PALM S Tucker Lima: Attalea Flower Color Vol. 53(4) 2009 Flower Color JOANNA M. T UCKER LIMA School of Natural Resources Variation in and Environment University of Florida Attalea PO Box 110410 Gainesville, FL 32611-0410 USA phalerata [email protected] (Arecaceae) Over the past few years, I have been conducting a phenology study of the arborescent palm Attalea phalerata Mart. ex Spreng. in southwestern Amazonia. Although botanical records have consistently reported yellow flowers on A. phalerata inflorescences, I observed multiple cases of non-yellow staminate flowers. Flower color varied from dark purple to violet, or a mixture of yellow- orange to magenta flowers within the same male inflorescence (Fig. 1; hereafter I refer to non-yellow flowers as purple). This article reports on field observations of flower color polymorphism in A. phalerata and discusses possible explanations for this anomaly. Field observations the number of sides of the palm crown directly exposed to sunlight (four lateral sides plus top) Phenology (Bechtold 2003). Within old-growth forest, A. phalerata is mainly a lower canopy palm. I monitored flowering phenology of Attalea phalerata in Acre, Brazil, between January 2006 Attalea species alternate between pistillate, and December 2007. Using binoculars, I staminate, and sometimes hermaphroditic observed flowering from the ground at inflorescences on the same plant. During 24 monthly intervals at six study sites (three months of observations of 72 A. phalerata actively grazed pastures and three areas of old- palms, I registered only four instances of growth tropical moist forest). At each site I hermaphroditic inflorescences. The remaining observed 12 reproductive palms. Between July inflorescences were either exclusively pistillate to December 2007, observations were reduced or exclusively staminate. The majority of A. to two sites per habitat. For each individual I phalerata staminate inflorescences initiated recorded sex and reproductive phase of all flowering at the beginning of the dry season inflorescences – closed inflorescence buds between May and June, peaked in September (bracts), inflorescences in anthesis (open at the end of the dry season, and dwindled flowers) and dried, post-anthesis inflorescence during the wet season (Fig. 2). Palms growing structures. I also categorized crown illumi- in old-growth forest were more likely to nation on a scale of zero to five by counting suspend inflorescence production for a short PALMS 53(4): 197 –203 197 PALM S Tucker Lima: Attalea Flower Color Vol. 53(4) 2009 1. Color variation from yellow to dark purple in Attalea phalerata staminate inflorescences observed in eastern Acre, Brazil. period each year between February and April, Flower color variation whereas pasture palms produced inflorescences continuously year-round. Still, pasture palms To my surprise, of 55 male inflorescences mimicked the overall seasonal patterns of observed in anthesis, the majority (55%) flowering peaks and lulls in the forest. produced purple flowers rather than the 198 PALM S Tucker Lima: Attalea Flower Color Vol. 53(4) 2009 1. ( continued ) Color variation from yellow to dark purple in Attalea phalerata staminate inflorescences. familiar yellow flowers. During two years of different palms). Some A. phalerata individuals monthly phenological observations, I recorded alternated between purple and yellow flowers, 19 purple staminate inflorescences in anthesis while a few palms (n=5) repeatedly produced in pastures (on 15 different palms) and 11 in purple flowers. Of the 22 A. phalerata forests (on nine different palms). Over the individuals with purple flowers, more than same two-year period, I observed 14 yellow half (n = 12) also produced the better known staminate inflorescences in pastures (on 12 yellow flowers either before or after a purple different palms) and 11 in forest (on ten flowering event, indicating phenotypic 2. Proportion of Attalea phalerata palms with staminate inflorescence and monthly rainfall from January 2006 until December 2007 in pastures and old-growth forests in Acre, Brazil. Old-growth forest Pasture RAINFALL (mm) 0.50 400 2006 2007 0.45 350 h e t 0.40 ) i c n 300 w m e s 0.35 m c ( s m l l l e 250 a r 0.30 a f p o l n f f i a o n I 0.25 200 R n e t y o l i a t 0.20 h r n 150 t i o n m p 0.15 o a o t r 100 M S P 0.10 50 0.05 0.00 0 l l t t r r r r v v n n n n b g p b p c g y