Kitaibelia vol. 8 – no. 1. (2003) p.65-73.
Adatok hazai Nanocyperion-fajok ismeretéhez VIII. Az Elatine hungarica Moesz kísérletes taxonómiai és biológiai vizsgálata
Molnár V. Attila
To reveal the phenological rhythm, ecological requirements and general biological behaviour of the studied species experiments were set in phytotron between November of 1999 and July of 2000. Seeds of Elatine hydropiper, E. hungarica, E. triandra and Lindernia procumbens collected from different sites (the surroundings of villages Tarpa, Pocsaj and Tiszagyenda) were planted and successfully raised using the method of Salisbury (1967) applied for Elatine hexandra (14 hour lighting, 200 mmol/min/sec light intensity, 24 °C daytime and 18 °C night temperature, 50-60 % relative humidity, pouring with falling water or distilled water, cover max. 2-3 mm). The radicles of Elatine species appeared quickly, after 60 hours following the sowing. The appearance of the first flowers required 25-32 days. The growth rates are significantly higher than it was experienced by Salisbury (1967) in the case of E. hexandra. Elatine hungarica and E. hydropiper produce chasmogamous flowers. They are open for 1 (or 2) day. The flowers of E. triandra and Lindernia procumbens are cleistogamous. The first capsules of Lindernia opened after 50 days following the sowing. The ripening of the seeds of Elatine species required 25–30 days counted from the flowering. One part of these mature seeds germinated as soon as they were sowed.
The number of seeds per capsule ripened in field is larger in the case of water stature than that of terrestrial one at Elatine hungarica (t = 2,619784, df = 98, p < 0,02). Salisbury (1967) found the opposite at Elatine hexandra.
The seed number per capsule shows significant differences comparing the individuals of Elatine hungarica (terrestrial form) grown in the field with that of grown in phytotron (t = –3,7173, df = 128, p < 0,001). The results indicate that in phytotron our plants somehow could not get as optimal ecological conditions as in nature.
The terrestrial forms of Elatine hungarica raised on wet mud from seeds changed into water stature with longer internodes and pedicels, and larger leaves after flood (up to 6-8 cm water cover). These findings sign that the individuals developed under different environmental conditions can get only at most the „forma” in taxonomic hierarchy. To distinguish them as varietas is not reasonable.
In literature the authors discuss a lot on the importance of the different characteristics in identifying certain Elatine species. Some botanists (e.g. Seubert 1845, Düben 1839, Kosinskii 1917 cit. Casper – Krausch 1980, Cook 1968) insist on the importance of the pedicels length, while others (Borbás 1881, Margittai 1939, Soó 1974) doubt or deny that. Cook 1968 neglect the seed form in identification. Our study proved that seed form does not depend on growing conditions. The seeds of the terrestrial and aquatic forms do not differ. The experiments show that the shape, curvature, torsion of them plus the shape of the seed coat cells are unambiguous features for the separation of Elatine hydropiper, E. hungarica, E. macropoda and E. orthosperma (the latest two species have not been found in Hungary). The seeds of E. hungarica and the Mediterranean E. campylosperma are very similar, they can not be used for the taxonomic separation of two species. To reveal their taxonomic position needs further studies.