جستجوی مقالات مرتبط با کلیدواژه "ارزیابی زیستی" در نشریات گروه "زیست شناسی"

The garlic plant (Allium sativum L.) has many medicinal and industrial properties. Due to the great importance of garlic, various aspects of it have been researched. An experimental design with the arrangement of a randomized complete block design with three replications in the crop year 2023-2024 was investigated with the aim of evaluating the biodiversity of garlic ecotypes. Variance analysis of different morphological traits studied showed high and acceptable diversity for preliminary study in multi-racial programs. Based on the analysis and comparison of means, in this study, the ecotypes of Bahar 2, Soolan, and Asadabad had favorable yield indicators. According to the correlation relations that existed between the traits, it seems that most of the studied traits are suitable selection traits for garlic plant breeding to achieve high yield and these relationships can be used to modify the complex yield trait and increase it. Based on the cluster analysis of different garlic ecotypes using Ward's method, Bahar 2, Soolan, and Asadabad ecotypes were in the first group, Maryanj and Bahar 1 ecotypes were in the second group, and Imamzadeh Kuh ecotype (Toeejin) was in the third group, and the detection function analysis also confirmed this grouping. Based on the general results, the weight of a garlic bulb, the weight of a garlic clove, and the length of a garlic bulb are the most suitable traits for indirect selection to increase economic yield. Ecotypes of Bahar 2, Soolan, and Asadabad are the most suitable ecotypes in terms of having the highest amount of traits: weight of one garlic bulb, weight of one garlic clove, and weight of five garlic cloves, while the ecotype of emam zadeh Kuh is an unfavorable ecotype in the growth conditions of Asadabad. The results of this study can be used to select desirable traits with the greatest effect on yield.

Crude oil pollution in the Persian Gulf is a major problem in this important marine environment. Today, the use of biological degradation methods to remove these pollutants is considered. The purpose of the present study is to compare the two methods of biological stimulation and biological enhancement for the degradation of sediments contaminated with crude oil in the Persian Gulf.

In this research, six types of microcosms were designed to understand the effectiveness of biostimulation and bioaugmentation on the microbial population of Khark Island sediments. Indicators such as the quantity of degrader, heterotrophs, and the rate of crude oil degradation were investigated at different times and finally, the degradation over time was measured by the Gas Chromatography method.

The results of this study showed that the combined microcosm of biostimulation and bio-augmentation (SB) with the amount of heterotrophic bacteria (equal to 3.9 x 106) and degrader (equal to 1 x 106) had the highest quantity. Population dynamics in microcosms were also studied and the lowest quantity of heterotrophic bacteria with a numerical value of 1x104 was related to natural sediments. The statistical results of this research proved that there is a significant relationship between the type of method chosen for biodegradation with the sampling time and the quantity of the dynamic population, and finally, with the increase of incubation time, the biodegradation of oil in all microcosms increased significantly (95%), but the best biodegradation of oil was related to the integrated microcosm of biostimulation and bio-augmentation.

By using the type of biological remediation method according to the nature of the contaminated sediments, oil-contaminated sediments can be rehabilitated with the help of biological methods and contribute to the stability of marine ecosystems.

Human activities are the main cause of river pollution that continuously affect the water quality of the rivers. In this study, the population structure of macroinvertebrates was investigated as a biological indicator for water quality in the Khorram-rud River. For this purpose, a number of 4 stations were selected and some physicochemical parameters along with macroinvertebrates sampling were done monthly for 12 months (December 2018- November 2019) in each station. Totally 26 families in 14 orders of macroinvertebrates with the domination of families Chironomidae, Baetidae, and Tricorythidae, respectively were found. The results of physicochemical factors showed that the lowest and highest water temperatures recorded were 8.66 ± 0.57 in December and 23.66 ± 0.57 in July, respectively, the maximum average dissolved oxygen in March 5.83 ± 0.28 mg/l  in the station (1), and the minimum was 0/00 mg/l in a station(4). pH value recorded with a minimum of 6 ± 0.86 in January and a maximum of 8 ± 0/00 in June. The average change of nitrite in different stations showed a slight fluctuation but was higher than the allowable limit in all stations. The highest amount of nitrate in a station (3) in June was 36.66 ± 5.77 and the lowest in a station (1) in December recorded as 2 ± 0/00 mg/l. The seasonal variations in density of macroinvertebrates indicate the maximum density in autumn and the minimum density in winter. The results based on (BMWP, ASPT) and richness and diversity indices (Shannon-Weiner, Margalef) indicated that the Khorram-rud river water is in the contaminated water class.

