Modelling kiwifruit budbreak as a function of temperature and bud interactions

This paper presents two models of budbreak on canes of 'Hayward' kiwifruit (Actinidia deliciosa). A conventional 'chill unit' (CU) type model is compared with an alternative 'loss of potential' (LOP) approach, which assumes that the number of buds developing in spring depends on climate and node position-dependent bud-to-bud interactions that vary in duration and intensity. Both models describe how temperature, and application of a dormancy-breaking chemical, determine the overall amount of budbreak for whole canes. However, the LOP model does so by describing patterns of budbreak along canes. To do this, the cumulative influence of distal neighbours is assumed to cause a progressive fall in the capacity for bud development over the autumn-winter period, an influence that gets stronger as temperature rises. The LOP model also assumes that the rate of decline varies along the cane, as a function of some inherent bud property. These two factors mean that buds towards the base of the cane break less often under the suppressive influence of distal neighbours, while low temperature ('chilling') increases budbreak by diminishing the intensity of suppression relative to bud development rate. Under this scenario, dormancy-breaking chemicals (such as hydrogen cyanamide, HC) enhance budbreak by diminishing the duration of suppression. Models were calibrated using daily temperature series and budbreak proportion data from a multi-year regional survey, and were then tested against independent data sets. Both models were run from a fixed start date until the time budbreak was almost complete, or until a standard date. The fitted models described 87 % of variation in amount of budbreak due to site, year, HC and node position effects in the original data set. Results suggest that the correlation between chilling and the amount of budbreak can be interpreted as a population-based phenomenon based on interaction among buds.     

Restriction-site variation of PCR-amplified chloroplast DNA regions and its implication for the evolution and taxonomy of Actinidia

 Twenty six restriction sites from five PCR-amplified chloroplast DNA sequences (rbcL, psbA, rpoB, and two spacers flanking the trnL gene) were mapped and analysed in 20 Actinidia taxa, encompassing all four sections into which the genus is divided. At least three species out of the 20 examined have been found to have originated through natural interspecific hybridisation on the basis of the discrepancy between morphological and biochemical traits and the cpDNA profiles of pairs of species. A widely reticulate evolution has therefore been postulated in Actinidia. Wagner and weighted parsimony analysis produced consensus trees that did not match the traditional taxonomy based on morphological characters. The molecular data clearly showed that some taxa, such as A. rufa and A. kolomikta, occupy a wrong position and most, if not all, of the traditional groups represented by sections and series are weakly supported, since they appear as polyphyletic. A. chinensis and A. deliciosa were confirmed to be very closely related. Since chloroplast DNA is paternally inherited in Actinidia, A. chinensis is a paternal progenitor, if not the only one, of A. deliciosa, the domesticated kiwifruit. Received: 18 August 1997 / Accepted: 6 October 1997     

采后钙处理对中华猕猴桃果实过氧化物酶活性、呼吸率及乙烯生成的影响

对中华猕猴桃果实采后进行钙处理,结果表明,适当提高果实钙含量,可以抑制过氧化物酶（POD）活性,降低呼吸率及乙烯生成量,延缓果实衰老。本实验以2％CaCl2处理效果最佳。     

江苏省云台山白粉菌研究Ⅳ．球针壳属一新种

报道了寄生在猕猴桃科（Actinidiaceae）猫人参ActinidiavalvataDunn上的新种连云港球针壳PhyllactinialianyungangensisS．J.Gu＆Y．S．Zhangsp．nov,新分类单位有汉文和拉丁文描述,并附有讨论。     

Cloning and characterization of five cDNAs for genes differentially expressed during fruit development of kiwifruit (Actinidia deliciosa var.deliciosa)

Five cDNAs for genes differentially expressed during fruit development of kiwifruit (Actinidia deliciosa var.deliciosa cv. Hayward) were isolated from a library made from young fruit, 8–10 days after anthesis. One gene (pKIWI503) has low levels of expression in young fruit but is induced late in fruit development and during fruit ripening, and has some homology to plant metallothionein-like proteins. The other four genes are highly expressed in young fruit with reduced expression in the later stages of fruit development. pKIWI504 has strong homology to plant metallothionein-like proteins and pKIWI505 exhibits homology to the -subunit of the mitochondrial ATP synthase gene. The two other genes (pKIWI501 and 502) encode proteins with no significant homology to other known sequences.     

广西植物小资料

<正> 近年来,我们在中草药资源调查工作中,发现有一些广西未曾记录过的植物,现在整理出来,以供有关部门参考。本文引用的标本,除圆叶西番莲外,其余均收藏在广西中医药研究所植物标本室(GXMI)。     

Plant Regeneration from Protoplasts of Actinidia chinensis Planch.

Protoplasts isolated from cotyledon callus line of A14N7 of Actinidia Chinensis Planch. were cultured in the improved NN-69 medium. First division of regenerated cells occurred during 7–10 days of culture, and percentage of the cell division was about 10% at day 20. The best result of protoplast culture was achieved when protoplasts were cukured in liquid medium at a density of 5× 104/ml, About 4 months, procoplast-derived calli were transferred stepwisely onto differentiation media where they developed into green compact calli, from which the perfect plants were regenerated.     

Chromosome Numbers of 10 Species and 3 Varieties in Actinidia Lindl.

Somatic chromosome numbers of 10 species and 3 varieties in Actinidia Lindl. are reported for the first time, except A. polygama (Sieb. et Zucc.) Maxim. Two ploidy levels, diploid and tetraploid, are found both in A. polygama and A. kolomikta (Maxim. et Rupr.) Maxim. Chromosome numbers are listed as follows: A. kolomikta (Maxim. et Rupr.) Maxim. 2n=58, 116, A. polygama (Sieb. et Zucc. Maxim. 2n=58, 116, A. macrosperma Liang 2n=116, A. callosa var. henryi Maxim. 2n=116, A. callosa var. discoler Liang 2n =116, A. cylindrica Liang 2n=58, A. chrysantha Liang 2n=116, A. sabiaefolia Dunn 2n= 58, A. melliana Hand.-Mazz. 2n=58, A. hemsleyana Dunn 2n=58, A. fulvicoma var. lanata (Hemsl.) Liang 2n=58, A. latifolia (Gardn. et Champ.) Merr. 2n=58, and A. lanceolata Dunn 2n=58.     

Morphological anomalies in pollen tubes of Actinidia deliciosa (kiwi) exposed to 50 Hz magnetic field

The role of the pollen grain, with respect to the reproductive process of higher plants, is to deliver the spermatic cells to the embryo sac for egg fertilisation. Delivery occurs through the pollen tube, a self produced organ that is generated when the pollen grain reaches the stigma surface. The effect of magnetic fields on pollen tube growth was reported in a recent publication by Germanà et al. Pollen tube growth is an interesting candidate for the detailed study of the effects of electromagnetic fields on cytoplasmic structures and organelles. In this research Actinidia deliciosa (kiwifruit) pollen grains were germinated in the presence of an alternating magnetic field (50 Hz). Our results, although of preliminary nature, show that pollen tube growth is affected by magnetic fields. The analysis of the observed anomalies in the pollen tube appear to be the result of changes in the ionic charges within the pollen tube cytoplasm.