西双版纳热带雨林优势植物假海桐的花气味及传粉昆虫多样性

Floral Scent and Insect Pollinator Diversity of Pittosporopsiskerrii-the Dominant Tropical Plant Species in Xishuangbanna Rainforest

指出了假海桐(Pittosporopsis kerrii)是西双版纳热带雨林林下的优势植物,为探讨其花气味及传粉昆虫多样性,针对其开花特性、花气味及访花昆虫进行了相关研究。结果表明:假海桐开花早,种群内花期持续时间长,主要集中在2～3月份,单花期3～4d,单株盛花期8～10d。访花昆虫54种,大蜜蜂(Apis dorsata)是最为优势的传粉昆虫。鉴定出花气味的13种化合物,主要由萜类、脂肪酸衍生物和芳香族化合物三大类构成,含量最高的是α-甲基-α-[4-甲基-3-戊烯基]环氧乙烷基甲醇。传粉后花气味中没有化合物消失,但有2种化合物含量显著减少、3种化合物含量显著增加,并新增1种化合物。深入研究传粉前后含量变化大,对优势传粉昆虫具引诱活性的化合物,有助于揭示林下假海桐的传粉繁殖特点,为热带雨林物种保护提供依据。

Pittosporopsiskerriiis the dominant species in the understory of Xishuangbanna tropical rainforest. In order to understand the floral scent and insect pollinator diversity of Pittosporopsiskerrii,the flowering characteristics and insect visitors of P. kerriiwerewas observed.Meanwhile the floral volatiles emitted by P. kerrii were collected to analyzechemical compounds by gas chromatography-mass spectrometry (GC-MS). The results showedthat the flowering duration of P. kerrii sustained for a long time, mainly in February to March.The individual flowering period lasted for 3-4 days, and the peak flowering duration per tree lasted for 8-10 days. 54species of insects visiting flowers of P. kerrii were observed in Xishuangbanna tropical rainforest. The giant honey bee (Apisdorsata) is the dominant pollinator according to the highest visiting frequency. Furthermore, the dynamic headspace technique was used to collect the volatiles emitted by P.kerrii before and after pollination. The components and the relative contents of each component were identified. 13 compounds were emitted by P.kerrii which mainly consisted of terpenes, fatty acid derivatives and aromatic compounds.The component with the highest relative content wasα-Methyl-α-[4-methyl-3-pentenyl] oxiranemethanol.After pollination,there was no any component to disappear among floral scents, but 2 compounds dramatically decreased, 3 compounds significantly increased andnewly appeared 1 compound. Further study focus on the compounds with great change before and after pollination, and tests the behavioral response of dominant pollinators, whichwill contributed to reveal the biological characteristics of P.kerrii pollination and provide a scientific basis for species conservation in tropical rainforest.