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11.
The essential oil of Oliveria decumbens was investigated for its components and antimicrobial activity against six bacteria and two fungal strains. The essential oil was characterized by a high amount of oxygenated monoterpene components of which thymol (47.06%) and carvacrol (23.31%) were the major components. The oil exhibited high antimicrobial activity against all tested Gram+ and Gram- bacteria and fungal strains. 相似文献
12.
Nitrogen plays a major role in the growth and yield of strawberry. For optimizing nitrogen fertilizer application, it is necessary to understand the response of strawberry to nitrogen supply. The objective of this study was to determine the effect of nitrate supply and plant size on strawberry nitrate uptake and nitrate reductase activity (NRA). Strawberry plants cv. Selva were grown under growth chamber conditions in nutrient solutions containing 0, 0.1, 0.25, 0.7 or 4 mM nitrate. Cumulative nitrate uptake increased with the increase in nitrate supply. Increasing nitrate concentrations from 0 to 0.25 mM decreased leaf NRA; however, further increases to 4 mM nitrate restored NRA to activities observed at 0 mM nitrate. The activity of NADH- and NADPH-dependent NR was similar at every external nitrate concentration. Activity of NR was greater in the smallest plants and decreased as plant size increased. However, increasing external nitrate concentration increased nitrate uptake, but had not the same effect on nitrate reductase activity, showing that NRA and nitrate uptake are not necessarily correlated. 相似文献
13.
The effect of in planta TIBA and L-proline onin vitro seedlings and cell culture of sugar beet was investigated. Sterilized seeds were grownin vitro on 1/2 MS medium supplemented with 0 or3 mg/l TIBA. Calli obtained on young leaves cultured on MS medium containing 1 mg/l
BAP, were used for the initiation of cell suspension cultures using MS basal composition supplemented with 0 or 50 mM proline.
Aliquots of 1 ml from cell suspension culture were inoculated onto the first somatic embryo induction MS medium containing
TIBA 0.5 mg/l, BAP 1.0 mg/l, and proline at 0 or 50 mM. After three weeks of culture, embryogenic calli were transferred to
the second embryo induction medium supplemented with NAA and BAP at 0.2 and 0.5 mg/l, respectively. The frequency of somatic
embryos of calli obtained from in plantaTIBA together with proline treatments on average was20 which was higher than that of the other treatments.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
14.
Side Sadat Ebrahimi Hassan Pourbabaei David Potheir Ali Omidi Javad Torkaman 《林业研究》2014,25(2):455-462
Plant diversity plays key ecological roles in forest ecosystems, including influencing succession, resilience and nutrient cycling. This study was conducted to investigate the effect of livestock grazing and human uses on herbaceous species diversity. We surveyed 50 ha of protected area and 50 ha of unprotected area to evaluate herbaceous species diversity in oriental beech （Fagus orientalis Lipsky） forests in northern Iran. We calculated and compared three indices each of diversity and evenness, and species richness between the two areas. Herbaceous cover was higher in the unprotected area while leaf litter depth and tree canopy cover were higher in the protected area. The diversity indices, H （Shan- non-Wiener index ）, N~ （McArthur index）, N2 （Hill＇s index）, EQ （Modified Nee index）, E,ar （Smith-Wilson index）, E5 （modified index of Hill） and R=S （species richness） and species richness R=S were greater in the protected area than in the unprotected area, suggesting that protection from grazing results in increased numbers of plants and species. The effect of land protection on plant diversity was more pronounced for evenness than for species richness and the positive correlation between diversity and evenness indices was higher than that between diversity and richness. 相似文献
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16.
Assessment for salinity tolerance through intergeneric hybridisation: Triticum durum × Aegilops speltoides 总被引：1，自引：0，他引：1
Seyed Ahmad Sadat Noori 《Euphytica》2005,146(1-2):149-155
Summary Triploid hybrid embryos (AABB × SS = ABS) were produced by crossing two moderately salt-tolerant wheats, namely Triticum turgidum durum and Aegilops speltoides subsp. speltoides. The embryos were rescued by culturing on agar No. 1. Chromosome doubling was achieved by using 0.05% colchicine. The resulting
hexaploid plants grew to maturity, and produced a considerable amount of seed (≈40,000). The synthetic hexaploid (C2) was tested for salinity tolerance, grown at 0, 100, 125, 150, 160, 170, 180 and 200 mM NaCl in a standard nutrient solution
for 2 weeks. The criterion of salt tolerance was root growth in different NaCl concentrations. The amphidiploid material showed
greater salinity tolerance than either parent, suggesting the presence of different genes for tolerance in the parents. 相似文献
17.
