Rhabditis pellio Schneider (Nematoda) from the Earthworm,Aporrectodea trapezoides Duges (Annelida)

Studies were conducted on the behak, ior of the nematode, Rhabditis pellio, in the earthworm, Aporrectodea trapezoides, from southern California. Juvenile and adult nematodes were found in the bladders and tubules of the metanephridia of the host. Similar nematodes that entered the coelom were encapsulated and incorporated into multiple capsules ("brown bodies"). It was demonstrated that this host response is an effective defense reaction since dead and dying nematodes, as well as living forms, were found in the capsules.     

Activity of Antheridiogen from the Fern Anemia phyllitidis in Three Flowering Plant Bioassays

Pure samples of the antheridiogen of Anemia phyllitidis (A_An) were tested for their ability to affect the growth of dwarf corn (d₅) and lettuce seedlings, and to influence α-amylase production by barley half-seeds. Stimulation of dwarf corn growth and barley amylase production was, on a molar basis, from 1/2 to 1/250 that given by GA_3. In lettuce, A_An had a synergistic effect with low levels of GA₃; alone, A_An was inhibitory or ineffective. Therefore, in addition to having a close chemical resemblance to gibberellin, A_An induces similar, but not identical physiological responses in flowering plants as well as ferns.     

Inhibition of ion accumulation in maize roots by abscisic acid

Summary An inhibition of root growth, a decrease in the amount of potassium (as ⁸⁶Rb) and phosphate (³²P) accumulation by the root, and a partial depolarization of transmembrane electropotential were observed to develop with a similar time course and to a similar extent when intact maize (Zea mays L.) roots were treated with 10^-5 M abscisic acid (ABA). Potassium uptake was inhibited by ABA when excised, low-salt roots were bathed in KCl, KH₂PO₄, or K₂SO₄. ABA did not affect the ATP content of the tissues, the activity of isolated mitochondria, nor the activity of microsomal K⁺-stimulated ATPases.     

Growth of the haploid phase of the myxomycete Physarum flavicomum in defined minimal medium

The haploid phase (myxamoebae-swarm cells) of the myxomycete Physarum flavicomum grew readily in chemically defined liquid media. The minimal medium contained salts, glucose, biotin, thiamine, hematin, glycine, l-arginine and l-methionine. Cell yields of 1.4x10⁷ cells/ml were obtained in this medium in aerobic shake culture. These cells consumed about 35 μliters of oxygen/mg protein·hr in the minimal medium. The morphology of cells maintained in this medium appeared to be “normal”. l-valine replaced either glycine or l-methionine in the minimal medium but the growth rates and cell yields were reduced. Growth rates increased in media containing four, seven, or fourteen amino acids.     

Biology of the flea beetle,Altica carduorum [Col.: Chrysomelidae] on Canada thistle (Cirsium arvense) in South Dakota

A laboratory colony of 50 adults ofAltica carduorum Guérin-Méneville was established at South Dakota State University. Beetles reared in this colony had an average preoviposition period of 7 days when exposed to a regular cycle of 16 hr of light (24°C) and 8 hr of darkness (12.7°C). The laboratory reared females, whose longevity averaged 100 days, laid an average of 259.3±9.7 eggs. High temperatures and/or low RH are limiting factors to beetle survival. In the field eggs were laid throughout June on the underside of leaves along the edges of the veins. Adults fed throughout the summer and then over-wintered in the soil. Some of these beetles emerged the following spring and laid viable eggs. Factors limiting establishment in South Dakota, however, were high temperatures, low humidities, and the predators,Lebia viridis Say andHarpalus pennsylvanicus Degeer.A. carduorum originates from the Swiss Rhône valley where there is a relatively “continental” climate, but is limited to special habitats where comparatively high humidity occurs. South Dakota climate is characterized by cold winters, and hot, dry summers, therefore establishment would be most difficult.