Ice-nucleation Gene of Pseudomonas viridiflava KUIN-2 Coded on a Plasmid

Mepanipyrim, N-(4-methyl-6-prop-1-ynylpyrimidin-2-yl)aniline, diminished the cell surface expression of envelope glycoproteins of Newcastle disease and vesicular stomatitis viruses at concentrations where their synthesis was not profoundly affected. Intoxication by diphtheria toxin and ricin and recycling of transferrin were not affected even when cells were treated with mepanipyrim for 2 h before the addition of these probes, indicating that mepanipyrim does not act on the endocytic and recycling pathways of these proteins. Metabolic conversion of C₆-NBD-ceramide to sphingomyelin and its back-exchange to the medium was also not affected, but synthesis and back-exchange of C₆-NBD-glucosylceramide were greatly influenced, and an accumulation of LDL-derived, unesterified cholesterol was induced by the drug. These results are discussed relating to the site(s) of action of mepanipyrim.     

Characteristics of Ice-nucleation Activity in Fusarium avenaceum IFO 7158

The extracellular ice nuclei of Fusarium avenaceum IFO 7158 (FEIN) were stable at pH levels from 2 to 12 and tolerated temperatures up to 40°C. In an activity of the FEIN, proteins were important, however, saccharide and lipid which were proved to be a part of components of bacterial ice nuclei did not participate.     

Germination of kiwifruit,

Silvereyes, Zosterops lateralis Latham, commonly feed on kiwifruit rejected for export and either stored in open bins at packhouses or in piles ready to be fed to livestock, and may play a role in the spread of wild kiwifruit in native and exotic forest in the Bay of Plenty, New Zealand. We determined the germination rate and percentage germination of Actinidia chinensis Planch. seed sown (1) after gut passage through silvereyes, (ingested seed), (2) after a standard laboratory fruit pulp removal method (enzyme-extracted seed), (3) as entire fruit and (4) as fruit sections. Ingested and enzyme-extracted seed sown in trays in a glasshouse had nearly identical percentage germination (63.7% and 64.7% respectively) after 71 days. No seed germinated from intact fruit or fruit slices during the experiment. Gut-passage accelerated the germination rate compared with enzyme-extracted seed. This study supports the view that Z. lateralis is involved in dispersing kiwifruit seed into native and exotic forest.     

Bacterial blight of kiwifruit

Bacterial blight of kiwifruit (Actinidia deliciosa) is caused by Pseudomonas viridiflava. Symptoms are rot of floral buds and flowers, and spots on leaves. Buds and flowers nearest the ground are most likely to be affected. Isolations made from healthy buds, flowers and leaves suggest that the pathogen is an epiphyte on vines throughout the year. Disease incidence fluctuates between seasons, and varies between orchards. A relationship between disease incidence and rainfall in spring is indicated.     

Disruption of an Ice-nucleation Barrier in Cold Hardy Azalea Buds by Sublethal Heat Stress

Ice nucleating barriers of undetermined composition are knownto occur in floral buds of several cold hardy species, includingAzalea. Fluorescence microscopy indicated the presence of phenolic-nchareas within hardy Azalea flower buds, which could be ice barriers.Hardy buds were subjected to a sublethal heat stress of 45 °Cfor 2 h to disrupt barrier integrity. Two hours after treatmentthe low temperature exotherms (LTEs) of flowers were observedusing differential thermal analysis (DTA). The LTEs of budsexposed to heat stress were either fewer in number and/or occurredat higher temperatures than in controls. Visual assay of theflowers following DTA confirmed that heat-stressed flowers werekilled at higher temperatures than control flowers. Heat-stressedbuds also have lower resultant hardiness compared to controlsas demonstrated by controlled freezing experiments. Acclimation, phenolics, resistance, stress     

