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1978 - 197911980 - 19891

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Has files: YesSubject: search.filters.subject.Growth and flowering behaviour

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    The influence of temperature on the growth and flowering of oriental lilies (Lilium cultivars) : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy at Massey University
    (Massey University, 1978) Salinger, John Paiba
    The potentiality of growing dwarf cultivars of Oriental lilies as flowering pot plants was investigated. Two cultivars, L. auratum 'Little Gem'and L. x parkmanni 'Little Robin' were grown to assess their suitability and determine a predictable schedule of production. Initially it was established that these plants could be grown satisfactorily in containers and that after adequate vernalization adequate growth and flowering took place. In bulbs selected after natural senescence, vernalization can be achieved by planting and storing the bulbs outdoors to experience natural winter chilling and also artificially by storage at controlled cool temperatures. Planting prior to artificial cool storage was not advantageous. There is a minimum period of storage of 35 days and preferably 42 days for both cultivars, while temperatures may range from 1.7°C to 8°C for L. auratum 'Little Gem and to 12°C for L. x parkmanni 'Little Robin'. The periods from planting to emergence and emergence to macroscopically visible flower buds are inversely related to the length of time the bulbs are stored, irrespective of the cool temperature. Subsequent growth to anthesis is directly related to the temperature at which the plants are grown and independant of previous storage times and temperatures. The time required to achieve anthesis is consistent in any one temperature regime. Although the longer the time the bulbs experience cool temperatures, the sooner the plants achieve anthesis, the total time from commencement of storage to anthesis is similar for all storage periods up to 10 weeks. When bulbs are inadequately vernalized, growth and flowering is irregular; growth being resetted and anthesis delayed or occuring spasmodically. The growth and development of lilies is considered and compared with that of other bulbous geophyles.
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    Seed production in birdsfoot trefoil (Lotus corniculatus L.) : a thesis presented in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Seed Technology at Massey University, Palmerston North, New Zealand
    (Massey University, 1989) Li, Qingfeng
    This thesis reports the results of three years' research on seed production of birdsfoot trefoil (Lotus corniculatus L.). Previous work by other researchers has suggested that a protracted flowering period is a major factor limiting seed production in this legume. The research programme was begun in 1986 with an investigation of the cause(s) of this protracted flowering period. By carefully examining the growth and flowering behaviour of tagged shoots formed at different times of the year, it was identified that the protracted flowering pattern in this plant is caused by the continuous production of shoots with the capacity to flower. The continuous development of new shoots replacing older flowering shoots was the main cause of the long flowering period. Results of the first year's research also showed that seed yield is primarily determined by the number of inflorescences produced. In turn, inflorescence numbers are primarily dependent on the number of shoots available at the time of flowering. It was suggested by the results that manipulation of the number and branching of shoots should be an important management strategy for improving seed production in this plant. The second stage of the study involved a number of hand removal and cutting treatments designed to investigate the possible effects of shoot removal on plant growth and seed production. Hand removal of crown shoots affected branching behaviour in this plant. Removal of young crown shoots at different growth stages resulted in a range of plant structural forms which influenced seed production potential. Cutting treatments, the major effect of which was to remove a section of shoot from the top, showed no obvious beneficial effects on seed yield in birdsfoot trefoil. In the third stage studies were extended to investigate a more practical situation in which plant growth regulating chemicals (paclobutrazol (PP333), ethofumesate (Nortron) and fatty alcohols (Fatol Super)) were used to manipulate shoot growth and development. Research at this stage involved both widely spaced individual plants and plants grown in a sward to simulate commercially practised situations. Results showed that PP333 is a promising pre-peak flowering shoot manipulator which acts by promoting branching. Nearly a 40% increase in seed yield was consistently obtainedin two years' experiments when this chemical were applied during the time from the pre-bud stage to the early flowering stage. Nortron showed its value in sward situations when applied at early plant development stage. However, Nortron was of limited value when it was used as a post-peak flowering shoot manipulator because of its injurious effect on plant growth and flowering. Fatol Super showed some potential as a post-peak flowering shoot manipulator, particularly when applied to spaced plants, but was less effective in sward situations. This reduces its value for use in the narrow row or sward seed production systems currently practiced in New Zealand for birdsfoot trefoil.