Flowering nectar secretion and pollinators activity of Camellia perpetua in different seasons, a perpetual flowering plant in south China

Camellia perpetua is a rare and unique species in the karst regions in Guangxi of south China, it is a rare camellia group that blooms almost all year round and its peak flowering period is in summer. To understand the rhythm of nectar secretion and the pattern of pollination of this species in different seasons, and exploring the influence of composition and amount of nectar on the behavior of its pollinator species. The average amount of nectar a single flower of C. perpetua was 129.14 ± 4.48 μL in the summer and sugar concentration was 25.77 ± 5.94%, which was 453.66 ± 4.67 μL and 25.77 ± 5.94% in winter, respectively. The rhythm of nectar secretion showed that less nectar was secreted during the day, much more nectar was secreted during the evening and night. The nectar was sucrose dominant in summer and winter, and composed mainly of sucrose, glucose and fructose. There were 18 types of amino acids in C. perpetua in summer, with a total of 1,317 ± 23.68 μg·mL-1, and 9 types of amino acids in winter, with a total of 530 ± 15.96 μg·mL-1. The bee pollinators visited the flowers more frequently in the summer than in the winter, while the birds visited the flowers more frequently in the winter. The change of pollinators’ adaptive behavior may be related to nectar production, sugar concentration and amino acid type and content in different seasons.