Rates of cross-pollination inLycopersicon pimpinellifolium: Impact of genetic variation in floral characters

Cross-pollination was tested between different genotypes ofLycopersicon pimpinellifolium in an experimental plot situated in the southerly range of the species. Rates of cross-pollination were found to be highly correlated with flower size and were related to a lesser extent with degree of stigma exsertion. Comparisons of fertility suggest that exsertion of 1.5 mm or more from the anther tube orifice interferes with automatic self-pollination, thereby increasing rates of cross-pollination. A single species ofExomalopsis (Anthophoridae), observed to visit all tested genotypes ofL. pimpinellifolium, was responsible for most of the pollination. Other species of solitary bees and other bee families participated in cross-pollination.     

Immigrant Spirorbids (Polyclaeta Sedentaria) on the Japanese Sargassum at Portsmouth, England

The Japanese Sargassum recently established at Portsmouth, U.K., is described and figured. It commonly bears two spirorbids which are new to Europe. One, Janua ( Dexiospira ) brasiliensis (Grube) = Dexiospira oshoroensis Uchida, is widespread in warm latitudes, whilst the other, Pileolaria rosepigmentata (Uchida), was previously known only from Japan. The former is distinguished from J. (D.) pseudocorrugata (= Spirorbis corrugalus ) principally by its more opaque brood chamber and shorter, wider juvenile talon. The latter is one of the Pileolaria moerchi complex and can be recognised by its bilobed brood chamber, conical juvenile talon and single diffuse patch of pigment.     

Effects of carbohydrate loading and underwater exercise on circulating cortisol, insulin and urinary losses of chromium and zinc.

The effects of carbohydrate loading on relative stress responses of eight male subjects performing intermittent leg exercise at 80% maximum oxygen consumption during headout immersion in 25 degrees C water were tested. Carbohydrate loading increased the number of work cycles completed, with less physical stress compared with that completed following the control diet period. Pre-exercise serum cortisol values were similar on both diets prior to exercise but following exercise control values were greater (1152, 94 vs 858, 77 nmol l-1; mean, SEM). Chromium losses, which have been shown to correlate with stress, were lower during the carbohydrate loading period, 8.6, 1.3 vs 12.4, 2.0 ng h-1, and were correlated with post-exercise serum cortisol. Urinary zinc losses were also lower during carbohydrate loading, while urinary losses of potassium, magnesium and calcium remained constant. Insulin values decreased similarly following exercise in both groups and were not altered by carbohydrate loading. These data demonstrate that carbohydrate loading increases immersion exercise output with less stress as determined by serum cortisol and urinary chromium losses.     

POLLINATION ECOLOGY OF PYRRHOPAPPUS CAROLINIANUS (COMPOSITAE)

Pyrrhopappus carolinianus and Hemihalictus lustrans constitute a mutualistic association: the early morning flowering of Pyrrhopappus provides the matinal bee with a nearly exclusive pollen source, although other plants must be visited for nectar. Female Hemihalictus, the primary pollen vector, tear open the anthers and remove the pollen before it is available to other bees. The foraging behavior of the bee insures cross-pollination. The flight pattern of the bees generally restricts the pollen dispersal range. If cross-pollination fails, then autogamy results from twisting of the styles that brings the stigmas in contact with the pollen presented on the styles of other florets. Schinia mitis is an important predator of the capitulae of P. carolinianus.