摘要:

Typical apple (Malus domesticaBorkh.) flavour develops during ripening. Maximum endogenous volatile concentration occurs at the climacteric peak but it is not known whether the volatile biosynthetic enzymes are constitutive or induced during the climacteric. Exposing apples to hypoxic conditions induces accumulation of high concentrations of acetaldehyde and ethanol; after return to air ethyl esters are enhanced and non‐ethyl esters decrease. There are differences in degree of ethyl ester enhancement among cultivars. These may be because of: differential activity or synthesis of alcohol acyl CoA transferase (AAT) or alcohol dehydrogenase (ADH); separate iso‐forms of AAT and ADH each with their own substrate specificity; variation in alcohol precursors in different cultivars; or a combination of all three. Volatile production is greater at higher temperatures in the range from 0 to 30°C but exposure to low temperatures (<3°C) for more than 3 months decreases production. Temperature influences the production of specific volatiles with some compounds only being produced at certain temperatures. It is not known how temperature will affect volatile production after exposure to hypoxia. It is suggested that the enhanced volatile production that occurs in apples following an hypoxic treatment might overcome or reverse the decreases that are induced by low temperatures and controlled atmosphere (CA) storage. The use of hypoxia to enhance volatile concentrations may be a beneficial side effect when such treatments are used for disinfes‐tation purposes. It is possible that given equal efficacy, hypoxia could be either preferred or used as an adjunct to heat treatments to eradicate insects. In addition hypoxic treatment of fresh fruit could induce significant increases in volatile concentrations that could be used in production of high quality essences from apple juice.

ISSN:0114-0671    

DOI:10.1080/01140671.2000.9514136

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Lisianthus(Eustoma grandiflorumGrise.) with novel flower colour patterns have been generated by genetic modification techniques that alter flavonoid biosynthesis. As described previously, the level and pattern of pigmentation in purple‐flowered lisianthus cultivars was altered by the introduction of a lisianthus chalcone synthase (CHS) cDNA in an antisense orientation. As the next step towards commercial development of these new cultivars, the consistency of altered flower patterns in the progeny and the performance of these lines under conditions resembling those used by commercial lisianthus growers in New Zealand have now been assessed. The introduced antisense CHS transgene had no apparent effect on germination rates or plant survival. Altered flower patterns observed in the progeny correlated with the inheritance of the transgenes, as measured by kanamycin resistance and reduction in CHS expression. At least two of the lines showed sufficient consistency in flower pattern to warrant continued development. Additionally, no transfer of the introduced DNA between transgenic and neighbouring non‐transformed lisianthus was observed during this trial.

ISSN:0114-0671    

DOI:10.1080/01140671.2000.9514137

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Doubled haploid (DH) technology allows the production of homozygous cereal lines in a single generation. The integration of DH technology into New Zealand wheat(Triticum aestivum)breeding and genetics programmes has the potential to reduce the breeding time of new cultivars and improve our understanding of agronomic ally important genetic traits. Wheat × maize(Zea mays)crosses are now widely used in the production of wheat DHs. The aim of this study was to develop a wheat × maize method of DH production using New Zealand germplasm. A number of New Zealand wheat cultivars were crossed with different maize genotypes. A successful method for producing wheat DHs was achieved with all genotypes. Several factors were identified as being important in the efficiency of wheat DH production. These included: seasonal constraints, time of embryo excision, method of auxin application, and culture media composition. Of these factors, seasonal constraints were the major limitation in the use of the wheat × maize method for producing DHs in New Zealand.

ISSN:0114-0671    

DOI:10.1080/01140671.2000.9514138

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Ginseng (Panax ginsengC.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 forP. ginsengand standards forP. quinquefolius. Botrytis cinereawas present on plant material throughout the experiment, and there was evidence of predation by the scarab larvae ofCostelytra novae‐zealandicain 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.

