Bakker, M. L.

Cepeda, R. E.

Cesa, A.

Marinelli, C. B.

English

University of Kentucky

University of Kentucky UKnowledge International Grassland Congress Proceedings XXI International Grassland Congress / VIII International Rangeland Congress Study on Alkane Patterns of Grassland Species from the Patagonian Steppe A. Cesa INTA, Argentina M. L. Bakker UNCPBA, Argentina C. B. Marinelli UNCPBA, Argentina R. E. Cepeda UNCPBA, Argentina Follow this and additional works at: https://uknowledge.uky.edu/igc  Part of the Plant Sciences Commons, and the Soil Science Commons This document is available at https://uknowledge.uky.edu/igc/21/13-1/3 The XXI International Grassland Congress / VIII International Rangeland Congress took place in Hohhot, China from June 29 through July 5, 2008. Proceedings edited by Organizing Committee of 2008 IGC/IRC Conference Published by Guangdong People's Publishing House This Event is brought to you for free and open access by the Plant and Soil Sciences at UKnowledge. It has been accepted for inclusion in International Grassland Congress Proceedings by an authorized administrator of UKnowledge. For more information, please contact UKnowledge@lsv.uky.edu. 瞯 ]446　 瞯 　 Multifunctional Grasslands in a Changing World 　 Volume Ⅱ 　Grasslands/Rangelands Production Systems——— Domestication of Native Grasslands/Rangelands Plants for Regional UseStudy on alkane patterns of grassland species from the Patagonian steppeA . Cesa1 ,2 , M .L . Bakker3 , C .B . Marinelli4 and R .E . Cepeda31 IN TA , EEA , Chacra 45A , 9400 Río Gallegos , Santa Cruz , A rgentina , 2 UN PA , Río Gallegos , Santa Cruz , A rgentina ,E‐mail : acesa＠ correo .inta .gov .ar , 3 FCV , UNCPBA , Tandil , A rgentina , E‐mail : bakker＠ vet .unicen .edu .ar , E‐mail :rcepeda＠ vet .unicen .edu .ar , 4 FCExactas , UNCPBA , Tandil , A rgentina , E‐mail : cmarine＠ exa .unicen .edu .arKey words : alkanes ,grassland ,diet composition ,Patagonian steppeIntroduction A reliable estimation of diet composition and forage intake in grazing animals under extensive management in thegreat rangelands of the world is a relevant aspect for production and conservation programmes . Grassland species from thePatagonian steppe of Argentina‐where sheep production is a major enterprise‐ would differ in their preference by sheep , butstudies are scarce and mostly restricted to a few conspicuous species using visual or micro‐histological techniques ( Pelliza etal . , １９９７) . Differences in alkane patterns between species or plant parts may be combined with the preceding techniques to aidin the estimation of diet composition ( Mayes and Dove , ２０００ ) . The aim of this work was to explore these differences on somemain grazed species using Principal Component Analysis ( PCA) .Materials and methods Eight grass species [ Poa dusenii ( Pd) , Rytidosperma virescens ( Rv ) , Carex andina ( Ca) , Hordeumcomosum ( Hc) , Festuca pyrogea ( Fpi) , Festuca gracillima ( Fg ) , Festuca pallescens ( Fpa ) , Stipa crisophyla ( Sc ) ] , onelegume [ Lathyrus magellanicus ( Lm ) ] and one shrub [ Junellia tridens ( Jt ) ] were collected in November ２００６ f rom thesouthern region of Santa Cruz , Argentina (５１°５５′ S , ７０°２５′ W) , and either the entire plant ( ep) or different parts [ live leaf( ll) , dead leaf ( dl) , grazed ( g ) , ungrazed ( u) , spikes ( s) , one‐year bud ( b) , leaf ( l) , wood ( w ) , flowers ( f ) ] ( n ＝ ２２ ) wereanalysed for odd n‐alkane ( C２３ to C３５ ) contents ( mg .kg DM‐１ ) ( Bakker and Alvarado , ２００６ ) . Alkane contents weretransformed into compositional data ( ％ of total) ( alkane patterns) and these were further transformed into centred log ratiosbefore PCA ( Aitchinson , １９８６) . Statistical analysis was done with GNU R and InfoStat / Profesional .Results and discussion First two principal components ( PC１ and PC２ ) accounted for ６６ ％ of total variance ( Figure １ ) .Correlation of alkanes with PC１ and PC２ indicates which alkanes produce major variation among species and plant parts ( Table１ ) . PC１ clearly separated some grazed parts of Junellia ( leaves and one‐year bud) due to higher C３３ and C３５ f rom grass spikesand Lathy rus , due to higher C２７ and C２５ . PC２ clearly separated Hordeum due to lower C２９ and C３１ from other grasses( Rytidosperma , F . py rogea , Stip a and Poa) . Leaves and spikes in grasses showed contrasting alkane patterns , which is inline with other reports .　 　 Figure 1 Covariance bip lot o f alkane patterns .Table 1 Correlation o f alkanes w ith f irst twop rincipal components .alkanes PC１ 谮PC２ "C２３ ‐０ k.３８ ‐0 吵.65C２５ ‐0 k.47 ‐0 吵.55C２７ ‐0 k.76 ‐０ 吵.０７C２９ ‐０ k.４２ 0 い.77C３１ ０ \.１０ 0 い.68C３３ 0 \.97 ０ い.０３C３５ 0 \.78 ‐０ 吵.３１Conclusions Differences in alkane patterns betweenspecies and plant parts encourage further studies toevaluate the scope of the alkane technique to aid inthe estimation of diet composition and forage intakein the Patagonian steppe .ReferencesAitchinson , J . ( １９８６) The Statistical A nalysis o f Compositional Data . Chapman and Hall . London , UK .Bakker , M .L . and Alvarado , P . I . ( ２００６ ) Alcanos de la cera cuticular de hojas de Populus alba , Populus deltoides( Salicaceae) , Robinia pseudoacacia ( Fabaceae) , Ulmus pumila ( Ulmaceae ) y Fraxinus americana ( Oleaceae) en Tandil ,Buenos Aires , Argentina . Darw iniana , ４４ , ５８‐６３ .Mayes , R .W . and Dove , H . (２０００) Measurement of dietary nutrient intake in free ranging mammalian herbivores . NutritionResearch Rev iews , １３ , １０７‐１３８ .Pelliza‐Sbriller , A . , Willems , P . , Nakamatsu , V . , Manero , A . and Somlo , R . ( １９９７ ) A tlas dietario de herbí vorospatagónicos . PRODESAR‐INTA‐GTZ . Bariloche , Argentina .

Study on Alkane Patterns of Grassland Species from the Patagonian Steppe

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Study on Alkane Patterns of Grassland Species from the Patagonian Steppe

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