Pollination Ecology of Rhynchosia Heynei Wight and Arn. (Leguminosae), An Endemic Medicinal Herbaceous Shrub Species of Peninsular India

Rhynchosia heynei is an endemic shrub in dry deciduous forests of peninsular India. It is medicinally important and used locally for the treatment of different diseases. Despite its medicinal value and endemic status, no studies were made on the pollination ecology of this shrub to understand the factors leading to its endemic status. In this connection, the standard protocols were followed for the systematic study of the pollination in the Nallamalai forest of Eastern Ghats of Andhra Pradesh. The study indicated that the plant produces nectariferous bisexual flowers. The flowers were self-compatible and equipped with explosive pollination mechanism adapted for melittophily. The fruit set occurred through self and cross-pollination. Mature and dry pods dehisce explosively to disperse seeds. Regeneration occurred through perennial root stock and seeds during rainy season but the regeneration rate is poor due to rocky and dry habitat with little moisture and nutrient content. Journal of Institute of Science and Technology Volume 22, Issue 2, January 2018, Page: 32-44

Reproductive Ecology of Bruguiera cylindrica (L.) Bl. (Rhizophoraceae), A True Viviparous Mangrove Tree Species in Coringa Mangrove Forest, Andhra Pradesh (India)

Bruguiera cylindrica (L.) Bl. bloom during September-March. It is hermaphroditic, protandrous, self-compatible and facultative xenogamous. The flowers possess an explosive pollination mechanism and are pollinated by bees and wasps. The pollination mechanism is characterized by special petal-stamen configuration in which each petal encloses two stamens and becomes tensed after anthesis. Each petal behaves independently and the explosion of all petals of a flower requires one or two visits. Individual flowers produce only one seed which produces seedlings on the maternal plant. The seedlings use self-planting strategy at low tide and stranding strategy at high tide. Both strategies are useful for regeneration in maternal environment and in areas away from material environment.

Pollination ecology of Rhynchosia cana (Willd.) DC. (Fabaceae), an erect sub-shrub, in peninsular India

Rhynchosia cana is a perennial erect sub-shrub. It flowers during November-January with peak flowering in December. The flowers are hermaphroditic, nectariferous, self-compatible and display explosive pollination mechanism adapted for pollination by bees. They do not fruit through autonomous selfing, but rather through manipulated selfing, geitonogamy and xenogamy mediated principally by bees and occasionally by lycaenid butterflies. In the localities of this herb, weeds such as Hyptis suaveolens (Lamiaceae) and Chromolaena odorata (Asteraceae) show luxuriant growth and flower simultaneously, and their intense flowering and high flower density ensures that most flower-visiting insects visit their flowers. In this situation only two bee species, Nomia and Anthidium exhibited fidelity to R. cana flowers. Un-tripped flowers fall off while tripped ones set fruit. In open-pollinations, fruit set was 81% and seed set was 54%. Seed dispersal occurs by explosive pod dehiscence. Perennial root stock resurrects back to life and restarts its reproductive cycle during the rainy season. Seeds also germinate at the same time but their continued growth is subject to the availability of soil moisture content. This study suggests that R. cana is unable to compete with the co-flowering weed species for pollinators, and also has regeneration constraints due to nutrient-deficient rocky habitats with prolific growth of weeds.

REPRODUCTIVE ECOLOGY OF BIRDVILLE INDIGO, INDIGOFERA LINNAEI ALI. (FABACEAE)

Indigofera linnaei, a low ground herb is an important species of herbaceous cover. It forms extensive mats of populations carpeting the soil. But, it is not known how it is able to increase its population size and spread into other areas. The knowledge of its reproductive ecology is important to understand its reproductive capabilities and evaluate its use in eco-restoration initiatives. The study aims to provide information on its reproductive ecology. I. linnaei flowers are papilionaceous, bisexual, monostylous, weakly protandrous, self-compatible, facultatively xenogamous and possess explosive pollination mechanism. High winds, high temperature and heavy rain trip the pollination mechanism and effect only selfing while bees and lycaenid butterflies trip pollination mechanism and affect both selfing and outcrossing. Thrips use the flower buds for breeding, emerge during anthesis and pollinate the flowers by feeding on pollen and nectar. The fruit is a pod which dehisces explosively to disperse seeds; long distance dispersal is facilitated by their irregular shape, oily nature, and carried away by wind and rain water. Therefore, ballistichory, anemochory and hydrochory are the functional modes of seed dispersal that enable the plant to invade and colonize especially open, sandy dry areas. The plant provides food for certain local insects and protects the soil cover with its clustered root system and spreading form of multi-stemmed branching pattern. Therefore, I. linnaei has the potential for use in the restoration of destroyed, degraded and damaged habitats.Journal of Institute of Science and TechnologyVolume 22, Issue 1, July 2017, Page: 84-93