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The relationships between temperature and light on vegetative growth of the foliage house plants Epipremnum aureum (Linden and Andre) Bund, and X Fatshedera lizei (Guillaum) were investigated in a controlled environment study during the exponential growth phase. Responses were examined under conditions with a constant day temperature (30°C) in combination with constant night, split-night or sliding night temperatures with means of either 15° or 20°C. Two PFDs of 150 and 320 μmol·s-1·m-2 were included in each temperature treatment. Growth parameters (including dry matter increase, shoot elongation rate and leaf production rate) were all influenced by species but not by each temperature profile within the same temperature integral (ie all growth responses were directly related to mean night temperature). Growth rates were highest under the high PFD conditions but dry weight accumulation per unit of PFD was markedly higher at low PFD than at high PFD. The optimum temperature for vegetative growth of Epipremnum aureum was higher than that for X Fatshedera lizei and Epipremnum aureum was particularly sensitive to temperatures below 10°C.
Abstract
Tubers of Zantedeschia elliottiana (Watson) Engl. and the hybrid Z. ‘Pink Satin’, a Z. rehmannii Engl.-like selection, were stored at 5°C. Over a 3-month period they were transferred to incubators at 12°, 18°, or 24° for 2, 4, 6, 8, or 12 weeks of holding. One-third of these tubers were planted in moist media during this time; the remaining tubers were stored dry and on removal were sprayed with either gibberellic acid (GA3) at 50 mg·liter−1 or distilled water before planting and transfer to a greenhouse. The proportion of flowering of dry-stored tubers of Z. elliottiana was reduced by prolonged storage at 5°. Subsequent storage at 12° did not reduce this proportion, but, at 18° and 24° flowering was reduced further. Tubers of Z. ‘Pink Satin’ were less sensitive to the duration of dry storage at 5°, but increasing time of storage at all subsequent temperatures caused a progressive decrease in the proportion of tubers that flowered. The proportion of moist-stored tubers of both selections that flowered was greater than that for tubers stored dry for an equivalent time. A preplant treatment with GA3 enabled almost total compensation for reduced flowering except after the longest period of storage.