Developmental and Structural Section
Pabon Mora, Natalia , Litt, Amy .
The evolution of capsules and berries in Solanaceae: A histological perspective.
The occurrence of both dry and fleshy fruits (capsules and berries, respectively) in the Solanaceae provides a potential model system for studies in fruit evolution and development. Capsules appear to be plesiomorphic, and berries are derived and characterize the large Solanoideae clade. Independent evolutionary events appear to have occurred, resulting in convergent berry-like fruits (e.g. Cestrum) or reversals to capsule-like fruits (e.g Datura). Berry development in Solanaceae has been well characterized, and histologically fruit set of tomato has been divided in four major stages: ovary development before anthesis, cell division, cell expansion, and ripening. We examined capsule development in Nicotiana sylvestris and Petunia x hybrida (examples of typical Solanaceae capsules), comparing it to that of the “berries” of Cestrum diurnum, and “capsules” of Datura inoxa. Our results show that in general the same stages can be identified in N. sylvestris capsules, but endocarp differentiation and lignification play an important role in the change from cell division to cell expansion. They occur at the same time as the increase in ovule vacuolization and differentiation of the testa. Lignification is uniform along the endocarp, except in the septa and the main vascular bundles of the carpels, where septicidal-loculicidal dehiscence occurs. The process in Petunia is roughly similar. Although Cestrum fruits have been considered fleshy, they share several traits with capsule development. Furthermore, development of Datura “capsules” suggest that the process through which dehiscence occurs differs from that occurring in Nicotiana and Petunia capsules. These developmental pathways support patterns in fruit formation in a way congruent with phylogeny. Adult fruit morphology may still be misleading without further exploration of early events. These results provide us a basis for our continuing investigating into the identities and roles of genes involved in the development of dry and fleshy fruits in the family.
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1 - Graduate Center CUNY/ New York Botanical Garden, Plant Sciences, 200th St and Southern Blvd, Plant Research Laboratory, Bronx, NY, 10458, USA
2 - New York Botanical Garden, Institute of Systematic Botany, 200Th Street & Southern Boulevard, Bronx, New York, 10458-5126, USA
Presentation Type: Oral Paper:Papers for Sections
Location: Boulevard C/Hilton
Date: Tuesday, July 10th, 2007
Time: 8:15 AM