Growth and disease response of soybeans from early maturity groups to ozone and Fusarium oxysporum.

The single and combined effects of ozone (O(3)) and Fusarium oxysporum on growth and disease expression of soybean genotypes differing in foliar sensitivity to O(3) were studied in the greenhouse. O(3) had no effect on root and hypocotyl rot severity of PI 153.283 (O(3)-sensitive, S) or PI 189.

Bioassaying for ozone with pollen systems.

Sensitivity to ozone of pollen germinating in vitro is closely correlated with ozone sensitivity of the pollen parent. Ozone-sensitive and tolerant pollen populations have been identified in tobacco, petunia, and tomato cultivars. The rate of tube elongation can be reversibly slowed or stopped by exposure to low concentrations of ozone.

Plants as bioassay systems for monitoring atmospheric pollutants.

Plant species act as natural bioindicators of atmospheric pollutants. Plants can be used as bioassay systems for monitoring atmospheric pollutants. Plant injury symptoms, altered growth and reproductive pattern, changes in yield and/or productivity, and changes in species distribution can be used singly or in combination as monitoring devices.

Ozone: depression of frond multiplication and floral production in duckweed.

Plants of Lemna perpusilla #6746 grown in an environment charged daily with a low concentration of ozone over 2 weeks were slower to begin multiplying, had a significantly lower rate of frond doubling, and required longer to produce fewer flowers than control plants. Treated plants produced smaller, slightly yellow fronds but had no symptoms of acute injury. Control plants produced four times as many fronds and six times as many flowers as plants continuously exposed to ozone (0.

Reduction in tobacco pollen germination and tube elongation, induced by low levels of ozone.

Pollen of the ozone-sensitive tobacco variety Bel W-3 undergoes a reduction in germination rate and tube elongation when exposed to ozone. As little as 0.1 part of ozone per million for a 5.

Nutritional Relationships among Certain Filamentous Fungi and a Marine Nematode.

A marine form of nematode, Aphelenchoides sp., can develop and reproduce effectively on viable mycelia of various filamentous fungi including certain widespread marine species. The efficiency of utilization of fungal mycelium by the animal, based on the ratio of the number of nematodes to the dry weight of fungal mycelium, varies greatly among fungi, from less than 100 to as much as 5000 for several of the marine species studied.

Heterocaryotic Nature of Ring Formation in the Predaceous Fungus Dactylella doedycoides.

Morphologically indistinguishable conidia of the predaceous nematodeattacking hyphomycete Dactylella doedycoides Drechsler vary in their ability to produce constricting rings, depending upon their heterocaryotic state. Three types are noted: those producing rings with or without stimulation, those never producing rings, and a mixed or wild type, made up of a mixture of the first two types.