Xylose in the nectar of Puya raimondii (Bromeliaceae), the Queen of the Puna

Abstract

1. Subject and sourcePuya raimo ndii Harm s is the largest bromel iad in the world, reachin g up to 12 m in height (F oste r,1950; Hornung-Leoni and Sosa, 2005 ). It gro ws at high altitudes in the Puna of scatte red loca tions in the Ande s of Peru and Boli viaand is kno wn as the OOQueen of the PunaO O (Raimondi , 1874 ; Smith and Do wns , 1974 ). Only a few plan ts of everypopulation of this monocar pic species produc e insoresc ences in a given year or even in a period of 2 or 3 year sand plan ts take from 80 to 150 year s to s ower (F oster ,1984; Benzing, 2000; Hor nung-Le oni and So sa, 2004 ). Nectarof P. raimondi iwas collec ted in two areas of Peru to determin e quantity ,sugar concentr ation and com position. Theywere Huascar a«n P ark, in the OOCordil lera BlancaO O (around 6000 m); and Canchay llo, in the OOCordil lera Ne graO O(3600 e 4100 m), 147 km from Lima. In Huascar a«n three indi vidua ls from four populations were blooming, inCanchay llo only one plant was bloomi ng. V oucher speci mens hav e been deposit ed in Peru at the USM herba rium(Hornun g 1118; Hor nung 1120 e 1126).2. Pre vious wor kPre vious studies of nect ar in bromelia ds sho wed difference s in sugar conce ntration (8.2 e 45.2% ) and volume(0.06 e 43.2 ml) in species such as Dyckia ragones ei, Puya alpes tris and Puy a soccosa (Galet to and Bernard ello,1992; Scogi n and Freeman ,1984; Ba ker and Ba ker ,1990 ). In Puya ,differences in nectar com position hav e repor tedthat in species of subgen us Puya ,the nectar is dominated by hexoses (glucose and fructose) and in speci es of subgen usPuyopsi s the nect ar is dominated by sucr ose (Scog in and Freeman , 1984 ; Baker and Baker , 1990 ). In P. raimondi i,which belongs to subgen us Puy a,a sugar ratio (Sucrose/ Glucose ! Fruct ose) of 0.05 was reporte d, while P. soccosafrom subgen us Puyopsi s a sugar ratio of 1.13 was accou nted (Baker and Ba ker , 1990 ). Ho we ver , analyses with thinlayer chrom atograph y or gas chromatogr aphy hav e never been conduc ted in the nect ar of P. raim ondii to determ ineother sugars in the nectar in addi tion to sucr ose, glucose or fruc tose.