Mantuano et al. 2015 (Conference Paper) Neoregelia

Intraclonal physiological specialization in the endemic nurse-plant Neoregelia cruenta

Author(s):—D. Mantuano, T.C. Neves & L. Rocha da Silva in Benko-Iseppon, A.M.; Alves, M. & Louzada, R. (2015) An overview and abstracts of the First World Congress on Bromeliaceae Evolution. Rodriguésia 66(2): A1-A66.

Publication:— (2015).

Abstract:—Clonal plant species can be considered as populations of interconnected ramets which are basically identical in form and function, and potentially independent from each other. Experimental studies suggest that an intraclonal specialization of ramets with different roles can increase the performance of clonal systems under heterogeneous condition. This study explores structural and functional variation of rosettes of Neoregeliacruenta (R. Graham) L.B. Smith (Bromeliaceae), a CAM tank bromeliad, under three environmental conditions in sandy coastal plain vegetation in Southeast Brazil. The main question asked is if heterogeneous habitats are able to induce different transpiration rates on connected ramets. It would allow water source sharing among connected ramets. We assumed it is an essential mechanism to sustain exposed ramets. N. cruenta plays animportant ecological role, increasing soil nutrient content and initiating vegetation islands in sandy soils, which are related to species diversity enhancement. In field conditions, clonal clumps can be found shaded or fully exposed to sunlight (homogeneous microhabitats), and partially exposed to full sunlight (heterogeneous microhabitat). We compared morphological and physiological parameters among intraclonal and interclonal rosettes in all microhabitats. Leaf area and length of leaf blade vary strongly, decreasing with increased light exposure. Leaf succulence and specific leaf weight were similar between connected ramets but lower in the exposed microhabitat. Chlorophyll and carotenoid contents decrease as the light gradient increases. This result suggest that, although acclimation features could be observed, exposed ramets (entire clonal clump of exposed microhabitat and half clump of partially exposed microhabitat) are under light stress conditions. Stomatal conductance was different between rosettes of heterogeneous habitat, contributing support to the contention that directional xylem flow between ramets is likely to occur.

Keywords:—Clonal Specialization; Physiology; Neoregelia cruenta.