Exploration and exploitation of soil by apple,kiwifruit, peach,Asian pear and grape roots

Measurements of root-length density (RLD) in a range of 31 apple, kiwifruit, peach, Asian pear and grape orchards were used to derive indices to describe the exploration and exploitation of rooting volumes. Orchards were of various ages and located on a range of soil types, geographic regions, management systems etc. Data were obtained from core samples of volume 1.66×10^-4 m³ randomly taken within a standard volume, determined by average planting grids, of 2 m radius centred on tree stems, and 1 m depth. Root systems were described using an exploitation index, E(), and an exploration index, E(0). E() is defined as the proportion of the soil volume which contains roots at RLD greater than or equal to some specified value, . E(0) is defined as the proportion of the soil volume which contains roots at any RLD greater than zero. These indices are dependent on sample size, as are all volumetric or soil-coring data.Estimates of E(0) for each orchard were obtained as the proportions of cores containing any RLD>O and assessed for dependence on species. Peach trees had a significantly higher value of E(0), equal to almost 1.0, compared to the other four species where E(0) was approximately 0.8 (p0.01) or less. There was also some variation with age. E(0) was lower for very young plants which had not fully occupied the sampled soil volume. Exploration indices for woody roots increased with rootstock age but otherwise did not explain large differences in E() between species for given values.For example at =0.05×10⁴ m.m^-3, E() was approximately 0.45 for peach and kiwifruit, and 0.05 for apple, Asian pear and grape, whereas at =0.5×10⁴ m.m^-3 the corresponding values were 0.1 and almost zero. Negative exponential curves relating E(), scaled by dividing by E(0), to were fitted for each of the 31 orchards. Exponents for these curves, k, were significantly smaller for kiwifruit and peaches than apples, grapes and Asian pears (p0.05), and smaller for apples than grapes and Asian pears (p0.05). A larger k implies a rapid fall-off in E() as increases. Although all five species contained zero and low RLD samples, only kiwifruit and peaches contained higher RLD values and consequently have higher mean RLD. This trend was consistent across all soils, regions, sampling dates, and plant ages.The analyses demonstrate that core sampling can give useful insights into macro-scale root-system distribution, such as the proportion of a soil volume explored and how it is exploited. If positions of core samples are noted during sampling using angular direction, depth and radial distance as spatial coordinates the method can be used to describe root-system structures.     

美味猕猴桃和软枣猕猴桃种间杂交花粉管行为和早期胚胎发生的观察

美味猕猴桃（Ａｃｔｉｎｉｄｉａ ｄｅｌｉｃｉｏｓａ Ｎｏ．２６）和软枣猕猴桃（Ａ． ａｒｇｕｔａ）杂交,观察了花粉管在花柱内的行为和早期胚胎发生,结果如下： 花粉粒在柱头的乳突细胞表面萌发,在开放型的Ｖ 形花柱道内生长,生长速度比对照的缓慢, 到达胚珠珠孔处的时间延迟５０ 到６０ ｈ。当花粉管生长到花柱基部时出现波纹状弯曲;顶端膨大或尖细;部分花粉管的直径发生变化;少数花粉管生长极不规则。花粉管中胼胝质沿管壁不规则沉积, 有的不形成胼胝质塞,或整个管壁被胼胝质所覆盖。约有２６．７４％ 的胚珠受精, 并发育成种子,其中正常种子占６８．５０％ ;败育种子占３１．５０％ ,其中约有１１．４１％ 为空瘪种子;未受精胚珠占６１．４５％ 。正常种子及其胚均较对照的小。胚发育为茄型,胚乳为细胞型,合子保持休眠十几天后开始分裂形成胚,传粉后５０ｄ 见到子叶胚     

Sex determination in Actinidia. 1. Sex-linked markers and progeny sex ratio in diploid A. chinensis

 First results from two strategies aimed at elucidating the genetics of sex in the dioecious genus Actinidia Lindl. (Actinidiaceae) support the hypothesis that sex-determining genes are localized in a pair of chromosomes which, although cytologically indistinguishable, function like an XX/XY system with male heterogamety. A. chinensis Planch., a close relative of the kiwifruit [A. deliciosa (A. Chev.) CF Liang et AR Ferguson], has diploid and tetraploid races. Bulk segregant analysis to find sex-linked markers revealed two markers whose inheritance patterns in three diploid families showed X and Y linkage and indicated that the male is the heterogametic sex. Some recombination between the markers and the sex-determining loci was also demonstrated. Sex ratios in 12 progenies from controlled crosses varied around 1:1, as expected for an XX/XY system. Received: 20 December 1995 / Revision accepted: 24 April 1997     

