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

FERRERAS, A.; MARCORA P.; VENIER, P.; FUNES, G

SEED SCIENCE RESEARCH

CAMBRIDGE UNIV PRESS

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

0960-2585

Different fruit morphology among or within species might also indicate differences in other regenerative traits ?e.g., dormancy, germination, etc. In species with physical dormancy (PY) environmental conditions are indicated as a probably responsible of dormancy brakeage in nature. Seeds of Vachellia caven have PY. This species exhibit two fruit morphs highly represented in Córdoba forests, Argentina; one is dehiscent while the other is indehiscent. In this study we performed a burial experiment through which we aim to know if the differences in fruit morphology of V. caven were related to different patterns of PY breakage in nature. Also, we related these patterns with 1) environmental conditions that could influence the loss of PY, and 2) with histological features of the lens zone. Both morphs exhibit dormancy breakage within 14 months of starting the experiment, but different patterns were observed. The dehiscent morph showed an abrupt percentage of seeds that break dormancy at fourteen months after the beginning of the experiment, probably after expending environmental changes similar to those suggested by the two stage softening model. The indehiscent morph showed a gradual increase in seeds that break dormancy not clearly related to any of the environmental variables studied. No differences between morphs in testa structure of the lens zone were observed. The existence of both morphs could confer the species with higher possibilities of establishment and cope with environmental heterogeneity. Those characteristics contribute to understand the success of this species in open and disturbed environments.