Seed Structural Variability and Germination Capacity in Passiflora edulis Sims f. edulis

Abstract

Purple passion fruit, Passiflora edulis Sims f. edulis, is an important semi-perennial, fruit bearing vine originating in South America that produces a commercial tropical juice pulp for international and national consumption. Within the round purple passion fruit are a large number of membranous seed sacs each containing individual seeds.Little is known about the seed anatomy of the commercial passion fruit, differences between wild collected and commercial types, and its effect on seedling germination. Therefore, our main objective for this study was to analyze the seed anatomy variability of different germplasm as well as the effect on viability and germination of the seeds of this species. Germplasm was evaluated from three sources: (1) commercial cultivars grown in current production areas, (2) genebank accession from the national seed bank, and (3) landraces collected across different high and mid-elevation sites of the Andean region. A total of 12 morphometric descriptors related to seed anatomy were evaluated on the 56 genotypes, of which three were most informative: Angle to the vertex which is related to the shape of the seed, the thickness of the tegument and the horizontal length; separating the seed according to its source of origin. Germination was found to be positively correlated with the number (r = 0.789) and depth (r = 0.854) of seed pitting. Seeds of the commercial cultivars had more seed pits and higher germination compared to seeds of landraces or genebank accessions showing a possible effect of domestication on the crop. Interestingly, passion fruits often germinate during the rainy season as escaped or wild seedlings especially in the disturbed landscapes of coffee plantations, so some dormancy is needed but faster germination is needed for intensive cultivation. Harnessing passion fruit diversity would be useful as the semi-domesticated landraces have valuable adaptation characteristics to combine with rapid germination selected in the commercial cultivars. The variability of seed pitting with cultivars more pitted than landraces possibly resulting in faster germination may indicate that purple passion fruit is still undergoing a process of selection and domestication for this trait.

Seed morphoanatomy of the genus PassifloraL. (Passifloraceae) by scanning electron microscopy and light microscopy

“…The seeds of some Passiflora species had foveolate external and internal surfaces, a relief pattern of irregular indentations (notable depressions and cavities), which can be evaluated regarding number, perimeter and area, and can help to distinguish species. According to Castillo et al (2020), the surface of seeds where these cavities are located have thinner tegument and can capture water or permit its faster entry into and absorption by seeds, increasing the chances of germination.…”

“…Some works have been published describing the behavior of Passifloraceae seeds from their formation until germination, of which the standouts are studies of the embryogenesis of P. calcarata Mast. (Raju, 1956), the structure and development of the ovules and seeds of P. foetida (Singh, 1962), development of the aril of P. suberosa L. (Kloos & Bouman, 1980), development of the embryo sac of P. edulis (Souza et al, 2002), megasporogenesis and megagametogenesis of P. suberosa (Silvério et al, 2009), anatomy of the tegument (Cárdenas‐Hernández et al, 2011; Peréz‐Cortéz et al, 2009; Pérez‐Cortéz et al, 2005), ontogeny of fruits and seeds of five species of the genus Passiflora , subgenus Decaloba , section Xerogona (Milani, 2014); and structural variability and germination capacity of seeds of Passiflora edulis Sims f. edulis (Castillo et al, 2020). Therefore, studies of the comparative morphology and anatomy of the tegument and embryo are still scarce for Passiflora spp.…”

Insights into the Isolation, Identification, and Biological Characterization Analysis of and Novel Control Strategies for Diaporthe passiflorae in Postharvest Passion Fruit

“…Passion fruit (Passiflora cerulean L.) is a perennial, evergreen, climbing woody vine that originates from South America but is now widely cultivated in tropical and subtropical regions worldwide [1]. Brazil is the world's largest producer of passion fruit, with an annual production of 683,000 tons in 2021, covering an area of about 45,000 hectares and generating an income of about USD 286 million for farmers [2].…”

Pharmacological and Medicinal Importance of Passiflora Edulis: A Review

“…It comes from the Passiflora vine and is native to Brazil, Paraguay and Argentina. It is widely planted in especially in South America, Caribbean, south Florida, South Africa, and Asia As a member of the Passifloraceae family [2]. Few years ago, with the most effective work done on P. edulis development, passion fruit for human consumption due to the multiple eating of it's useable as a fruits, juiciness, attractive nutritional values, P.edulis give the essential health benefits [3].…”