‘LD-1'砧米良一号猕猴桃的耐涝性

猕猴桃是一类不耐涝的植物,为了解决猕猴桃的涝害问题,吉首大学近年来尝试用‘LD-1’作为猕猴桃的耐涝性砧木。该研究以米良一号实生苗砧米良一号猕猴桃和‘LD-1’砧米良一号猕猴桃为材料,观测根系淹水后叶片可溶性糖含量、丙二醛含量、叶绿素含量、可溶性蛋白质含量、SOD 活性和形态的变化规律,探讨了‘LD-1’砧米良一号猕猴桃的耐涝性。结果表明：(1)米良一号实生苗砧米良一号猕猴桃根系淹水后,可溶性糖含量6 d 后极显著(P<0.01)升高;丙二醛含量8 d 后显著(P<0.05)升高;叶绿素含量和可溶性蛋白质含量没有显著变化;SOD 活性6 d 后显著(P<0.05)升高,8 d 后不再有显著变化;叶片2 d 后出现轻度萎蔫,10 d后全部枯死。(2)‘LD-1’砧米良一号猕猴桃根系淹水后,可溶性糖的含量4 d 后显著(P<0.05)升高;丙二醛含量、叶绿素含量、可溶性蛋白质含量和 SOD 活性无显著变化;叶片10 d 后未出现显著的萎蔫和枯死现象,30 d 后仍正常。这说明米良一号实生苗砧米良一号猕猴桃耐涝性较弱,‘LD-1’砧米良一号猕猴桃耐涝性较强,‘LD-1’作砧木显著增强了米良一号猕猴桃的耐涝性。该研究结果为‘LD-1’在米良一号猕猴桃栽培上的应用提供了依据。     

猕猴桃嫁接试验

本文报道猕猴桃不同嫁接时期、嫁接方法和不同分类群的砧木试验结果,猕猴桃最适宜的嫁接时期是落叶后至翌年萌芽前,嫁接方法以切接为好,嫁接成活率均在90％以上。同种和同一分类群的砧穗间有良好的亲和力,嫁接均有较高的成活率。不同分类群间嫁接效果较差,如中华猕猴桃桂海4号嫁接于中华猕猴桃砧木上的成活率,生长情况均比嫁接其它分类群为砧的有显著差异。     

毛花猕猴桃两新变种

<正> 秃果毛花猕猴桃 新变种 (图版1) Actinidia eriantha Benth. var. calvescens C. F. Liang, var. nov. A typo differt baccis cylindricis, majoribus, circa 5 cm. longis, tomentosis non velutinis. Guangxi: Guilin, in the Research Orchard of Guangxi Institute of Botany, May 9, 1987, C. F. Liang 34511 (Type, IBK).     

猕猴桃在食品加工中的开发利用

猕猴桃是一种营养价值很高的水果,其在食品加工中具有很大的市场开发利用前景。猕猴桃制品营养丰富,风味独特,其鲜果不易贮藏等问题也正在得到解决。猕猴桃制品种类多样,本文从猕猴桃复合饮料,生态特色果酒等以猕猴桃为主要原料的加工产品进行综述,展望了猕猴桃果实的加工利用前景。     

燕山山脉软枣猕猴桃的居群结构与动态研究

为探究层间藤本植物软枣猕猴桃（Actinidia arguta）在群落中的生长格局和居群动态变化,以燕山区域内的野生软枣猕猴桃为研究对象,采用样圆法分区域进行了野生软枣猕猴桃的居群结构调查,编制了特定时间生命表并绘制存活曲线。结果表明：燕山区域Ⅰ-Ⅱ径级（幼苗阶段）种群个体分别占总数量的15.39%（东段）、31.25%（中段）和30.76%（西段）,总体居群结构呈"倒金字塔"型,种群表现出衰退趋势。调查区域软枣猕猴桃的高度结构基本符合连续发育特征,相对完整。燕山东段和中段的软枣猕猴桃较明显地趋近Deevey-Ⅱ型指数函数模型,燕山西段介于Deevey Ⅰ型与Ⅱ型之间,但更接近Ⅱ型;燕山山脉软枣猕猴桃居群整体呈现衰退型特征。软枣猕猴桃有较高的保护价值,但其居群数量稀少,自然更新能力较弱,种群未来的生长繁衍不容乐观,应加强关注与保护力度。     

A genome-specific repeat sequence from kiwifruit (Actinidia deliciosa var. deliciosa)

Summary Six members of a family of moderately repetitive DNA sequences from kiwifruit (Actinidia deliciosa var. deliciosa) have been cloned and characterized. The repeat family is composed of elements that have a unit length of 463 bp, are highly methylated, occur in tandem arrays of at least 50 kb in length, and constitute about 0.5% of the kiwifruit genome. Individual elements diverge in nucleotide sequence by up to 5%, which suggests that the repeat sequence is evolving rapidly. Homologous sequences were found in A. deliciosa var. chlorocarpa. The repeat sequence was not found under low stringency hybridization conditions in the diploid A. chinensis, the species most closely related to the hexaploid kiwifruit, or in eight other Actinidia species. However, homologous repeats were detected in a tetraploid species, A. chrysantha. The results provide the first molecular evidence to suggest that kiwifruit may be an allopolyploid species.