Floral biology, pollination biology, and breeding mechanisms reveal challenges to the restoration of Buchanania lanzan, a vulnerable plant species

Abstract

Understanding a species' reproductive biology, which encompasses floral biology, pollination biology, and breeding system, is necessary for the restoration of endangered plant species. Buchanania lanzan is a vulnerable evergreen tree in IUCN Red Data Book due to excessive deforestation and over-exploitation. Light and scanning electron microscopy and histochemical analysis were used to study floral and pollination biology. Experiments were conducted to study floral and pollination biology, including pollen viability, stigma receptivity, and pollen-pistil interactions. Bisexual, pentamerous, complete yellowish-white flowers have an annual growth of 11 months and are arranged in terminal and axillary panicles. Anthers dehisce between 10.30 and noon, 9–10 h after anthesis. Stigmas were receptive at the time of anther dehiscence and remained receptive for two days. The flowers contain sucrose-rich nectar and emit a mild scent to attract visitors, including Musca domestica, Apis cerena indica, and black ants. None of these visitors appeared to be an effective pollinator. The results of pollination trials showed that the species outcrosses with low levels of selfing. Cross-pollinated flowers had a higher percentage of fruit sets (74.4 %) compared to self-pollinated (43.4 %) and open (3 %). The index of self-incompatibility (ISI) indicates partial self-incompatibility. Due to the probable loss of pollinators or the lack of efficient pollinators, the natural population of B. lanzan has not yet been restored. To achieve the required fruit or seed set cross-pollination facilitated by humans would be a feasible technique. Therefore, to prevent the extinction of this species, human management is required in terms of cross-pollination. As a result, the scientific knowledge produced by the current study may prove helpful in various breeding initiatives and the preservation of this medicinal plant species. Further, this knowledge forms the basis for taking measures for the conservation and management of forests.