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Population variability of Acorus calamus L. in patterns of resource allocation with respect to environmental variability.
Pai, Aswini*,1, McCarthy, Brian 1, 1 Ohio University, Athens, Ohio
ABSTRACT- Acorus calamus L. (Sweetflag, Acoraceae) is a helophyte found in riparian areas in temperate and subtropical regions of the world. We investigated variation in shoot density, rhizome biomass, rhizome length, leaf scars and leaf scars per unit length on rhizomes in eleven population patches of A. calamus in southeastern Ohio with respect to edaphic variables. Soil samples were collected from the inside, periphery and areas adjacent to populations and subsequently analyzed for moisture, organic matter, pH, texture, Ca, Mg, Al and P content. Multivariate Analysis of Variance (MANOVA) indicated no significant variability (l = 0.29, P > 0.05) in soil variables within a population patch. However, significant (l = 0.00006, P < 0.001) differences were observed among population patches for all the soil variables measured. MANOVA also indicated significant (l = 0.45, P < 0.001) differences among population patches for all the biotic variables measured. Redundancy analysis indicated that edaphic variables explained 71.5 % of the variation in biotic variables. Monte Carlo simulations indicated significance of the overall model (F = 0., P > 0.01). A soil organic matter gradient defined the first RDA axis while the second axis was defined by a soil Ca and P content gradient. Rhizome length, rhizome biomass, total number of leaf scars and leaf scars per unit length are positively correlated to Ca and P but negatively correlated to the organic matter content. Shoot density is positively correlated with silt and nitrogen content but negatively correlated with organic matter content. Patterns of rhizome morphology and shoot density in A. calamus populations in southeastern Ohio indicate the life history patterns of a stress tolerator. The rhizome in A. calamus functions as a storage and foraging organ by means of sequestering biomass and varying rhizome length and shoot density respectively in sites with varying edaphic conditions.
Key words: Rhizome, Acorus calamus , Redundancy Analysis