Allelopathy in the Soviet Union - ACS Symposium Series (ACS

Chapter 4

Allelopathy in the Soviet Union A. M. Grodzinsky

Downloaded by FUDAN UNIV on January 4, 2017 | http://pubs.acs.org Publication Date: January 8, 1987 | doi: 10.1021/bk-1987-0330.ch004

Central Republic Botanical Garden, Ukrainian Academy of Sciences, Kiev, Union of Soviet Socialist Republics Allelopathy has been developed in several main directions throughout Russia, which has a long and distinguished record in this research area. Soil sickness under wheat, oats, corn, rye, alfalfa, peas, sugar beets, clover, flax, woody plants and shrubs has received much attention. A n understanding of recultivation-regulation of microbial activity and breeding of new plant varieties with less allelopathic activity are among the main objectives. Mechanisms of interactions between plants in various types of ecosystems have been intensively studied. Research on isolation and methods of evaluation of chemicals produced by plants and/or microorganisms and testing them are discussed. Allelopathy is an o l d tradition i n the Soviet Union. In the middle of the last century the botanist Levakovskii (1) from Kazan published his observations about interactions between forest trees and forest grasses. H e suggested that forest litter chemically influences plant seedlings. A t the beginning o f the present century Periturin (2) investigated the causes of soil fatigue under common cereals — oats, wheat, and barley. That found toxins accumulated i n soil, w h i c h c o u l d be extracted with alcohol; after this the soil regained its fertility. A special direction i n research on chemical interaction among plants began i n 1926, when T o k i n (2) discovered the presence of volatile protective substances of plants, w h i c h he called phytoncides. Besides their influence on pathogenic organisms, w h i c h cause illnesses o f men and animals, the most important function of phytoncides is the protection of plants against herbivorous animals and parasite damage and against fungal and bacterial infection. Independently of those researches K h o l o d n y i (4) at the end of the 1930s noted the ability of some microorganisms and the roots of higher plants to absorb volatile substances from air and to use them for growth. O n the basis of these investigations he developed the idea o f interaction among plants and between plants and microorganisms mediated by volatile compounds, such as terpenes and other hydrocarbons. In 1956 C h e r n o b r i v e n k o (5.) summarized many such observations and field experimental data. Some interesting observations on the biological effects o f volatile substances were also published by Sanadze (6). A t the end of the 1950s allelopathy was already w e l l known among botanists and plant physiologists, but it was considered rather a m i n o r and rare phenomenon that had no great ecological importance. W e have screened many plant exudates, and reached the conclusion that many species are allelopathically active; indeed, practically any plant under certain conditions so affects other plants 0097-6156/87/0330-0039$06.00/0 © 1987 A m e r i c a n C h e m i c a l Society

Waller; Allelochemicals: Role in Agriculture and Forestry ACS Symposium Series; American Chemical Society: Washington, DC, 1987.

40

ALLELOCHEMICALS: ROLE IN AGRICULTURE A N D FORESTRY

(7). Thus allelopathy is indeed very important ecologically, although skeptics remain.


M a n y investigations i n c h e m i c a l interactions i n different types o f phytocenoses (natural, artificial, forest, steppe, aquatic ecosystems) are currently conducted by specialists: botanists, plant physiologists, m i c r o b i o l o g i s t s , biochemists, soil scientists, agronomists, etc. B y drawing analogies with other sciences, we can mark several stages of allelopathy development and paradigms that change and add to each other. Originally, allelopathy was considered only as the harmful influence of certain active plant species on adjacent plants. This definition was extended by the author of the term allelopathy, M o l i s c h (&). M o l i s c h indicated that allelopathy included stimulatory as w e l l as inhibitory growth effects. M a n y of the phenomena he discussed i n v o l v e d growth stimulation or a combination of stimulation and inhibition e.g., effects of ethylene. M o s t researchers now accept allelopathy. A c t i v e substances can be likened to herbicides and their high specificity is accepted without question. For example, a very allelopathically active plant that we studied in 1959 is the crucifer Crambe tataria Sebeôk (9). It is a biennial or perennial herbaceous plant with a well-developed root and large spherical bushlike stems with many dry fruits. After ripening, the stem tears loose from the root and is rolled throughout the steppe by wind. E n route the fruits are lost i n the grass. The fruits contain very strongly inhibiting substances, a mixture of many phenolic acids, amino acids, and some sulfur-organic substances. W e still do not know the whole chemical constitution of fruit coats of Crambe tataria. but that plant first gave us the idea of chemical interaction between plants. The water-soluble inhibitors from the fruits go into the surroundings, suppress other plants, and make free places for germination and growth of Crambe. Such plants as Crambe are not numerous -- they may constitute less than 1% o f the general flora. However, allelochemicals can be not only harmful, but favorable, particularly at low concentration. Chernobrivenko (5) and other Soviet scientists assumed the possibility of positive chemical influence of adjacent plants. American authors, Rice QQ) among them, took this position much later. The notion of action by specific allelochemical compounds is also unjustified. Detailed study of some allelochemicals i n active species has shown the presence of phenolic acid mixtures and other phenolic derivatives or terpenes. I think that we can never talk about the action of a single substance; everywhere many compounds having different biological activity act simultaneously, perhaps mutually increasing their activity. A s a rule, such allelochemicals are the intermediate products of soil humus, synthesis, or the ground detritus i n aquatic ecosystems (11). H i g h concentrations of these substances are lethal, moderate ones inhibit growth processes, and low concentrations stimulate them. Accordingly, the second paradigm of allelopathy was formed. In this pattern the chemical mutual influence is manifested as a cycling of physiologically active substances, which play the role of regulators of internal and external interrelations — of initiation, development, and change of plant cover i n biocenosis (ecosystem) (12). Allelopathy is part of the whole recycling of organic substances i n the ecosystem; it involves low-molecular-weight carbon compounds, which are either mineralized or polymerized into large humic molecules. Such molecules do not penetrate into plants and thus have no allelopathic effect. This means that we are discussing the intermediate products in humus formation and decomposition.



