Malcolm H. Douglas

Essential oils from New Zealand manuka and kanuka: Chemotaxonomy of Leptospermum

Standardized steam distillation and GC analytical methods for oils from manuka, Leptospermum scoparium, are described. These methods were used to analyse two oils from each of 15 L. scoparium populations derived from all around New Zealand, seven Australian Leptospermum populations and one population of Kunzea sinclairii. These populations were all grown from seed at a single site. Principal component analyses of the levels of 50 GC peaks in these 46 oils revealed compositional patterns. Kunzea sinclairii oils were distinguished from Leptospermum oils by higher α-pinene levels (mean 76%). Australian Leptospermum oils had significantly higher 1,8-cineole (mean 20%) and total monoterpene levels (mean 51%) than New Zealand L. scoparium oils (1,8-cineole mean 0.9%, total monoterpene mean 14%). This indicates the need for further taxonomic study of plants currently included in L. scoparium in Australia and New Zealand. There is evidence for three chemotypes of L. scoparium in New Zealand, conforming in part to morphological types: a high-pinene chemotype in the far north, a high-triketone (especially leptospermone) chemotype on the East Cape, and a type containing a complex of sesquiterpenes found over the rest of the country. An oil from the East Cape chemotype showed the strongest antimicrobial activity.

Essential oils from new zealand manuka and kanuka: Chemotaxonomy of Kunzea

Abstract A standardized analytical GC method has been used to analyse essential oils from selected Australian and New Zealand Kunzea species, grown from seed at a single site. The distillation yields and analyses are reported for oils from 26 populations of K. ericoides (kanuka) and from single populations of each of K. flavescens , K. pauciflora , K. sinclairii and x Kunzspermum hirakimata (a Kunzea x Leptospermum cross). Principal components analyses of 37 GC peaks in these oils were used to distinguish compositional patterns. Oils from K. flavescens , K. pauciflora and x Kunzspermum hirakimata had chemical compositions distinct from K. sinclairii and K. ericoides . Oils front New Zealand K. ericoides were mainly α-pinene (mean 68%), but some oils had high p -cymene contents, particularly oils from one Marlborough provenance (mean 31%). A wild population of K. ericoides var. linearis gave oils with similar composition to other K. ericoides . Two K. ericoides oils showed weak antifungal activity.

Dalmatian sage. Part 1. Differing oil yields and compositions from flowering and non-flowering accessions

The components in essential oils of Dalmatian sage, Salvia officinalis L., were identified by 1 H- and 13 C-NMR spectroscopy and by GC-MS. The diterpene manool was identified for the first time in steam-distilled oil from Dalmatian sage. Several sesquiterpenes were also identified for the first time in Dalmatian sage oils. A rapid GC method was developed and used to analyse 13 oils from a preliminary study of Dalmatian sage accessions. Oil yields from pilot-scale distillations in summer were significantly higher from non-flowering accessions than from flowering accessions. Oils from flowering and non-flowering accessions had different compositions, with significantly higher levels of thujones, β-caryophyllene and viridiflorol in oils from flowering accessions

Effect of plant density and depth of harvest on the production and quality of licorice (Glycyrrhiza glabra) root harvested over 3 years

Abstract Licorice (Glycyrrhiza glabra) root production was investigated in Central Otago, Canterbury, and Waikato regions of New Zealand over 4 years. Increasing plant populations at establishment had a large effect on production. Maximum root and rhizome production was achieved with plant populations above 24 000 plants/ha. Low plant densities favoured rhizome production and high densities favoured root production. Sampling roots and rhizomes to 900 mm showed that the majority of production was in the top 300 mm. Roots harvested from below 300 mm contained less glycyrrhizin than surface roots. Glycyrrhizin concentration increased each year and surpassed the minimum international standard of 4% in the first harvest in the Waikato but not until the third harvest at South Island sites. By the third harvest both Waikato and Canterbury grown licorice contained similar amounts of glycyrrhizin but with 90% of the glycyrrhizin content in roots in the 0–300 mm soil layer in the Waikato and in the 0–600 mm soil layer in Canterbury. These trials show that licorice can be grown in New Zealand with fresh root and rhizome yields of 17–28 t/ha in the second and third years of production and with a glycyrrhizin content above the minimum international standard.

