Selective seed abortion increases offspring survival in Cynoglossum officinale (Boraginaceae).
Selective embryo abortion is one of the evolutionary explanations for the surplus of ovules found in many plant species. To manipulate the level of embryo abortion, we removed ovules and applied nutrients to plants of Cynoglossum officinale (Boraginaceae) after they started to flower. From these two treatments and a control series, seeds were collected, germinated, and transplanted in the field to assess the quality of the resulting offspring. Nutrient addition did not increase the number of seeds per flower significantly. Fewer embryos were aborted in the ovule removal treatment. The seeds produced in the ovule removal treatment had a significantly greater mass and significantly lower survival than the offspring from the control group. This difference in survival indicates that offspring of lower quality are selectively aborted in the control group. Offspring from the nutrient addition treatment survived longer. The offspring of the treatments did not differ significantly from the control group in growth. Simple mathematical calculations, based on the differences in offspring quality that we found, indicate that the selective abortion hypothesis can be an important factor explaining the advantage of the "surplus production" of ovules.
Melser
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Institute of Evolutionary and Ecological Sciences, P.O. Box 9516, 2300 RA Leiden, The Netherlands.
Klinkhamer
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