Reproductive ecology of a medicinal plant Barleria prionitis L.

Abstract

Barleria prionitis is a well-known medicinal plant. It has a global use in whooping cough bronchitis, leucoderma, toothache, inflammation and as expectorant. As observed in the field, Barleria prionitis reproduces only by seeds. Over-exploitation from wild source together with the loss of habitats due to anthropogenic onslaughts poses severe threat for sustenance of the species. Therefore, the knowledge of the reproductive ecology of any plant is most essential to formulate suitable strategies for its conservation and cultivation. Details of floral biology, pollen vectors, pollination mode, floral attractants and rewards and breading system come under the purview of pollination biology. Barleria prionitis flowers once in a year, spanning from mid-September to early-May with its peak during late-November to early-December. The species produces moderate sized, bright yellow, zygomorphic, hypogynous, bisexual, tetramerous gullet flowers. Two pairs of epipetalous stamens with hairy filaments are didynamously disposed. The estimated number of pollen grains produced per flower would be 1346 ± 75. Carpel is constituted long slender style, terminating into a pink-coloured bifid stigma and a superior syncarpous, two-chambered ovary. The species produces one day flowers. Flower opening is synchronous and gradual, Pollen dispersal starts only from the stamens with long filaments just after anther dehiscence. The bulk of pollen grains are removed from the anthers during the 1st to 3rd hour after dehiscence. 92.67% of the pollen grains are fertile. The stigma is wet in nature. The flower offers edible pollen grains and nectar as reward. Flowers are self-compatible, homogamous. Primarily allogamous- cross-pollinated by Hymenopteran insects, with co-existence of delayed autogamy overcome pollination crisis. The plant has relatively high percentage of fruit set and seed set.