جستجوی مقالات مرتبط با کلیدواژه « قند محلول » در نشریات گروه « اکولوژی »

Background & Adjective:

 In the recent years, studies have been focusing on the use of safe and biocompatible compounds to reduce the damage caused by drought stress. In this study, the effect of exogenous application of methyl jasmonate in modulating the effects of drought stress on Physalis plants and improvement of antioxidant activity was evaluated.

In the present study, drought stress at 3 levels (100, 75 and 50 % of field capacity) and different concentrations of methyl jasmonate at 3 levels (0, 10 and 100 μM) were used as the experimental factors.

According to the results, drought stress significantly reduced fresh and dry weight, relative water content, chlorophyll a and b, carotenoids and beta-carotene in physalis leaves while total phenol and flavonoid content and antioxidant activity (fruits and leaves), soluble sugar, proline and malondialdehyde (leaves) increased under drought stress conditions. Foliar application with methyl jasmonate reduced the negative effects of drought stress in physalis plants by affecting the relative water content, chlorophyll content, membrane stability (decrease of malondialdehyde), and increasing compatible solutions (soluble sugar and proline), total phenol and flavonoids and antioxidant activity so that the fresh weight of the fruit increased (54.73%) by spraying 100 μM methyl jasmonate in the second level of stress.

In general, the results of the study showed that foliar application of methyl jasmonate, especially at 100 μM concentration, reduced the effects of drought stress on the physalis plants, and improved antioxidant activity and fruit weight, thus improving the yield.

Intercropping of forage plants is considered as an effective startegy to achieve optimal yield and increase production in areas with water shortages. A field-based split plot experiment based on a randomized complete block design with three replications was conducted in Ashkezar research farm with the aim of evaluating the intercropping of millet and guar in improving physiological indices and forage yield. Irrigation intervals was considered as the main factor in three levels (irrigation at the time of discharge of 60, 70 and 80% of field capacity) and the cropping system was considered as the sub-factor in three levels (sole cropping of Millet, sole cropping of Guar, and intercropping of Millet and Guar). The intercropping system was implemented as row intercropping pattern with a replacement series design. Results showed that the amount of ionic leakage increased and the relative content of relative water content decreased when irrigation was delayed longer. The highest relative water content for Millet and Guar (70.3 and 78.4%, respectively) were obtained in intercropping system and their lowest relative water content (61.4 and 72.5%, respectively) were obtained in their sole cropping. The highest and lowest chlorophyll indices were observed in irrigation treatments at 60 and 80% of field capacity, respectively. The intercropping of Millet and Guar resulted in increased content of soluble sugar and proline and the highest forage yield compared to their sole culture, in all assessed irrigation intervals. Since intercropping system was shown to cause improved physiological indices of Guar and Millet, the consequent improvement of forage growth and yield could be expected. Overall, it can be concluded that intercropping system of Millet with Guar can significantly reduce the impacts of drought stress and can be considered as an effective management strategy in drought-prone areas.

The aim of this study was to investigate the effect of zinc oxide nanoparticles on some biochemical and morphological characteristics of wheat under drought stress and reduction of drought effects under the influence of zinc nano oxide foliar application.

A factorial experiment was conducted in a completely randomized design with three replications in the University of Mohaghegh Ardebili in 2016-2017. The first factor was drought stress at three levels (35, 60 and 85% of field capacity), the second factor was wheat cultivars (Mihan, Heydari, Sysons and Gasogen) and the third factor included foliar spraying with zinc oxide nanoparticles with concentrations of 0, 0.5 and 1 g.l-1. The foliar application was performed in three-leaf stage and three days after foliar application, drought stress was applied based on field capacity and sampling was performed ten days after stress.

The findings showed that under ZnO treatment, the amount of soluble protein, soluble sugar, proline, plant height and grain weight increased. As the severity of drought stress increased, the amount of protein decreased, but the amount of proline and soluble sugar increased. Stress also decreased plant height, dry and fresh root weight, as well as grain yield (15.95% of grain size and 11.93% of grain weight). Spraying wheat plants with zinc nano oxide in the Mihan and Heydari cultivars moderated the effects of stress, and in the cultivars of Sysons and Gascogen increased the plant's defense mechanisms against the destructive effects of drought stress.

In general, foliar feeding of ZnO at a concentration of 0.5 g.l-1 makes wheat plants tolerant to drought stress.

This study was conducted to evaluate the effects of water stress on dry matter and carbohydrate accumulation as well as nutrient status of Salvia macrosiphon. A completely randomized design with three replications was used in an experimental greenhouse at Yazd University. Different levels of drought stress including 100، 75، 50 and 25% of field capacity were considered as treatments. Results showed that absorption of potassium، calcium، magnesium، nitrogen، phosphorus، sodium، zinc، iron and copper as well as، dry matter accumulation were significantly affected by drought stress. Result also indicated that water stress has significant (P≤0. 01) effect on soluble carbohydrate. Mean comparison test showed that the dry matter accumulation rate (total dry weight of root and shoot dry weight) and concentration of potassium، calcium، magnesium، nitrogen and phosphorus decreased by increasing drought stress، whereas concentration of sodium، zinc، iron، copper and solution carbohydrate was increased in response to deficiency of water.

Drought as one of the environmental stresses، is the most significant factor restricting plant growth and crop production. Drought stress can results in disruption of water potential gradients، turgor loss، membrane integrity disruption and protein denaturation. In addition، it inhibits the photochemical activities. Potato is an important plant in agriculture that has an average sensitivity on salt and a high sensitivity on draught. In this study، potato’s residence against draught was investigated in two cultivars of Kenebeck and Concord under in vitro culture conditions. Potato cultivars were grown in MS medium containing 50 μM Silver Thiosulfate (STS) and they were transferred to liquid medium of MS after rooting then were treated for 14 days with concentration of 0، 2 and 4 percent of PEG (MW 6000). After four weeks post treatment، physiological factors such as fresh and dry weight، content of photosynthesis pigments (total chlorophyll and carotenoid) were measured in order to identify resistant and sensitive plants against water stress. Results indicated that Kenebec showed lower reduction in the above-mentioned factors under stress conditions compared to Concord. In order to study mechanisms of resistance against draught in these two types، proline and soluble carbohydrate in shoot were investigated. According to results، with increasing، PEG concentration proline and the soluble carbohydrate increase significantly in the shoots Kenebec. Proline concentration in Concord showed an increase only 2% PEG treatment. In comparison to control plants، soluble carbohydrates in Concord showed no significant increase