三种毛茛的核型研究

对３种（含１变种）毛莨属植物进行了核型研究,其染色体数目及核型资料为首次报道。三叶毛莨（ＲａｎｕｎｃｕｌｕｓｊａｐｏｎｉｃｕｓＴｈｕｎｂ．ｖａｒ．ｔｅｒｎａｔｉｆｏｌｉｕｓＬ．Ｌｉａｏ．）有两种核型。即基本型２ｎ＝２ｘ＝１４＝６ｍ＋４ｓｍ＋４ｓｔ（２ＳＡＴ）和杂合型２ｎ＝２ｘ＝１４＝６ｍ＋４ｓｍ＋４ｓｔ（１ＳＡＴ）,前者核型的特征是其随体较大,而后者核型变异发生在第２对和第３对同源染色体异形上,并     

日本龟蜡蚧卵期的预测预报研究

日本龟蜡蚧是园林花卉、林木和果树的重要害虫,繁殖量大,除初孵若虫外,体被较厚蜡质,为各种防治增加了难度．准确测报若虫盛孵期,是防治该虫的关键．利用自然变温测定卵期的发育起点温度和有效积温,经测定悬铃木：C=18.02±1.69（℃）,K=142.68±29.21（DD）;大叶黄杨：C=18.54±0.74（℃）．K=129.34±11.93（DD）,桅子花：C=19.97±0.87（℃）,K=106.81±13.92（DD）,这种测定简便易行而又更符合实际,仅计算较为复杂．     

Interactions between resources and abiotic conditions control plant performance on subarctic coastal dunes

Both abiotic conditions and resource levels affect the performance of plants on coastal dune systems. On the foredune, environmental factors are particularly limiting for plant growth and these vary along a short topographical gradient, from the foot to the ridge. On subarctic coastal dunes in northeastern Canada, this topographical gradient is paralleled by a plant sequence that typically involves Honckenya peploides, Elymus mollis, and Lathyrus japonicus. In this study, field nutrient additions were carried out to evaluate the importance of N and/or P limitation on foredune plant performance. Also, glasshouse experiments were done to determine the significance of interactions between substrate resources (i.e., nutrients and water), and between substrate resources (i.e., nutrients) and an abiotic condition (i.e., salt spray) on the growth of a dune species. Field nutrient additions did not result in any significant increase in plant biomass, although nutrients were accumulated in the rhizomes of all three species present on the foredune and in the aboveground tissues of Elymus. Glasshouse experiments on Elymus showed that nutrient addition could increase plant biomass. However, water availability and salt spray interfered with nutrient use by the plants. I suggest that such interactions between resources and abiotic conditions may significantly affect plant performance and plant sequence on the foredune of coastal dune systems.     

THE NATURAL CONTROL EFFECT OF EGG PARA-SITOIDS ON LITCHI STINK BUG TESSARATOMA PAPILLOSA (HETEROPTERA: PENTATOMIDAE) IN LITCHI ORCHARD

Abstract  The distribution of eggs of the litchi stink bug Tessaratoma papillosa Drury was observed. By marking the eggs of T. papillosa in an integrated pest managed litchi orchard and in an orchard with chemical control, respectively, the control effect of the egg parasitoids on T. papillosa in the two kinds of licthi orchards was investigated in Guangzhou in 1996. The female T. papillosa began to oviposit in mid-March and laid eggs vigorously from early April to early June, and then successively entered the declining stage of oviposition in 1996 in Guangzhou. 86% of the litchi stink bug eggs were laid in the peak period of oviposion. Two egg parasitoids, Anastatus japonicus and Ooencyrtus phongi , were obtained in the integrated managed litchi orchard. The rate of eggs parasitized by A. japonicus and O. phongi attained to 3.2% -18.4% and 3.2%-30.4%, respectively. The united attack of the two parasitoid wasps destroyed 30.6% - 47% host eggs in the middle and late stages of T. papillosa oviposition. Only A. japonicus was collected in the chemical controlled litchi orchard and the percentage of eggs parasitized by this wasp was only 0.2% -2.8%.     

Structural analysis of a Lotus japonicus genome. I. Sequence features and mapping of fifty-six TAC clones which cover the 5.4 mb regions of the genome.

