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Item Enhancement of calcium concentration in Zantedeschia plants : a thesis submitted in partial fulfilment of the requirements for the degree of Master of Horticultural Science in Plant Science at Massey University(Massey University, 1995) Rodil, Carlos NAs part of a research programme developing the use of enhanced calcium (Ca) concentrator of plant tissue as a means of control of bacterial soft rot in hybrid Zantedeschia, changes in Ca concentration were monitored using two methods of application. Gypsum application at 9 kg/m³ and a pre-plant vacuum application of 75% calcium chloride (CaCl₂) solution were used to follow changes in calcium (Ca) in concentration and its forms in tuber peel and matured leaves of hybrid Zantedescia plants. Throughout the period of growth, gypsum application increased approximately 2.0 mg/g Ca concentration of tuber peel tissue and matured leaves. The concentration in tuber peel tissue was increased to a maximum of 17.42 mg/g at 84 days after planting, then, declined to the concentration recorded at planting by 140 days. In contrast, the calcium concentration of the matured leaves increased continuously throughout the growing period. Plant available Ca in the gypsum amended medium was approximately three fold greater compared to that of the control (13.08 and 4.33mg/g at 14 days after planting or 15.53 and 4.96 mg/g at 98 days after palnting), and neither treatment showed any consistent trend of change over time. The decline in Ca concentration in tuber peel tissue coincided with the period of rapid tuber growth. Hence, it was suggested that this increase in tuber growth may have diluted the Ca concentration throughout the period of tuber enlargement. As evident by the continued accumulation of Ca within leaves, a further factor contributing to the decline in Ca concentration of the tuber peel may have been the limited ability of plants to regulate Ca distribution between the high (leaves) and low (tubers) transpiring tissues. lt was concluded that the application of gypsum is able to enhance the Ca concentration of the plant tissue. It was also concluded that there were no relationship between the trend of plant tissue calcium concentration and the plant available Ca in the growing medium. Pre-plant vacuum infiltration of 7.5% CaCl₂ increased the total Ca concentration of the tuber peel in addition to the different forms of Ca (i.e., soluble Ca, calcium oxalate and the Ca bound in the cell wall). However the increase was not maintained for the whole duration of growth. The concentration of all forms of Ca was increased to a maximum at post vacuum (PV) sampling and then subsequently declined before planting (BP). Once planted, and throughout the duration of growth, tubers vacuum infiltrated with 7.5% CaCl₂ did differences in the total Ca concentration or in the different forms of Ca were evident compared with those vacuum infiltrated with 0% CaCl₂ or the non vacuum treated tubers. Similarly with the matured leaves, the concentration of the total Ca and the different forms of Ca, did not result in any differences between treatments.Item An analysis of the New Zealand supply of calla to the Umeda wholesale auction market : a thesis presented in partial fulfilment of the requirements for the degree of Master of Horticultural Science in Economics at Massey University(Massey University, 1995) Rowe, Ivan StewartThis paper is an exploratory analysis and discussion of the supply of New Zealand Calla to the Umeda wholesale auction market in Osaka, Japan. The hypothesis, that total revenue has not been maximised at the Umeda market, was tested and found to be true. The test was conducted by optimising the supply schedule, constrained by the total volume of imported Calla (white and coloured) sold at Umeda each season. To conduct this test, data collection at the Umeda wholesale auction market was necessary. The results are based on observations of two and a half seasons (January 1992 to June 1994) for each Calla product (i.e. Japanese white Calla, Japanese coloured Calla, imported white Calla and imported coloured Calla). As New Zealand supplies 90-95 per cent of Calla imports each year, it was assumed that all imported Calla sold at Umeda were grown in New Zealand. 1 The statement that 90-95 per cent of imported Calla are from New Zealand holds for 1989-1994. In conjunction with data collection, many representatives of the Japanese cut-flower market were interviewed in order to provide descriptive information as well as the requirements and expectations of the Japanese market (not just the Umeda wholesale auction market). The results show that, in terms of maximising total revenue, imported Calla tend to be poorly allocated over the season. The exception to this was imported white Calla in the 1993/4 season, where maximum total revenue was only NZ$4,600 more than the actual. In the previous season, imported white Calla attained a total revenue of NZ$17,700 less than the maximum. The imported coloured Calla results show that maximum total revenue was NZ$20,000 more than the actual in 1992/3 and NZ$17,800 more in 1993/4. As this paper is of an exploratory nature, total revenue maximisation was not the only focus. Constant Market Shares Analysis was also applied to the data, in an attempt to explain changes in the share of imported Calla at Umeda. The results of Constant Market Shares Analysis were inconclusive with respect to explaining the observed changes. This tested the limits of this deterministic form of analysis. Specifically where the appropriateness