A Gompertz regression model for fern spores germination

Jose María Gabriel Y Galán,Carmen Prada,Cristina Martínez-Calvo,Rafael Lahoz-Beltrá

doi:10.3989/ajbm.2405

Abstract

Germination is one of the most important biological processes for both seed and spore plants, also for fungi. At present, mathematical models of germination have been developed in fungi, bryophytes and several plant species. However, ferns are the only group whose germination has never been modelled. In this work we develop a regression model of the germination of fern spores. We have found that for Blechnum serrulatum, Blechnum yungense, Cheilanthes pilosa, Niphidium macbridei and Polypodium feuillei species the Gompertz growth model describe satisfactorily cumulative germination. An important result is that regression parameters are independent of fern species and the model is not affected by intraspecific variation. Our results show that the Gompertz curve represents a general germination model for all the non-green spore leptosporangiate ferns, including in the paper a discussion about the physiological and ecological meaning of the model.

Highlights

Germination is one of the most important biological processes for plants, relevant from a strictly individual aspect as well as for the population recruitment
Five species were selected to study spore g ermination: Blechnum serrulatum Rich. and Blechnum yungense Ramos Giacosa (Blechnaceae), Cheilanthes pilosa Goldm. (Pteridaceae), Niphidium macbridei Lellinger and Polypodium feuillei Bertero (Polypodiaceae). Two criteria influenced this selection: a) all of them are species whose spores lack chlorophyll, as the presence of this pigment in the spore is known to drastically reduce their viability in a few days or weeks (Gabriel y Galán & Prada, 2010c); and b) to test the general value of the model for the ferns as a whole, we chose some species within the same genus (B. serrulatum and B. yungense), different genera from the same family (Niphidium and Polypodium) and from different families (Blechnaceae, Pteridaceae and Polypodiaceae)
We have found that for B. serrulatum, B. yungense, C. pilosa, N. macbridei and P. feuillei species the

Summary

Introduction

Germination is one of the most important biological processes for plants, relevant from a strictly individual aspect as well as for the population recruitment. It is defined, for both seed and spore plants, for fungi as the set of mechanisms occurring in the dormant germ (seed or spore) that culminates with the growth of the embryo or cell to form a seedling or sporeling able to establish in the substrate. Germination can be detected by observing signs of a body emergence, as radicle, protonema, filament or rhizoid (Bradbeer, 1988). More complex techniques could be used to detect in situ vitality, biochemical reactions, enzymatic activity, metabolite usage, etc., all of them symptoms of pre-germination processes. Germination dynamics of fungal and bacteria spores are of interest, those of pathological significance (Waggoner & Parlange, 1973; Lapp & Skoropad, 1976; Bosch & al., 1995)

Methods

Results

Discussion

Conclusion