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Effect of Copper, Zinc and Lead and Their Combinations on the Germination Capacity of Two Cereals
39-42Views:427The majority of researchers have studied the following group of microelements: B, Zn, Mn, Cu, Na, Co, Mo, I, Sn, Cl, Al, V, F, Cr, Hg, Cs, Li, Cd, As, Th, Rb, Cr, W, Ti, Sn, Se, Ba, Br. Sporadically, the following elements have been mentioned too: Au, Ra, Hg and Pb. In this study, the effects of copper treatments and their combination with zinc and lead microelements on the germination of maize and barley were investigated using different concentrations of these microelements. Six treatments were used: 1. Copper-sulphate (CuSO4) applied alone, 2. Zinc-sulphate (ZnSO4) applied alone, 3. Copper applied with zinc, 4. Lead-nitrate (Pb(NO3)2) applied alone, 5. Copper applied with lead and 6. Untreated control. Maize (Kiskun SC 297) and barley caryopsis were treated with copper and zinc solutions in the following concentrations: 0.03%, 0.003% and 0.0003%. Maize and barley caryopsis were treated with these solutions for 12 and 24 hours. Maize and barley caryopsis were also treated with lead solutions Pb(NO3)2 with different concentrations: 0.0005%, 0.005% and 0.05%. Maize and barley were treated with these solutions for 12 and 24 hours. In the combined treatments (3 and 5), the same concentration was used for each microelement as in treatments 1, 2 and 4. Control treatments were treated with water for both plant species. Our results showed that copper microelements significantly inhibit germination compared to the untreated control. The toxicity of copper is higher if concentration increases. Zinc microelements also inhibit germination, however its effect highly depends on the microelement concentration. Treatments of copper + zinc also inhibit germination. The two microelements applied together cause more phytotoxicity than they do alone. Lead is highly toxic to plants even in low concentrations. The toxic effect on germination dramatically increased when lead was applied with copper.
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The Effect of Zanthium Extracts on Germination in Relation to Interior and Exterior Factors
65-69Views:83In Hungary, the cocklebur species significantly endanger row crops (i.e. corn, sunflower, sugar beet). Their fast spreading is caused by many reasons: long-lasting emergence, reduced sensitivity to many kinds of herbicides, vigorous competitional ability, allelopathy, fast initial growth and changes in climate. The means of allelopathy is used by many species of plants in the competition with one another, as well as by the cockleburs. But the efficiency of this is influenced by many factors. Species with allelopathical effect could show different behaviour under different conditions: they can produce compounds with retarding and stimulating effects in different quantities or compositions. The actual condition of the acceptor plant and the mediator agent (i.e. soil) influence the final effect.
In this experiment influence of phenology and rainfall was studied on allelopathy of cockleburs in May, July and September. A stronger inhibition was observed on growth of cress before rain in July than in May, but this retarding effect disappeared after rainfall. However, the samples collected in September have significant inhibitory effect after rain. Inhibition of sugarbeet’s germination was stronger in May than in July, and the difference increased after rain. -
Allelopathic Effect of Italian Cocklebur on Sugar Beet
74-77Views:79Cockleburs are noxious weeds in Hungary, where they are widespread in row crops, especially in maize, sunflower and sugarbeet. A low density population of these weeds may be harmful because of their large competitive ability, fast growth in early phenological stages, allelopathy, and persistant sprouting.
Allelopathy of Xanthium italicum Mor. was examined during the growing season in 2004. Root and shoot samples were collected at 4 or 5 leaves stage (in the end of May and in the beginning of June) and before flowering (in the beginning of July) before and after rain. Extracts were made in tap water. The test plant was Beta vulgaris L.; its germination, root and shoot growth were evaluated at the 6th and 10th days after treatment.
Most of extracts inhibited the germination of sugar beet. In these experiments the phenological stage of the donor plant determined slightly the effectiveness of the extracts on sugar beet. Generally, significant differences existed between treatments only in cases of concentrated extracts.
Rainfall can modify the inhibitory effect of extracts (especially shoot extracts). Shoot extracts of young plants inhibited stronger germination and growth after rain than before rain. Density of cockleburs influenced the effect of extracts, as well. Generally, differences between the efficacy of extracts was larger after rain.
The results supported the hypothesis that the phenological stage and some environmental factors can modify allelopathy of cockleburs. -
Evaluation of chickpea (Cicer arietinum L.) in response to salinity stress
105-110Views:202Soil salinity is a severe and expanding soil degradation problem that affects 80 million ha of arable lands globally. Chickpea (Cicer arietinum L.) is very sensitive to saline conditions; the most susceptible genotypes may die in just 25 mM NaCl in hydroponics. Approximately 8–10% yield loss in chickpea production is estimated due to salinity stress. However, it is still not established why chickpea is so susceptible to salt affection. Salinity (NaCl) impedes germination of seeds, though chickpea varieties considerably differ from one another in this respect. Some chickpea genotypes are more tolerant in the stage of germination, tolerating even 320 mM NaCl. The reasons of this variation are unrevealed; there is a shortage of knowledge about the germination abilities of chickpea genotypes in saline conditions. Nevertheless, the effect of salt stress on vegetative growth can be analysed in hydroponics, in pot or field conditions, regardless the experimental environment, the ranking of genotypes regarding salt resistance is coherent. Chickpea genotypes can be different in their ability to retain water, maybe under salt affection; the more salt tolerant lines can maintain higher water content in the shoots, while the more sensitive ones cannot. The identification of salt tolerant chickpea landraces based on developing genetic variability is a suitable strategy to combat against salinity problems arising in arid and semi-arid areas.