From endosperm to triploid plants: a stepwise characterization of the de novo shoot organogenesis and morpho-agronomic aspects of an ornamental passion fruit ( Passiflora foetida L.)

The cellular and biochemical features associated with expression of pluripotency in endosperm cells during de novo shoot organogenesis, as well as the cytogenetic and morpho-agronomic features of regenerated Passiflora foetida triploid plants has been recently reported. Endosperms were cultured on Murashige and Skoog medium supplemented with 0.5, 0.75, 1.0, 1.5, and 2.0 mg L −1 of 6-benzyladenine, thidiazuron, or kinetin. No plant growth regulators were added to the control treatments. Morphogenetic responses were observed only in the presence of cytokinins, especially thidiazuron. The highest percentage of morphogenetic responses (27%) and number of adventitious shoots per explant (68.2) were observed with 1.5 and 2.0 mg L −1 thidiazuron, respectively. The regeneration of adventitious shoots occurred mostly from the outer face of the endosperm by cells that acquired meristematic-like features. Lipids and proteins were consumed rapidly, whereas carbohydrates increased considerably throughout the organogenic process. Cytogenetic analyses confirmed the triploid genotype of endosperm-derived plants, whose vegetative and floral structures were nearly all larger than their diploid counterparts. This study provides a complete morphological characterization of P. foetida endosperm-derived triploid plants and opens new possibilities for genetic breeding of passion fruit.