of Constant Market Shares Analysis on small data sets and products where the underlying product composition (cultivar and grade mix) changes from season to season. In both respects Constant Market Shares Analysis was found to be very limited as a simple means of explaining changes in supply.Item Dry matter partitioning in Zantedeschia K. Spreng, as influenced by temperature and photosynthetic photon flux : a thesis presented in partial fulfilment of the requirements for the degree of Doctorate of Philosophy in Horticultural Science at Massey University(Massey University, 1993) Funnell, Keith AllenThe in vivo and in vitro dry matter accumulation and partitioning in plants of the Zantedeschia pentlandii-like (Watson) Wittm. selection 'Best Gold' were described under a range of either temperature and photosynthetic photon flux (PPF) regimes, or sucrose concentrations, using plant growth analysis. The initiation of tuber growth, as denoted by increases in both structural and starch dry weights, did not require an obligative environmental trigger. Relative rates of dry matter accumulation (RGRW) increased linearly with increasing temperature up to a maximum of 28 C, with maximum final total and tuber dry weight occurring between 21 and 26 C both in vivo and in vitro. The linear relationship between the relative rate of dry matter accumulation of the tuber (RGRT) and temperature, indicated a PPF dependent base temperature for tuber growth between 4.8 and 6.1 C. By principally altering dry matter partitioning, total dry matter accumulation was highly adaptive to PPF regime. The ability to alter the photosynthetic rate and the partitioning of the daily increment of dry matter into leaf area (LWP), resulted in greater values of the estimated final total plant dry matter under the low PPF regime (348 µmol m-2s-1), at temperatures less than 22 C. At temperatures greater than 19 C the estimated maximum total plant dry weight was either not influenced by PPF or was slightly greater under the high PPF regime (694 µmol m-2s-1). This ability to effectively utilize a low PPF regime indicates that this selection is shade tolerant. The optimum PPF for growth was found to be temperature dependent: estimated maximum total plant dry weight occurred under high PPF at 25 C, whereas the estimated maximum tuber dry weight occurred at 24.5 C under low PPF. RGRW was highly correlated with LWP. In contrast, only a poor correlation was determined between RGRW, and either the efficiency of these leaves to produce additional dry matter, i.e., net assimilation rate (NAR), or starch concentration or soluble carbohydrate concentration. Photosynthetic rate was correlated with RGRW, but not with RGRT. While the photosynthetic process must be involved in contributing photoassimilates for tuber growth, it was suggested that the plant's response to dry matter partitioning into the leaf, i.e., LWP, and the tuber, i.e., TWP, had a greater influence in determining tuber growth than could be accounted for by the photosynthetic rate. Mechanisms of acclimation under both PPF regime suggested that tuber growth was principally source limited. Source limitation was expressed either in terms of: 1) enhanced intersink competition for assimilates, as occurred under the low PPF regime, where enhanced leaf area development (LWP) was in direct competition with enhanced tuber growth (RGRT). This was also confirmed in vitro where dry matter partitioning to the tuber was reduced under limited source strength. 2) efficiency of dry matter accumulation of leaf area present, as occurred under the high PPF regime, where large increases in RGRT were correlated with increased NAR. This was also confirmed in vitro where increased source strength increased tuber dry weight. However, in vitro experiments where source strength was controlled, illustrated that tuber growth was also potentially sink limited at temperatures both lower and higher than the optimum. At 31 C the sink limitation of tuber growth arose from more than the temperature-induced limitation on growth and respiration found at other sink limiting temperatures. At this temperature an additional form of sink limitation was evident where partitioning of dry matter towards the tuber was also restricted. It was suggested that this additional form of sink limitation may have arisen from high temperature inactivation of starch metabolising or sucrose unloading enzymes. Application of the dry matter partitioning term TWP, provided a more sensitive measure of short term changes in partitioning than the conventionally used term, harvest index. The optimum temperature range for growth was close to the average daily air temperature during the season for the sites of natural habitat of the suggested parent specie, Zantedeschia pentlandii. Similarly the shade tolerance status of this selection was paralleled by the diversity of PPF habitats it naturally occupies, as created by open grassland and forest margins. It was therefore suggested that Zantedeschia 'Best Gold' is well adapted to optimise growth under the temperature and PPF regimes of its natural habitat. This study suggests that improvements in commercial yield of Zantedeschia tubers can be achieved in all regions of New Zealand through the use of protected cultivation with supplemental heating. However, unless using protected cultivation, the potential improvements in commercial tuber yields, through the application of shading, are only likely to be evident in warmer regions of New Zealand where growers utilize extended periods of cultivation and optimise leaf area duration.Item Hormonal