保存多年苹果试管苗端粒酶活性具有相对稳定性

为明确苹果端粒酶特性与组培试管苗繁殖、衰老的关系,本试验选取‘金冠‘’富士’及‘嘎拉’3个苹果品种的不同继代次数、不同苗龄的试管苗叶片及不同的试管材料(试管苗叶片,茎段,愈伤组织),分别用改良TRAP法和实时荧光定量PCR法测定了端粒酶活性和端粒酶逆转录酶基因表达量。研究表明,随继代次数增加,保存多年的苹果试管苗端粒酶活性变化不显著;苹果试管苗在90 d的生长期内,不同苗龄叶片端粒酶活性呈现先升高后降低的趋势;不同试管材料端粒酶活性具有组织特异性,其中‘金冠’愈伤组织端粒酶活性最高,‘嘎拉’叶片的端粒酶活性最高。本研究中端粒酶逆转录酶基因表达量与端粒酶活性的变化规律一致。     

辽宁

北京室外展园主题为“独树一帜”，占地2000平方米。通过现代园林的艺术表现手法，以辽宁特色的君子兰花形象为载体，展示改革开放30年辽宁花卉产业蓬勃发展成果。种植有油松、雪松、黄杨、银杏、五角枫、国槐、丁香、金山绣线菊、洋槐等乔木、亚乔木、灌木，其中选用辽宁特有的灯台树和金叶榆，其枝条优美的姿态和金黄叶片相互呼应。     

油松端粒酶活性的测定方法

端粒酶具有修复延伸端粒的功能,对于维持真核生物染色体的完整性至关重要,因此对其活性的测定有着重要意义。通过大量的摸索实验,将常用于动物细胞端粒酶活性检测的端粒末端重复序列扩增法（TRAP法）运用到对植物材料的检测中来,对北方常见木本植物油松进行了端粒酶活性测定。基于TRAP法的原理,对体外延伸、引物选择、退火温度、电泳检测等实验条件进行优化。结果表明,油松端粒酶活性测定的最佳体外延伸条件为30℃延伸1 h,最适前导链引物和反向引物分别为TS21和ACX,PCR退火温度为61.8℃,电泳检测使用Gene Finder核酸染料染色效果更好,建立了一种有效测定木本植物油松松针叶端粒酶活性的测定方法。     

杂交稻及其三系生育过程中RuBP羧化酶及有关光合酶的变化

研究了杂交稻汕优６３及其三系生育过程中叶片ＲｕＢＰ羧化酶／加氧酶及有关光合酶活性的变化,结果表明,供试材料ＲｕＢＰ羧化酶／加氧酶等参数的变化无本质的差异。杂交稻不同叶位叶片的ＲｕＢＰ羧化酶活性低于其母不育系,但与父本较接近。从ＲｕＢＰ羧化酶／加氧酶这一光合特征值来分析,杂交稻叶片并不存在光合优势。随着叶龄增加,杂交稻及其三系叶片的ＲｕＢＰ羧化酶／加氧酶、乙醇酸氧化酶、过氧化氢酶活性下降,而酸性磷酸     

大豆叶片旱促衰老及其与膜脂过氧化的关系

干旱导致大豆叶片叶绿素和可溶性蛋白质含量下降,膜透性增加。不同叶位比较以生理老叶受影响较大。分析表明,干旱条件下叶片膜脂过氧化作用加强,H_2O_2累积,过氧化物酶活性提高;而活性氧清除系统的超氧化物歧化酶和过氧化氢酶活性以及抗坏血酸和还原型谷胱甘肽水平降低。干旱6天不同叶位叶间以生理老叶具较高的丙二醛和H_2O_2     

高粱叶片及其它营养器官细胞形态的初步观察

运用细胞离析法对高粱两个品种各叶位叶片细胞形态的观察表明,随叶位升高,三环以上的多环细胞所占的比例有增加趋势,但中部叶位的略有下降。叶肉细胞随叶位升高逐渐变小,但品种间叶肉细胞高度的变化趋势却有不同。冀杂6号叶片表皮气孔密度随叶位升高而增加,而y2203的却差异不大。高粱叶鞘薄壁细胞的形态与叶片细胞的显著     

