Reprodução de musgos sob a perspectiva da integração clonal

Abstract

Clonal integration involves the connection between clones of a genet, translocating resources and information, decreasing competition, promoting foraging, and division of labor. Bryophytes show high clonality, with colonial architecture that promotes moisture maintenance. The architecture of these patches is called life form, and because of its role in maintaining moisture for the colony, it is referred to as Capillary Integration. For the reproduction of mosses, in which proximity and humidity are fertilization propelling, characteristics of Clonal Integration can explain reproductive patterns, mainly in dioecious species. Therefore, the objective of this work was to understand the reproductive response of a moss species to clonal integration in different microsites. Our questions were: (1) Is the reproductive form found (ie, sexual or asexual) affected by Clonal Integration parameters (distance to nearest margin, density and length of ramets)? (2) Which of the Clonal Integration parameters are most correlated with reproductive modes? From different patches of a common urban moss (Hyophila involuta (Hook.) A. Jaeger), we evaluated two samples (1cm2), one from the center of distribution and the other from the nearest margin (totalizing 154), and measured the temperature, air relative humidity and radiation. We quantified of each sample parameters of clonal integration and sporophyte number. Five shoots were selected out per sample to measure their length (mm), the presence of sexual structures (archegonium and antheridium); and the number of asexual propagules (gemmae) when present. We cultured 4 replicates with c. 50 gemmae for each micro site in a common garden, to compare the germinability between the center and the margin of the distribution. The microsites differed in ramet length (about 1.19 mm bigger in center), but had similar densities of shoots per area (ca. 65 shoots/cm2). For each cm apart from the center probability of finding gemmae on the margin increases in 10%. In the center, with each new ramet the probability of finding gemmae decreased by -3%; with a similar effect (-3%) for sexual structures, but at the margin. Finally, for each 1mm increase in length, the chance increased by 43% for sexual structures at the margin, and 49% for gemmae in the center. Gemmae output was associated with increasing distance, length, and density; and this pattern was accentuated in the center. There was no difference in germinability between the center and margin gemmae. Our results reveal that the microsites influenciate the development of the patch by clonal growth, the function of the canopy in the reproduction of this moss and a bet hedging strategy in both reproductive forms. The characterization of the microsites highlights the role of asexual reproduction in patch expansion, for survival, dispersal to adjacent patches, and unique clonal growth for colony architecture. It also exhibits the relationship of division of labor in this species with larger individuals contributing more to sexual reproduction, as well as for the formation of a diaspore bank.