Nasrin Chowdhury 《Soil biology & biochemistry》2011,43(11):2265-2272
Drying and rewetting are common events in soils during summer, particularly in Mediterranean climate where soil microbes may be further challenged by salinity. Previous studies in non-saline soils have shown that rewetting induces a flush of soil respiration, but little is known about how the extent of drying affects the size of the respiration flush or how drying and rewetting affects soil respiration in saline soils. Five sandy loam soils, ranging in electrical conductivity of the saturated soil extract (ECe) from 2 to 48 dS m−1 (EC2, EC9, EC19, EC33 and EC48), were kept at soil water content optimal for respiration or dried for 1, 2, 3, 4 or 5 days (referred to 1D, 2D, 3D, 4D and 5D) and maintained at the achieved water content for 4 days. Then the soils were rewet to optimal water content and incubated moist for 5 days. Water potential decreased with increasing drying time; in the 5D treatment, the water potential ranged between −15 and −30 MPa, with the lowest potentials in soil EC33. In moist and dry conditions, respiration rates per unit soil organic C (SOC) were highest in soil EC19. Respiration rates decreased with increasing time of drying; when expressed relative to constantly moist soil, the decline was similar in all soils. Rewetting of soils only induced a flush of respiration compared to constantly moist soil when the soils were dried for 3 or more days. The flush in respiration was greatest in 5D and smallest in 3D, and greater in EC2 than in the saline soils. Cumulative respiration per unit SOC was highest in soil EC19 and lowest in soil EC2 Cumulative respiration decreased with increasing time of drying, but in a given soil, the relationship between water potential during the dry phase and cumulative respiration at the end of the experiment was weaker than that between respiration rate during drying and water potential. In conclusion, rewetting induced a flush in respiration only if the water potential of the soils was previously decreased at least 3-fold compared to the constantly moist soil. Hence, only marked increases in water potential induce a flush in respiration upon rewetting. The smaller flush in respiration upon rewetting of saline soils suggests that these soils may be less prone to lose C when exposed to drying and rewetting compared to non-saline soils. 相似文献
18.
Majid Aghaalikhani Majid Gholamhoseini Aria Dolatabadian Aydin Khodaei-Joghan Kamal Sadat Asilan 《Archives of Agronomy and Soil Science》2013,59(10):1149-1169
With regard to the low cation-exchange capacity and large saturated hydraulic conductivity of sandy soils, a field experiment was carried out in 2006–2007 to determine the impact of zeolite on nitrogen leaching and canola production. Four nitrogen (N) rates (0, 90, 180, and 270 kg ha–1) and three zeolite amounts (3, 6 and 9 t ha?1) were included as treatments. The results demonstrated that the highest growth parameters and seed yield were attained with 270 kg N ha?1 and 9 t zeolite ha?1. However, the highest and the lowest seed protein percentage and oil content were obtained with 270 kg N ha?1 accompanied by 9 t zeolite ha?1, respectively. Nitrate concentration in drained water was affected by nitrogen and zeolite. The lowest and highest leached nitrate values were found in control without N and zeolite (N0Z0) and in treatments with the highest N supply without zeolite (N270Z0), respectively. In general, nitrogen-use efficiency decreased with an increase in N supply. Application of 9 t zeolite ha?1 showed higher nitrogen use efficiency than other zeolite amounts. Also, application of more N fertilizer in soil reduced nitrogen uptake efficiency. In total, application of 270 kg N ha?1 and 9 t zeolite ha?1 could be suggested as superior treatment. 相似文献
19.
Elham Sadat Yazdi Almodarresi Javad Mokhtari Seyed Mohammad Taghi Almodarresi Mahdi Nouri Ali Shams Nateri 《Fibers and Polymers》2013,14(7):1196-1202
Conventional theory for color matching is Kubelka-Munk, but it fails in some situations. New intelligent procedures such as neural networks could learn the behavior of a complex system and produce accurate prediction. This paper investigates the ability of MLP (multiple layer perceptron) neural network for color matching of cotton fabric. Three reactive dyes, namely Levafix Red CA, Levafix Yellow CA and Levafix Blue CA were used for experiments. The dyed samples were scanned and L * a * b * histogram were extracted. Different neural networks were trained and tested using L * a * b * histogram of fabric’s images and also L * a * b * values (D65, 10°) of fabrics. The results were encouraging. For neural networks including the L * a * b * histogram in input vector, colorants and their concentration were predicted with a mean square error (MSE) less than 10?5 and an average value of color difference (CMC (1:2)) less than 1.5 for approximately 80 % of testing data. 相似文献
20.
SALEHNIA Nasrin 《干旱区科学》2017,9(6):797-809
Meteorological drought is a natural hazard that can occur under all climatic regimes. Monitoring the drought is a vital and important part of predicting and analyzing drought impacts. Because no single index can represent all facets of meteorological drought, we took a multi-index approach for drought monitoring in this study. We assessed the ability of eight precipitation-based drought indices(SPI(Standardized Precipitation Index), PNI(Percent of Normal Index), DI(Deciles index), EDI(Effective drought index), CZI(China-Z index), MCZI(Modified CZI), RAI(Rainfall Anomaly Index), and ZSI(Z-score Index)) calculated from the station-observed precipitation data and the Ag MERRA gridded precipitation data to assess historical drought events during the period 1987–2010 for the Kashafrood Basin of Iran. We also presented the Degree of Dryness Index(DDI) for comparing the intensities of different drought categories in each year of the study period(1987–2010). In general, the correlations among drought indices calculated from the Ag MERRA precipitation data were higher than those derived from the station-observed precipitation data. All indices indicated the most severe droughts for the study period occurred in 2001 and 2008. Regardless of data input source, SPI, PNI, and DI were highly inter-correlated(R~2=0.99). Furthermore, the higher correlations(R~2=0.99) were also found between CZI and MCZI, and between ZSI and RAI. All indices were able to track drought intensity, but EDI and RAI showed higher DDI values compared with the other indices. Based on the strong correlation among drought indices derived from the Ag MERRA precipitation data and from the station-observed precipitation data, we suggest that the Ag MERRA precipitation data can be accepted to fill the gaps existed in the station-observed precipitation data in future studies in Iran. In addition, if tested by station-observed precipitation data, the Ag MERRA precipitation data may be used for the data-lacking areas. 相似文献