Effects of High Air and Soil Temperature Stress on Growth and Tuberization in Solanum tuberosum

Potato plants (Solanum tuberosum L.) were grown at differentair and soil temperatures to determine the effects of high-temperaturestress on root, tuber, and shoot growth. Cooling the soil (17–27C) at high air temperatures (30–40 C) relieved noneof the visible symptoms of heat stress on shoot growth; norwas the degree of induction to tuberize in leaves increased,as reflected in tuberization of leaf-bud cuttings. Heating thesoil (27–35 C) at cool (17–27 C) air temperatureshad no apparent detrimental effect on shoot growth or inductionof leaves to tuberize. However, in each case hot soil largelyeliminated tuber development. In one experiment stolons grewup out of the hot soil and formed aerial tubers upon reachingthe cool air. When leaf-bud cuttings from induced plants wereused as a model system, high soil temperatures inhibited tuberdevelopment from the buried leaf buds, in the absence of anyroot growth. Apparently the induction of leaves to tuberizeis affected principally by air rather than soil temperature,but expression of the signal to tuberize can be blocked by highsoil temperature. Solanum tuberosum L., potato, temperature stress, soil temperature, tuberization