无菌猕猴桃种子采集方法研究

无菌的猕猴桃种子是猕猴桃胚乳培养、实生苗微嫁接等技术的基础材料,利用消毒剂灭菌是常用的无菌种子采集手段,应用最广泛的消毒剂为升汞(mercuric chloride)和次氯酸钠(NaClO)。为了避免使用消毒剂,该研究提出了一种新的无菌猕猴桃种子采集方法——无菌搅拌法,同时为探索其准确性和应用性,比较了0.2%升汞灭菌20 min、10%次氯酸钠灭菌20 min、无菌搅拌法三种方式采集无菌猕猴桃种子的效果,并对种子萌发和幼苗形成的影响进行了研究。结果表明:无菌搅拌法、0.2%升汞灭菌20 min是稳定有效的无菌猕猴桃采集方式,10%次氯酸钠灭菌20 min的采集效果不稳定;在相同的时间内,无菌搅拌法的种子发芽率最高,为89.90%,但发芽势较低,均可正常成苗; 10%次氯酸钠灭菌20 min的发芽率次之,与无菌搅拌法的种子无显著差异,发芽势和成苗率最高,分别为47.47%和67.86%,且有打破猕猴桃种子休眠的作用,整体作用类似于赤霉素(GA_3)浸种的效果; 0.2%升汞灭菌20 min对猕猴桃种子的萌发有抑制作用,各项指标均显著低于无菌搅拌法种子,且生长缓慢。此外,无菌搅拌法是物理处理,对种子、操作人员、环境均无害。这证实了无菌搅拌法的实用性和优势,发现了次氯酸钠在打破猕猴桃种子休眠方面的作用,为其它同类型果实的无菌种子采集提供了参考。     

茶翅蝽对猕猴桃果实的为害研究

【目的】茶翅蝽Halyomorpha halys St?l是为害猕猴桃果实的重要害虫,且为害日益加重。本研究主要为明确茶翅蝽取食为害后的特征、果实的敏感易受害阶段及果实受害后的品质变化。【方法】利用田间网罩试验,研究茶翅蝽取食不同发育阶段的猕猴桃果实的受害特征、果实受害率、每果受害点的数量及受害果实品质。【结果】生长发育阶段的果实受茶翅蝽刺吸为害后,果实表面为绿色或者白色水浸状斑点,受害斑点在果实的各个部位均有发生。其中94.39%为绿色斑点,0.71%为白色斑点,4.90%为绿色与白色斑点混合发生;果实在6月和7月的受害率最高为100%,且在7月受害程度最重,平均每果达到26.00个受害点;受害果实与未受害果实的长、宽、重、硬度、含糖量和干物质含量均未发现显著差异。成熟后的猕猴桃果实受茶翅蝽为害后表现为白色受害点,随着存放时间的增加,受害点的范围逐渐扩大并转变为絮状的腐烂组织,而未受害果实则无明显变化。【结论】猕猴桃坐果伊始便可受茶翅蝽为害,且持续整个生长发育阶段,其中在较快生长阶段（7月）受害水平最高,成熟后的猕猴桃果实如果保护不及时受到茶翅蝽为害后会缩短贮存期。     

猕猴桃三子叶突变体的形态特征研究

以“猕猴桃; 三子叶植株; 形态特性和平一号”美味猕猴桃辐射诱变过程所获得的三子叶突变体植株为材料,对猕猴桃三子叶植株的形态特征如单叶长、单叶宽以及叶片气孔分布和表面毛状体等进行观察分析,以获得其与双子叶猕猴桃植株的形态差异信息。结果表明:三子叶植株的单叶长、宽大于正常的双子叶猕猴桃植株单叶长、宽; 三子叶植株的气孔数目与双子叶猕猴桃植株的差异不大; 三子叶植株叶表面的毛状体比双子叶猕猴桃植株更加浓密,为三子叶猕猴桃育种利用打下基础。     

猕猴桃后熟软化影响因素的研究

就采前立地条件、栽培技术、采后的处理和环境条件与生理变化的关系以及软腐病等因素对猕猴桃后熟软化的影响进行了阐述。     

不同嫁接方法对猕猴桃成活率的影响

以野生美味猕猴桃1年生苗木作砧木,猕猴桃新品种金魁1年生枝条作接穗,进行不同嫁接方法试验。结果表明:舌接、单芽枝腹接成活率高达98.4%、96.1%,嫁接苗生长势旺,新苗基粗、新梢长度、新梢叶片数均显著高于其它几种嫁接苗。该法操作简便,是猕猴桃理想的嫁接方法,可在生产中推广应用。     

