مقالات رزومه طیبه جعفریان

This study the effect of seed preparation (priming) with different concentrations of hydrogen peroxide on the anatomy of the flag leaf and spike two wheat genotypes( Cross Sabalan ( bread wheat) and Saji(durum wheat)) and its relationship with grain yield, under dry land farming system condition, Experimental design was factorial, arranged in randomized complete block. Results showed that the number of grains per spike, grain yield, grain weight per spike 4-8, leaf area, number and length of stomata and the anatomic characteristics of flag leaf and spike studied in this research affected by seed preparation with hydrogen peroxide. Seeds of plants that were pre-treated with hydrogen peroxide more leaf area and stomata length, area and diameter of xylem and phloem, mesophill, bundle sheath, the upper and lower epidermis of the flag leaf, As well as influenced by hydrogen peroxide, anatomical features of spike including area xylem and phloem, the vascular bundles was greater than control. also, the seed treatment with hydrogen peroxide through a positive impact on anatomical features thereby increasing the number seeds per plant, grain weight per spike 4-8 and grain yield in both wheat genotypes. Finally seed priming with concentration of 80 Mm hydrogen peroxide than other concentrations positive impact on anatomical characteristics of flag leaves and spike because increased grain yield in both cultivars of wheat

IntroductionWater deficit is the major abiotic factor limiting plant growth and crop productivity around the world. In all agricultural regions, yields of rain-fed crops are periodically reduced by drought. Among various strategies, pre-sowing treatment and priming of seeds are easy, low cost, low risk and effective approaches to overcome the environmental stress problems. Various priming strategies include osmopriming, halopriming, hormonal priming or hydropriming, etc. Hydrogen peroxide, a stress signal molecule, was evaluated as seed treatment to produce the metabolic changes, which could lead to improved drought tolerance in wheat. The interaction of signals conferring stress tolerance in accomplishing better crop growth and yield is a priority area of research. Here we report some anatomical, physiological and biochemical changes induced by Hydrogen peroxide during seed treatment and their involvement in conferring drought tolerance upon wheat.
Materials and MethodsA field study was conducted out at the research farm of agricultural collage of Ilam university during 2014-2015 cropping season. This study was aimed to investigate the priming seed with hydrogen peroxide on two wheat genotypes (Cross Sabalan (bread wheat) and Saji (durum wheat)), under dryland farming system condition. Experimental design was factorial, arranged in randomized complete block, with three replications. Two main factors were wheat genotypes and four soaking treatments of seeds with different concentration (zero, 25, 50 and 80 Mm) of Hydrogen Peroxide. Seeds of each genotype were sown at 6 rows of 3 m length with lines space of 20 cm in depth 5 cm. At heading stage physiological traits were measured on selected leaves and then samples were taken to determine leaf area, Leaf rolling, number and length of Stomata on the epidermis, RWC, electrolyte leakage, photosynthetic pigments concentrations (Chla, b and carotenoid) and antioxidant enzyme contents (catalase, ascorbate peroxidase) and at tillering stage Anatomical traits (mesophyll area, bundle sheet area, upper and lower epidermis cells layer and both length and area of xylem and phloem vessels)were measured using image analysis technique by Dino-eyeanalysis software. Data were analyzed based on experimental design model. Means comparison was performed based on LSD test (P≤0.05). All calculations were performed using SAS (version 9.1) software.
Results and DiscussionAll studied parameters, anatomical, physiological and grain yield, of genotypes were significantly affected by priming seeds with hydrogen peroxide. Positive changes in anatomical and physiological traits in response to hydrogen peroxide increased grain yield in both experimental genotypes. Priming of seeds with hydrogen peroxide produced plants with higher relative water contents, photosynthetic pigments concentrations (Chla, b and carotenoid) and antioxidant enzyme contents (catalase, ascorbate peroxidase) comparing with non -primed seeds. Plants of hydrogen peroxide primed seeds produced higher leaf area, stomata length, fresh and dry weights, and lower rate of electrolyte leakage and leaf rolling comparing to non-primed seeds. Priming seeds with hydrogen peroxide increased mesophyll area, bundle sheet area, upper and lower epidermis cells layer and both length and area of xylem and phloem vessels. Anatomical changing due to hydrogen peroxide priming in enhanced growth and yield of both genotypes was positive since primed plants with hydrogen peroxide had produced higher grain yield compared to non-primed plants. Overall, priming seeds with hydrogen peroxide improved grain yield of both wheat genotypes, especially grain yield of bread wheat Cross Sabalan cultivar.
ConclusionsThe anatomical and physiological characteristics improved in dry conditions and lack of available water to the plant is essential for achieving high yield. The results showed that the concentration of 80 Mm hydrogen peroxide as a pre-treatment seed through positive effects on physiological and anatomical features could increase the yield of Saji and cross Sabalan under rain-fed conditions.

