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.

roots of deserticolous herbs and subherbaceous plants, and its duration, are ecological indicators and the standard measure of continentality. By an increase of continentality, particularization is effected sooner and its intensity also increases. POPLAVSKAIA (1948) elaborated in great details the life-form system of aquatic plants, with extensive consideration of anatomical adaptation and their behaviour in water. Her criteria are, among others : the losing or failure in developing of the supporting tissues, and the development of aerial passages between the tissues. YUNATOV investigates (1950) the composition of the life-forms, and the rhythm of their annual development, of the diverse zones of the Mongolian styeps. GOLUBEV (1957) studies interrelationship between the several root-types and the types of soil. His other aim is an analysis of the life-form composition of va, rious plant associations, allowing biomorphological comparisons in vegetation. For the characterization and differentiation of the zonal styep and deserticolous associations in Kazahstan, BORISOVA (1961) applies the root-types ( = lifeforms) of several dicotyledonous herbs. TIKHOMIROV (1963) describes the quantitative distribution on the Arctic Region of rosetted, semirosetted, rosetteless, taprooted, etc., plants. GORSKOVA (1966) investigates the interaction of perennial plants of diverse developmental cycles, and the role of various age groups, in styep communities. SENNIKOV (1964) again represents the wider life-form concept by stating that "Plant species similar according to their form and adaptation to the substrate are united in the same life-form". Under adaptation, he means also an ecological and not merely a morphological one. A more concrete approach to SENNIKOV'S life-form concept appears in LAVRENKO & SVESNIKOVA'S work (1965). According to these authors, life-form is an adaptive-organizational system, characterized by both structural (morphological) and physiological features, hence the life-forms ( = ecobiomorphs) should be studied from all sides. In their work, the above authors studied the cespitose, xerophilous, microthermic grasses characteristic of the styeps. This concept is the designation there of a type of the ecobiomorph. They investigate (especially on Stipa Lessingiand) the morphology of the grass tufts, their vegetative growth, the particularization and age of the tufts, the anatomy and xeromorphous characteristics of the vegetative organs, the—very short—period of the embriogenesis adapted to this climate, the conditions of seed distribution, mycotrophy, phenophases, and the daily rhythm of the convolution of the blades for the regulation of transpiration. They attempt to trace the regulative role and the changes in the regulating factors in the styep community and the process of assimilation. They establish that assimilation shows two intensive periods in the daily course in spring : in the morning and in the afternoon. During the summer, temperature regulates and decreases the activity of photosynthesis by the amount of water uptakable by the plant and the osmotic press of the cellular content. All these features, surveyed together and in their dynamism as well as in the coenosis supplying the basic conditions, determine, according to the authors, the life-forms designated as the ecobiomorphs. The ecobiomorphs studied by LAVRENKO and SVESNLKOVA are characterized not only by the fact that the effects of the environment are, as it were, not only fixed into their anatomical and morphological characteristics, but also by the measurability of adaptation in the extraordinarily rapid regulation of the physiological processes and ontogenetic features.