Szekessy Vilmos (szerk.): A Magyar Természettudományi Múzeum évkönyve 62. (Budapest 1970)

Fekete, G. ; Szujkó-Lacza, J.: A survey of the plant life-form systems and the respective research approaches, II.

'thirties — if not everywhere. (On the other hand, the investigation of formations enjoys its renaissance today, if not entirely on the basis of the earlier great formational units). During the same period, new problems have locally arisen, and mainly in the investigation of the structure of coenoses. The questions of this new era of vegetational studies are, among others, the following : 1. What is and in which way can be measured the ecological and physiological effect (that is, the coenotic effect or that of associatedness) of the population of two or more species on the present individuals of a third or further species? — 2. How do the ecological effects of the biosphere influence the morphogenesis of the species? — 3. What are the effects of the biosphere on the structure of the soil, the state of nutritive substances, the course of soil dynamism, etc.? It is in answering these questions, comprising an intense amount of problems (locally still containing attempts to describe vegetational zones or certain formations), that the Russian-Soviet zhiznennaya forma investigations, or the more restricted growth-form and Wuchsform studies, submit significant contributions. The Soviet zhiznennaya forma investigations are comprehensively characterized bySENNIKOV'S (1950) statement: "The ecologists of the Soviet Union go their own ways in the elaboration of the life-forms : they do not start, in general, from an analysis of the flora and a classification of the climate, or from physiognomical features — all of which lead inevitably to abstractions and formalism — but from an ecologico-biological analysis of the factual forms of vegetation." One of the founders of the ecologico-coenological life-form concept in the Soviet Union is WILLIAMS. He elaborated in 1922 specific life-form groups, having regarded as significant the role, the morphological characteristics, and the trophobiologic functions, of vegetation in forming the soil and its dynamic changes in the regions where he conducted his investigations. WILLIAMS'S groups are: ligneous plants and fungi, of principal role in energy turnover (ligneous plants adsorb inorganic matter and produce organic substances, fungi decompose the latter), styeptype herbaceous plants and the connected aerobic bacteria (damaging soil structure in humid climates), meadow-type herbaceous plants and anaerobic bacteria (accumulating humus). WILLIAMS'S categories are in fact great categories, his generalizations are more extensive than were necessary, but his is indubitably a new appraoch which, in the construction of groups, considers the functional features as factors shaping the biosphere. POPLAVSKAIA and STJKACHEV (cited by SENNIKOV, 1950) attempt another approach. They contend that interrelationships change according to environment and the age of plants. Hence a given species can be assigned to diverse phytocoenological types under various conditions. Thus we have edificators which create plant association environments (further subdivisable into natural and degressive groups,) and accessory species which play a subordinate role in the formation of the habitat. This is an extreme life-form concept, with but few followers. KELLER (1933, 1938) emphasizes in his life-form system the formative effects of the environment, in expounding per lifeforms the vegetation of diverse zones. KAZAKEVICH conducts investigations based on rather morphological grounds. In 1922, he studied life-forms based on various root types, and their role in the diverse coenoses. He established that the proportion of plants producing taproots is higher in styep meadows than in forests, whereas this latter is inhabited in a greater per cent by plants with shortened root-stocks. According to RADKEVICH and SUBINA (1935), the particularization of the