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  • Author or Editor: Frank B. Salisbury x
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Abstract

Greenhouse tomatoes (Lycopersicon esculentum Mill. cv. Tropic) subjected to 10 seconds of gentle water spraying each day were inhibited up to 40% in plant height, compared to unsprayed controls or plants wet each day with a water mist. Manual shaking of the stems for 10 seconds each day produced reduction in stem elongation similar to the spraying. Spraying or shaking also slightly reduced fresh weights and yields.

Open Access

Abstract

To assess the cost and area/volume requirements of a farm in a space station or Lunar or Martian base, a few laboratories in the United States, the Soviet Union, France, and Japan are studying optimum controlled environments for the production of selected crops. Temperature, light, photoperiod, CO2, humidity, the root–zone environment, and cultivars are the primary factors being manipulated to increase yields and harvest index. Our best wheat yields on a time basis (24 g·m–2·day–1 of edible biomass) are five times good field yields and twice the world record. Similar yields have been obtained in other laboratories with potatoes and lettuce; soybeans are also promising. These figures suggest that ≈30 m2 under continuous production could support an astronaut with sufficient protein and about 2800 kcal-day-1. Scientists under Iosif Gitelzon in Krasnoyarsk, Siberia, have lived in a closed system for up to 5 months, producing 80% of their own food. Thirty square meters for crops were allotted to each of the two men taking part in the experiment.

Open Access

Abstract

Radiation in controlled environments was characterized using fluorescent and various high-intensity-discharge (HID) lamps, including metal halide, low-pressure sodium, and high-pressure sodium as the radiation source. The effects of water, glass, or Plexiglas filters on radiation were determined. Photosynthetic photon flux (PPF, 400 to 700 nm), spectra (400 to 1000 nm), shortwave radiation (285 to 2800 nm), and total radiation (300 to 100,000 nm) were measured, and photosynthetically active radiation (PAR, 400 to 700 nm) and longwave radiation (2800 to 100,000 nm) were calculated. Measurement of PPF alone was not an adequate characterization of the radiation environment. Total radiant flux varied among lamp types at equal PPF. HID lamps provided a lower percentage of longwave radiation than fluorescent lamps, but, when HID lamps provided PPF levels greater than that possible with fluorescent lamps, the amount of longwave radiation was high. Water was the most effective longwave radiation filter. Glass and Plexiglas similarly filtered longwave more than shortwave radiation, but transmission of nonphotosynthetic shortwave radiation was less with Plexiglas than glass. The filter materials tested would not be expected to influence photomorphogenesis because radiation in the action spectrum of phytochrome was not altered, but this may not be the only pigment involved.

Open Access

Abstract

At last year's W-130 Regional Project meeting in Penticton, B.C., Edward L. Proebsting, Jr., chairman of the meeting, requested that we communicate our interest and discussion in the Oct. 1985 Viewpoint article by Lang, Early, Arroyave, Darnell, Martin, and Stutte concerning dormancy terminology (HortScience 20:809–812).

Open Access