control of branching and flowering in Zantedeschia species : a thesis presented in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Plant Physiology at Massey University, Palmerston North, New Zealand(Massey University, 2011) Subbaraj, Arvind KumarCalla lilies (Zantedeschia sp. Family: Araceae) are perennial herbaceous geophytes, gaining commercial importance as a cut flower and potted flowering plant. Stimulating branching in Zantedeschia would equate to higher floral productivity via increasing tuber size/weight and/or via triggering the sympodial flowering cascade. Bud outgrowth is however controlled by an autonomous developmental programme, executed via different degrees of para- (apical dominance) and/or endodormancy. Based on visual clues that represent underlying changes in the shoot apical meristem, the growth cycle of Zantedeschia was demarcated into three phases, which coincide with the transition of buds from apical dominance to endodormancy. Application of 6-benzylaminopurine (BAP; an aromatic cytokinin) was successful in stimulating branching in phase 1. This equated to an increase in tuber size/weight, which in turn resulted in increased floral productivity in the next growth cycle. . Efficacy of BAP alone to stimulate branching declined from phase 1 to phase 3, and the need for a sequential application of gibberellin (GA3) increased concomitantly. GA3 alone had no effect on branching. Efficacy of GA3 alone to stimulate flowering declined from phase 1 to phase 3, and the need for a sequential application of BAP increased concomitantly. BAP alone had no effect on flowering. Stimulation of branching and enhanced flowering achieved by the reciprocal cross-talk between cytokinin and gibberellin may have major commercial implications. When applied with unlabelled BAP, a significant decline in the uptake of [8-14C] BAP ([8-14C] BAP + BAP) was observed in phase 3, resulting in a decline in radioactivity available in the buds and upper region of the tuber. With unlabelled GA3 ([8-14C] BAP + GA3) however, increased radioactivity was available in these parts in phase 3. Meta-topolin (mT) was identified as a metabolic product of BAP. Application of [8-14C] BAP + BAP resulted in a decline in the amount of mT from phase 1 to phase 3. However, application of [8-14C] BAP + GA3 resulted in an increase in the amount of mT in phase 3. mT and 6-benzylaminopurine riboside (BAR) were also identified in natural plants. Further studies on branching control in phase 1 involving topolins and strigolactones, elucidating the mechanisms of cross-talk between cytokinin and gibberellin in phase 3, reevaluating the relationship between branching and floral productivity, and corroborating the common mechanisms between dormancy and flowering are recommended.Item Interspecific hybridisation and molecular characterisation of hybrids in the genus Zantedeschia : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Plant Health at Massey University(Massey University, 1992) Yao, Jia-LongThe genus Zantedeschia consists of two sections: a section containing Z. aethiopica, a white-flowered, evergreen species and a second section containing five winter-dormant species. A new species, Z. odorata, was recently described which does not fit into either of the two sections. Chromosome karyotypes of five species and two hybrid cultivars were prepared. Karyotypes are distinct between the two sections but not distinct within the second section. The karyotype of Z. odorata falls between the two sections although it is more closely related to Z. aethiopica. Colchicine treatment of multiplying shoots in vitro produced tetraploid plants from eight cultivars and two species of the second section of the genus. Most of these plants were pure tetraploids. Z. aethiopica did not multiply tn vitro. Colchicine treatment of Z. aethiopica 'Childsiana' germinating seed produced a few tetraploid plants and many diploid/tetraploid chimeric plants. A screening procedure for tetraploids using stomatal measurements, with confirmation by chromosome counting, was demonstrated to be an efficient and accurate way to identify tetraploids. Triploid plants were produced from two diploid/tetraploid crosses with the aid of in vitro embryo culture. Crosses were made between the two sections using a number of species and genotypes at the diploid and tetraploid levels. In these crosses, endosperms were watery and transparent and embryos were small (in most cases less than 0.3 mm). Embryos embedded within endosperms were cultured because the embryos were too small to be cultured separately from the endosperms. From these cultures, over one hundred hybrid embryos were rescued. These hybrids were all albino. In an electron microscopy study, it was found that the plastids of these albino hybrids had no prolamellar body in the dark nor grana in the light. Z. odorata was tested as a bridge for gene transfer between the two sections because it falls in between them. Hybridisation between Z. odorata and Z. aethiopica produced a number of virescent, albino and chimeric (green/albino) hybrids following embryo culture and seed germination. Hybrid production was much easier, however, when Z. aethiopica was used as the maternal parent. All hybrids rescued from crosses between Z. odorata and the second section of the genus were albino. This study also demonstrated that Z. odorata stigmas can receive pollen from the same spadix. Z. odorata embryos become dormant before the seeds matured. Plants of Z. odorata did not produce any flowers unless they were treated with gibberellic acid (GA). However, two or three flowers