Subject(s)
Arteriovenous Fistula/congenital , Intracranial Arteriovenous Malformations/diagnostic imaging , Adult , Embolization, Therapeutic , Epilepsy, Tonic-Clonic/etiology , Humans , Intracranial Arteriovenous Malformations/complications , Intracranial Arteriovenous Malformations/therapy , Male , Paresis/etiology , Postoperative Complications , RadiographyABSTRACT
Photosynthetic gas exchange and malic acid fluctuations were monitored in 69 well-watered plants from five morphologically similar species of Talinum in an investigation of the ecophysiological significance of the Crassulacean acid metabolism (CAM)-cycling mode of photosynthesis. Unlike CAM, atmospheric CO(2) uptake in CAM-cycling occurs exclusively during the day; at night, the stomata are closed and respiratory CO(2) is recaptured to form malic acid. All species showed similar patterns of day-night gas exchange and overnight malic acid accumulation, confirming the presence of CAM-cycling. Species averages for gas exchange parameters and malic acid fluctuation were significantly different such that the species with the highest daytime gas exchange had the lowest malic acid accumulation and vice versa. Also, daytime CO(2) exchange and transpiration were negatively correlated with overnight malic acid fluctuation for all individuals examined together, as well as within one species. This suggests that malic acid may effect reductions in both atmospheric CO(2) uptake and transpiration during the day. No significant correlation between malic acid fluctuation and water-use efficiency was found, although a nonsignificant trend of increasing water-use efficiency with increasing malic acid fluctuation was observed among species averages. This study provides evidence that CO(2) recycling via malic acid is negatively correlated with daytime transpirational water losses in well-watered plants. Thus, CAM-cycling could be important for survival in the thin, frequently desiccated soils of rock outcrops on which these plants occur.
ABSTRACT
Developments of interest to the optics community reported in NASA Tech Briefs, Vol. 11, No. 7 (July/August) 1987 are given below. Further information can be obtained by writing to NASA STI Facility, Manager TU Division, P. O. Box 8757, Baltimore, MD 21240-9985, citing the identifying number.
ABSTRACT
Developments of interest to the optics community reported in NASA Tech Briefs 11, No. 2 (February 1987) are given below. Further information can be obtained by writing to NASA STI Facility, Manager TU Division, P.O. Box 8757, BWI Airport, MD 21240-0757, and giving the identifying number.
