ABSTRACT
Background and aims: The transition from outcrossing to selfing is a repeated pattern in angiosperm diversification and according to general theory this transition should occur quickly and mixed reproductive systems should be infrequent. However, a large proportion of flowering plants have mixed reproductive systems, even showing inbreeding depression. Recently, several theoretical studies have shown that mixed mating systems can be stable, but empirical studies supporting these assumptions are still scarce. Methods: Hypochaeris salzmanniana, an annual species with populations differing in their self-incompatibility expression, was used as a study case to assess the stability of its mixed reproductive system. Here a descriptive study of the pollination environment was combined with measurements of the stability of the self-incompatibility system, outcrossing rate, reproductive assurance and inbreeding depression in four populations for two consecutive years. Key Results: The reproductive system of populations exhibited a geographical pattern: the proportion of plants decreased from west to east. Pollinator environment also varied geographically, being less favourable from west to east. The self-incompatibility expression of some populations changed markedly in only one year. After selfing, progeny was mainly self-compatible, while after outcrossing both self-incompatible and self-compatible plants were produced. In general, both reproductive assurance and high inbreeding depression were found in all populations and years. The lowest values of inbreeding depression were found in 2014 in the easternmost populations, which experienced a marked increase in self-compatibility in 2015. Conclusions: The mixed reproductive system of H. salzmanniana seems to be an evolutionarily stable strategy, with selfing conferring reproductive assurance when pollinator attendance is low, but strongly limited by inbreeding depression. The fact that the highest frequencies of self-compatible plants appeared in the environments most unfavourable to pollination suggests that these plants are selected in these sites, although high rates of inbreeding depression should impede the complete loss of self-incompatibility. In H. salzmanniana, year-to-year changes in the frequency of self-incompatible individuals are directly derived from the balance between reproductive assurance and inbreeding depression.
Subject(s)
Asteraceae/physiology , Pollination , Self-Incompatibility in Flowering Plants , Environment , Inbreeding Depression , ReproductionABSTRACT
It is presented a case of a 62-year old male, with an illness of two months duration suggestive of an hepatic abscess; six months prior to admission he had surgery done because of a suspected cholelitiasis. Because of treatment failure and taking into account the result of the hepatic punctures (dark blood) with decreasing size of the liver, it was assumed to be a case of angioma. His intrahospital evolution was poor and died in hypovolemic shock complicated with acute pulmonary edema despite medical efforts. The post mortem study showed: a 13 cm. cavernous hepatic angioma, variable number of mesenteric, intestinal and cerebral angiomas. The surgical specimen of the gallbladder showed also angiomatosis. A brief review of the literature is done and particular emphasis is placed upon the clinical and angiographic studies of value to reach the diagnosis. The present case is similar to those in the literature because of the confusing clinical picture and fatal outcome.