per plant were produced when 50 ppm GA3 or GA4 + 7 was applied to tubers as a pre-planting treatment. A partial library was constructed with total leaf DNA of Z. aethiopica 'Childsiana'. A species-specific nuclear DNA clone, pZAC3, was isolated by differentially screening this library with radioactively-labelled total DNA of different species. This clone was characterised by restriction enzyme mapping and RFLP (restriction fragment length polymorphism) analysis. By RFLP analysis, an apple rDNA clone differentiated between the sections of the genus. The apple rDNA clone and pZAC3 were successfully used for hybrid identification. From this library, six plastid (pt) DNA clones were also isolated by hybridisation with kiwifruit ptDNA clones. Using these ptDNA clones, RFLP bands were identified to differentiate between species and, in one case, between genotypes within a species. Biparental ptDNA inheritance and a ptDNA deletion were detected in the albino hybrids between the two sections with these ptDNA clones. The data from RFLP analyses gives the first molecular data on the phylogeny of Zantedeschia and indicates that Z. odorata is distinct from the previously-described two sections and falls in between the two sections.Item The physiology and control of re-greening in spathes of Zantedeschia : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Plant Physiology at Massey University, Palmerston North, New Zealand(Massey University, 2011) Chen, JianyuSpathe re-greening is a primary determinant limiting postharvest quality of Zantedeschia Spreng. as a cut flower, pot- or landscape-plant. A treatment that can be utilised by growers to delay re-greening offers potential to improve the postharvest quality and provide a marketing advantage. To achieve this, and develop an understanding of the physiological mechanism of re-greening, this project investigated the changes in colour, levels and types of pigment, and differentiation of plastids in spathe tissue durng re-greening; and how this process was controlled by various factors including fructification, light and various plant hormones (e.g. cytokinin and gibberellin). In the hybrid ‘Best Gold’, spathe re-greening was initiated within three days after horticultural harvest-maturity and, within two weeks the whole abaxial surface of the spathe had re-greened. During this period, the adaxial surface did not re-green and remained yellow in colour. The change in colour of the abaxial surface primarily resulted from the accumulation of chlorophyll within the subepidermal layers, as reflected by a strong correlation between the colour coordinate hue angle (Hº) and total chlorophyll content in that surface (r = 0.98). Monitoring Hº can therefore, be used to evaluate the degree of re-greening for ‘Best Gold’ without chlorophyll analysis. The content of carotenoid (in particular lutein which was predominant) was comparatively steady during re-greening. From an ultrastructural perspective, spathe re-greening was characterized by redifferentiation of chloroplasts from chromoplasts, as compared with de novo synthesis of chloroplasts from proplastids. The redifferentiation of chloroplasts involved thylakoid reformation through multiple mechanisms. In addition to de novo synthesis of thylakoid by invaginations of the inner-envelope membrane, it is likely that the thylakoids were either derived from primary thylakoids or plastoglobuli present in mature chromoplasts. The occurrence of re-greening in the spathe of both Zantedeschia aethiopica and ‘Best Gold’ following the removal of the spadix prior to pollination, contradicted the hypothesis that re-greening was induced by fructification (Pais and Neves, 1982- 1983). Further to this, the occurrence of re-greening in the spathe of ‘Best Gold’ with a spadix naturally devoid of female flowers, and the re-greening of pigmented leaves devoid of any true flower parts, also contradicted this hypothesis. The current findings therefore, indicate that fructification is not necessarily a prerequisite for induction of re-greening. In absence of light, no chlorophyll accumulated in spathe tissue of ‘Best Gold’, but the initial redifferentiation of chloroplasts from chromoplasts, as characterized by the formation of double-membrane lamella, was noted. Without light however, redifferentiation of chloroplasts was not completed. These suggest spathe re-greening requires light for the process to complete, but the onset of re-greening can be induced in darkness. The application of 6-benzylaminopurine (BAP) stimulated re-greening in spathe tissue by enhancing accumulation of carotenoid and chlorophyll, and also stacking of grana. But the response to BAP was dependent on the presence/absence of light, the stage of re-greening, and which surface, i.e. abaxial or adaxial. In contrast, the application of gibberellin (GA3) retarded formation of double-membrane lamella, and thus delayed the onset of re-greening. Hence, a synergistic effect of BAP and GA3 in delaying the onset of re-greening was likely to be a result of co-regulation between BAP-stimulated accumulation of carotenoid and GA3-stimulated retardation of chloroplast redifferentiation. By integrating both light and hormonal factors, several methods were tested on the actual horticultural commodity, i.e. flowers (peduncle, spathe and spadix) of ‘Best Gold’, so as to evaluate their efficacy in delaying re-greening. Pulsing flowers in darkness at 5 ºC for 24-h in a solution containing both GA3 and BAP, was the most effective treatment in postponing re-greening, resulting in a seven-day delay in regreening of the spathe.