我国不同年代玉米品种开花后叶片保护酶活性及膜脂过氧化作用的演进

通过比较研究我国50年代、70年代和90年代的几个主栽玉米((Zea mays L.)品种开花后叶片中抗氧化保护酶活性的变化得出：随品种更替叶片SOD、CAT和POD活性增加，膜脂过氧化产物MDA含量降低，在生育后期这种趋势愈加明显，不同叶位间以中下部叶片尤为显著。这些特征可能是近代玉米品种高产抗逆的有利因素之一。     

不同基因型玉米叶片衰老与活性氧代谢的关系及其调控

以玉米品种豫单2002和郑单 958 为材料,研究不同基因型玉米叶片衰老与活性氧代谢的关系及其化学调控.结果表明:两品种 4 个叶位叶片的可溶性蛋白含量、SOD、CAT活性呈由高到低的变化趋势(第 5 叶位除外),但 MDA 含量随着叶片的衰老而升高.与豫单2002 相比,郑单 958 各叶位叶片衰老过程中SOD、CA...     

不同钾肥用量对玉米叶片SPAD值含量的影响

通过田间试验,研究了不同钾肥用量对玉米叶片叶绿素含量的影响。结果表明,在不同钾肥用量处理下玉米叶片SPAD值从苗期开始逐渐增加,达到高峰后下降,成熟期最低。抽穗期以后,进入籽粒形成期,此阶段K4处理叶片中叶绿素含量最高。对钾肥用量处理下不同时期玉米叶片SPAD值的叶位差异进行分析,玉米叶片叶位叶绿素含量在苗期和拔节期以中部叶片最为高,喇叭口期和抽穗期以上部叶片最高,每个叶位叶绿素含量的均随着生育期的推移而逐渐增加。     

四种臭椿不同叶位叶片色素组成及分布变化

为揭示臭椿不同叶位叶色变化生理机制，以期为臭椿的育种和推广提供依据。以4种臭椿（‘朝阳椿’、‘千红椿’、‘普通臭椿’、‘聊红椿’）的1年生无性系苗木为材料，对5个存在明显叶色转换的叶位的叶片色素含量、叶色参数、以及叶片表皮和横切面的结构和颜色进行观测。结果表明：各品种随着叶位的下降，总叶绿素(Chl)含量和类胡萝卜素(Car)含量均显著增加(P<0.05)，花青素(Ant)含量、Car:Chl和Ant:Chl均显著减少(P<0.05)，叶绿素a与叶绿素b的含量比值(Chla:Chlb)呈增加趋势。同一叶位Chl、Car含量以‘普通臭椿’和‘千红椿’较高、Ant含量以‘千红椿’最高、Ant:Chl以‘朝阳椿’和‘千红椿’较高、Car:Chl和Chla:Chlb均以‘朝阳椿’最高。各品种叶肉厚度(LM)和栅栏组织厚度(PT)均随叶位下降而增加(P<0.05)，各叶位LM和PT多以‘朝阳椿’和‘聊红椿’较大。各叶位亮度L*值、黄蓝属性色相b*值、彩度C*值多以‘朝阳椿’最大（叶位4时最大），叶位1～4的红绿属性色相a*值均以‘朝阳椿’和‘千红椿’较大（叶位1时最大）。叶片腺...     

A note on the origin of Kalanchoë x vadensis Boom & Zeilinga (Crassulaceae)

Summary K x vadensis is a hybrid of K. blossfeldiana and K. marmorata obtained after doubling the number of chromosomes.     

Mechanisms and diversity of resistance to sorghum shoot fly,Atherigona soccata

Sorghum shoot fly, Atherigona soccata, is one of the important pests of postrainy season sorghums. Of the 90 sorghum genotypes evaluated for resistance to this pest, RHRB 12, ICSV 713, 25026, 93046 and 25027, IS 33844‐5, Giddi Maldandi and RVRT 3 exhibited resistance in postrainy season, while ICSB 463, Phule Anuradha, RHRB 19, Parbhani Moti, ICSV 705, PS 35805, IS 5480, 5622, 17726, 18368 and 34722, RVRT 1, ICSR 93031 and Dagidi Solapur showed resistance in rainy season, suggesting season‐specific expression of resistance to A. soccata. ICSB 461, ICSB 463, Phule Yasodha, M 35‐1, ICSV 700, 711, 25010, 25019 and 93089, IS 18662, Phule Vasudha, IS 18551 and 33844‐5 and Barsizoot had fewer deadhearts than plants with eggs across seasons, suggesting antibiosis as one of the resistance mechanism. Five genotypes exhibited resistance with high grain yield across seasons. Correlation, path and stepwise regression analyses indicated that leaf glossiness, seedling vigour, trichome density, oviposition and leaf sheath pigmentation were associated with the expression of resistance/susceptibility to shoot fly, and these can be used as marker traits to select and develop shoot fly‐resistant sorghums.     

