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- Author or Editor: T. L. Gilbertson-Ferriss x
Abstract
Vacuum infusion or soaking of freshly harvested Freesia hybrida Bailey ‘Moya’ corms in solutions of ethephon, gibberellic acid (GA3), abscisic acid (ABA), benzylamino purine (BA) or indoie-acetic acid (I A A), or in solutions with combinations of these growth regulators, did not decrease the time required for shoot emergence. Ethephon delayed shoot emergence and acted synergistically when combined with GA3, or with GA3 and BA, to further delay shoot emergence. Ethephon or ethephon + B A treatments increased the number of shoots produced per corm. Days to flower and flower quality were not influenced by any of the exogenous growth regulator treatments. Presently, there appears to be little horticultural advantage in applying these growth regulators to freesia corms to hasten shoot emergence prior to planting in order to circumvent the need for 10 to 13 week storage treatment at 28°C to remove dormancy and to ensure rapid shoot emergence.
Abstract
Corms of Freesia hybrida Bailey ‘Moya’ and F. hybrida ‘Maria’ were stored at 2°, 13°, or 30°C immediately after harvest and sampled at 0, 6, or 13 weeks for fresh weight, sprouting ability, free indoleacetic acid (IAA), free abscisic acid (ABA) and conjugated ABA (conj-ABA). High performance liquid and gas-liquid chromatography methods were used for identification and quantification of the extractable IAA, ABA, and conj-ABA. Shoots from corms planted immediately after harvest emerged in 33 to 57 days. It is suggested that freshly harvested F. hybrida corms exhibit physiological dormancy for not more than 4 to 6 weeks and subsequently enter a state of imposed dormancy in storage at 30° or 2°. Physiological dormancy was released more rapidly and corm shoots emerged more rapidly during imposed dormancy when stored at 30° versus 2°. The 30° treatment did not appear to be mandatory for shoot emergence since corms stored at 2° or 13° for 6 weeks emerged within 5 or 20 days, respectively. Extended storage at 13° promoted pupation whereas storage at 30° and 2° prevented pupation. Pupated corms did not emerge when planted. The IAA, ABA, and conj-ABA levels in the corms during storage did not correspond with growth inhibition but rather appeared to relate to the formation of the new corm during pupation.
Abstract
Freesia hybrida Bailey ‘Moya’ corms were analyzed for extractable indole-3-acetic acid (IAA), abscisic acid (ABA) and conjugated ABA (conj.-ABA) before and after 13 weeks of storage at 30°C. After 13 weeks of 30° storage, which is required for emergence, IAA levels did not change in the apical node + bud; however, there was a decrease in ABA and no statistically significant change in the conj.-ABA levels. IAA level increased (0.5 to 14 ng/g fresh weight) in the lateral buds after 13 weeks of heat while the ABA and conj.-ABA did not statistically change. Over the same period, IAA increased slightly (3 to 7 ng/g fresh weight) in the remaining corm tissue while ABA and conj.-ABA levels remained statistically constant.
Abstract
Corm, shoot, and flower development in seed grown Freesia hybrida Bailey cv. Super Emerald Mixture were compared with levels of endogenous indoleacetic acid (IAA), abscisic acid (ABA) and conjugated ABA (conj-ABA) in the developing corm tissue. Lowering the forcing temperature to below 15°C stimulated floral initiation and corm filling. IAA levels decreased midway through corm filling in 1977 whereas in 1978 the decrease was not statistically significant. During the period of rapid corm filling, ABA levels increased as the temperature decreased below 15° suggesting an association between temperature, corm filling, and ABA.