A total of 56 TAC clones with an average insert size of 100 kb were isolated from a TAC library of the Lotus japonicus genome based on the expressed sequences tags (ESTs), cDNA and gene information, and their nucleotide sequences were determined according to the shot-gun based strategy. The total length of the sequenced regions is 5,473,195 bp. By comparison with the sequences in protein and EST databases and analysis with computer programs for gene modeling, a total of 605 potential protein-encoding genes with known or predicted functions, 69 gene segments, and 172 pseudogenes were identified. The average density of the genes assigned so far is 1 gene/8120 bp. Introns were identified in approximately 78% of the potential genes. There was an average of 3.8 introns per gene and the average length of the introns was 375 bp. DNA markers were generated based on the nucleotide sequences obtained, and each clone was mapped onto the linkage map using the F2 mapping population derived from a cross of L. japonicus Gifu B-129 and Miyakojima MG-20. The sequence data, gene information and mapping information are available through the World Wide Web at http://www.kazusa.or.jp/lotus/.     

濒危植物木根麦冬的胚胎学研究

木根麦冬的花药壁分为4层,即:表皮、药室内壁、中层与绒毡层。绒毡层为腺质型。大孢子母细 胞减数分裂过程中的胞质分裂为连续型。小孢子四分体排列为左右对称型与四面体型。雌蕊子房壁在 授粉后4～5天破裂。胚珠倒生,双珠被,厚珠心。大孢子四分体线形排列,胚囊发育为蓼型。极核在受 精前融合成一个大的次生核。胚胎发育为紫菀型。核型胚乳。木根麦冬居群中存在雄性不育植株,约 占55．8％。胚胎在其发育早期约有43．3％败育。根据本研究的实验观察,(1)雄性不育和自花授粉以 及低效率的传粉机制而导致的异花传粉的失败;(2)部分胚胎的败育;(3)子房壁破裂而导致胚珠裸露等是木根麦冬有性生殖过程中的薄弱环节,也可能是导致该植物濒危的部分因素。     

珠子参愈伤组织培养与花色甙的形成

从珠子参(panax japonicus var.major)叶柄诱导的愈伤组织在暗培养条件下主要形成3种花色甙色素,且均以矢车菊素为甙元。2,4-二氯苯氧乙酸和激动素的组合能明显地促进色素的合成,色素含量可达34.14mg/g fw。     

Fusions between green fluorescent protein and β-glucuronidase as sensitive and vital bifunctional reporters in plants

By fusing the genes encoding green fluorescent protein (GFP) and -glucuronidase (GUS) we have created a set of bifunctional reporter constructs which are optimized for use in transient and stable expression studies in plants. This approach makes it possible to combine the advantage of GUS, its high sensitivity in histochemical staining, with the advantages of GFP as a vital marker. The fusion proteins were functional in transient expression studies in tobacco using either DNA bombardment or potato virus X as a vector, and in stably transformed Arabidopsis thaliana and Lotus japonicus plants. The results show that high level of expression does not interfere with efficient stable transformation in A. thaliana and L. japonicus. Using confocal laser scanning microscopy we show that the fusion constructs are very suitable for promoter expression studies in all organs of living plants, including root nodules. The use of these reporter constructs in the model legume L. japonicus offers exciting new possibilities for the study of the root nodulation process.     

Reproductive strategy of the sugi bark borer,Semanotus japonicus (Coleoptera: Cerambycidae) on Japanese cedar,Cryptomeria japonica

The inner bark of Japanese cedar,Cryptomeria japonica D. Don., is the main food of the sugi bark borer,Semanotus japonicus Lacordaire, but may also be involved in resistance to attack by the borer. I used newly hatched larvae to inoculate cedar logs that had been cut 2-weeks to 12-months earlier, and undamaged living cedar trees. On living trees, all larvae were killed by resin flow from the traumatic resin canals between the outer- and inner bark or between the inner bark and cambium. In logs that were cut more than 4 months prior to inoculation, larvae were unable to complete development. In logs cut 2 weeks prior to inoculation, almost all larvae were able to reach the adult stage but they were smaller in size than adults from living trees damaged by this borer. These results suggest that poor nutrient conditions in the inner bark of logs affected development and survival of the borer. Because of its nutritional advantage, living cedars provide a better environment for the sugi bark borer. However, all larvae are killed by resin flow, suggesting that this insect is “in between” being primary and secondary with respect to living trees, or a “weak” primary insect. The sugi bark borer seems to develop early in the season so that early instar larvae encounter reduced amounts of resin flow and so that late-instar larvae feed mostly in summer when nutrient levels in the inner bark are at their highest.