Matskási István (szerk.): A Magyar Természettudományi Múzeum évkönyve 86. (Budapest 1994)

Barbacka, M.: Reconstructions of stomata in Komlopteris Barbacka and Pachypteris Brongniart and their adaptation to climate

ANNALES HISTORTCO-NATURALES MUSEI NATIONALIS HUNGARICI Tomus 86. Budapest, 1994 p. 5-11 Reconstructions of stomata in Komlopteris Barbacka and Pachypteris Brongniart and their adaptation to climate by M. BARBACKA, Budapest BARBACKA, M. (1994): Reconstructions of stomata in Komlopteris Barbacka and Pachypteris Brongniart and their adaptation to climate. - Annls hist.-nat. Mus. natu. hung. 86: 5-11. Abstract - The SEM investigation of stomata of Komlopteris BARBACKA and Pachypteris BRONGNIART supported the theory of adaptation of Komlopteris to a wet, tropical climate and swamp-like environment. This is contrary to the opinion of some authors who investigated Komlopteris-Yikc leaves (before revision some of them were described as Thinnfeldia) as xeromorphic. The examination of stomatal structure in Pachypteris has suggested that this plant might have required different conditions. With 18 figures. INTRODUCTION The structure of stomata of Komlopteris (BARBACKA 1994a) leaves (before revision Ihey were known under the name of Thinnfeldia) was inteipreted by some authors (GOTIIAN 1914, ANTEVS 1914) as being typical of xeromorphic plants in view of their thick cuticles and sunken guard cells. About 80 specimens of Komlopteris from the Mecsek Mountains (Southern Hungary) and several specimens of different species of Pachypteris from various localities were examined (one from the Mecsek Mountains, one from Georgia, and five from Steierdorf-Anina in Romania). Besides the morphological and cuticular differences between the two genera (Barbacka 1994a), the investigation of stomata in SEM shows that these genera might be adapted to different conditions. RESULTS AND INTERPRETATION The stoma of Komlopteris consists of 5-8 small subsidiary cells which form a regular ring around the stomatal pit. The inner (near the stomatal pit) and outer outlines of the ring create the characteristic thickenings which probably mark anticlinal walls of subsidiary cells (Figs 1-4). In different forms of leaves two different types of thickenings were observed. In the first one, the inner and outer anticlinal walls are very thick and the periclinal walls form a narrow, sunk line in between (Figs 1-2, 11). This type looks like a double concentric ring around the stomatal pit, the ring is interrupted by the radial anticlinal walls. In the second type, there is no thickening around the stomatal pit, the periclinal walls are not sunken and the concave line is formed by the contact of the periclinal wall and an outer anticlinal wall (Figs 3-4, 12). In this case the ring is double too, but the outer one is narrower than the inner one. Generally speaking, stomata of Komlopteris were described as bowl-shaped with protruding outer margins and the guard cells situating at the bottom. The character of the cuticle layer is better visible under SEM and shows, that on the outer surface of the cuticle stomata were marked only by holes with flat margins (Fig. 14). The inner surface, viewed from the mesophyll side, showed all epidermal structures and the outer margins of the rings formed by subsidiary cells appeared to be sunken into the epidermis. Consequently, the guard cells must have been situated near the surface of the leaves (Figs 5-6). The relatively broad stomatal pit allowed the large area of guard cell walls to make contact with their surroundings.