IRANIAN JOURNAL OF PLANT PHYSIOLOGY
Year:2017 | Volume:7 | Issue:2|Papers Count:8

Taxanes are widely known as great family of antitumor compounds. Identification of certain taxanes, particularly taxol, has opened new perspectives for further researches in plant and medical sciences. The aim of the present study was to manipulate chromatographic method in order to detect and quantified novel trace taxanes in suspension-cultured hazel (Corylus avellana L.) cells. A rapid growing cell line established from hazel seeds were grown in a modified LS media. The cells were harvested and extracted at days 10 and 15 when based on growth curve they were in the second half of logarithmic growth phase. Separation of taxanes was conducted by a coupled gradient-isocratic high performance liquid chromatography, equipped with a photo diode array detector. Base on chromatographic behavior and UV spectrum, the method enabled us to determine and quantified not only previously reported taxoides i.e., taxol, 10-deacetylbaccatin III, baccatin III, but also trace novel ones e.g., cephalomannine, 7-epi-taxol, 7-epi-10-deacetyltaxol and 10-deacetyltaxol. Certain taxanes i.e., 10-deacetylbaccatin III, baccatin III, taxol, and 10-deacetyltaxol were the most abundant taxanes detected at day 10, while 7-epitaxol, 7-epi-10-deacetyltaxol, cephalomannine were identified and quantified at day 15. Moreover, total content of taxanes was higher in day 15 than day 10. It should be noted that different taxanes bear different applications, for example taxol is directly used in medicine while 10- deacetylbaccatin III, baccatin III, 10-deacetyltaxol are more considered as valuable precursors in semisynthetic production of other taxanes. Therefore, the results presented here can provide approaches in decision making and time management toward extract maximum amounts of a desired taxane.

Gamma-linoleic acid in the seed oil of evening primrose makes it nutritionally and pharmaceutically valuable. If evening primrose wants to be cultivated as an annual plant, sowing time is important. By the late sowing and depends to time most plants do not produce flower stem and stay in rosette stage until next spring. To solve this problem, the present study was performed. Seedling were transplanted to 4 kg plastic pots containing a mixture of leaf compost: local soil: perlite (1: 2: 1 ratio) and placed in outdoor conditions. Non-vernalized plants were then selected and treated with different temperature regimes (1, 2 and 3 weeks in 4-6oC) and gibberellic acid (GA3) application in different concentrations of 0, 500, 1000, 2000 ppm, separately. The results showed that although some physiological parameters were affected by low temperature, no flower stem was produced. In contrast, plants that were treated with GA3 produced flower stem. Time of flowering and the number of flowers were significantly affected by the concentrations of applied GA3. Although yield components of GA3 induced plants were higher than that of normal growth plant, the seed yield of them was low. Surprisingly, the gamma linolenic acid (GLA) percentage of seed oil of plants treated with 2000 ppm GA3 was significantly higher than that of non- treated plants. Finally, it can be concluded that, although the application of GA3 guarantees delayed sowing evening primrose flowering and better GLA production, but low seed yield is a subject that cannot be easily ignored in production.

A factorial pot experiment was conducted based on randomized complete blocks design in green house condition to investigate the effect of short-term salt stress on leaf photosynthesis and ion relations of two sugar beet cultivars (Madison and 7233-P29). Plants were exposed to 0, 50, 150, 250, and 350 mM salinity (NaCl and CaCl2 in 5: 1 molar ratio) for 48 hours. Measurements were done on youngest fully expanded leaves. Salinity caused a significant reduction in stomatal conductance and consequently leaf net photosynthesis in both cultivars. Net photosynthesis of cv 7233-P29 at low level of salinity (50 mM) at 12 h, 24 h and 48 hours after salinity application decreased by 7.4%, 15.1% and 20%, respectively, compared to control. However, reduction in photosynthesis at highest level of salinity (350 mM) at the same times were 62.4%, 73%, and 72.3%, respectively, compared to control. For Madison the percent of reduction was significantly higher than P29. Cultivar P29 at 12 and 24 hours after salinization had significantly higher Na+ content than Madison up to 250 mM. Potassium concentration tended to decrease with increase in salinity. Salinity led to increased Cl- concentration in both cultivars. However, Madison had significantly higher Cl- content than P29 at the highest level of salinity at all three times of sampling. A strong correlation between photosynthesis and stomatal conductance (R2=0.98) and weak correlation between photosynthesis and sodium concentration (R2=0.22), and photosynthesis and chloride concentration (R2=0.55) indicated that in short-term exposure to salinity, stomatal conductance was one of the main causes of photosynthesis.

