Effect of night temperature on daytime stomatal conductance in early and late successional plants.

Sixteen annuals, biennials, and herbaceous and woody perennials characteristic of early and late successional old field ecosystems and upland and floodplain habitats were analyzed for their response of stomatal conductance to changes in night temperature. Early successional species that germinate in early spring when temperatures are low, but above freezing are insensitive to cool nights, i.e.

Response of stomatal resistance and photosynthesis to night temperature in Populus deltoides.

Ramets from stem cuttings of three populations of Populus deltoides Bartr. from Wisconsin, Illinois, and Louisiana representing a latitudinal gradient were grown in pots outdoors at Urbana, Illinois and brought indoors for growth chamber studies. Leaf resistance and photosynthetic response to low night temperatures of 4° and 10° C were determined relative to 20° C controls for plants measured over one growing season.

Hallervorden-Spatz syndrome.

Two siblings with Hallervorden-Spatz syndrome showed striking homotypism and homochronism. Neuropathologic examination and electron microscopic studies were done; neutron activation analysis showed an increase in the uptake of iron in the basal ganglia. Of particular relevance is the application of radioactive iron studies in the clinical course of this syndrome.

Serum cholinesterase (pseudocholinesterase) in Down's syndrome: 2. Quantitative levels.

The observation elsewhere (Drew and Rundle, 1977) that increase frequencies of the C5 + variant of the serum cholinesterase in Down's syndrome may be due to a protective influence against adverse environmental factors has been investigated for such factors as age, sex, duration of institutionalisation, presence of the hepatitis -B antigen and maternal age. With the exception of the maternal age none of the factors tested appear to affect the circulating levels of cholinesterase. A maternal age effect in the Down's subjects was detected with lower levels of the enzyme being found in the subject positive for the C5 + variant born to mothers over thirty-five years when compared to the C5 + subjects born to mothers under thirty-five years.

Serum cholinesterase (pseudocholinesterase) in Down's syndrome: 1. Phenotype frequencies at the E1 and E2 loci.

Dibucaine, fluoride and RO2-0683 inhibition studies were used to determine the serum cholinesterase (pseudocholinesterase) phenotypes at the E1 locus in a sample of 130 subject with Down's syndrome and fifty-three mentally retarded control subjects. No example of the Ef1 and Es1 allele was detected in either group, nor were any of the genotype E1a E1a detected. The gene frequency of E1a for the control group (0.