A Preliminary Study Of Pollination Biology In Three Aspidistra Species

Aspidistra(Asparagaceae)species are herbaceous perennials monocotyledon,its flowers usually growing closely to the ground and cryptic,which are covered by litter fall such as dead branches and leaves.In order to understand pollination characteristics and strategies of these,we studied pollination biology in three Aspidistra species including A.elatior,A.fimbriata and A.funguiliformis.We investigated habitats of the three species in the field,observed and recorded insect visitors' behavior on flowers,Floral traits and reflectance spectrum of each floral organ was measured,and flowering phenology was recorded.Hand pollination experiments were performed in A.elatior and A.fimbriata,We measured floral temperature(inside and outside the corolla)and collected floral scent in the three Aspidistra species.To test whether potential pollinators are susceptible to the floral odor in a given species,we examined visiting preference by a Y-type tube experiment.In A.elatior,pollination characteristics different habitats,locating in Wuhan and Guilin,were compared.The flowering period in A.funguiliformis and A.elatior(Guilin population)was in November and December,but A.elatior(Wuhan population)was in April and May,In A.fimbriata,twice flowering was observed from November to December,and from April to May.Difference in floral temperature between the corolla inside and outside in the three species was all less than 1?.Our measurement of floral reflectance showed that flowers of all two species could reflect the UV band,suggesting that they could be perceived by insects visually.Hand pollination experiments showed that the two species were all self-incompatible,fruit set depended on pollinator visits.Field observation showed that the main pollinators were fungus gnats in both A.elatior and A.fimbriata.The corolla in these two species was ajar like shaped,smell like mushroom.We speculate that they are the mimicry of the spawning ground of the fungus gnats,attracting the fungus gnats to spawn.Amounts of pollen grains available inside the corolla,provide a direct food source for the growth of insect larvae.Floral traits in A.elatior varied in Wuhan and Guilin populations,which may be related to the local habitats,but the main pollinators were fungus gnats in both sites.The wild habitat in A.funguiliformis was destroyed.A Collembola was observed to be the main flower visitor in the plant garden of Guilin,Guangxi,and the eggs and larvae of the Collembola appeared in the flowers.Although ants and other insects were observed in A.funguiliformis,their pollination role seems to be questionable.Our experiments on the odor preference of Y-tube showed that both fungus gnats and Collembola had specific preference for the floral odor of the Aspidistra species,It is first reported that Collembola functions as pollinators of Aspidistra species.The genus Aspidistra has greatly differentiated in Guangxi Province and surrounding limestone areas in South China.Due to its diverse habitats and special pollinators,Aspidistra has formed a nursing pollination system that attracts pollinators(mimicry)by smell and uses pollen as food for pollinators.Further study of chemical ecology will provide a better understanding of the reproductive strategy in Aspidistra species.