جستجوی مقالات مرتبط با کلیدواژه « Phenologic stages » در نشریات گروه « کشاورزی »

Teucrium polium L. belongs to the fam. Lamiaceae and grows mostly in the barren, rocky, and sandy areas of various parts of Europe, the Mediterranean, North Africa, and southwest Asia including Iran. It has various therapeutic properties such as analgesic, antipyretic, antioxidant, and antihypertensive. These healing properties are due to the presence of various chemical compounds in the essential oil. Plant harvest at the different phenological stages has a great impact on the amount of essential oil compounds of this species. This study was conducted to evaluate the quantitative and qualitative changes of T. polium essential oil (EO) during the growing season in Cheshmeh-e-Anjir rangelands of Fars province and at three phenological stages (vegetative peak, beginning of flowering, and flowering peak) in a completely randomized block design in 2017. The EOs were analyzed by GC and GC/MS. The results of this study showed that the main EO constituents were caryophyllene oxide (12.1%), α-pinene (11.8%), germacrene D (9.1%), myrcene (8.5%), limonene (7.2%), β-pinene (6.7%), bicyclogermacrene (6.6%), E-caryophyllene (4.6%), and α-bisabolol oxide B (3.4%) at the vegetative peak stage with the EO percentage of 0.9%, germacrene A (26.6%), bicyclogermacrene (18.3%), (E)-β-ocimene (8.9%), myrcene (7.8%), spathulenol (6.0%), limonene (5.3%), α-pinene (3.6%), and β-pinene (2.6%) at the begining of flowering with the EO percentage of 0.3%, and α-pinene (25.8%), myrcene (12.5%), germacrene D (11.8%), β-pinene (11.7%), limonene (8.5%), spathulenol (4.6%), and bicyclogermacrene (7.2%) at the flowering peak with the EO percentage of 0.2%.

This research was conducted to study the role of phenology in wheat cultivars’ reaction to salinity stress. The experiment was carried out as factorial، based on a randomized complete block design with three replications، in Bu-Ali Sina University، Hamadan، Iran. Treatments included four wheat cultivars (Alvand، Toos، Navid and Sayson) and five levels of water salinity (0، 4، 8، 12 and 16 dS/m). Results showed that except for emergence stage، the salinity stress had reductive effect on other phenological stages of wheat cultivars. Chlorophyll index، plant height، spike dry weight، percentage of fertile stem، spike length and grain and biological yield of wheat were reduced by salinity stress. Wheat cultivars showed significant differences in each one of the studied traits. Maximum salinity effect on phenology and other studied traits was obtained in Sayson cultivar. By increasing the salinity level، Navid and Toos cultivars showed fewer changes in most of the measured traits، as compared to two other cultivars. Overall، Toos cultivar was the most compatible cultivar to salinity stress because of the need for less cumulative growing degree day for completion of phenological stages and more stability of yield.

The cold limits germination and growth of corn (Zea mays L.) but the varieties of corn significantly have differences with each other in reaction to temperatures. To determine the response of some phenological and agronomical traits affected by low and optimal temperatures in corn and to primary recognizing the cold tolerance corn inbred lines in early growth and development، an experiment was conducted، in two separately parts، in farm (in randomized complete block design with three replications) and the laboratory of Agriculture College، Shahrekord University، Shahrekord، Iran (in two completely randomized design in 12 and 25 oC temperatures with four replications) in 2007. Both experiments were done on ten corn inbred lines. The results showed that varieties on topic of germination and reaction ability to temperatures showed more variation in temperature 25 oC than in temperature 12 oC and with reducing temperature، the traits were strongly affected. Also varieties which had higher mean rate of germination (25 oC) and faster growth in the laboratorial conditions especially in the temperature of، 12 oC emerged sooner in the farm and reached to the establishment stage. At cold stress conditions، the early maturity lines and in favorite conditions، the late maturity varieties complete faster early growth and development stages until plant establishment. So with concerning the results of mean comparisons، the V5 inbred line was known as the best genotype tolerant to low temperature in this experiment.