猕猴桃不同季节的嫁接法比较试验

在湖北的试验表明,猕猴桃春季嫁接以切接法较好,夏秋季嫁接则以单芽枝腹接法较好;嫁接后采用遮阳网遮荫可以显著提高嫁接成活率,但对出圃率无明显影响。     

Identification and characterization of flowering genes in kiwifruit: sequence conservation and role in kiwifruit flower development

Background  

Flower development in kiwifruit (Actinidia spp.) is initiated in the first growing season, when undifferentiated primordia are established in latent shoot buds. These primordia can differentiate into flowers in the second growing season, after the winter dormancy period and upon accumulation of adequate winter chilling. Kiwifruit is an important horticultural crop, yet little is known about the molecular regulation of flower development.     

Endosperm response to pollen irradiation in kiwifruit

 Cytological details of endosperm development after pollination with irradiated pollen were studied in Actinidia deliciosa (kiwifruit) cultivar Hayward. Pollinations were carried out involving five different sources of pollen (Matua, Tomuri, Burt, Berryman, and fruiting male) irradiated with gamma rays at doses of 700 and 900 Gy. Non-irradiated crosses were used as controls. Irradiated pollen induced development of approximately 25–30% of the ovules. Two types of ovules were observed: (1) with both embryo and endosperm and (2) with endosperm only. No mitotic abnormalities were found in control or irradiated endosperms. Mitotic divisions were regular and nuclei spherical and evenly spaced. However, the cells of irradiated endosperm usually contained low amounts of storage products. Ploidy level of the endosperms was evaluated by nuclear size (volume) with the use of image analyzis. Mean nuclear size in control and irradiated endosperms was 1598.3 and 750.9 μm³, respectively. It is concluded that endosperm produced after pollination with irradiated pollen is autonomous and represents the 2n level. Received: 14 October 1998 / Revision accepted: 10 March 1999     

Carbohydrate metabolism during postharvest ripening in kiwifruit

Mature fruit (kiwifruit) of Actinidia deliciosa var. deliciosa (A. Chev.), (C.F.) Liang and Ferguson cv. Haywood (Chinese gooseberry) were harvested and allowed to ripen in the dark at 20° C. Changes were recorded in metabolites, starch and sugars, adenine nucleotides, respiration, and sucrose and glycolytic enzymes during the initiation of starch degradation, net starch-to-sucrose conversion and the respiratory climacteric. The conversion of starch to sucrose was not accompanied by a consistent increase in hexose-phosphates, and UDP-glucose declined. The activity of sucrose phosphate synthase (SPS) measured with saturating substrate rose soon after harvesting and long before net sucrose synthesis commenced. The onset of sugar accumulation correlated with an increase in SPS activity measured with limiting substrates. Throughout ripening, until sucrose accumulation ceased, feeding [¹⁴C] glucose led to labelling of sucrose and fructose, providing evidence for a cycle of sucrose synthesis and degradation. It is suggested that activation of SPS, amplified by futile cycles, may regulate the conversion of starch to sugars. The respiratory climacteric was delayed, compared with net starchsugar interconversion, and was accompanied by a general decline of pyruvate and all the glycolytic intermediates except fructose-1,6-bisphosphate. The ATP/ ADP ratio was maintained or even increased. It is argued that the respiratory climacteric cannot be simply a consequence of increased availability of respiratory substrate during starch-sugar conversion, nor can it result from an increased demand for ATP during this process.Abbreviations Frul,6bisP fructose-1,6-bisphosphate - Frul,6Pase fructose-1,6-bisphosphatase - Fru6P fructose-6-phosphate - PEP phosphoenolpyruvate - PFK phosphofructokinase - PFP pyrophosphate: fructose-6-phosphate phosphotransferase - SPS sucrose phosphate synthase - UDPGlc uridine 5'-diphosphoglucose We thank Professor G. Costa, University of Udine and Flavia Succhi, University of Bologna for their help in obtaining the fruit in Italy. E.A.M. was the recipient of a travel grant through the NZ/German Technological Agreement.     