ISSN:0114-0671    

DOI:10.1080/01140671.2000.9514139

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

The fatty acid composition of cherry laurel (Laurocerasus officinalisRoem. ‘Globigemmis') varied significantly different among the five stages sampled from 1 June to 15 August. Principal fatty acids, found in cherry laurel fruits harvested from June to August were palmitic acid (16:0), stearic acid (18:0), oleic acid (18:1), linoleic acid (18:2), and linolenic acid (18:3). ‘Globigemmis’ appears to be a rich source of palmitic, stearic, linoleic, and linolenic acids. The minor fatty acids were myristic acid (14:0) and palmitoleic acid (16:1). Arachidic acid (20:0), however, was detected throughout some stages of fruit maturation. Results of this study indicate that the variation in the fatty acid composition of cherry laurel ‘Globigemmis’ during maturation may be useful in understanding the source of flavours and nutritionally important fatty acids in this fruit. The level of of total unsaturation among stages except 181 and 226 days of year (DOY) were found to be significantly different whereas the level of unsaturation/saturation was not different among the stages.

ISSN:0114-0671    

DOI:10.1080/01140671.2000.9514140

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

ISSN:0114-0671    

DOI:10.1080/01140671.2000.9514141

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Apothecial emergence ofMonilinia fructicolaWint. (Honey), potential ascospore dose (PAD), infection periods (IPs), and blossom blight (BB) were quantified in a peach(Prunus persica)block in 1996 during bloom. Flowering began on 21 August, with full bloom 1–7 September and last flowers on 20 September. First apothecia appeared on 25 August after 15 mm rain on 18–20 August, but shrivelled after a few days of drying weather. Main apothecial emergence began, peaked, and declined on 4, 7, and 13 September respectively. Apothecial density from 4 to 13 September was 4.4 per m2of ground but 90% of these were confined to a 15 m wheel rut in the observation plot. Apothecia on bare ground were short‐lived compared with those protected by overhanging grass. Total hymenial surface area within the observation plot was 58.7, 88.6, 18.2, and 5.7 cm2on 4, 7, 10, and 13 September respectively. PAD on each date was 9.35, 14.14, 2.85, and 0.92 × 106/m2, or 27.26 × 106/m2for the whole period. From 4 to 6 September, airborne ascospores trapped by a cyclone spore trap during daylight ranged from 0 to 39/litre air per min. Percentage of flowers contaminated by spores on 3, 5, 12, and 20 September was 10, 65, 68, and 92% respectively. Moderate IPs occurred on 2, 3, 5, 11–12 September, marginal on 16 September, and light on 19 September, resulting in blossom infections of 3, 12, 29, 29, 5, and 50% respectively. This corresponded to natural BB levels of 25% on 7 September and 62% on 27 September. A gradient of increasing BB from the windward to leeward end of the plot occurred. Primary inoculum for BB up to 15 September was primarily ascospores, and thereafter conidia. Sources of conidia were initially twig cankers, then diseased blossoms.

ISSN:0114-0671    

DOI:10.1080/01140671.2000.9514142

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

The incidence and severity of soft rot, flower grades, and tuber yields of calla (Zantedeschiaspp.) plants were affected by the quantity of water received during the growing season, sawdust mulch, and Enhance®biocide applications to tubers before planting. Incidence of plants with soft rot symptoms increased at a relatively constant rate during the season reaching an average for all treatments of 61% at the end of flowering. Irrigated plus mulched callas had 15% less soft rot than the irrigation without mulch or the mulch without irrigation treatments. Yield of tubers was 90% greater from irrigated plants. Dipping tubers in Enhance®before planting slightly reduced the severity of rotting in harvested tubers from non‐irrigated plants. The total number of flowers was not affected by irrigation but was slightly reduced by sawdust mulch. However, the number of long stemmed flowers was increased 41% by irrigation, to over 1.5 per tuber.

ISSN:0114-0671    

DOI:10.1080/01140671.2000.9514143

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

ISSN:0114-0671    

DOI:10.1080/01140671.2000.9514144

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor