A Study On The Spore Morphological Characteristics And Its Variation Of Adiantum From China

Spores of 30 species and 6 varieties of Adiantum which were kept at the PYU, were examined using scanning electron microscopy (SEM),among which spores of A. menglianense, A. induratum, and A. monochlamys, were observed at first time by SEM. By samples observing of the spore’s traits, such as trilete, polar, equatorial and spore ornamentation, as well as combining former reports, we comprehensively surveyed Adiantum spore morphology of the Chinese species. A key for the classification of species in Adiantum was given based on the morphology of spores. We intended systematically and comprehensively reveal the genus spore morphology from spore morphology differences to distinguish easily confused and controversial classification of closely related species.Meanwhile, the impact of spore morphology of Adiantum species on ecological gradients such as longitude, latitude, altitude and soil factors were analyzed. The results were as follow:1. Adiantum spores were actinomorphic, polar view was obtuse triangle, triangle circle, triangle, equatorial view was a half round, half round, trilete, the length of trilete was from 1/2,2/3 to equal the radius of the microspores. Spore size was 37.98 (26.73～48.99)×42.74 (30.16～53.74)μm.2. The Adiantum perispore was shedding and the ornamentation could be divided into five types:psilate, tuberculate, verrucate, folds(rugate and reticulate folds), granulate(scabrate and granulate). The dominant type was granulate. Ornamentation characters had certain significance for species identification.3. There were few differentiation in the spore morphology of A. capillus-junonis and A. bonatianum from different regions. Howerver, small spores occurred in a higher altitude, the spore from low place were large. Longitude, latitude, and soil factors had no significant correlationship with spore morphological characteristics.4.The spore morphology can be used as the classification basis for relative species of Adiantum.A. philippense spore was characteristic of small holes on the surface, the length of trilete to equal the radius of the microspores. Adiantum menglianense’s granulars integrated as verruculose, the length of trilete was 2/3 of the microspores. There was not much clear distinction between the two species, except the crack length and fine structures of spore.