Ontogeny of fruits and seeds of Passiflora species (Passifloraceae - subgenus Decaloba (DC.) Rchb. section Xerogona (Raf.) Killip)

Author(s)

Juliana Foresti Milani

• Document type: Doctoral Thesis
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Instituto de Biologia
• Defense date: 2014-08-27

Examining board members

Sandra Maria Carmello Guerreiro; Michaele Alvim Milward de Azevedo; Letícia Silva Souto; Simone de Pádua Teixeira; Juliana Lischka Sampaio Mayer

• Advisor: Sandra Maria Carmello Guerreiro

Abstract

External and internal morphology of Passifloraceae Juss. ex Roussel fruits and seeds is little known or even unknown for many species. Morphological and anatomical studies of fruits and seeds have great importance since they exhibit little phenotypic plasticity. In this context, this study aimed to elucidate the fruit and seed ontogeny of four species of Passiflora L. Decaloba (DC.) Rchb. subgenus Decaloba (DC.) J.M. Macdougal & Feulliet supersection Xerogona (Raf.) Killip section that present capsule type of fruit, unusual condition in the family. For this, the plant material were collected and processed according to conventional techniques for light and electron microscopy; specific technique (TUNEL) were also applied to detect programmed cell death in the stage of fruit dehiscence. Four developmental stages were established: Stage I: Ovary and ovule; Stage II - fruit and seed in early development: frequent cell divisions; Stage III - young fruit and young seed: cell elongation; Stage IV - mature fruit and mature seed: cell differentiation and fruit dehiscence. In the stages II to IV of the fruit, epicarp and endocarp are unistratified and major changes from the development of the fruit occurs on mesocarp. During the development, the intercellular spaces increase from the endocarp towards the epicarp. There is no line of dehiscence. The intercellular spaces occur due to programmed cell death forming gaps that breaks the pericarp. Histochemical test indicated the presence of phenolic compounds and idioblasts containing proteins in fundamental tissue of ovary and mesocarp. The seeds of all species were bitegmic. The testa consists of two layers: exotesta and endotesta. The tegmen is composed of three layers: exotegmen, mesotegmen and endotegmen. At the beginning of seed development, aryl of funicular origin, formed by parenchyma cells that may containing phenolic compounds and starch, was observed. The development of the integument of the seed occurs by differential cell elongation of exotegmen and endostesta. This process results in a ruminate endosperm. In the mature seed, the outer integument forms the sarcotesta. At this stage, the exotegmen is the mechanical layer formed by macrosclereids in palisade, representing esclerotesta. Information found in this study reveals that morphoanatomical characteristics of fruit and seed are quite conserved and unified in the section. Given that, we highlight the importance of further studies including more species and addressing the evolution of characters and adding new ones to facilitate the elucidation of infrageneric relationships in Passiflora which has been expanded due to the cooperation of morpho-anatomical and genetic studies (AU)

• FAPESP's process: 10/01779-3 - Fruit and seed ontogeny of Passiflora species (Passifloraceae- subgenus Decaloba (DC.)Rchb. -Section Xerogona (Raf.) Killip
• Grantee: Juliana Foresti Milani
• Support Opportunities: Scholarships in Brazil - Doctorate