Kaszab Zoltán (szerk.): A Magyar Természettudományi Múzeum évkönyve 64. (Budapest 1972)

Szujkó-Lacza, J. ; Fekete, G.: A survey of the plant life-form systems and the respective research approaches IV. Taxonomic aspects of the life-form protection of the embryonal and meristematic tissues in the dormancy stage

he equalled ecological adaptations of diverse character, including also stature, the epharmonic habitANDREÁNSZKY puts forth a number of excellent examples of the staturemoulding role of the environment; these examples concurrently prove the utility of aprroach by the systematical point of view. He points out that "life form" (stature, habit) may come into being monophyletically or polyphyletically from other life-form (s). The cactiform habit evolved in the Cactaceae in America, in the genus Euphorbia and the family Asclepiadaceae in arid Africa — hence polyphyletically as to plant systematics. Since they derived from species of a spinoso-suffrutescent life-form (Phanerophytes), the means of origin of the life-form is monophyletic. Similarly polyphyletic as to systematics and monophyletic as to origin of life-form are the species of the mangrove-shruberries, and their life-form the socalled mangrove life-form, which, according to ANDREÁNSZKY, evolved from the evergreen life-form (Phanerophytes). The salty swamp environment permitted the prevalence of a highly homogeneous habit and growth form from the various taxa, and filtered out every other type. Both systemtically and as to life-form, the spinose sphaerical shrub "life-form" ("Kügelpolster", HAURI in Du RIETZ, 1931) also exemplifies the polyphyletic descent. It cannot be left out of consideration that the cactiform shape, the spinose sphaerical shrub form, and the mangrove habit are characteristics persisting during the entire life-cycle of the plant, and therefore have to conclude that these uniform habitual features — though representing adaptations of a protective character — •cannot belong to RAUNKIAER'S life-form system. Protection of the embryonal and meristematic tissues in the dormancy stage The rest period (dormancy

) In creating his life-form system and assigning the phanerogamous plants to main and subtypes, RAUNKIAER (1907) subdivided them, on the basis of bud protection in his first approach, into three large groups by considering their morphological features and habit as adaptations to the unfavourable season. The first group contains trees and shrubs protecting both their vegetative and generative buds by bud scales only: this is the group of the Phanerophyton life-form (MM, M, etc.). In the next group (e.g. Chamaephytes, Hemieryptophytes), there is also some other, external or abiotic, form of protection (snow

r cover, litter, aqatic submersion) beside the bud scales. The third considerable group is formed by plant species which retreat with their organs of diverse origin, including also their seeds, below the soil surface, so that the substrate gives the major part of protection (Cryptophytes, Therophytes). We propose to submit in this chapter a survey of the mechanism of bud and seed protection, that is, dormancy, and of some other related problems from the point of view of other sciences. RAUNKIAER (1907) justifies the importance, emphasized by him, of bud protection in the characterization of the life-forms as follows : "... all parts of the plants are not equally sensitive to the effect of the unfavourable seasons. The young embryonic tissue of the growing points is the most sensitive of all, and since it is this very tissue on which the plant's continued growth depends, it is of the greatest possible importance that it should survive the unfavourable season unscathed." RAUNKIAER was wholly aware of the importance of protecting the embryonal and meristematic tissues, and also used it in the elaboration of his life-form con-