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31.
32.
Naoto Sugiura 《Ecological Research》1996,11(3):249-255
The behavior of visitors to the flowers of the orchidEpipactis thunbergii was studied, with special attention to the role of the epichile in the pollination process. Only four species of syrphid
flies legitimately pollinated the flower, among whichSphaerophoria macrogaster was regarded as the most effective pollinator. The movable epichile, possessing a furrow at its base, played a critical role
in the pollination process: it threw the syrphid fly onto the stigmatic surface when both sides of the basal slanting surface
of the furrow were presumably pressed in the direction of the hypochile by the fore (and middle) legs of the retreating syrphid
fly. At this moment, the fly received a set of pollinia on the thorax. 相似文献
33.
34.
S. CARRÉ J. N. TASEI J. Le GUEN J. MESQUIDA G. MORIN 《The Annals of applied biology》1993,122(3):555-568
A simplified and non-destructive method using starch gel electrophoresis has been developed on seeds to identify inbred lines of Vicia faba and assess outcrossing rates and gene dispersal in pollination experiments. Six enzyme systems (Alcohol dehydrogenase, Aspartate aminotransferase, Glucose-6-phosphate isomerase, Isocitrate dehydrogenase, Phosphogluconate dehydrogenase and Shikimate dehydrogenase) were analysed from parental lines, crosses performed between lines bearing dissimilar isozyme patterns in pollination cages with Bombus and F2 progenies obtained from manual selfing of F1 hybrids. The allozymes at each of the seven studied loci segregated in the expected Mendelian fashion and behaved in a co-dominant manner except for the Adh-2 locus where the only variant was a null allele. No evidence of genetic linkage was observed between at least 13 of the 15 pairs of the studied loci. Percentage of cross fertilisation by Bombus between seven pairs of inbred lines ranged between 1.7% and 28.3%. Pollen transfer between a donor line and a recipient line by two species of Bombus did not lead to differences in outcrossing rates (both about 8%). The new PGD marker with two loci at three alleles each is particularly discriminating and valuable in pollination studies and breeding of V. faba. 相似文献
35.
《Revista espa?ola de geriatría y gerontología》2023,58(1):8-14
ObjectiveThere is increased interest in studying ATTR-CA, a pathology that primarily affects patients of geriatric age and is frequently underdiagnosed. We aim to establish the prevalence of ATTR-CA in a cohort of patients with a history of HFpEF and to describe its characteristics.MethodsWe conducted a prospective observational study. Patients ≥75 years, clinical history of HFpEF, atrial dilation ≥34 ml/m2 and left ventricular wall thickening >13 mm, were included. Demographic and analytical parameters were collected, and a comprehensive geriatric assessment was performed, along with a transthoracic echocardiogram and cardiac scintigraphy. Finally, telephone follow-up was carried out at 6 and 12 months.Results50 patients were recruited, mean age 86 ± 6 years, 54% women. Age and functional class (I–II vs. III–IV) were factors associated with presenting with ATTR-CA. Patients with positive scintigraphy had a median time to admission of 5.2 months (confidence interval [CI] 95% 0–10.9), while in those with negative scintigraphy, it was 12.2 months (95% CI 11.7–12.8); log-rank: p = 0.064. Patients with positive scintigraphy had a median time to the combined endpoint (death and readmission) of 1.9 months (95% CI 0–6.1), and patients with negative scintigraphy of 11.9 months (95% CI 11.7–12); log-rank: p = 0.027.ConclusionsATTR-CA appears to be a prevalent etiology in elderly patients within the spectrum of HFpEF. Patients with a diagnosis of ATTR-CA had a shorter time to admission for HF and the combined event of death and admission than patients with a negative result on scintigraphy. 相似文献
36.
37.
Diane R. Campbell Nickolas M. Waser Mary V. Price Elizabeth A. Lynch Randall J. Mitchell 《Evolution; international journal of organic evolution》1991,45(6):1458-1467
In the hummingbird-pollinated herb Ipomopsis aggregata, selection through male function during pollination favors wide corolla tubes. We explored the mechanisms behind this selection, using phenotypic selection analysis to compare effects of corolla width on two components of male pollination success, pollinator visit rate and pollen exported per visit. During single visits by captive hummingbirds, flowers with wider corollas exported more pollen, and more dye used as a pollen analogue, to stigmas of recipient flowers. Corolla width was less strongly related to visit rate in the field, and had no direct effect on visit rate after nectar production and corolla length were controlled for. Moreover, the phenotypic selection differential was 80% higher for the effect on pollen exported per visit, suggesting that this is the more important mechanism of selection. 相似文献
38.
39.
Sandra L. Davis 《Sexual plant reproduction》1997,10(5):293-299
It has been hypothesized that females of some dioecious species maintain stamens that produce sterile pollen as a means of
attracting pollinators to promote greater seed set. However, this hypothesis has rarely been tested. This paper examines the
role of pollinators in the maintenance of sterile stamens in the cryptically dioecious species, Thalictrum pubescens. Wind was found to contribute to pollination; branches of female T. pubescens enclosed in cheesecloth to exclude insects but not wind were still able to set seed. Therefore, females may not need the stamens
for pollination. In 1994, insects were found to discriminate against emasculated female flowers, but this discrimination did
not lead to a significant difference in either the amount of pollen received or seed set. In 1995, emasculation was combined
with the addition of pollen to determine if emasculated females were pollen limited. No significant effect of pollen addition
or emasculation was found. Emasculated branches in the pollen-addition treatment appeared to have slightly lower seed set
than non-emasculated branches that received pollen, indicating that the slight reduction in seed set was caused by emasculation
rather than pollen limitation. Since stamens do not appear to be maintained as pollinator attractants, other explanations,
such as genetic constraints, must be investigated.
Received: 4 February 1997 / Revision accepted: 20 May 1997 相似文献
40.
Pollination Ecology of Pedicularis in the Teton Mountain Region 总被引:1,自引:0,他引:1
LAZARUS WALTER MACIOR 《Plant Species Biology》1995,10(2):77-82