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Showing 3 results for Phenological Stage
Apex Development of Three Wheat Cultivars in the Presence of Salinity
M. Kafi,
Volume 3, Issue 1 (1-2001)
Abstract
Intra-specific variations in apex development of two salt-tolerant cultivars (Cross Rowshan 11 (CR) and Kharchia-65) and one salt-sensitive cultivar (Ghods) of spring wheat (Triticum aestivum L.) grown in sand culture at selected levels of salinity (0, 100, 200, and 300 mol m-3 NaCl and CaCl2 in 5:1 molar ratio) were studied. To determine the apex lengths and the number of spikelet primordia in the apex, the main shoot apex was dissected. Results indicated that final spikelet number of wheat cultivars decreased with increasing salinity. Cultivars showed different responses to a particular level of salinity. Duration of spikelet development from double ridge to terminal spikelet, spikelet number and apex length declined in the presence of salinity. Both shorter duration and reduced rate of spikelet initiation were responsible for reduction in spikelet number in salt-treated plants. Cultivar CR showed a better performance during spikelet initiation period and produced relatively more spikelets under saline conditions than the others.
Essential oil Composition and Antioxidant Properties of Artemisia sieberi Besser in Two Enclosure and Grazed Sites at Three Phenological Stages

Volume 7, Issue 1 (1-2019)
Abstract
Aims: The use of plants for treatment and food returns to ancient times. This study was conducted to examine the essential oil composition and antioxidant activity of the essential oil of Artemisia sieberi Besser at 3 phenological stages and effect of grazing livestock on these properties.
Materials & Methods: For this purpose, 5 shrubs from two sites (under grazing site and enclosure site) were selected randomly at 3 phenological stages. In laboratory operations, essential oil of the species was extracted in by SDE method.
Findings: The results of GC/MS analysis indicated 45 compounds for grazed site with essential oil content 98.73%, and 42 compounds for enclosure site with essential oil content 98.54%. Also, α-tujune (21.63%), α-Pinene (19.53%), and Camphene (10.34%) were the main compounds in the enclosure site and α-tujune (23.70%), α-Pinene (20.33%), and Camphene (12.60%) were the main compounds in the grazed site. The results of screening antioxidant activity using two assays (DPPH and β-carotene-linoleic acid) showed that the free radical scavenging activity of essential oil (IC50 µg ml-1) in the first phenological stage (vegetative stage) was more than other phenological stages in two sites. Also, the inhibition of essential oil in the grazed sites had a significant difference with essential oil's inhibition in the enclosure site.
Conclusions: Effect of grazing on the composition and properties of the essential oil of this species can be considered in the planning of livestock grazing management. We wish our future research on this plant leads to the finding of new natural antioxidant compounds.

Qualitative and Quantitative Changes in the Essential Oil of Origanum vulgare ssp. gracile as Affected by Different Harvesting Times
M. Moradi, A. Hassani, F. Sefidkon, H. Maroofi,
Volume 23, Issue 1 (1-2021)
Abstract
Qualitative and quantitative variations in the essential oil of wild growing Origanum vulgare L. ssp. gracile plants were studied in response to different phenological stages (pre, full and post-flowering). The essential oil of air-dried leaves was isolated by water distillation using a Clevenger-type apparatus and was analyzed by Gas Chromatography (GC) and Gas Chromatography–Mass Spectrometry (GC/MS). The highest (1.87%) and the lowest (1.01%) essential oil content were obtained from post-flowering and pre-flowering stages, respectively. In total, 24 components were identified and quantified in three phenological stages representing 96.75, 97.63, and 98.59% of the oil, respectively. Carvacrol (46.62, 46.5 and 27.6%), ρ-cymene (7.76, 13.54 and 37.08%) and γ-terpinene (21.54, 13.91 and 6.82%) were the main constituents of essential oils in pre, full, and post-flowering stages, respectively. Oxygenated monoterpenes (43.35-61.32%) and monoterpene hydrocarbons (30.81-48.02%) were the main classes of identified compounds in three essential oils. According to the findings of this research, the post-flowering stage can be considered as the most appropriate time for obtaining the highest essential oil content, but to achieve the highest rate of phenolic compounds, the pre-flowering and full-flowering stages can be recommended.
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