Reaction of tritordeum to Fusarium culmorum and Septoria nodorum

Summary Hordeum chilense is a wild barley extensively used in wide crosses in the Triticeae. It could be a valuable source of resistance to Fusarium culmorum and Septoria nodorum. Some H. chilense x Triticum spp. amphiploids, named tritordeums, were more resistant than the parental wheat line to these diseases, others were not. Average contents of ergosterol and deoxynivalenol (DON) suggested that resistance to colonization by Fusarium was the highest for Hordeum chilense, followed by tritordeum and wheat in decreasing order. In particular, the H. chilense genotypes H7 and H17 enhanced the wheat resistance to F. culmorum in its tritordeum offsprings. Resistance to S. nodorum in tritordeum was not associated with tall plant height. There is sufficient genetic variation for resistance to F. culmorum and S. nodorum among tritordeum to allow the breeding of lines combining short straw and resistance to both diseases.     

Avoidance of leaf rust fungi in wild relatives of cultivated cereals

Summary Avoidance of rust fungi that was based on poor appressorium induction was previously found in Hordeum chilense. In the present study 95 accessions of Triticeae were screened for avoidance of Puccinia hordei. The percentage of appressorium formation per germinated spore ranged from 6 to 90%. On none of the 41 accessions of Aegilops, Agropyron, Elymus, Secale, Thinopyrum or Triticum studied was the rate of appressorium formation lower than 25%. Lower rates of appressorium formation were, however, found on accessions of wild barley species Hordeum brachyantherum, H. marinum, H. parodii and H. secalinum. Its implications in cereal breeding are discussed.     

Disease resistance in protected crops and mushrooms

Summary Cultivars of tomatoes, cucumbers, lettuce and peppers have been bred for resistance to one or more pathogens. Some tomato and cucumber cultivars have resistance to a wide range of diseases. Resistance has been transient in many cases and a succession of cultivars with new genes or new combinations of resistance genes has been necessary to maintain control. There has been a number of notable exceptions and these have included durable resistance to such pathogens asFulvia fulva and tomato mosaic virus. With lettuce the resistance situation is complicated by the occurrence of fungicide resistant pathotypes. There are no strains ofAgaricus bisporus purposely bred for disease resistance.In protected flower crops only resistance to Fusarium wilt in carnations has been purposely bred but differences in disease resistance are apparent in cultivars of many ornamental crops. This is particularly so in chrysanthemums where there are cultivars with resistance to many of the major pathogens. Similar situations occur with other flower crops and pot plants. Cultivars of some species have not been systematically investigated for resistance.The need for genetic resistance will increase with the further reduction, in the limits on pesticide use and an increasing public awareness and importance of pesticide pollution.ADAS is an executive agency of the Ministry of Agiculture, Fisheries and Food and the Welsh Office.     

Genetic constitution and diversity in four narrow endemic redwoods from the family Cupressaceae

The genetic constitution and diversity of four relictual redwoods are discussed in this review. These include monotypic genera of the family Cupressaceae: coast redwood (Sequoia sempervirens), giant sequoia (Sequoiadendron giganteum), dawn redwood (Metasequoia glyptostroboides), and alerce (Fitzroya cupressoides). All four species are narrow endemics, share a number of common phenotypic traits, including red wood, and are threatened species. Fossil history suggests that the ancestors of redwoods probably originated during the Cretaceous and Tertiary periods and flourished thereafter for millions of years. Towards the end of the Tertiary period began their decline and struggle for existence that continued during the subsequent geologic upheavals and climate changes, until the survival of the present-day redwoods in the current restricted locations in the world (USA, China, and South America). Although two species, Sequoiadendron and Metasequoia, are diploids (2n = 22), and the other two are polyploids: Fitzroya a tetraploid (2n = 4x = 44), and Sequoia a hexaploid (2n = 6x = 66); they all share the same basic chromosome number x = 11. The genome size in the hexaploid Sequoia is one of the largest (31,500 MB) in the conifers, while the genome sizes of diploid Metasequoia and Sequoiadendron are about one-third (~10,000 MB) of Sequoia. Genetic diversity in the redwoods is lower than most other gymnosperms, except in Sequoia, which seems to rank near the upper quarter of the coniferous forest trees. Genomic research is sparse in the redwoods, and should be pursued for a better understanding of their genome structure, function, and adaptive genetic diversity.     

