Sexual expression and genetic diversity in populations of Cryptogramma crispa (Pteridaceae)

Abstract

The reproductive biology of Cryptogramma crispa, a tetraploid species with a broad circumboreal and alpine distribution, growing mainly in siliceous boulder fields and crevices, was studied in the laboratory by growing gametophytes in plates with both solidified agar media and sterilized soil. In addition, an electrophoretic study of isozymes was carried out on frond samples from five natural populations, as an additional source of evidence concerning the breeding system and the genetic structure of sporophyte populations. Populations throughout the Iberian range of the species were selected for this study, and a Scottish population was included to represent plants from outside our local area and ecology. The morphological development of gametophytes is of the Adiantum type. All multispore cultures developed into a bigametophytic system, consisting in most cases of male and female prothalli. This pattern of sexual expression provides evidence for outcrossing as the main breeding system in this species. Moreover, there is good evidence that the species possesses an antheridiogen system to promote outcrossing. The long time needed by gametophytes to produce gametangia, and afterwards to fertilize and produce sporophytes, might be the primary reason why so few young sporophytes are found in the wild. The values of the percentage of polymorphic loci and the similarity levels obtained from the isozyme analyses indicate a level of genetic variability that would be expected in an outcrossing species. All these characteristics are usually associated with diploid fern species rather than polyploid species.

Genetic variation in the allotetraploid Dryopteris corleyi (Dryopteridaceae) and its diploid parental species in the Iberian Peninsula

“…Consequently, occasional arrival of wind-dispersed spores from other populations can maintain the levels of genetic variation observed in D. oreades . This result is in accordance with those for other alpine ferns that may have undergone similar evolutionary events, such as Cryptogramma crispa in the Iberian Peninsula ( Pajar ó n et al, 1999 ) and Athyrium distentifolium in North America ( Woodhead et al, 2005 ). The allotetraploid D. corleyi presented little genetic variation, with only one polymorphic locus, 6-Pgd-1 .…”

“…This result is in accordance with those for other alpine ferns that may have undergone similar evolutionary events, such as Cryptogramma crispa in the Iberian Peninsula ( Pajar ó n et al, 1999 ) and Athyrium distentifolium in North America ( Woodhead et al, 2005 ). This result is in accordance with those for other alpine ferns that may have undergone similar evolutionary events, such as Cryptogramma crispa in the Iberian Peninsula ( Pajar ó n et al, 1999 ) and Athyrium distentifolium in North America ( Woodhead et al, 2005 ).…”

“…Ferns have been the target of numerous studies on genetic diversity because of their unusual life histories, potential for long-distance dispersal, and frequently fragmented populations (e.g., Pajar ó n et al, 1999 ;Landergott et al, 2001 ;Schneller and Liebst, 2007 ). The life history of these organisms typically consists of a haploid stage, the gametophyte, and a diploid stage, the sporophyte, which are independent of each other.…”

In vitro culture of Drynaria fortunei, a fern species source of Chinese medicine “Gu-Sui-Bu”

“…As elongated and uniseriate gametophytes of D. fortunei developed under far-red light, and growth of these gametophytes was abnormal and did not reach maturity, this may offer an explanation as to why sex organ development is absent in some gametophytes. The diversity in sexual expression in gametophytes has also been reported in Cryptogramma crispa (Pajaron et al 1999).…”

Short Communication: Selected medicinal plants in East and North Kalimantan (Indonesia) against Propionibacterium acnes

“…Three modes of sexual reproduction are recognized in ferns and fern-allies (following Klekowski 1969): (i) Intragametophytic selfing, a zygote is formed from the same gametophyte; (ii) Intergametophytic selfing, a zygote is formed via the cross-fertilization between different gametophytes produced by a single sporophyte, and (iii) Intergametophytic crossing, a zygote is formed via the cross-fertilization between different gametophytes produced by different sporophytes (Soltis and Soltis 1987). A bigametophytic system, consisting in most cases of male and female prothalli, provides evidence for outcrossing of fern species (Pajarón et al 1999).…”