猕猴桃实生苗再生体系的建立

以成熟饱满的美味猕猴桃种子发芽获得实生苗,分别以实生苗的茎段、叶柄和叶片为材料建立了再生体系。结果表明:种子以2.5mg/L的赤霉素(GA3)处理8h较适合;以培养基发芽较为适合;茎段、叶柄和叶片的愈伤组织的诱导率均为100%,且茎段、叶柄比叶片容易脱分化,但叶片的平均出苗率最高。再生苗在移栽5d后,开始长出新叶,10d后就能完全适应外界环境。     

Micropropagation of kiwifruit using non-axenic shoot tips

Kiwifruit (Actinidia chinensis Planch.) shoot tips were subjected to a standard surface sterilization procedure and cultured on a Murashige and Skoog basal medium in the presence of two surviving bacterial contaminants. The fresh weight increase of the cultures and the number of shoots produced were greater in liquid medium than in medium solidified with 0.4 or 0.8% agar. A greater number of shoots was obtained with 125 ml than with 50, 250, or 500 ml Erlenmeyer flasks. A concentration of 2 mgl^-1 N⁶-benzylaminopurine (BAP) gave a greater increase in fresh weight than either 0 or 4 mgl^-1.Shoots cut from proliferating cultures were dipped in 0.05% indolebutyric acid (IBA) and rooted directly in a peat: vermiculite: perlite mix. Over 93 % of 907 plantlets produced were successfully acclimatized. The productivity of the method was comparable to that reported for the axenic culture of meristems. The contaminants which survived the initial surface sterilization procedure thus presented no major obstacle to the in vitro propagation of kiwifruit.     

猕猴桃果实采后生理研究进展

猕猴桃（Actinidia chinensis Planch.）属于呼吸跃变型果实,采后易软化腐烂,不耐贮藏,如何延长猕猴桃果实贮藏期限已成为猕猴桃产业发展壮大亟待解决的问题。猕猴桃果实采后生理变化强烈影响果实的贮藏期限和果实品质,特别是呼吸作用、乙烯合成及其信号转导系统和果实软化等,并且它们与猕猴桃贮藏保鲜技术的研发与应用密切相关。本文重点从这3个方面就国内外相关研究进展进行综述,并讨论它们对猕猴桃耐贮性的影响,以期为猕猴桃耐贮新品种的培育和贮藏保鲜技术的研发提供理论依据。     

Comparative study on Pseudaulacaspis pentagona resistance of four different cultivars of kiwifruit

Kiwifruit is a common and popular fruit around the world. However, white peach scale (Pseudaulacaspis pentagona [Targioni-Tozzetti]), a scale insect with a wide range of hosts, seriously affects the yield and quality of kiwifruit. To investigate the differences in resistance of different kiwifruit cultivars to P. pentagona, cellular structure and gene expression assays were used to explain the mechanism. Based on the stability of the infestation rate, we selected four cultivars from 50 kiwifruits for in-depth study, including ‘LC-04285’, ‘CF-3’, ‘DA-7B’ and ‘Hayward’. The anatomical structure of the canes analysis revealed that the resistant cultivar ‘LC-04285’ had thicker cuticle, denser epidermis and cortex. The expression levels of genes related to cuticle synthesis and formation of epidermis and cortex were also higher in ‘LC-04285’. Further investigation revealed that Jasmonic acid (JA) receptors COI1 were highly expressed in ‘LC-04285’. However, the expression levels of AcJAZs were higher in the susceptible cultivar ‘Hayward’. Besides, AcICS, AcPAL4, AcPAL5 and AcNPRs, which were involved in salicylic acid (SA) synthesis and SA response, were also highly expressed in ‘LC-04285’. Our results preliminarily revealed the mechanism of kiwifruit resistance to P. pentagona at the molecular and cellular levels. This study provided useful guidance for breeding insect-resistant kiwifruit in the future.