4.

GRODZINSKY

Allelopathy

in the Soviet

Union

41

This paradigm provided our basic notion of allelopathic soil fatigue (13). A s a broad ecological notion it includes accumulation of toxic products o f the vital activity o f plants and heterotrophic organisms; this adversely affects the productivity of f o l l o w i n g plants. A s a consequence o f specialization and concentration of the agricultural industry, the s o i l fatigue problem became particularly serious and urgent. W e managed to devise an isolation method for allelochemicals by using ion-exchange resins, which permitted us to obtain those substances without destruction of humus complexes that could not be absorbed by living plant roots. O u r method simulates plant root absorption of allelochemicals. It was shown that cinnamic, g-coumaric, £- hydroxybenzoic, and other phenolic acids accumulate under monocultures of wheat, rye, and other cereals. The concentrations o f these acids increase two- or threefold under permanent wheat culture, while that of neutral humus decreases. A t the same time we observe changes in microflora; the diversity and number of bacteria decrease and the mass of soil fungi increases (14). To relieve allelopathic soil fatigue we can use either the o l d tested method of crop rotation or, i f we know the chemical basis o f the problem, the agrotechnical method, which accelerates mineralization/polymerization of allelochemicals into stable humus, or else use allelopathically inactive species and varieties that don't cause soil fatigue. W e think that the last method is the most reliable. This second paradigm includes both negative and positive allelochemical effects on plant growth and physiological processes. This new view of allelopathy, its new paradigm, conveys the notion of chemical information exchange among plants and other organisms. Current plant physiology makes it possible to suggest that plants are able to "perceive" a chemical environment and respond with appropriate reaction. This can be shown in changes of their life strategy and tactics. In this case an allelochemical plays the role of a signal; its effect does not depend on concentration, but releases a trigger connected with a genetic program. For example, seeds and bulbs of many herbal plants may rest i n the soil many years under cover of a forest and germinate only after the trees are removed; humidity, temperature, and extent of aeration often changed and several times there were apparently perfect conditions for germination, except that the seeds were under l i v i n g dominant plants. Obviously, the signal of mature trees holds the plant embryos i n the resting stage. In other cases, root exudates, for example, those of oats, stimulate germination of weeds i n the field. The research of G a j i c ' (15) from Yugoslavia found that the weed Agrostemma githago stimulates germination and growth of wheat. After many years of research she identified the allelochemicals, which is a mixture of amino acids, and includes allantoin and tryptophan. B y analogy G a j i c ' created the biostimulator Agrostemin, commercially marketed, which accelerates growth and germination, and increases productivity of many cultivated plants and native meadows by 10-15%. Agrostemin is used at remarkably low concentrations ~ about 10 g/ha. F o r a long time phenomena of this k i n d have attracted Soviet researchers' attention. In the 1920s G u r v i t c h (16) suggested the existence of so-called mitogenetic rays, which were supposed to stimulate cell division of yeast, lower plants, protozoa, and so on. But no such physical rays could be found and in the 1950s Moiseeva (17) showed that the signal for mitosis is indeed chemical i n nature. However, such signal substances have not been discovered yet. In recent years i n the agricultural high school i n Kharkov, Naumov and his students (18) demonstrated that a water extract from 2 k g of grain (wheat, rye,


42

ALLELOCHEMICALS: ROLE IN AGRICULTURE AND FORESTRY

oats, barley) when added to 700 k g o f the same or other cereal grain before sowing stimulates all vital functions o f the growing plants and reliably increases the harvest. Moreover, reciprocally soaking the seeds o f wheat i n seed extract of rye, and o f rye seeds i n wheat extract a few times, is claimed to facilitate fructification by hybridization between the two genuses. The soaking o f seeds i n extracts from some weeds made the new plants more resistant to the weeds used.