Distribution,ecology and reproductive biology of wild tomatoes and related nightshades from the Atacama Desert region of northern Chile

Over the past 20 years, several expeditions were made to northern Chile to collect populations of wild tomatoes (Solanum chilense, S. peruvianum) and allied nightshades (S. lycopersicoides, S. sitiens), and obtain information about their geographic distribution, ecology and reproductive biology. Restricted mainly to drainages of the Andean and the coastal cordillera, populations are geographically fragmented. The two nightshade species are rare and threatened by human activities. Adaptation to extreme aridity and soil salinity are evident in S. chilense and S. sitiens (the latter exhibits several xerophytic traits not seen in the tomatoes) and to low temperatures in S. lycopersicoides and S. chilense. All tested accessions are self-incompatible, with the exception of one S. peruvianum population collected at the southern limit of its distribution. Several distinguishing reproductive traits—anther color, attachment, and dehiscence, pollen size, and flower scent—suggest S. sitiens and S. lycopersicoides attract different pollinators than S. chilense and S. peruvianum. The four Solanum spp. native or endemic to Chile provide a variety of novel traits which, through hybridization and introgression with cultivated tomato, could facilitate development of improved varieties, as well as research on a variety of basic topics, including plant-pollinator interactions, abiotic stress responses, and evolution of reproductive barriers.     

The induction in vitro of adventitious shoots in Rosa

Summary Adventitious shoots were formed on excised leaves, roots and callus of Rosa persica x xanthina and on excised leaves of R. laevigata and R. wichuraiana on culture media that included BAP and NAA as growth regulators. Shoots formed freely on freshly cultured callus of R. persica x xanthina but their production declined in successive cultures and ceased after twelve weeks. Transplantation to soil was improved by rooting plantlets in cellulose plugs in vitro and transferring plantlets to soil while still in the plugs.     

The exploration of genetic resources of Portuguese cabbage and kale for resistance to several Brassica diseases

Summary Twenty three accessions of nine Portuguese cabbage and kale land races from different geographic origins were tested at the seedling stage for resistance to several important brassica diseases. Resistance to downy mildew (Peronospora parasitica), expressed as necrosis of the cotyledon mesophyll, was found in all the accessions. Type A resistance to cabbage yellows (Fusarium oxysporum f. sp. conglutinans race 1) was present in most of the landraces. Resistance to clubroot (Plasmodiophora brassicae race 6) was found in one accession of the Portuguese tree kale. High resistance to blackleg (Leptosphaeria maculans) and white rust (Albuco candida) was not detected, although several accessions showed 20 to 30% of plants with intermediate expression of resistance. All Portuguese cole accessions were susceptible to blackrot (Xanthomonas campestris pv. campestris).     

Production and characterization of intergeneric diploid cybrids derived from symmetric fusion between Microcitrus papuana Swingle and sour orange (Citrus aurantium)

Plants were regenerated from intergeneric somatic hybridization between embryogenic protoplasts of Microcitrus papuana Swingle and leaf-derived protoplasts of sour orange (Citrus aurantium L.) via electrofusion. The regenerated plants were morphologically similar to the leaf parent in growth vigor, leaf and branch structure. FCM analysis showed that they were diploids. Simple-sequence-repeat (SSR) and cleaved-amplified-polymorphic-sequence(CAPS) were employed for hybridity characterization. SSR banding patterns of the regenerated plants were identical to the leaf parent, sour orange, indicating that they possessed nuclear component derived from sour orange. DNA amplification with chloroplast and mitochondrial universal primers, followed by restriction endonuclease digestion, revealed polymorphism between the fusion parents. Therefore, this method was used to determine the cytoplasmic compositions of the regenerated plants. Banding patterns for all the polymorphic primer/enzyme combinations of the regenerated plants were similar to those of the embryogenic parent, M. papuana, suggesting that only the cytoplasmic components derived from the embryogenic parent were present in the regenerated plants. FCM, SSR and CAPS demonstrated that intergeneric diploid cybrids have been successfully obtained by symmetric fusion. Related results concerning nuclear and cytoplasmic composition of previous diploid somatic hybrids and potential mechanism for regeneration of such kind of plants are discussed herein. This revised version was published online in July 2006 with corrections to the Cover Date.