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Allelopatyczne właściwości metabolitów wtórnych roślin uprawnych

Jasicka-Misiak I.

Wiadomości Chemiczne

2009

[Z] 63, 1-2

39-62

Allelopathy has been defined by the International Allelopathy Society as "any process involving secondary metabolites produced by plants, microorganisms, viruses and fungi that influence the growth and development of agricultural and biological systems, including positive and negative effects [1]". Allelochemicals can be released into the environment and despite what effect they evoke towards living organisms this kind of specific chemical interactions is known as "allelopathy". Allelopathic phenomena have been observed and studied from ancient times. Theophrastus from Eresos, a disciple of Aristotle, reported an inhibitory effect of pigweed Polygonum spp. on alfalfa in ca. 350 B.C., whereas Pliny described the harmful effects of several plants on cropland in ca. 1 A.D. [2-5]. Although chemical interactions between plants have been known for thousands years, the term allelopathy was used for the first time in 1937 [5]. It derives from Latin words allelon ("of each other") and pathos ("to suffer") and refers to the chemical interactions among species. In recent years there has been an increasing interest towards the perspective of exploiting allelopathy and allelochemicals as an alternative strategy for controlling weeds in particular, but also for controlling insects and plant diseases. Plants produce a wide variety of secondary metabolites that play important roles in ecological interactions. This is one, probably the most pronounced, of a variety of ways in which certain plants can protect themselves against competition, infection or feeding in their natural habitats. Some of secondary metabolites may also play an important role in chemical mediation of growth and development of plant communities. These substances are called "allelochemicals" and are relea-sed into the environment in order to interfere with the growth of competing plants or act as chemical defence against pathogens and animals. Therefore such compounds might be considered as constituents of plant defence system and could be treated as a kind of chemical weapons. Originally, compounds like allelochemicals were thought to occur exclusively in higher plants. Ongoing research, however, has revealed them also to be synthesized by bacteria, lower plants and fungi. Allelochemicals may furnish an entirely new generation of naturally produced weed-controlling compounds, replacing synthetic herbicides and other pesticides with non-acumulatting easy-degradable substances.

Starch dialdehyde derivatives as novel complexons protecting entomopathogenic nematodes from heavy metals

Para A., Ropek D.

Chemia i Inżynieria Ekologiczna

2000

Vol. 7, nr 11

1213-1220

High concentrations of Cd(II), Cu(II), Ni(ll), Pb(II), and Zn(II) ions are harmful for Steinernema carpocapsae nematodes. Possibility of reduction of Ibis harm was investigated. Thus, derivatives of starch dialdehyde were applied as ligands of complexes with the above-mentioned ions. Water-insoluble complexes were formed with disemicarbazone (DSC), dithiosemicarbazone (DTSC), dihydrazone (DHZ), and dioxime (DOX) of starch dialdehyde. These complexons protected nematodes from the toxic effect of metal ions in aqueaus solutions. Pathogenicity of the nematodes stored in aqueous solutions of metal ions, in solutions containing corresponding metal complexes, as well as pure complexons was determined based on the invasiveness of the nematodes to test Galeria mellonella caterpillars and in respect to the mortality of these test organisms. It was found that complexons were non-toxic to the nematodes and they could protect them from the toxicity of the metal ions even at high concentrations. dialdehyde starch disemicarbazone, dialdehyde starch dithiosemicarbazone, dialdehyde starch dihydrazone, dialdehyde starch dioxime, metal complexes, natural pesticides

Duże stężenia jonów Cd, Cu(Il), Ni(Il), Pb(ll) i Zn niekorzystnie wpływają na nicienie Steinernema car. pocapsae. Zbadano możliwość ograniczenia tego wpływu przez zastosowanie pochodnych skrobi dialdehydo. wej jako ligandów nierozpuszczalnych kompleksów z tymi jonami. Jako kompleksony zastosowano disemikarbazon (DSC), ditiosemikarbazon (DTSC), dihydrazon (DHZ) i dioksym (DOX) skrobi dialdehydowej. Kompleksony, zmniejszając stężenie jonów metali w roztworze, stanowiły ochronę nicieni przed ujemnym wpływem tych metali. Patogeniczność nicieni przechowywanych w roztworach jonów metali i w roztworach, w których jony metalu związano w nierozpuszczalne kompleksy, określono na podstawie śmiertelności owadów testowych - gąsienic Galeria me/lone/la. Stwierdzono, że użyte kompleksy nie są toksyczne dla nicieni i wykazują działanie ochronne w stosunku do nicieni przechowywanych w roztworach o dużym stężeniu jonów metali ciężkich.