Martin M E, Lee T D
Department of Plant Biology, University of New Hampshire, 03824, Durham, NH, USA.
Oecologia. 1993 Jul;94(4):503-509. doi: 10.1007/BF00566965.
We examined the effects of pollen source and resource availability on ovule abortion in the annual legumeCassia fasciculata. Pollen source was controlled by hand-pollinating flowers with cross- or self-pollen. Resource availability to developing fruits was controlled by adjusting fruit loads (heavy versus light) on each plant and exposing plants to different photoperiod cycles (16 vs 12 h of light; short days favor fruit growth at the expense of vegetative growth). In mature fruits the proportion of ovules expanding (showing some development over virgin ovules) ranged from 89-95% and did not increase with resource availability, suggesting that unexpanded ovules were either unfertilized or obligately aborted shortly after fertilization. The proportion of expanded ovules maturing in mature fruits was near 97% for both self- and crosspollinations in the treatment with highest resource availability (light load, short days) and lower in the remaining treatments, where self-pollination resulted in up to 9% lower seed maturation than cross-pollination. In the latter three treatments a pollen source effect was dependent upon the maternal plant; in some plants selfing increased abortion and in others it did not. Collectively, the results suggest that (1) both pollen source and resource availability affect ovule abortion, (2) at least some abortion is facultative, and (3) when resources are limited, self-pollination increases abortion in some but not all maternal plants.
我们研究了花粉来源和资源可利用性对一年生豆科植物束花决明胚珠败育的影响。通过用异花或自花花粉对花朵进行人工授粉来控制花粉来源。通过调整每株植物上的果实负载量（重负载与轻负载）以及使植物暴露于不同的光周期（16小时光照与12小时光照；短日照有利于果实生长，但以营养生长为代价）来控制发育中果实的资源可利用性。在成熟果实中，胚珠膨大（相对于未授粉的胚珠有一定发育）的比例在89%至95%之间，且不随资源可利用性增加，这表明未膨大的胚珠要么未受精，要么在受精后不久就必然败育。在资源可利用性最高的处理（轻负载，短日照）中，自花授粉和异花授粉的成熟果实中膨大胚珠成熟的比例都接近97%，而在其余处理中该比例较低，其中自花授粉导致的种子成熟率比异花授粉低达9%。在后三种处理中，花粉来源效应取决于母本植物；在一些植物中自交增加了败育，而在另一些植物中则没有。总体而言，结果表明：（1）花粉来源和资源可利用性都影响胚珠败育；（2）至少部分败育是兼性的；（3）当资源有限时，自花授粉在一些但不是所有母本植物中增加了败育。
