Kwak Manja M, Jennersten Ola
Department of Plant Biology, University of Groningen, P.O. Box 14, NL-9750 AA, Haren (Gn), The Netherlands.
Department of Zoology, Uppsala University, Box 561, S-751-22, Uppsala, Sweden.
Oecologia. 1991 Mar;86(1):99-104. doi: 10.1007/BF00317395.
Fruiting and seed set in two bumblebee-pollinated herbs, Melampyrum pratense L. (annual, Scrophulariaceae) and Viscaria vulgaris Bernh. (perennial, Caryophyllaceae) were studied on a dry meadow in southwestern Sweden in June 1986 and 1988. Both species produced seeds by self-fertilization. In Melampyrum (homogamous) fruiting and seed set by selfing were much lower than by natural pollination; in Viscaria (protandrous) fruiting by selfing and by natural polination were similar, but seed set per flower was lower by selfing than by natural pollination. Sequential hand pollinations increased seed set in Melampyrum, but not in Viscaria. Thus, the number of pollinations is important for high seed set in Melampyrum, and number of pollen grains deposited one pollination is important for high seed set in Viscaria. Late flowering resulted in the production of fewer seeds in both species, although the visitation rate in pure Viscaria stands was sufficient, because of limited resources. Pollen was the limiting resource in Viscaria, because hand pollination increased natural seed set. In Melampyrum pollen was limiting in 1988 but so were consumable resources, because the seedset decreased with time despite hand pollination. Pure stands of Viscaria had sced set similar to plants in mixed stands (with Melampyrum and Rhinanthus), although plants in mixed stands received fewer visits. Many seeds produced late in the season are the result of self pollination; emasculated Viscaria flowers had a very low seedset late in the season. Pollen loads containing approximately 50% heterospecific grains did not affect seed set in either species. Application of heterospecific (Lupinus) pollen to receptive Viscaria styles 6 h before conspecific pollen did not affect seed set.
1986年6月和1988年，在瑞典西南部的一片干燥草甸上，对两种由熊蜂授粉的草本植物进行了研究，它们分别是草原山萝花（一年生，玄参科）和普通蝇子草（多年生，石竹科）。这两个物种都能通过自花授粉产生种子。在草原山萝花（同花受精）中，自花授粉产生的果实和种子量远低于自然授粉；在普通蝇子草（雄蕊先熟）中，自花授粉和自然授粉产生的果实量相似，但每朵花的种子量自花授粉低于自然授粉。连续人工授粉增加了草原山萝花的种子量，但对普通蝇子草没有作用。因此，授粉次数对草原山萝花的高种子产量很重要，而一次授粉时沉积的花粉粒数量对普通蝇子草的高种子产量很重要。花期较晚导致两个物种产生的种子较少，尽管在纯普通蝇子草群落中访花率足够，但由于资源有限。在普通蝇子草中，花粉是限制资源，因为人工授粉增加了自然种子产量。在1988年的草原山萝花中，花粉是限制因素，但可消耗资源也是，因为尽管进行了人工授粉，种子产量仍随时间下降。纯普通蝇子草群落的种子产量与混合群落（与草原山萝花和小米草混生）中的植物相似，尽管混合群落中的植物接受的访花较少。季节后期产生的许多种子是自花授粉的结果；去雄的普通蝇子草花在季节后期种子产量很低。含有约50%异种花粉粒的花粉负载量对两个物种的种子产量均无影响。在同种花粉授粉前6小时，将异种（羽扇豆属）花粉施用于可受精的普通蝇子草柱头上，不影响种子产量。
