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Biomedical subjects

K E Cushman

Publications and source records attributed to K E Cushman.

5 recordsLinked to original sources
PubMed1998

Factors controlling activity of zirconia-titania for photocatalytic oxidation of ethylene.

Small photocatalytic devices were developed to remove ethylene from closed plant growth units flown in space. The devices utilized sol-gel-derived catalyst pellets of zirconia-titania. This study was undertaken to understand the significance of different factors on the photocatalytic activity of the catalyst. Increasing reaction temperatures and decreasing humidity of the air significantly increased oxidation of ethylene. The quantity of ethylene oxidized per unit time increased linearly with increasing flow rates, and increasing concentrations of ethylene. Zirconia-titania pellet size and heel depth had little effect on oxidation of ethylene. Platinizing the zirconia-titania significantly increased ethylene oxidation. The catalyst was found to absorb large quantities of water when the humidity of the air stream was elevated and this greatly decreased catalytic activity.

Air Conditioning↗
PubMed1998

The role of ethylene in the development of constant-light injury of potato and tomato.

The role of ethylene in the development of constant-light injury of potato (Solanum tuberosum L.) and tomato (Lycopersicon esculentum Mill.) was investigated. In one study, silver thiosulfate (STS) was applied to the foliage of four potato cultivars growing under constant light. Leaf area and shoot dry mass of 'Kennebec' and 'Superior', cultivars normally injured by constant light, were greater (P < 0.05) than those of control plants given foliar applications of distilled water. Examination of STS-treated 'Kennebec' leaflets revealed significantly less injury (necrotic spotting and reduced starch content) than the water-treated controls. 'Norland' and 'Denali', cultivars tolerant of constant light, exhibited no differences in growth between treatments. In a second study, injury (necrotic spotting and reduced starch content) was induced in leaflets of 'Denali' when exposed to spray applications of 0.5 mmol L-1 ethephon or air containing 0.5 to 0.8 microL L-1 ethylene. In a third study, three genotypes of 'Ailsa Craig' tomato were grown under constant light. Leaves of the normal 'Ailsa Craig' exhibited epinasty, reduced chlorophyll concentration, and reduced starch content. Leaves of a mutant 'Ailsa Craig', containing the Never ripe mutation, did not exhibit epinasty but exhibited the same amount of reduced chlorophyll concentration and starch content as normal plants. Leaves of a transgenic 'Ailsa Craig', containing an antisense gene of 1-aminocyclopropane 1-carboxylate (ACC) oxidase, were epinastic, but chlorophyll concentration and starch content were greater than in leaves of normal and mutant plants. These results suggest that transgenic plants were more tolerant of constant light than the other genotypes. Evidence from these studies indicates that ethylene, combined with constant light, has an important role in the development of constant-light injury.

Biomass↗
PubMed1996

Size of tuber propagule influences injury of 'Kennebec' potato plants by constant light.

Chlorosis and necrotic spotting develop on the foliage of particular cultivars of potato (Solanum tuberosum L.) when grown under constant light. 'Kennebec', a cultivar severely injured by constant light when propagated from tissue-cultured plantlets, also was injured when plants were propagated from small tuber pieces (approximately 1 g). However, plants did not develop injury when propagated from large tuber pieces (approximately 100 g). Plants from large tuber pieces grew more rapidly than plants from small tuber pieces. The role of plant vigor and carbohydrate translocation in controlling injury development is discussed.

Culture Techniques↗