فصلنامه گیاه و زیست فناوری ایران
سال پانزدهم شماره 2 (تابستان 1399)

In this research, biological synthesis of silver nanoparticles from Aspergillus fumigatus fungus and cytotoxicity and its antioxidant properties was investigated. Aspergillus fumigatus mushroom was cultured in Sabouraud Dextrose Broth. For the production of silver nanoparticles, supernatant from the culture was exposed to a solution of silver nitrate with a final concentration of 1 mM. Approval of silver nanoparticles production was confirmed by spectrophotometry, X-ray diffraction and Transmission Electron Microscopy. Investigation of the toxicity of the solutions was investigated by MTT method. Images obtained from X-ray diffraction show that nanoparticles are spherical and the nanoparticle size is between 5- 40 nm. In this study, the IC50 antioxidant was 0.06 and IC50 was 70.68 cytotoxicity. The IC50 hole has the same cellular and antioxidant properties, so it can be concluded that the nanoparticles produced in this study have good antioxidants.

The purpose of this paper was to investigate the role of transgenic crops in human health. In this paper, which is based on studies conducted in the corners of the vast world, the role of biological reinforcement of plant products, transgenic functional foods and biological drugs derived from these plants is discussed. The results indicate the undeniable benefit and effect of these products on the prevention and treatment of many diseases and physical problems. By using the right strategies and creating the necessary conditions for this industry, it is possible to benefit from this industry and take a step towards the production of technology, resistance economy and job creation. Transgenic plants (genetically modified) are widely distributed around the world. It may be tempting to kill and plant these plants in the short term, but their longterm effects on the environment and human health are in a state of ambiguity. Unfortunately, for more than a decade, transgenic plants have entered Iran's food basket without any labeling or compliance with the Carthage Protocol. Given the ambiguous state of transgenics and the risk to Iran's organic farming and exports, it does not seem necessary to rush into cultivating them. With the release of transgenics in farms and gene escape, there will be no turning back.

Every year hundreds of new cultivars are produced and introduced. Each ornamental plant is a valuable genetic pool that is used as a source for breeding program. In the last decade there has been an alarming increase in the number of disappearing and dangered species. Several valuable ornamental plants such as Fritillaria imperialis, Buxus hyrcana, Lilium ledebourii, Taxus sempervirens and some orchids are in danger of extinction. Some of these species have medicinal value in addition to aesthetic value. Therefore, the rapid development of approaches to long-term preservation of germplasm of these species under extinction seems to be necessary. Many of these plants are preserved in seed banks or as live plants in natural conditions. These preservation methods are unreliable, hard and costly. Therefore, complementary in vitro approaches represent an important tool for ex situ conservation of plants germplasm. Today, the conservation of ornamentals germplasm can take advantage of innovative techniques which allow preservation in vitro (slow growth storage and cryopreservation) of plant material. Periodic subcultures decrease in slow growth storage. Cryopreservation is the storage of explants at ultra-low temperature (−196°C/−321ºF). At such temperature, all the biological reactions within the cells are hampered; hence the technique makes available the storage of plant material for theoretically unlimited periods of time. Cryopreservation is the only technique currently available for the long-term preservation of the germplasm of plant species that are vegetatively propagated or has recalcitrant seeds. In recent years, some cryopreservation methods based on vitrification of intracellular solution such as encapsulation-vitrification and droplet-vitrification and the use of aluminum cryo-plate (D and V types) have been developed. Today, the encapsulation-dehydration technique is most often used. In the future, combined techniques, DNA conservation, survey of genetic stability of cryopreserved species, especially chimeras, cryotherapy and finding a simple, reliable and inexpensive approach and simpler regeneration of preserved explants will probably be the much popular. Unlike micropropagation, there is not much study on cryopreservation of ornamental plants especially those under danger of extinction and rare. Thus, the aim of this review paper is to evaluate different in vitro conservation and cryopreservation techniques and their use for the storage, breeding and exchange of genetic sources of ornamental plants especially those under the threat of extinction.

The current research was conducted with the aim to investigate the effect of salicylic acid on the growth traits, photosynthetic pigments and the amount of essential oil in Mentha piperita under drought stress. The factorial experiment was carried out in the form of randomized complete block design and with three repetitions. Factors included irrigation round at four levels (90 (control), 75, 45, and 20% field capacity) and salicylic acid at two levels (zero (control) and 60 ppm). The investigated traits included the plant height, number of lateral branches, length of lateral branches, number of nodes, fresh and dry weight of the plant, fresh and dry weight of the stem, chlorophyll a, b, and total, carotenoids, and essential oil percentage and yield. Results from this experiment showed that the effect of drought stress on all studied traits was significant at the statistical level of 1%. The mutual effect of drought stress on salicylic acid hormone for the length of lateral branches, fresh and dry weight of the plant, chlorophyll a, b, and total, and essential oil percentage and yield traits was significant. Stress caused a reduction in all traits except for fresh and dry weight of the stem; and the use of salicylic acid led to the reduced effects of stress such that the highest values of these traits were obtained from 60 ppm salicylic acid. Given the mutual effects, the highest values of essential oil percentage and yield obtained from 90% of field capacity and application of salicylic acid. Overall, the application of this hormone led to the improvement of qualitative and quantitative characteristics of Mentha piperita under drought stress.

In order to investigate the variation of some morphological, physiological and enzymatic characteristics of Zataria multiflora with the application of Humic acid and Fowlowic acid, as completely randomzed design with 7 treatments, 3 replicates and each replicate containing 3 units of plant, in total 63 units were evaluated. The treatments consisted of Humic acid and Fluvic acid with 3 levels of 25, 50 and 100 mg/L. Sparying the pots with the desired compounds were carried out three times in a week. Sampling and evaluation of the traits were carried out about two weeks after the last spraying. The evaluated traits included fresh and dry weight of shoot and root, total leaf chlorophyll, protein, superoxide dismutase enzyme activity, iron and nitrogen content. The results showed that Humic acid 100ppm treatment had the most effect on improving traits such as fresh weight of shoot and root, shoot and root dry weight, protein, superoxid dismutase enzyme activity and nitrogen content. Also Fluvic acid 100ppm treatment improvement of total leaf chlorophyll and iron content.

Considering the destructive consequences of unilateral application of nitrogen fertilizers on water and soil resources, biofertilizers will be of special importance. Regarding that native bacterial strains are capable of sustainability and efficiency, the present study was conducted on 95 isolates of bacteria in the microbial collection of Soil and Water Research Institute. Symbiotic efficiency (S.E) and plant infection tests were carried out. Lentil seeds of Bilesavar cultivar were cultured in test tubes containing nutrient solution without nitrogen and agar in three replications and inoculated with each bacterial isolate. Inoculated Seeds were grown under controlled greenhouse conditions for two months then measured in terms of dry weight of shoot, length of shoot and number of nodules as well as isolates SE using shoot dry weight. Results of analysis of variance showed that bacterial inoculation had a significant effect on shoot dry weight and length, number of root nodules and symbiotic efficiency (p < 0.01). All isolates were able to form root nodules on lentil. Symbiosis efficiency was measured very well and well in 87.3% of the isolates, while 12.7% were moderate to poor. Isolates BK11-1 and GL10-1 had the highest measured SE (250.4 and 247.16, respectively). Finally 19 superior isolate were selected in terms of shoot dry weight and symbiotic efficiency according to distribution of provinces.