Biology and bulb production of Eleutherine bulbosa (Iridaceae), a native species from Borneo, Indonesia

Abstract

Abstract Eleutherine bulbosa is a known ornamental plant of the Iris family, which originated from Central Borneo, Indonesia. The bulbs of E. bulbosa have long been used as a medicinal source by the local people of Borneo. Despite its known medicinal and other values, studies on the morphology and efficiency in bulb production of this species are limited. The aims of our study are to examine the vegetative and reproductive morphology of E. bulbosa, and to determine the effect of various dosages of NPK fertilizer on flowering and bulb production. The plants were grown in pots using potting mix consists of equal volume of burnt rice hulls, cocopeat, and organic manures (1:1:1). Our study showed that E. bulbosa has a cymose rhipidium inflorescence with 25-50 mm long peduncles, have 3-4 umbel on the secondary axis, each consists of 10-12 florets that opens in turn every day. Florets are 20-30 mm long, 20 mm in diameter, 10-15 mm pedicels, and short-lived. The perianth is white, about 25 mm wide with yellow anthers and stigma. Fruits were not formed during the duration of the study. NPK fertilizer application at the lowest dose of 1 g per pot had promoted earlier shoot emergence and vegetative growth, including plant height, leaf number, leaf size, number of tillers, and bulb production compared to control (no fertilizer). Application of fertilizer at 1 and 2 g per plant significantly promoted earlier flowering, whereas application at 3 g per plant delayed and reduced the proportion of flowering plants. The results of this study can aid in taxonomic identification and efficient cultivation of this plant for uses as potted flowering ornamentals or bulb production for different purposes. Higher cultivation and reduced wild harvesting can result in the conservation of this species.