Selective seed abortion increases offspring survival in Cynoglossum officinale (Boraginaceae)

Selective embryo abortion is one of the evolutionary explanations for the s urplus of ovules found in many plant species. To manipulate the level of em bryo abortion, we removed ovules and applied nutrients to plants of Cynoglo ssum officinalpe (Boraginaceae) after they started to flower. From these tw o treatments and a control series, seeds were collected, germinated, and tr ansplanted in the field to assess the quality of the resulting offspring. N utrient addition did not increase the number of seeds per flower significan tly. Fewer embryos were aborted in the ovule removal treatment. The seeds p roduced in the ovule: removal treatment had a significantly greater mass an d significantly lower survival than the offspring from the control group. T his difference in survival indicates that offspring of lower quality are se lectively aborted in the control group. Offspring from the nutrient additio n treatment survived longer. The offspring of the treatments did not differ significantly from the control group in growth. Simple mathematical calcul ations, based on the differences in offspring quality that we found, indica te that the selective abortion hypothesis can be an important factor explai ning the advantage of the "surplus production" of ovules.