Rivers are vital ecosystems and their protection is of outmost importance. In this study effects of physicochemical parameters of water on the population structure of Ephemeroptera in three sampling locations e.g. upstream, middle and downstream of the Tajan River were examined. Sampling was carried out on monthly bases from April to March 2019. One-way analysis of variance was used to evaluate the qualitative status of the sampling stations, Principal component analysis was utilized to determine the effect of environmental factors on separation or overlap of the studied stations and comparative conventional analysis was used to determine the relationship between environmental variables with presence and absence of Ephemeroptera families. Results showed that physicochemical factors varied significantly during the study period. The average of factors such as the flow rate (68.3 m3/sec), dissolved oxygen (9.53 mg/lit) and pH (8.31) were at highest levels in February and March while average of EC (1181µm/cm) and TDS (815 mg/lit) were at their lowest values in in September. Significant differences were observed in physicochemical factors at different stations. The differences were apparent between Mohammadabad station with other two sampling stations in terms of temperature and dissolved oxygen and Tajan station varied significantly with others in terms of EC, TDS and Debi. Significant relationship was observed between frequency and presence of some families of Ephemeroptera including Baetidae with EC and TDS and Oligoneuridae with pH and dissolved oxygen which allows considering these groups as qualitative indicator or indicator species of surface water resources.

Kardeh River is one of the most important permanent rivers of Khorasan Razavi province Which supplies a large part of Mashhad's drinking and agricultural water. Multivariate analysis was used to find out the quality of Kardeh River in this study and to understand the impact of macroinvertebrates community structure drivers on ecosystem management. For this purpose, macroinvertebrates sampling was performed from four study stations during four seasons in 2018-2019, physical and chemical parameters also were measured. In this study, Of the Ephemeroptera, the total number of Caenidae and Baetidae families had the highest abundance (66 / 60 %). The results showed that the Index of Biotic Integrity varied from 3 to 1.1 and based on this biodiversity indicator, Kardeh River water quality was classified into three relatively good, poor and very poor quality classes. The Stream Invertebrate Grade Number Average Level index was classified into two categories: moderate pollution and severe pollution. Canonical Corrspondence Analysis also showed that nitrate, biochemical oxygen demand and chemical oxygen demand had the most effect on the distribution of macroinvertebrates at the study stations. In general, the Kardeh River water quality was poorly evaluated and among the study stations the station conditions were relatively better than the other stations. Therefore, among the available indices, multimetric indices are more reliable. However, these index should be calibrated according to the conditions of Iranian rivers.

The current study aims to investigate the community structure of macrobenthos to evaluate water quality of Jajrood River, Northeast Tehran, Iran. We conducted this study in 12 stations during the Spring and Winter seasons of 2014-2015. The sampling method of macrobenthos is use of the surber sampler device with three replications in each station. We measured physical and chemical parameters in each station (temperature, pH, electrical conductivity, BOD, total suspended solids, nitrate, dissolved oxygen, ammonia, and fecal coliform). We used Canonical Correspondence Analysis to examine the effects of the physical-chemical parameters on the population distribution of macrobenthos. According to the results, we identified 11362 of macrobenthos 6 orders and 25 families. The greatest frequency (52/56) of creatures belonged to the order Ephemeroptera, whereas the lowest frequencies (0.07) was seen in the order Coleopteran. Water temperature, ammonia, and electrical conductivity parameters had the largest effect in distribution of macrobenthos. The correlation between biology index and physical and chemical index of IRWQISC showed that margalef, TBI, and IBI indices were the best metrics that assessed water quality. Other than the Abnic and Taletange stations, the water quality in the other stations was unsuitable. We propose that efficient management practices should be implemented to improve water quality of this river.

This study aimed to investigate the population structure of benthic communities in Haji Abad River, West of Hormuzgan province. The study was conducted from October 91 till September 92. The three sites were determined based on regional topography and large benthic fauna. Sampling was performed monthly using a 500 micron Surber sampler with three replicates at each station. Samples were fixed in 4% formalin and identified. A total of 5 classes, 9 orders, and 24 families were identified in which the greatest diversity and abundance was recorded for aquatic insect larvae. The order Diptera and Ephemeroptera were dominant in all three stations. Maximum number of animals during the sampling period was 4195 individual at station 3, and the minimum was 2,935 sq m at station 1. Data on large benthic community structure metrics were summarized using the EPT richness (Ephemeroptera, Plecoptera, Trichoptera), the ratio of EPT frequency to Chironomidae family, the Shannon diversity index and Biological indicators Bauer.