Summary A total of 74 independently run bioassays with soil incorporated metsulfuron‐methyl from 12 different laboratories was analysed by a logistic dose‐response curve to assess the precision of regression parameters and relate ED50 to soil properties. The potency in terms of ED50 of metsulfuron‐methyl in Brassica rapa L., which was used by all laboratories, varied between 0.05 and 3.9 g a.i. ha‐1. ED50 was negatively correlated with pH and positively correlated with organic matter. The majority of laboratories had ED50 within the interval 0.1‐1.0 g a.i. ha‐1. At one laboratory using three test species, the most sensitive species was Beta vulgaris L. followed by Brassica rapa L. and Lepidium sativum L. The coefficients of variation were smallest for the ED50 and ED90 response levels and largest for the ED10. The slope of the response curves had considerably lower coefficients of variation than the EDs. The results are discussed in relation to a previous collaborative bioassay study. Finally it is suggested that standardization of bioassays with herbicides could be achieved in the same way as standardization of chemical analyses.
This paper presents the analysis of results obtained during long- term studies on the response of maize inbred lines to herbicides. Under the agroecological conditions of Zemun Polje the response (reaction of maize inbred lines to herbicides of different classes was investigated. Biological tests were performed and some agronomic, morphological, physiological and biochemical parameters were determined when the response of maize inbred lines to herbicides was estimated. The use of active ingredients of herbicides from triazine, acetanilide, thiocarbamate to new chemical groups (sulfonylurea etc.), have been resulted in changes in weed suppression and susceptibility of inbred lines. Obtained results show that effects of herbicides on susceptible maize genotypes can be different: they can slowdown the growth and development and affect the plant height; they can also affect the stages of the tassel and ear development and at the end they can reduced grain yield of the tested inbreds. Numerous studies confirmed the existence of differences in susceptibility level of maize genotypes in relation to herbicides. According to gained results the recommendations for growers are made on the possibility of the application of new herbicides in the hybrid seed production
SUMMARYThe anatomy of stems and leaves of two populations of the weed species Amaranthus retroflexus L. (red-root amaranth) (pop. AMARE 1 having green stems covered in sparse hairs and pop. AMARE 2 with green but notably dense stem hairs) was analysed in order better to understand the uptake and translocation of herbicides that could be indicative of the species' evolving resistance to herbicides. Samples of the two populations (AMARE 1 and AMARE 2 ) were collected from arable land of the Institute of Maize Research at Zemun Polje in 2006. Sampling was performed at the stage of full vegetative growth of plants. Permanent microscoping preparations were made to measure and analyze elements of the anatomy of stems (stem epidermis, cortex, collenchyma, central cylinder and diameter) and leaves (leaf epidermis upper surface and underside, mesophyll, leaf thickness and bundle sheath thickness).Both analysed populations of A. retroflexus, morphologically characterized by different density of stem hairiness, were found to have a typical structure of herbaceous dicots. The stem had three distinctive zones: epidermis, cortex and central cylinder. Amaranth leaves have dorsoventral structure, i.e. their upper surface and underside can be differentiated. The results indicated high and very high significance of differences found in stem anatomy between the two analysed populations, while leaf anatomy was not found to display significant differences other than in mesophyll thickness.
Two populations ofAmaranthus retroflexus with different morphology were collected from field of the Maize Research Institute Zemun Polje, Serbia. Random amplified polymorphic DNA (RAPD) and seed protein analysis were performed to study the genetic differences in two grain Amaranthus populations. The studied populations have different protein and DNA profile. A total of 171 DNA fragments were generated by 31 RAPD primers, with an average of 5.5 fragments per primer. Of these, 61.4% fragments were polymorphic among the two populations. 18 protein fraction were obtained by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS PAGE). The populations differed in the four protein fractions of different molecular weight. The seed protein electrophoresis and RAPD markers are useful for genetic determination of A. retroflexus populations and identification of biotypes with atypical morphology.
The effect of different concentrations of lead was investigated in two different ways in the leaves of Helianthus annuus plants. In the first way, removed leaf discs from 5-wceks old plants were floated in 0.05, 0.25, 2.50 and 5.00 mM PbNO3 solutions for 2, 4 and 6 days. In addition, the chlorophyll content and the activity of peroxidase enzyme which are the parameters of stress conditions in plants were also measured. In this experimental series, a decrease was determined in polyamine and chlorophyll contents and in the peroxidase activity in leaf discs which were treated with different concentrations of lead. In the second experimental series, one half of the upper leaves of 5-wceks old plants were used for lead treatments, while the other half for control. In half leaf experiments, lead in 0.05, 1.25 and 5.00 mM concentrations were sprayed to the both sides of the half leaves. According to the results of the half leaf experiments, 0.05, 1.25 and 5.00 mM lead treatments increased the putrescine content in 27, 15 and 9 % respectively. On the other hand, chlorophyll content and the activity of peroxidnse enzyme were decreased with the treatments of lead.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.