Influence of photoperiod on tuber production in various races of Hydrilla (Hydrilla verticillata)

The potential for asexual reproduction throughproduction of tubers was evaluated in various races ofan International Hydrilla [Hydrilla verticillata (L.f.)Royle] germplasm collection. Interracecomparisons were made under both shortday and longdayphotoperiods in environmental growth chambers. Allthe races evaluated produced rates varying from91-7182 tubers per sq m of production under shortdayconditions. Tuber production occurred under longdayphotoperiods in several races. Under propertemperature conditions, all the monoecious racescurrently established in the U.S. appear capable oftuber production throughout the year.     

Failure of Intravenous Aspirin to Increase Gastrointestinal Blood Loss

Studies of the effect of intravenous sodium acetylsalicylate (aspirin) on gastrointestinal blood loss with ⁵¹Cr-labelled red cells were made on 15 healthy male volunteers. After a control period of five days 1 g. of sodium acetylsalicylate was infused over a period of 100 minutes twice daily for three days. Faecal blood loss was not increased.In a further six subjects 3 g. of sodium acetylsalicylate was infused over a period of 120 minutes. No salicylate or acetylsalicylate was detected in saliva or gastric washings from these six subjects. Hence gastrointestinal blood loss induced by aspirin may be explained by a local effect on mucosa and not by any systemic effect.