in order to investigate diversity of weed species in wheat fields in eastern parts of mashhad, an investigation was made in the year 2009. wheat fields was classified based on the acreage from 3-5 ha, 5-10 ha and higher than 10 ha. sampling was made randomly by a quadrate 0.5×0.5 in 9 fields of each group from jointing to heading of wheat in tow separate stages. type and total number of weeds w...

Weed communities can be influenced by nutrient availability, form (e. g., ammonium vs. nitrate), amendment timing, type (e.g., organic inorganic), and immigration of seeds during applications. The objective this research was to compare the long-term effect different fertility treatments in a corn ( Zea mays L.)-alfalfa Medicago sativa L.) rotation on taxonomic functional structure composition w...

Premise of research. Plant silica content depends on the phylogenetic position a taxon; however, biological or ecological factors may also affect it. In this work, we analyzed data silicophytolith from 105 species South America, examining, in context, its relationship with anatomy and features such as life cycle, growth form, plant origin, environmental preferences.Methodology. Data bioecologic...

Aim. This work is devoted to the search for potential partners integrated application of flumioxazine in sunflower crops. herbicide an inhibitor protoporphyrinogen oxidase (PPO) weed plants. The resistance this class herbicides not yet common today, compared other classes. Therefore, aimed at de- veloping flumioxazine-based compositions that effectively prevent emergence herbicide-resistant bio...

In recent studies evidence was obtained that chioropiasts of higher plants possess an autonotnic system of isoprenoid synthesis. The prenyl moiety of the chloroplast isoprenoid compounds [i,e, carotenoids, chlorophylls, plastoquinones, tocopherols and phylloquinone (vitamin K,)] originates frotn geranyigeranyi-PP, The present review deals with some aspects of the fonnatioo of the plastidic pren...

Studies of chromosome disposition at metaphase using serial thin-sectioning and three-dimensional reconstruction techniques have produced accurate estimates of the total volume of chromosomes per cell in 15 plant and two animal species. Comparing this character with the 4C DNA amount showed no indiction of systemic differences in DNA density between either organisms with widely different (great...

In Phalaris coerulescens, gametophytic self-incompatibility is controlled by two unlinked genes: S and Z. A probable S gene has now been isolated and sequenced. This represents a novel self-incompatibility gene isolated from pollen in the multilocus system of a monocotyledonous plant. The gene is approximately 3 kb long, split by five introns, and exclusively expressed in the mature pollen. The...

Using a powerful computer-assisted analysis strategy, a large-scale search of small nucleolar RNA (snoRNA) genes in the recently released draft sequence of the rice genome was carried out. This analysis identified 120 different box C/D snoRNA genes with a total of 346 gene variants, which were predicted to guide 135 2'-O-ribose methylation sites in rice rRNAs. Though not exhaustive, this analys...