In this experiment the effect of inoculation with Azospirillum on the flag leaf and spike rachis anatomical features and also on grain yield and grain weight was investigated for the first time in bread and durum wheats during 2015-2016 growing season under semi-arid condition. The crop yield increased due to the inoculation with Azospirillum with a maximum yield increase of about 8.0 per cent for bread wheat. Azospirillum led to an increase in grain weight per spike. Yield increase due to Azospirillum inoculation was higher for bread wheat than durum wheat. The two wheat species exhibited differences in flag leaf and spike axis anatomic features. Although Azospirillum inoculation decreased the number of flag leaf stomata by 11.5% irrespective of the wheat type, stomatal length of the inoculated plants increased by about 3.6 and 11.5% for bread wheat and durum wheat, respectively. Azospirillum inoculation significantly enhanced the area and length of xylem and phloem vessels by about 12.5 and 12.39% and 14.42 and 33.33%, respectively. Area of the bundle sheath and mesophyll layers of inoculated plants was increased by 20 and 31.5%, respectively. Azospirillum inoculation enhanced the area of upper and lower epidermis of the bread wheat much more than the durum wheat. Anatomic changes due to Azospirillum was not limited to the flag leaf but also extended to the spike rachis and, therefore the inoculated plants had higher area of vascular bundle, xylem vessel and phloem vessel. Overall,the effect of Azospirillum on anatomical features and grain yield of wheat was slightly species specific and it was more pronounced in the bread wheat as compared to the durum wheat.

Leaf rolling, especially in cereals, Mechanisms for reducing the light receiving surface of the leaves to reduce transpiration rate in response to drought caused. To investigate the effect of drought stress on leaf rolling and leaf anatomical characteristics, Yield and yield components in field experiment was conducted Bahonar University. In this experiment, five varieties of wheat (Shole, Omid, Azar2, Shahpasand and Azadi) and two levels of irrigation (optimum irrigation, water stress at vegetative stage) in a split plot design in randomized complete block design with three replications were compared. The results showed that under drought stress area and the number of cells Baliform, leaf thickness, specific leaf area, yield and spike, number of grains per spike and grain weight decreased while increasing leaf rolling. Due to the significant negative correlation between leaf rolling and grain yield and number of spikes per unit area, Leaf rolling in the Shahpasand reduced the number of grains per spike and grain yield than the other varieties. While the Azar2 with leaf rolling, because of negative impact of drought stress on specific leaf area, and also, the effect of less Undesirable effects of stress on the number of seeds per spike and number of spikes per unit area compared to other varieties, The higher grain yield.

The aim of this study was to determine the effects of water stress on the anatomy of xylem and phloem vessels, mesophyll and epidermal cells, relative water content and ion transfer rate of two wheat cultivars including Azar2 as drought tolerant and Shole as drought susceptible cultivars at four leaf stages. Seeds were sown in pots under normal (soil water content at 100% of FC) and the water stress (60% of FC) conditions in a factorial experiment based on CRBD design at the Experimental Farm of Kerman University in 2011. Four samples were taken from different positions of the fully expanded 4th leaf. Results showed that in both cultivars water stress decreased the xylem and phloem vessel diameter and the area of the mesophyll and upper epidermal cells at all positions. However, no significant effect of water stress by cultivar interaction was found on lower surface epidermal cell size and RWC. Water stress effect on the amount of ion leakage up to 30 min after soaking the leaf samples in distilled water was highly significant while it was not significant at 60 min after soaking. The effect of water stress on ion leakage was higher in Shole compared to Azar 2. Anatomical changes of the wheat leaf under water stress condition can be considered as adaptation responses. The effects of such anatomical changes on the final yield need to be investigated in future studies.