An Association Between Variability in Ovule Development Within Ovaries and Self-Incompatibility in Lotus (Leguminosae)

Abstract

Ovules within each ovary of self-fertile Lotus species develop uniformly while those within each ovary of self-sterile species vary considerably in rate of development. All ovules in self-fertile species may be fertilized while less than one-half of those in self-sterile species are generally fertilized. Time of pollination is determined by the time when the stigmatic membrane ruptures in self-fertile species, by the time of rupturing by pollinating insects in self-sterile species. Higher numbers of ovules per ovary compensate for the proportion not fertilized in self-sterile species. The relationships of self-sterility to self-incompatibility in this genus, the evolution of this mechanism, and evidence that similar mechanisms are found in other legumes are discussed.

Variation in the colour of the keel petals in Lotus corniculatus L.

“…On the other hand, we cannot exclude the possibility that at other times of the year there may be a correlation, because of the variable expressian of the cyanogenic phenotype. In an earlier paper Bubar (1958) described the growth conditions of his experimental plants. These were raised in field nurseries during the summer and transferred to glasshouses during the intervening winters, but he makes no mention of the time of year when he tested plants …”

LOTUS CORNICULATUS REGULATES OFFSPRING QUALITY THROUGH SELECTIVE FRUIT ABORTION

“…We now know that the reduction in seed number commonly associated with inbreeding has several causes, including partial self-incompatibility, genetic load, and post-zygotic incompatibility (see Crowe, 1971;Solbrig, 1976;de Nettancourt, 1977). For example, when self-pollen is placed on stigmas of L. corniculatus, it is less likely than cross-pollen to effect fertilization, due to a partial incompatibility expressed in the ovary (Tome and Johnson, 1945;Bubar, 1958;Wojciechowska, 1963;Spiss, 1969). Moreover, those seeds that are produced from self-fertilization are more likely to abort (Tome and Johnson, 1945;Wojciechowska, 1963), probably because of the expression oflethal recessives.…”

“…The sequentially produced inflorescences are umbels that consist of one to twelve pealike, yellow, bisexual flowers. The flowers are pollinated by a variety of bees and are incompletely self-incompatible (Tome and Johnson, 1945;Bubar, 1958;Wojciechowska, 1963;Spiss, 1969). That is, in some individuals the incompatibility is only partial-some fruits are produced upon selfpollination.…”

THE BIOLOGY OF CANADIAN WEEDS.: 41. Lotus corniculatus L.

“…Bubar (1958) states that the proportion of self-seed obtained is also reduced by post-fenilization abortion of the type frequently described as somatoplastic sterility.…”