Current world achievements in allelopathy researches

Abstract

Since the idea of the allelopathy emerged the numerous works contributed to the formulation of the notional base in this area of knowledge. In the present review the large number of the novel allelopathical methods and approaches, developed for several recent decades, are analyzed. Furthermore various opinions on the subject, the forms, the mechanisms and the symptoms of the allelopathy are compared. The interdependence between the notions of ‘allelopathy’, ‘competition’ and ‘interference’ is discovered. The separate attention is paid to a) the principles of the realization of allelopathic interactions; b) the peculiarities in the approaches to the organization of the investigations; c) the significance of edaphic factor; d) the mediated influence of allelochemicals through the medium, where plants grow; e) the concept of the two-phases respond of the bioobjects – the hormesis and to some other interesting respects in the interpretation of the allelopathic phenomena. The controversial points of view on the possibility of synergism in the allelopathy are described. The great piece of the allelopathical works was focused on various aspects of release and chemical identification allelochemicals during the recent decades. Also the phytocenotical manifestations of the allelopathy were widely researched. The relationships of the plants-edificators with their subordinate species are reviewed. These papers mostly pertained to the extrusions of the native flora by the alien species. In some cases this entails the profound transformations of the ecosystems. Because such phenomena pose a risk, the control of the invasive flora involves the considerable costs. It gives the idea that of the edaphic factor considerably takes part in the development of the allelopathic processes (especially, soil biota, mycorhizzal fungi, free-living microorganisms, moisture and humus). They can strongly modify the character and intensity of the allelochemical-induced effects. The roles of both mycorrhiza and free-living microflora in the development of the allelopathic processes are discussed. The first of them often is regarded as the target and the canal of the alleviated transport for the allelochemicals, and the second one – as the sink for them. Particularly the common mycorhizza network is analyzed as the factor of the facilitation of the allelochemical transport between the plants (even if they belong to different species). Some researches are devoted the fungi as the target for the allelochemicals impact. The essential research direction in the recent decade was the determination of the precise chemical mechanisms, causing the allelopathy. It was comprehensively shown by the example with cathechin. The action of this substance was studied in the biophysical, cell-biological and physiological points of view. Some papers testify the stimulatory and other – the depressive effect of catechin. It appears that the degree of the soil toxicity can vary in the result of the habitat alternation of the same allelopathic donor-species. The temperature factor plays the similar role for the effect of the putative allelochemicals. The current ideas about the probable mechanisms of plant adaptation to the allelopathical stresses are presented.

Allelopathic effect of couch grass (Elymus repens L.) on germination of common wheat seeds

“…Thus, today the most pressing methodological issues are the sufficient concentration for the effects of phytotoxicity in natural ecosystems, the dependence of allelochemicals on soil properties, and the distinction between the direct and indirect action of allelochemicals on plants (Grakhov et al, 2014;Gruznova et al, 2018). Any plant of the phytocenosis can be a producer, that is, a donor of physiologically active substances, and their consumer, i.e., an acceptor or recipient.…”