Study on Gametophytes of Four Species of Maiden Hair Ferns (Adiantum L.) and Their Systematic Implications

Sanatombi Devi YUMKHAM,Sumitra SALAM,Sandhyarani D. KHOMDRAM

doi:10.15835/nsb11310471

Sanatombi Devi YUMKHAM, Sumitra SALAM + Show 1 more

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https://doi.org/10.15835/nsb11310471

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Abstract

Matured spores of four (4) species of maiden hair ferns namely, Adiantum capillus-veneris L., A. caudatum L., A. edgeworthii Hook. and A. incisum Forssk. were collected and grown in petri-dishes containing natural media formed by mixing dead wood of tree fern (Cyathea Sm.), sand and charcoal powder (2:1:1). The cultures in triplicates for each species were monitored every day from the stage of sowing to the chimera formation. After disintegration of gametophytes, juvenile sporophytes were shifted to pots and morphological characters were studied till the dehiscence of sporangia. Spore germination initiated between 4-6 days for A. capillus-veneris, 7-9 days in A. caudatum and A. incisum and 10-12 days in A. edgeworthii. Prothallia in all the Adiantum are autotrophic, Vittaria type, cordate-shaped, homosporous with antheridia developing earlier than archegonia and remain confined on the adaxial surface. The gametophytes showed considerable variation in their shapes, orientation of lobes, presence or absence of hairs and placement of sex organs on the prothallia. The gametophytic and sporophytic characters are correlated and used in structuring key to species. The study concludes that gametophytic characters also constitute a dependable criterion for assessing their systematics.

Highlights

The maiden hair fern, Adiantum L. (PteridaceaeVittarioideae) is a genus of about 200 species distributed in temperate to tropical regions (Prado et al, 2007)
As soon as the spores landed on the media, water and nutrients are imbibed resulting in bulging of spore wall
During the course of the experiment, we have studied the germination of spores, stages of gametophyte development and formation of sporophytes in the four species of maiden ferns (A. capillus-veneris, A. edgeworthii, A. caudatum, A. incisum) found in two states of India (Manipur & Nagaland)

Summary

Introduction

The maiden hair fern, Adiantum L. (PteridaceaeVittarioideae) is a genus of about 200 species distributed in temperate to tropical regions (Prado et al, 2007). The Adiantum-Vittaroid fern clade accounts about 10% of extant fern diversity, and plays an important role in the fern flora (Lu et al, 2012). It usually grows in moisture rich shady areas, along water courses, iron rich soil and even in extreme lithophytic condition. According to Mithraja et al (2012), India harbors 23 species of Adiantum with maximum species diversity occurring in South India and Western Ghats. These ferns are medicinal plants with multiple pharmacological and therapeutic properties. Many alkaloids and bioactive components responsible for their medicinal properties have been isolated and identified (Brahmachari et al, 2003)

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