Effects of elevated temperature on radish growth and development

摘要

Fluctuating temperatures (20 deg C - 32 deg C) are typical of plant growth conditions aboard orbiting spacecraft. Because salad-type crops are being considered for future use as a dietary supplement for short duration spaceflight missions, the effects of microgravity on their growth must be tested in these conditions. To understand how the spaceflight environment affects these crops, the effect of elevated temperatures without the effect of weightlessness must first be understood. Radish is being used as a model for the RASTA (Radish Assimilation hi Spaceflight Testbed Atmospheres) experiment to study carbon partitioning in weightlessness. Ground studies are underway to determine the effects of elevated temperature on their growth. Several radishcultivars were grown in a series of temperatures ranging from 18 deg C - 30 deg C. Although the extent of the effect varied between cultivars, temperatures from 26 deg C - 30 deg C elicited more rapid seed germination and earlier cotyledon emergence andexpansion during the first 7 days after planting (DAP). Plants grown at 26 deg C were significantly taller and had greater leaf area at 21 DAP than other treatments. By 21 DAP, the plants grown at 30 deg C were shorter, had lower leaf area and smaller (if any) radish production. Some cultivars exhibited a greater tolerance to the highest temperature, showing normal growth even at 30 deg C.