The soybean (Glycine max l. merr) is one of oil seed plants from leguminous family. In this study, the effect of gamma radiation on chlorophyll, soluble and insoluble carbohydrate and composition oil seeds were investigated in soybean. Soybean variety J.K was irradiated with 0, 100, 200 and 300 gamma ray. The treatment and control seeds planed in with four replicates. The highest amount of total chlorophyll content was obtained in control plants. The highest amount of soluble carbohydrate was obtained in 200 gamma ray treatments. The contents of carbohydrates in the leaves tend to increase with increasing gamma ray doses. The elevated levels of the total soluble and insoluble carbohydrates in leaf are considered to be playing an important role in the osmotic adjustment. The results showed that the highest amount of total protein content was obtained in control plants. The contents of protein in the leaves tended to decrease with increasing gamma ray doses. The oil soybean seeds were extracted and analyzed for their chemical and physical properties such as acid value, percentage free fatty acids (% FFA), iodine value, and refractive index.

Studies have shown the importance of oxygenated compounds in beverage and food products. Citrus rootstocks seem to have a profound influence on oxygenated compounds in plants. The goal of the present study was to investigate the effect of rootstocks on the oxygenated compounds in Citrus clementina. Flower oil components were extracted using an ultrasonic bath and eluted with n-pentane: diethyl ether (1: 2). The oils were then analyzed using GC and GC-MS. Data were analyzed using one-way analysis of variance (ANOVA) and Duncan’s multiple range tests. Forty-one, 41, and 39 flower components were identified in Sour orange, Swingle citromelo and Troyer citrange, respectively. These included aldehydes, alcohols, ketones, monoterpenes, and sesquiterpenes. The major flavor components identified included linalool and sabinene. Among the three rootstocks examined, Swingle citromelo showed the highest content of aldehydes. Since aldehyde content of citrus is one of the most important indicators of quality, it seems that Citrus rootstocks have a profound influence on this factor.

In order to evaluate the effects of potassium nitrate nutrition on some low temperature tolerance indices in Citrus aurantium seedlings a factorial experiment was conducted based on a completely randomized design with four replications at the Institute of Citrus Research in Ramsar. Treatments were potassium nitrate nutrition at four levels (0, 2.5, 5, and 10 mM) and temperature at four levels (25, 0, -3, and -6 °C). Results showed that increasing the concentration of KNO3 reduced superoxide dismutase activity and carotenoid. Concentration of 10 mM potassium nitrate also increased water content, leaf color, proline, phenol, and total chlorophyll. Maximum leaf damage, electrolyte leakage, and carotenoid were observed at -6 °C, while the highest antioxidant capacity and superoxide dismutase activity with means 37.7% and 24.4 IU. mg -1 FW, respectively were observed in Citrus aurantium leaves at -3 °C. Highest electrolyte leakage was observed at concentration 0 mM potassium nitrate and temperature of -6 °C while highest superoxide dismutase was observed at -3 °C with the same concentration of potassium nitrate. Results revealed that concentration of 10 mM potassium nitrate increases Citrus aurantium tolerance under low temperature stress.

Essential oils of two wild-growing Artemisia species collected from west of Iran during the flowering stage were obtained by hydro-distillation and analyzed by gas chromatography (GC) and gas chromatography/mass spectrometry (GC–MS). Under the optimum extraction and analysis conditions, 23 and 19 constituents were identified in A. fragrans and A. hausskenechtii which represented 92.96% and 90.20% of the oils, respectively. The main constituents of A. hausskenechtii were camphor (42.50), 1, 8-cineol (20.91 %) and isoborneol (7.27%). Chrysanthenone (41.05%), 1, 8-cineol (11.09%), and n-pentane (9.07%) were the major components of essential oils in A. fragrans. Antioxidant activity was assayed by two complementary test systems, namely 2, 2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging and β-carotene/linoleic acid systems. Antioxidant activity of polar sub-fraction of A. hausskenechtii was found to be higher than those of the others in DPPH assay while essential oil in A. hausskenechtii had the highest level of antioxidant activity in b-carotene/linoleic acid test (54.2 ± 0.5 mg/ml and 80.2±0.8% inhibition rate, respectively).

The effects of postharvest oxalic acid (OA) treatment on ethylene production, fruit quality, bioactive compounds and antioxidant activity of peach fruit, were examined. Fruits were treated with oxalic acid immediately after harvest and stored at 1° C and 90% relative humidity for 28 days. The oxalic acid treated peach fruit exhibited significantly lower levels of ethylene production, pH, total soluble solids and weight loss and higher levels of firmness and titratable acidity than control. Also, OA treated fruit exhibited significantly higher total antioxidant capacity, which resulted from higher total phenols and flavonoids accumulation. During storage, activity of peroxidase, catalase, and superoxide dismutase enzymes increased in both control and treated peaches, and peroxidase and superoxide dismutase activities in OA treated fruit were significantly greater than those in control. But, there was no significant difference in catalase activity between OA treated and control fruit. Results suggested that OA treatments could be a promising strategy to delay softening and enhance the phenolic content and antioxidant activity of peaches.