植物生态学报 ›› 2003, Vol. 27 ›› Issue (1): 111-117.DOI: 10.17521/cjpe.2003.0017

• 论文 • 上一篇    下一篇

木瓜榕传粉生物学

彭艳琼, 杨大荣, 周芳, 张光明, 宋启示   

  • 发布日期:2003-01-10
  • 通讯作者: 彭艳琼

Pollination Biology of Ficus Auriculata Lour.in Tropical Rainforest of Xishuangbanna

PENG Yan-Qiong, YANG Da-Rong, ZHOU Fang, ZHANG Guang-Ming, SONG Qi-Shi   

  • Published:2003-01-10
  • Contact: PENG Yan-Qiong

摘要:

木瓜榕(Ficus auriculata Lour.)是雌雄异株植物,它只有通过大果榕小蜂(Ceratosolen emarginatus Mayr)传粉才能获得有性繁殖,大果榕小蜂也仅在木瓜榕雄果内产卵才得以繁衍后代。经两年来的实验和研究结果表明:木瓜榕繁殖能力在不同季节随进蜂量的多少而变化,雌树在4月和11月出现的两次结果高峰期与进蜂量最多的时期相遇;同时雄树与雌树在11月挂果高峰期重叠,导致该期进入雄果产卵的雌蜂量减少,进蜂量高峰推迟到部分雄果成熟、只有稀少接受果的3月下旬和4月上旬。木瓜榕在与大果榕小蜂互惠共生的进化历程中,逐渐完善了自身保证远交的繁殖机制,它们在不同程度上受到雌雄异熟、雌雄异株和短花柱雌花不亲和3种机制的共同作用。温湿度对大果榕小蜂访果行为有明显的影响,在温湿度变化缓和的早晚,有利于榕小蜂出行,雌蜂访果最为频繁。大果榕小蜂活动最佳的温湿度是:温度20~24 ℃之间、湿度85%~93%之间;温度高于29 ℃、湿度低于58% 或风雨天均不利于该蜂出行活动。榕小蜂日活动高峰的出现先后在不同季节略有差异,高温高湿的夏季榕小蜂活动出现早,7∶40达高峰;秋季榕小蜂活动推迟,高峰出现在11∶00;干凉的冬季最晚,13∶00才到达高峰。通过人工套袋、放蜂传粉试验,平均进8头的隐头果传粉效率最高,单果平均种子数量为11 247粒,结实率50.8%,未受精的败育花8 207朵;平均进蜂4头以下或10头以上的隐头果,由于花粉量不足或者雌蜂争夺资源的损伤使种子量下降,平均结实率分别达37.2% 和44.4%;放蜂试验结果与大量调查自然界中每果进蜂量和结实率的结果一致。

Abstract:

Ficus auriculata Lour. is a widely distributed and common species in the tropical rainforests in Xishuangbanna, China. The pollination of Ficus auriculata is done by Ceratosolen emarginatus Mayr, their unique symbiotic associates. The fig-pollination wasps cannot develop anywhere except in the host syconia, and so both are highly co-evolved mutualists that depended completely on each other for propagation. The present paper reported on the growing character of syconia and flowering phenology of Ficus auriculata, as well as the pollination behavior, regularity of fig visitation and pollination efficiency of Ceratosolen emarginatus based on our observations in the rainforests of Xishuangbanna, southern Yunnan, China. Ficus auriculata is a dioecious plant that bore fruit all year round in the population, with two fruit-bearing peaks on the female trees and one fruit-bearing peak on the male trees. The male trees produced pollen and provided fig wasps with havens, while the female trees produced fig seeds after pollination by fig wasps. The reproduction of Ceratosolen emarginatus varied with foundress number of females entering into a syconium in different seasons. The fruit-bearing peaks of female trees appeared from April to June and from September to November each year, and foundress number per syconium also peaked during these periods. Male trees bore the most fruits in January, however, due to the number restriction of fig wasps, the foundress number entering into a male syconium was low; its peak was postponed between 25th of March and 10th of April, when some syconia had matured. In order to ensure reproductive success, Ficus auriculata has evolved three out-breeding mechanisms: dichogamy, gynodioecy and incompatibility of short-style female flower. Ceratosolen emarginatus visited syconia when female flowers were blossoming, and entered into the fig cavity to lay eggs or pollinate pollen. The fig wasps’ behavior of visiting syconia was controlled by temperature and humidity: the fig wasps actively visited receptive syconia when temperature and humidity varied mitigatively in the morning and afternoon; few fig wasps flew at noon. The optimum temperature was 20-24 ℃ and optimum humidity was 85%-93%. The fig wasps stopped hovering if the temperature was over 29 ℃, humidity was less than 58% or the weather was windy and rainy. The visiting peak of fig wasps appeared at different times in four seasons, it appeared at 10∶00 in spring, 7∶40 in summer, 11∶00 in autumn and 13∶00 in winter. The pollination efficiency of Ceratosolen emarginatus was examined by introducing eight, ten and fifteen fig wasps to a female syconium. The pollination ratio was the highest when mean eight fig wasps enter into a syconium. The mean percentage of seed was 50.8%. Mean seed ratio reached 37.2% if only four foundresses pollinate a syconium and 44.4% with ten foundresses. The result showed no difference with natural syconium of the same foundress number.