These investigations are i n progress and sometimes may be o f doubtful validity, but suggest that allelochemicals of a plant can act on the expression of the heredity program i n another plant. In other words, chemical signals coming from l i v i n g plants causes recipient plants to follow a suitable life strategy — for example, resting. Perhaps the signal is other than chemical; i n particular maybe it is slow (circadian) vibrations of electric fields near l i v i n g plants (for example mature trees) and this is what prevents the germination o f resting seeds and b u l b s . Although concentration does not change essentially the character o f the recipient reaction, the signal is operative only i n a certain interval; at too high concentration the substance does not convey the message. This is related to a recent interesting observation on birch and pine trees by Marchenko (19) i n Bryansk. W h e n a coniferous tree and birch grow together, their needles and twigs deviate on opposite sides. M a r c h e n k o calculated that the forces required to cause such deviation amount to a few hundred or thousand horsepower. T o show the dimensions o f the allelochemical effect with a l l three abovementioned paradigms: before the era o f mineral fertilizers, production of a crop required application o f 20 tons of manure per hectare; later, w i t h mineral fertilizers only several centner per hectare are required, with regulators such as herbicides, 2 to 20 k g , and regulators such as Agrostemin only a few grams per hectare. O f course, the above-mentioned paradigms do not exclude or contradict each other; each o f them concerns its o w n circle o f phenomena, but a l l these phenomena apply to allelopathy. I think that Soviet researchers contribute much to the development o f this science, w h i c h is very important for understanding the nature o f vegetation development and species evolution and especially for increasing production of consecutive crops.

Literature Cited 1. 2. 3. 4. 5. 6.

Levakovskii, N. Trudy Obshch. Estestv. Pri. Kazan Univ. 1971, 33-52. (Cited by Gortinskii, G. B. Bull. Mosk. Obshch. Ispyt. Prir. Otd. Biol. 1966, 71, (5), 128-133). Periturin, F. T. Izv. Mosk. s.-kh. Inst. 1913, kn. 4. Tokin, B. P. "Salubrious Poisons of Plants: Story of Phytoncides"; Publ. Leningrad University: Leningrad, 3d ed., 1980. Kholodnyi, N. G. Izv. AN. Arm. SSR 1944, (3), 31-42. Chernobrivenko, S. I. "Biological Role of Plant Excretions and Interspecific Interrelation in Mixed Culture"; Nauka: Moscow. Sanadze, G. Α. Izd. An. Gruz. SSR. (Tbilisi), 1961.


4. GRODZINSKY Allelopathy in the Soviet Union 43

7. 8. 9. 10. 11. 12.


13. 14. 15. 16. 17. 18. 19.

Grodzinsky, A. M . "Allelopathy in Life of Plants and Their Communities"; Naukova Dumka: Kiev, 1985 Molisch, H. "Der Einflus seiner Pflanzen auf die andere -- Allelopathie"; G. Fischer: Jena, 1937. Grodzinsky, A. M.; Kuznetsova, G. O. Ukr. Bot. Zh. 1960, 17, (1), 2930. Rice, E. L. "Allelopathy", 2nd ed; Academic Press: Orlando, Florida, 1984. Khailov, K. J. "Ecological Metabolism in the Sea"; Naukova Dumka: Kiev, 1971. Grodzinsky, A. M . "Principles of Chemical Interaction of Plants"; Naukova Dumka: Kiev, 1973. Grodzinsky, A. M., Bogdan, G. P., Golovko, Ε. Α., Dzyubenko, N . N.; Moroz, P. Αp.; Prutenskaya, Ν. I. "Allelopathic Soil Sickness"; Naukova Dumka: Kiev, 1984 Golovko, E. A. "Microorganisms In Allelopathy of Higher Plants"; Naukova Dumka: Kiev, 1984. Gajic', D. Fragmenta Herbol. Croatica (Zagreb) 1972, 12, 1-6. Gurvitch, A. G. Moscov. Sovetsk. Nauka 1944, 167. Moiseeva, M . M . Ukr. Bot. Zh. 1960, 17, (4), 29-33. Naumov, G. F.; Teteryatchenko, K. G.; Moskienko, N . F. Sborn. Nauch. Truji. Khark. s.-kh. Inst. (Kharkov) 1982, 288, 31-39. Marchenko, I. S. Br' anski: Izd. Tekhnol. Inst. 1973, 91 pp.

RECEIVED

June 9, 1986


Allelopathy in the Soviet Union - ACS Symposium Series (ACS

Recommend Documents