c y u u c c p p a a o o a u u a e e u e e a u a e e J J A J J A J J O N O N F M F M D A S D S A M M Month 199 PALM S Tucker Lima: Attalea Flower Color Vol. 53(4) 2009 3. Purple coloration of petal tips on flowers of an Attalea phalerata pistillate inflorescence in eastern Acre, Brazil. plasticity within individual palms. In one case, 1). Most flowering anthesis events occurred a single palm exhibited one yellow and one between observation visits, and for these I was purple inflorescence simultaneously. Both unable to determine flower color. yellow and purple inflorescences were Color polymorphism in palms observed in anthesis, and the colors remained constant as they developed. I also observed Flower color polymorphism in plants is purple coloration at the tips of creamy yellow common in nature and appears within genera, petals of A. phalerata pistillate flowers (Fig. 3), within species, and even within isolated but only three pistillate inflorescences were populations. Several examples from observed in anthesis during the entire study herbaceous and other short-lived plants, both period. wild and cultivated, exist in the research literature (Armbruster 2002). Larry Noblick Staminate flower color variation occurred not (pers. comm.) detected flower color variation only within and among individual palm trees, between yellow and magenta in Attalea palms but also in both the wet (November to April) near Corumba, Mato Grosso do Sul, Brazil, in and dry seasons (May to October), across the Pantanal region, but to my knowledge no different habitats (pasture and forest), and on records of within-species color variation in a regional scale dispersed over 100 km 2. Purple palm inflorescences have been published. flowers appeared at various times throughout the year, although mostly during the dry Palms, such as the lipstick palm, Cyrtostachys season, which corresponds to the peak renda , with its bright red crown shaft, Geonoma flowering season of A. phalerata (Fig. 2, Tab. epetiolata, with reddish purple underside of 200 P A L M S Table 1. Number of yellow and purple-shaded staminate inflorescences of Attalea phalerata observed in anthesis in pasture and old-growth forest during monthly visits in (a) 2006 when I observed 36 reproductive individuals in pastures and 36 in old-growth forests, and (b) 2007 when I observed 36 individuals in each habitat until June and 24 in each habitat from June-December. (a) 2006 J F M A M J J A S O N D TOTAL Purple-shaded (no. palms=11) 0 0 0 0 1 3 0 3 2 0 2 2 13 PASTURE Yellow (no. palms=9) 1 0 0 0 0 1 1 1 0 2 2 1 9 Purple-shaded T OLD-GROWTH u (no. palms=6) 0 0 0 0 0 1 0 2 2 0 1 1 7 c k FOREST e Yellow r L i (no. palms=4) 0 0 0 0 0 1 0 1 0 1 1 1 4 m a TOTAL 1 0 0 0 1 5 1 7 4 3 6 5 33 : A t t a l e a (b) 2007 J F M A M J J A S O N D TOTAL F l o Purple-shaded w (no. palms=4) 0 1 1 0 0 0 0 0 3 1 0 0 6 e r PASTURE C Yellow o l o (no. palms=5) 0 0 0 1 0 0 0 3 1 0 0 0 5 r Purple-shaded OLD-GROWTH (no. palms=4) 0 0 0 0 1 1 0 0 0 0 2 0 4 FOREST Yellow (no. palms=7) 0 0 0 0 0 0 0 3 2 1 1 0 7 V o l . TOTAL 0 1 1 1 1 1 0 6 6 2 3 0 22 5 3 ( 4 ) 2 2 0 0 0 1 9 PALM S Tucker Lima: Attalea Flower Color Vol. 53(4) 2009 young leaves (Blanco & Martén-Rodríguez to deter pollinators. Further research may help 2007), and various palm genera with purple determine if purple staminate flowers fruits (e.g., Euterpe , Bactris , Butia , Coccothrinax ), negatively affect fertilization, fruit set and testify to widespread anthocyanin production reproductive success in A. phalerata . within Arecaceae. Anthocyanins (a flavonoid Associations between anthocyanins in sub-group) are responsible for most orange, vegetative organs and flowers and environ- red, purple and blue flower colors and occur mental stresses may also help explain flower in almost all vascular plants (Grotewold 2006). color variation in A. phalerata . In vegetative Harborne et al. (1974) found flavonoid organs, plants manufacture anthocyanins to pigments (glycosides) specifically in the flowers protect against environmental stresses, such of ten different palm species, and a few studies as herbivory (Fineblum & Rausher 1997), have identified other types of flavonoids in photo-damage (Close & Beadle 2003) and the vegetative structures of Attalea and other drought (Levin & Brack 1995). Plants also cocosoid palm species (Williams et al. 1983, synthesize pigments in response to extreme Williams et al.