Abstract Detail

Reproductive biology

Blake-Mahmud, Jennifer [1], Struwe, Lena [2].

Late season changes in sex expression in striped maple, Acer pensylvanicum (Sapindaceae).

In plants sex is usually a fixed trait: while the environment may modulate sex allocation in some species, the individual’s sex remains constant. However, in some situations, a plant may change gender during its lifetime. The change from one primary gender phase to another phase, diphasy, is most commonly attributed to developmental changes in size. A better understanding of the mechanisms influencing gender plasticity is important to our understanding of theory regarding sex allocation and the evolution of dioecy.
One of these rare sex-changing species is striped maple (Acer pensylvanicum; Sapindaceae), which grows at higher elevations along the Appalachian mountains. Unlike other documented diphasic species, a striped maple tree can change sex repeatedly over its lifetime. Amongst five study populations located in New Jersey, approximately one in four trees exhibited a change in sex expression between flowering seasons. The most common transition was from male to female, while non-reproductive trees that became reproductive the following year changed exclusively to male. Among trees that maintained their sex expression, males were most likely to remain male in the second year. Of trees dying of natural causes, almost all were female before dying.
The mechanisms causing changes in sex expression in striped maple are poorly understood. Preliminary data suggest that both size, injury, and carbohydrate reserves may impact the frequency and direction of gender change. The switch in sex expression from male to female correlates with increased carbohydrate reserves the winter immediately prior to flowering and with decreased health. Furthermore, forced flowering studies indicate that the final sex of a flower is determined within one month of flowering, in contrast to most woody perennials which set buds the previous year. The combination of sexual plasticity and late-developing buds suggest that striped maple may remain receptive to environmental sex-determining cues through early spring. The resulting changes in in sex ratios may change mortality rates, seed set, and persistence of striped maple and the recruitment of other desirable hardwoods witch striped maple commonly suppresses.

1 - Rutgers University, Ecology, Evolution, And Natural Resources, 237 Foran Hall, 59 Dudley Rd, Cook Campus, New Brunswick, NJ, 08901-8551, USA
2 - Rutgers University, Dept of Ecology, Evolution, and Natural Resources & Dept of Plant Biology and Pathology, 59 Dudley Road, New Brunswick, NJ, 08901, USA

Keywords:
sexual plasticity
diphasy
Reproductive Biology
sex allocation
sex ratios
Maples.

Presentation Type: Oral Paper
Session: 42, Reproductive Biology
Location: 205/Savannah International Trade and Convention Center
Date: Wednesday, August 3rd, 2016
Time: 10:15 AM
Number: 42001
Abstract ID:852
Candidate for Awards:None