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The effect of some of the gibberellins (GA3 , GA4+7 und GA13) on seed germination and subsequent seedling growth of Early Muscat grape was investigated. The after-ripened seeds were treated with 0, 50, 100, 250, 500 and 1000 ppm concentrations of each gibberellin. All gibberellins, except GA4+7 , at concentrations beyond 50 ppm promoted germination. Generally, the lower concentrations were found more efficacious for enhancing the germination. GA4+7 at 1000 ppm completely inhibited the germination. The activity of GA3 was gradual and regular, whereas GA4+7 and GA13 showed swift activity with a narrow germination-promotive-concentrationrange. The variable influence of gibberellins an seedling growth was also observed. Der Einfluß der Gibberelline GA3 , GA4+7 und GA13 auf die Samenkeimung und das anschließende Sämlingswachstum bei der Rebensorte Early Muscat (Vitis vinifera) Bei der Rebensorte Early Muscat wurde der Einfluß einiger Gibberelline (GA3 , GA4+7 und GA13) auf die Samenkeimung und das anschließende Wachstum der Sämlinge untersucht. Die nachgereiften Samen wurden jeweils mit Gibberellinkonzentrationen von 0, 50, 100, 250, 500 und 1000 ppm behandelt. Alle Gibberelline, mit Ausnahme von GA4+7 , förderten bei Konzentrationen über 50 ppm die Samenkeimung. Im allgemeinen erwiesen sich niedrigere Konzentrationen hierbei als wirksamer. 1000 ppm GA4+7 hemmten die Keimung vollkommen. Die Wirkungskurve des GA3 in Abhängigkeit von der Konzentration verlief stetig und ausgeglichen, während sie bei GA4+7 und GA13 einen raschen Anstieg mit einem schmalen keimungsfördernden Konzentrationsbereich zeigte. Auch beim Wachstum der Sämlinge wurde der unterschiedliche Einfluß der Gibberelline beobachtet., VITIS - Journal of Grapevine Research, Vol. 14 No. 4 (1975): Vitis

BACKGROUND: Blood centers are interested in understanding determinants of frequent blood donation. We hypothesized that participation in uncompensated research could result in higher donation rates. STUDY DESIGN AND METHODS: Donation rates for 2425 subjects from six US blood centers enrolled in the Retrovirus Epidemiology Donor Study-II Donor Iron Status Evaluation Study were compared to those of nonenrolled donors (n = 202,383). Over 15 months, we compared mean donation rates and adjusted rate ratios (RRs) between enrolled and nonenrolled for three subgroups, first-time, reactivated, and frequent donors, and donation rates before and after the study enrollment period for frequent donors only. RESULTS: Enrolled donors had higher 15-month mean donation rates than nonenrolled donors (first-time, 1.21 [RR = 1.91]; reactivated, 1.68 [RR = 1.83]; frequent, 3.40 [RR = 1.12]). However, frequent donors donated at approximately the same rate after enrollment as they did before enrollment in the study (3.62 per 15 months [RR = 1.12]). CONCLUSION: Donors enrolled in the study donated at a higher rate than nonenrolled donors, but frequent donors remained consistent in their donation frequency both before and after enrollment. Although increased donation rates could have been causally related to study enrollment, we cannot rule out an enrollment bias whereby more committed donors were more likely to enroll in the study. © 2010 American Association of Blood Banks.

BackgroundRegular blood donors are at risk of iron deficiency, but characteristics that predispose to this condition are poorly defined.Study design and methodsA total of 2425 red blood cell donors, either first-time (FT) or reactivated donors (no donations for 2 years) or frequent donors, were recruited for follow-up. At enrollment, ferritin, soluble transferrin receptor (sTfR), and hemoglobin were determined. Donor variables included demographics, smoking, dietary intake, use of iron supplements, and menstrual and/or pregnancy history. Models to predict two measures of iron deficiency were developed: Absent iron stores (AIS) were indicated by a ferritin level of less than 12 ng/mL and iron-deficient erythropoiesis (IDE) by a log(sTfR/ferritin) value of 2.07 or greater.ResultsA total of 15.0% of donors had AIS and 41.7% IDE. In frequent donors, 16.4 and 48.7% of males had AIS and IDE, respectively, with corresponding proportions of 27.1 and 66.1% for females. Donation intensity was most closely associated with AIS and/or IDE (odds ratios from 5.3 to 52.2 for different donation intensity compared to FT donors). Being female, younger, and/or menstruating also increased the likelihood of having AIS and/or IDE, as did having a lower weight. Marginally significant variables for AIS and/or IDE were being a nonsmoker, previous pregnancy, and not taking iron supplements. Dietary variables were in general unrelated to AIS and/or IDE, as was race and/or ethnicity.ConclusionA large proportion of both female and male frequent blood donors have iron depletion. Donation intensity, sex and/or menstrual status, weight, and age are important independent predictors of AIS and/or IDE. Reducing the frequency of blood donation is likely to reduce the prevalence of iron deficiency among blood donors, as might implementing routine iron supplementation.