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Sexual dimorphism in gender plasticity and its consequences for breeding system evolution
1Department of Biology, Jordan Hall, 1001 E. Third Streed, Indiana University, Bloomington, IN 47405, USA. idelph@bio.inidana.edu
Evolution & Development
|December 21, 2002
Summary
Environmental conditions influence flowering plant gender development and breeding systems. Greater plasticity in hermaphrodites can shift sex ratios, potentially driving transitions between gynodioecy and dioecy, especially in harsh environments.
Area of Science:
- Plant reproductive biology
- Evolutionary ecology
- Developmental plasticity
Background:
- Flowering plants exhibit continuous gamete development, making them susceptible to environmental influences on gender expression.
- Two common breeding systems, gynodioecy (hermaphrodites and females) and dioecy (males and females), are widespread in angiosperms.
- Gynodioecy can transition to dioecy through the loss of female function in hermaphrodites or remain stable.
Purpose of the Study:
- To explore how developmental plasticity of gender impacts population sex ratios.
- To understand the influence of plasticity on the evolution and stability of dimorphic breeding systems (gynodioecy and dioecy).
- To review how environmental conditions mediate these transitions.
Main Methods:
- Review of existing studies on plant breeding systems and developmental plasticity.
- Analysis of how environmental factors affect functional gender and fitness.
- Examination of theoretical and empirical evidence for sex ratio variation and its evolutionary consequences.
Main Results:
- Environmental conditions significantly alter functional gender and fitness contributions of male and female reproductive functions.
- Greater plasticity in fruit production by hermaphrodites compared to females leads to environmentally dependent sex ratios.
- Harsh or low-quality environments are predicted to favor higher frequencies of females.
Conclusions:
- Developmental plasticity of gender is a crucial factor in the evolutionary dynamics of breeding systems.
- Environmental influences on plasticity can drive shifts between gynodioecy and dioecy.
- Understanding ecological development is key to predicting the stability and malleability of plant breeding systems.
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