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        1 - Leaf Gas Exchange, Yield and Yield Components of Wheat (Triticum aestivum L.) Cultivars as Affected by Plant Density
        Reza Hosseinipour Seyyed Alireza Valadabady Mohammad Reza Mehrvar Saeed Sayfzadeh
        Determination of optimal plant density is one of the main factors that may affect crop growth and seed yield when planting is performed in the plant residues especially in conservation tillage systems. To investigate the effect of plant density on leaf gas exchange of w More
        Determination of optimal plant density is one of the main factors that may affect crop growth and seed yield when planting is performed in the plant residues especially in conservation tillage systems. To investigate the effect of plant density on leaf gas exchange of wheat cultivars, a field split plot experiment based on randomized complete blocks design with three replications was carried out at Karaj Research Farm of Seed and Plant Improvement Institute in Iran. In this study, the main factor was three levels at plant densities (400, 500 and 600 seed per m2) assigned to main plots and five wheat cultivars (Sivand, Sirvan, Pishtaz, Pishgam and Parsi) to sub-plots. Results of analysis of variance showed that transpiration rate (E) (p<0.05), stomatal conductance (Gs) (p<0.01), net photosynthetic rate (Pn) (p<0.01) and Quantum yield (Qy) (p<0.01), number of grain per spike (GPS), seed weight (SW), seed yield (SY), biological yield (BY) and harvest index (HI) were affected by plant density and cultivar significantly. In addition, interaction effect of plant density×cultivar was significant on leaf temperature (LT) (p<0.01), intercellular CO2 concentration (Ci) (p<0.05) and biological yield (BY) (p<0.01). The results also indicated that increment of plant densities of 400 to 600 seed per m2 decreased E, Gs, Pn and Qy. Increasing plant density decreased GPS and HI. The Pishgam cultivar had the highest E and Gs, while higher values of Pn, Qy and water use efficiency belonged to Parsi cultivar. The highest value of SY was obtained from Sirvan cultivar. Manuscript profile
      • Open Access Article

        2 - The Effect of Growth Regulators on Some Photosynthetic Traits and Maintenance of Cell Membrane Structure of Flag Leaf of Two Wheat Cultivars under Rainfed Conditions
        Ali  Rasaei Saeid Jalali-Honarmand Mohsen Saeidi Mohammad-Eghbal Ghobadi
        When the plant is exposed to abiotic stresses, the cell membrane is the first part of the cell to be affected by stress, and the relationships of the many of physiological and biochemical cell of the plant are disrupted. The effect of three growth hormones (3 indoleacet More
        When the plant is exposed to abiotic stresses, the cell membrane is the first part of the cell to be affected by stress, and the relationships of the many of physiological and biochemical cell of the plant are disrupted. The effect of three growth hormones (3 indoleacetic acid [IAA], gibberellic acid [GA3] and 6 benzylaminopurine [6 BAP]) with a control (distilled water) was evaluated at booting stage of two wheat cultivars (Rijaw and Azar 2). A factorial experiment using a randomized complete block design (RCBD) with three replications was setup at Campus of Agriculture and Natural Resources, Razi University, Kermanshah, Iran in 2013-14 and 2014-15. Based on the results, the effect of different growth hormones on SPAD, relative water content, Fv/Fm, performance index, leaf cell membrane stability and photosynthetic rate of both cultivars were significant. Among growth hormones, foliar application of Cytokinin and Auxin had the greatest effect on the measured leaf traits and the lowest mean of the traits was obtained in non-spraying treatment (control). Between the two cultivars, Rijaw cultivar was superior to Azar-2. There was also a positive and significant correlation between cell membrane stability and photosynthesis rate, Fv/Fm and performance index. In general, in dryland conditions (water deficiency) with external application of cytokinin in booting stage in superior wheat cultivar (Rijaw) cell membrane stability, relative water content, photosynthetic rate and Fv/Fm were 16, 18, 38 and 45 percent higher than the control, respectively. Manuscript profile