TITLE:
Somatic Polymorphism Variation in Crotalaria retusa L. Seeds
AUTHORS:
Paulo Sérgio de Figueiredo, Natale M. Lindoso Silva
KEYWORDS:
Somatic Polymorphism, Phenols, Seed Coat Impermeability, Chemical Defenses, Predation
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.9 No.1,
January
11,
2018
ABSTRACT: The article describes the somatic polymorphism in Crotalaria retusa L. seeds. Each individual may produce yellow dormant seeds, brown
quiescent seeds and unviable dark brown ones. Therefore, regarding physiology
it is a dimorphism. We show that
autogamy reduces dimorphism, favoring the formation
of dormant seeds. However, the significant variation in dimorphism is
seasonal as consequence of increased viability of dormant seeds under drier
weather conditions. The
variation is a phenotypic response to changes of humidity in the environment
during plant reproduction, a mechanism inducing the prevalence of dormant seeds
in the dry season and
quiescent seeds during the rainy season. The seasonal alternation between
dormancy and quiescence in seasonally dry environments has an apparent adaptive
value. The chromatic polymorphism increases on the more humid coast and during
the rainy season, due to increased mortality of dormant seeds under wetter
weather conditions. Unviable seeds accumulate oxidized phenols in their seed
coat that possibly act as induced chemical defenses. Its proportion increases
with humidity, accentuating polymorphism, also in response to the increase in
the predation rate by larvae of U.
ornatrix during the rainy season.