福州笔管榕传粉生物学特征

Pollination Biology of Ficus superba var. japonica in Fuzhou

【目的】研究福州笔管榕传粉生物学特征,为城市绿化和热带雨林生物多样性保护提供数据和科学支持。【方法】以福州地区的30株笔管榕为样本,对其传粉生物学进行研究。【结果】1）笔管榕不同植株的年结果批次不同（每年每株0-5批次）,以年结果 1-2批次为主,榕果发育株内同步,株间有时同步,有时异步,无发育期交叠的现象。笔管榕榕果的发育具明显的季节性,在日照短、温度低的秋冬季（11月至翌年的2月）,榕果发育周期（A期至E期）通常需要2-5个月;而在日照长、温度较高的春夏季（3—10月）,榕果发育明显变快,其发育周期仅需要1-2个月;2）每年单株笔管榕一般发生1-2次换叶。初春夏末是笔管榕落叶的高峰期,新叶在落叶后1-2周内萌发,老叶的脱落与新叶和果芽的萌发之间具关联性,叶通过光合作用为榕果萌发与发育提供良好的物质基础;3）笔管榕雌花期单果进蜂数量以1-3只占绝对优势,使个体小、数量多的榕果能够获得有效进蜂,既保证了榕树的结实率,也避免因过多的传粉小蜂拥挤在榕果狭小空间内相互打斗而造成的小蜂死亡和产卵效率低下。进入榕果的传粉小蜂均有不同程度的伤残;4）雌花期榕果内雌花的花柄（含子房柄）越短,其花柱（含柱头）的长度越长,反之亦然,从而使雌花柱头基本处于同一平面上,便于传粉小蜂的传粉与产卵,而雌花子房错落分布,使榕果有限空间得以充分利用。传粉小蜂产卵器的平均长度显著长于雌花花柱的平均长度（P〈0.001）,表明笔管榕传粉榕小蜂产卵器可达到绝大部分的雌花子房。【结论】笔管榕与其传粉小蜂之间形成互惠共生、高度统一的协同进化关系。

Ficus superba var. japonica is one type of deciduous and monoecious trees,however its reproductive behavior is very little known. In this study,we investigated the reproductive biology of F. superba var. japonica in Fuzhou and the results are shown in the following. （1） F. superba var. japonica plants bear multiple batches of fruits （0 -5 crops） annually,among which the 1 or 2 batches per year is the most case. The fig developmental patterns exhibited synchronous intra-tree,asynchronous or synchronous inter-tree. There was no overlap of different developmental stages in trees. The fig developmental period was obviously affected by seasons. In the autumn and winter （ from November to the next February） when the sunshine period is short and the temperature is lower related to the rest of year,the fig developmental cycle usually lasted for 2 to 5 months;while in the spring and summer （ from March to October） ,the plant grows faster,and the fig developmental cycle was completed in only 1 to 2 months. 2） F. superba var. japonica plants renewed their leaves 1 to 2 times each year. Both defoliation and leaf-renewing peaked in early spring and late summer. The new leaves always started to emerge within 1 or 2 weeks after defoliation. It seems that the fig development and the growth of new leaves would be associated with defoliation of old leaves. The carbohydrates for fig production are provided by leaves through the process of photosynthesis. 3 ） The foundress of F. superba var. japonica during the female flowering phase was usually occupied by only 1 -3 wasps. Therefore,the large quantity of small-sized figs had chances to host sufficient pollinating wasps to ensure their development. This circumstance can also avoid the adverse consequences such as the wasp death and the low spawning efficiency caused by too many pollinators in the limited fig space. It was found that the pollinators that enter syconia all had to some degrees disability. 4） In the female phase,the flower stalk （including gynophore） was shorter while its style （ including stigma） was longer,and vice versa. Therefore,the female flowers’stigma stayed in the same plane which conduced to fig wasps ’ pollination and spawning. The ovaries of female flowers were dispersedly distributed,forming two layers to maximally took the limited space of figs. The mean length of the pollinators’ovipositors was significantly longer than that of the style of female flowers （P 〈0. 001）,indicating that the pollinators’ovipositors could reach almost all of the ovaries. In summary,our data provide the basic and useful information regarding the pollination biology of F. superba. var. japonica and for supporting city afforestation and conservation in tropical rain forests.