Effects of storage temperature and duration on the dormancy ofSandersonia aurantiacatubers

Abstract

The effects of three storage temperatures (1,4, and 9.5°C) and six storage durations (0, 30, 60, 90, 120, and 150 days) on tuber sprouting and stem quality of Sandersonia aurantiaca were investigated. Tubers did not sprout at lifting when given inductive conditions, but high percentages sprouted (91.7%) after only 30 days of chilling. Percent sprouting remained high (93.8%) after 90 days of storage, but decreased to 86.5% with 150 days of storage. Sprouting percentages were high for all storage durations at 4°C. Sprouting was significantly less after storage at 9.5°C than at 1 and 4°C at all storage durations. Time to initiation of sprouting and the sprouting period decreased with storage duration up to 90-120 days and were lowest at 4°C. Stem length and flower numbers per stem were significantly higher at storage durations of 90-120 days. Following 90 days of storage, stem length was greater for storage at 9.5°C than at 1 or 4°C. Storage at 4°C for 90-120 days is required to ensure rapid and even sprouting of sandersonia.

Effects of lifting time, curing, and storage treatments on tuber quality and cut‐stem production ofSandersonia aurantiaca

“…In contrast, Clark (1995) found that at a warmer storage temperature of 9.5°C sprouting was reduced to 82.5% compared with 97% at 4°C. In the present study the mean sprouting time decreased with increasing storage duration, and at storage durations of 120-150 days, mean sprouting time decreased with increasing storage temperature.…”

“…Sprouting percentage averaged 84% for tubers lifted between 16 and 22 weeks after planting but only 64% for those lifted at Week 24. In previous studies tuber sprouting was still high (95%) after 171 days of storage at 3-5°C (Clark 1994b), whereas a sprouting percentage of 87% across all storage temperatures was found after 150 days of storage for tubers lifted at Week 22.5 (Clark 1995). The tubers lifted at Week 24 had sufficient cool storage (118 days) to break dormancy (Clark 1995), so it is unclear why they had a lower percent sprouting.…”

“…These temperatures were selected because 4°C was the optimum temperature (3-5 °C) for longterm storage of sandersonia tubers (Clark 1994b); 8.5°C would approximate to the higher temperatures (10 and 9.5°C) used in the sprouting and dormancy experiments of Clark (1994bClark ( , 1995; and 6°C provided a mid-range temperature.…”

“…Cooler storage temperatures (1°C) reduced tuber viability and subsequent sprouting and also reduced stem length (Clark 1994b). Clark (1995) found that storage at 9.5°C for 90 days resulted in greater stem length during forcing than storage at 3-5°C. Market returns are greater for longer sandersonia stems.…”

“…Curing can improve skin colour or formation, dry and senesce remaining roots, heal wounds from leaf stems, and reduce the incidence of disease during storage. Clark (1994bClark ( , 1995 showed that sandersonia tubers should be stored at 3-5°C for 90-120 days to break dormancy and that these storage temperatures were suitable for storage durations of up to 200 days. Cooler storage temperatures (1°C) reduced tuber viability and subsequent sprouting and also reduced stem length (Clark 1994b).…”