Response to carbon monoxide by geographic variants in Acacia farnesiana.
A B S T R A C T Differences in degree of defoliation in CO-air mixtures were shown by geographic variants in Acacia farnesiana (L.) Willd., a widespread, weedy, pantropic, leguminous tree. Laboratorygerminated seedlings from MazatlAn (MAME-1), Sinaloa, Mexico, showed greater sensitivity to a CO gradient than plants from Point Tuna (PORO), Puerto Rico. Seedlings of both strains grown under a light intensity of 200 ft-c showed greater sensitivity to CO than those grown under 1,800 ft-c. When intact plants of 17 geographic variants grown at low-light intensities were exposed to 2%Fo CO in air, 11 strains (Mexico,8; Texas, 1; California, 1; Guatemala, 1) showed almost complete defoliation. The other six strains-from Brazil, Hawaii, Puerto Rico, 1Ttaly, Algeria, and Michoac4n, Mexico-showed defoliation averaging from 23 to 70%. The significance of the CO-defoliation response is difficult to explain in terms of the natural distribution of A. farnesiana. It is suggested that this response may be correlated with some biochemical process of adaptive significance. GEOGRAPHIC variants in Acacia farnesiana (L.) Willd. being studied at the Plant Ecology Research Laboratory differ in several parameters, but the most bizarre difference is one shown by exposure to low concentrations of carbon monoxide. While certain strains show nearly total leaf loss after 24-hr exposure to CO, other strains show little or no defoliation. First observed as a result of accidental exposure to CO, the geo
Stem Orientation in Two Populations of Acacia farnesiana from Mexico Under Controlled Environmental Conditions
The orientation of stem growth in upright plants from an inland population at Saltillo, Coahuila, and in prostrate plants from a beach population at Mazatlan, Sinaloa, was examined under several conditions of photoperiod, temperature, and light intensity. Prostrateness is enhanced by lower temperatures, shorter photoperiods, and higher light intensities in both populations but is induced to a greater degree and over a wider range of conditions in the naturally prostrate form. Under longer day lengths, 16 hr, and higher temperatures, 32-24 C, the prostrate form develops almost upright and is not significantly more prostrate than the naturally upright form. Regenerated stems produced under high light intensities were significantly more prostrate in the beach population than were stems of the inland population, but under low light intensities both populations produced upright stems. The results suggest that niche plasticity of the prostrate population offers selective advantage in a subtropical beach ecosystem.
Reconceptualizing Vagrancy and Reconstructing the Vagrant: A Socio-Legal Analysis of Criminal Law Reform in Canada, 1953-1972
This article explores significant reforms to the vagrancy section of the Criminal Code during the mid-to-late twentieth century. By locating the reforms within their unique social, political, and economic climates, I examine how they reconceptualized the offence of vagrancy and concomitantly reconstructed the vagrant as a social problem. The reforms played a seminal role in reducing the number of vagrancy offences, eventually leading to the demise of vagrancy in the criminal law. Yet, while the "vagrant" ceased to exist in the law, the law still continues to preserve vestiges of the vagrant in a highly gendered manner.