaining cells’ water balance which, consequently, leads to cells’ structures stability against deficit stress.