Polianthes Tuberosa as Edible Flower: In Vitro Propagation and Nutritional Properties

Abstract

Tuberose (Polianthes tuberosa) is a bulbous species belonging to Asparagaceae family, characterized by a very high ornamental value, pleasant flower scent and taste. For all these reasons, flowers are currently used to produce perfumes or valorized as actual ingredient of different recipes, since they are completely edible. P. tuberosa is one out of 40 species studied in INTERREG ALCOTRA “ANTEA” project, which aim is to extend the use of edible flowers as functional food and enlarge the number of the species used for the supply chain of the edible flowers. Fresh flowers were analyzed in order to characterize them from the nutrition point of view. They show good polyphenols content and antioxidant activity (DPPH assay), while flavonoids, anthocyanins and carotenoids amounts are low. On the other hand, P. tuberosa flowers can be a real source of vitamin C, because of the high quantities of this molecule in the petals. Soluble sugars are present in small amount. High quantities of P. tuberosa flowers are difficult to obtain due to low bulb multiplication rate and poor seed germination. For these reasons, in vitro culture was performed to facilitate plant propagation. Bulbs were surface-sterilized for 30’’ in ethanol 70 % and then for 20’ in NaClO 2.5 % solution, while seeds were surface-sterilized for 20’in NaClO 1 % solution. Both were rinsed twice with autoclaved distilled water for 10 minutes after sterilization. The bulbs were cultured in jars containing MS agarized substrate enriched with 3% sucrose, 1.5 mg/L BA, 0.5 mg/L IAA and 0.7% agar (pH 5.8). Seeds were germinated in Petri dishes with agar-water substrate and then 14 different clones were selected and cultured in jars. The multiplication rate of the clones was very variable but some of them reached a good multiplication rate.