Different strategies for breaking physical seed dormancy in field conditions in two fruit morphs of Vachellia caven (Fabaceae)

FERRERAS, ANA E.; MARCORA, PAULA I.; VENIER, M. PAULA; FUNES, GUILLERMO

SEED SCIENCE RESEARCH

CAMBRIDGE UNIV PRESS

Lugar: Cambridge; Año: 2018 vol. 28 p. 8 - 15

0960-2585

Differences in fruit morphology among or within species might indicate differences in otherregenerative traits, such as seed dormancy and germination. In species with physical dormancy(PY), environmental conditions are suggested to be responsible for dormancy breakin field. Seeds of Vachellia caven have PY. This species exhibits two fruit morphs highly representedin Córdoba forests, Argentina: one is dehiscent and the other is indehiscent. In thisstudy we performed a burial experiment with the aim to determine if the differences in V.caven fruit morphology were related to different patterns of PY break of their seeds in fieldconditions. We related these patterns to (1) environmental conditions that could influencethe loss of PY, and (2) histological features of the lens zone. Seeds of both morphs exhibiteddormancy break within 14 months of the start of the experiment, but with different patterns.The dehiscent morph showed an abrupt percentage of seeds that broke dormancy 14 monthsafter the beginning of the experiment, probably after undergoing environmental changes similarto those suggested by the two-stage softening model. The indehiscent morph showed agradual increase in seeds that broke dormancy, not clearly related to any of the environmentalvariables studied. No differences in seed coat structure of the lens zone were observed betweenmorphs. The existence of both morphs could confer the species with higher possibilities ofestablishing and coping with environmental heterogeneity. Those characteristics contributeto the understanding of the success of this species in open and disturbed environments.