Effect of environment and time of planting on the production and quality of yacon (Smallanthus sonchifolius) storage roots

Abstract The tuberous root yields of yacon (Smallanthus sonchifolius) were compared from field trials planted in September, October, and November at four sites (Pukekohe, Hamilton, Lincoln, Mosgiel) across New Zealand. The September plantings gave the highest yields at all sites, with the October plantings giving 17% less yield and the November plantings 61% less. The September planting at Hamilton produced the highest yield of 90 t/ha, Pukekohe 64 t/ha, Lincoln 22 t/ha, and Mosgiel 15 t/ha. Regression analysis established a strong positive relationship between dry root yield and accumulated growing degree days (GDD) below 10°C calculated for base temperatures 0, 6, and 8°C (R2 = 0.87–0.88). Regression analysis R2 values declined above 10°C. Dry root yields were high where heat accumulation was at least 1800 GDD8 for the growing season with c. 1 t/ha of dried roots being produced for every additional 100 GDD8 above 1200 degree days. This relationship helps to identify suitable production environments for yacon. Best root production also needs an undefined level of cool temperatures as at the warmest site crown production was favoured. Total fructo‐oligosaccharide (FOS) content of the yacon roots varied from 48.2% to 67.5%. November yacon had the lowest FOS content and conversely the highest content of non‐FOS carbohydrates.

Mount Cook lily (Ranunculus lyallii)—a potential cut flower?

Abstract Five experiments were undertaken to assess the potential of Ranunculus lyallii Hook. f. (Mount Cook lily) as a cut flower. Three measures of vase life were calculated, and the most useful for this species was found to be the number of days until 30% of flowers plus buds on a stem had senesced. Eleven postharvest chemical treatments (including biocides, commercial preservatives, a wetting agent, and combinations of these) were applied to scapes as pulse or vase solutions, but none significantly extended vase life. However, cool storage (at 3°C) and scape maturity at harvest both significantly influenced vase life. The vase life of scapes cool stored for 6 days averaged 2.4 days longer than the vase life of unchilled controls. Scapes harvested when the terminal bud was starting to open lasted an average of 10.2 days, a gain of 4 days compared with mature scapes harvested with a fully open or senescent terminal bud. Bud opening on scapes occurred in two distinct flushes, 3.5 days apart, and no postharvest treatment significantly affected the length of this gap. Flower quality was higher in buds opening in the first flush. R. lyallii senesced atypi‐cally for the Ranunculaceae; petal wilt rather than abscission was the initial symptom of senescence. There was no evidence that ethylene accelerated senescence, and the ethylene antagonist, silver thio‐sulphate, also failed to delay senescence. R. lyallii has commercial potential as a cut flower.

Effect of growing media on the production of ginseng (Panax ginseng) in Central Otago, New Zealand

Abstract Ginseng (Panax ginseng C.A. Meyer) is a potential new crop for New Zealand. Under artificial shade, 1‐year‐old seedlings were grown in either peat‐ or soil‐based media for 4 years. At the final harvest mean root fresh weight was 55 g/plant in the peat media and 40 g/plant in the soil media. Total ginsenoside % of the 5‐year‐old roots was up to 6.9%. Macrochemical content (N, P, K, S, Mg, Ca) and trace element (Mn, Zn, Cu, Fe, B) content of roots at each harvest and of the leaves at the final harvest, were determined and compared with reported levels for P. ginseng and standards for P. quinquefolius. Botrytis cinerea was present on plant material throughout the experiment, and there was evidence of predation by the scarab larvae of Costelytra novae‐zealandica in the first year. After 4 years of growth, 45% of the plants in the soil media and 63% of plants in the peat‐based media survived.