The influence of pollinator abundance on the dynamics and efficiency of pollination in agricultural Brassica napus:: implications for landscape-scale gene dispersal
The influence of pollinator abundance on the dynamics and efficiency of pollination in agricultural Brassica napus:: implications for landscape-scale gene dispersal
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DOI：
10.1111/j.1365-2664.2006.01219.x
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发表时间：
2006-12-01
影响因子：
5.7
通讯作者：
Cresswell, James E.
中科院分区：
文献类型：
--
作者：
Hayter, Katrina E.;Cresswell, James E.
1. 了解授粉过程在植物中产生景观尺度的基因传播是很重要的，特别是在具有转基因品种的作物中。在一种这样的作物——甘蓝型油菜中，由于两种花粉载体——风和昆虫的相对重要性的不确定性，情况变得复杂起来。我们在两个不同开花时间（4月和7月）的甘蓝型油菜地进行了授粉调查，并对不同丰度的觅食工蜂进行了调查。通过计算开花后每隔一段时间沉积在柱头上和留在花药中的花粉粒数来定量花粉传递率。4月份开放的花在5天后才被充分授粉，只有10%的花甚至有一只蜜蜂来访。7月开放的花每小时有三次蜜蜂来访，在3小时内完全授粉。根据已发表的空气中花粉传播的测量结果，我们估计，当蜜蜂在4月份稀少时，从1公里远的假想田地里吹来的风媒传粉可以使该田地的种子受精0.3%，而当蜜蜂在7月份丰富时，这一比例仅为0.007%。授粉效率（花粉从花药中释放到接受柱头上的比例）在7月份（1.5%）是4月份（0.2%）的7倍。昆虫传粉的相对高效率可能有助于解释嗜虫性的进化维持。合成与应用。我们的研究结果开始解决以往研究中长期存在的不一致，表明甘蓝型油菜田间对长距离风异花授粉的敏感性取决于蜜蜂的活动水平。预测这种作物在景观尺度上的转基因基因流动的模型应该考虑到这一点。
1. It is important to understand the pollination processes that generate landscape-scale gene dispersal in plants, particularly in crop plants with genetically modified (GM) varieties. In one such crop, Brassica napus, the situation is complicated by uncertainty over the relative importance of two pollen vectors, wind and insects.2. We investigated pollination in two fields of B. napus that bloomed at different times of year (April vs. July) and attracted different abundances of foraging social bees. Rates of pollen transfer were quantified by counting the pollen grains deposited on stigmas and remaining in the anthers at intervals after flower opening.3. Flowers open in April were adequately pollinated only after 5 days and only 10% received even a single bee visit. Flowers open in July received three bee visits per hour and were fully pollinated within 3 h.4. Based on published measurements of airborne pollen dispersal, we estimate that wind-pollination from a hypothetical field 1 km distant could have fertilized up to 0.3% of the field's seed when bees were scarce in April but only up to 0.007% when bees were abundant in July.5. The efficiency of pollination (the proportion of pollen released from anthers that landed on receptive stigmas) was seven times greater in July (1.5%) than in April (0.2%). The relatively high efficiency of insect pollination may help to explain the evolutionary maintenance of entomophily.6. Synthesis and applications. Our results begin to resolve a long-standing inconsistency among previous studies by suggesting that the susceptibility of fields of B. napus to long-distance cross-pollination by wind depends on the level of bee activity. Models for predicting GM gene flow at the landscape-scale in this crop should take this into account.