The reproductive biology of three perennial Sesbania species (Leguminosae)

Summary The reproductive biology of Sesbania sesban, S. goetzei and S. keniensis (Leguminosae; Papilionoideae) was studied. Fifty percent flowering was observed at 102 to 153 days after germination for S. sesban accessions; 96 to 146 days for S. goetzei and 131 to 176 days for S. keniensis accessions. Flowers opened in the afternoon and remained fresh for 2–3 days. Bee species including Xylocopa sp., Apis mellifera, Megachile bituberculata and Chalicodoma sp. visited the flowers. Hand pollination experiments showed that all three species were self and cross compatible. The percentage of fully developed seeds was greater in pods formed after cross pollination compared to self pollination. No evidence was found for stigmatic or stylar self incompatibility. Outcrossing is probably the common method of reproduction under natural conditions, although in isolated trees substantial seed set by selfing might occur. Pod production under natural conditions was 34% for S. sesban; 49% for S. goetzei and 39% for S. keniensis. Considerable variation was found in pod production under open pollination between accessions of the same species. Selective abortion was observed within pods, with more mature seeds formed at the distal end of the pod.     

Seasonal distribution of young sole (Solea solea (L.)) in the nursery ground of the bay of Vilaine (Northern bay of Biscay)

The distribution of young sole was studied in the bay of Vilaine nursery ground as a function of age and season for the 0, 1 and 2-groups. During 1988 and 1989, bimonthly trawl surveys were carried out from the estuary to the 50-m-isobath along a 65-km transect. A regular seasonal pattern demonstrated two combined trends. An offshore movement is observed with increasing age; this general trend is marked by an inshore migration in spring and an offshore one in winter. The fluctuations of the distribution pattern are discussed in relation to sedimentary characteristics, to trophic requirements and to hydroclimatic variations. The main conclusion is that young soles are concentrated inside a closed nursery area. In their third winter some participate in spawning migration and they get mixed, to a certain extent, with newly recruted soles from nearby nursery grounds.     

The influence of environmental conditions on settlement,distribution and growth of 0-group sole (Solea solea (L.)) in a macrotidal estuary (Vilaine,France)

In the Vilaine estuary, the environmental conditions at the onset of the settlement of metamorphosing sole have been surveyed for 5 years. The inshore migration occurs either in early or in late April depending on the hydroclimatic conditions: sole are observed in the estuary when bottom water salinity varies between 25 and 30 S and water temperature is up to 11°C. During spring, their distribution pattern is similar in all years: first, accumulation at the entrance of the estuary, then concentration in the upper parts and finally, colonization of the whole estuarine area by juveniles. Interannual variations in growth rates were observed during their first estuarine phase, in particular when the estuary is transformed into a ‘ria’ with high water temperature and salinity. These biological features are discussed according to ontogenic changes occurring during these early life stages. From field and experimental data and from literature information on sole and other pleuronectiform species, a conceptual model on relationships between environmental parameters and metamorphosis processes in estuarine areas is proposed.     

Floral biology in the Zanzibar type clove (Syzygium aromaticum) in Indonesia

Summary Investigations of the floral biology of Zanzibar type cloves were carried out on five mature trees. The majority of flowers opened in the afternoon. Anther dehiscence occurred shortly after anthesis and stamens were shed almost 2 days later. Nectar appeared around the base of the stigma as anthers dehisced and remained in evidence for approximately 60 hours. Three days after anthesis a constriction around the tip of the stigma became apparent. The stigma tip subsequently withered, turned brown and was shed after a further four days. Maximum pollen viability and stigma receptivity were attained simultaneously, 48 hours after anthesis. Indications concerning the breeding system in clove are discussed and a procedure for artificial pollination is suggested     

2个群体秀丽白虾生物学特征及基于RAPD的遗传多样性研究

对太湖和巢湖2个群体秀丽白虾的生物学特征和基于RAPD的遗传多样性进行了研究。结果表明,6月份太湖秀丽白虾的体长优势组为40-50mm（占样本数的69.3%）,体重优势组为0.5-2.0g（占样本数的83.4%）,体长（L/mm）、体重(W/g)的关系式为：W=2.6E-05L2.8777;6月份巢湖秀丽白虾的体长优势组为45-55mm（占样本数的73.8%）,体重优势组为1.5-2.5g（占样本数的69.0%）,体长（L/mm）、体重(W/g)的关系式为：W=2.8E-05L2.8471。15个随机引物的RAPD研究结果表明,太湖群体多态位点比例为49.16%,巢湖群体多态位点比例为48.78%;太湖、巢湖2个群体内遗传相似系数分别为0.8817和0.8735, 2个群体之间的遗传距离为0.0311,群体间没有发生明显的遗传分化。     

达里湖鲫鱼的种群特征

通过对在达里湖、岗更湖采取的鲫鱼进行形态特征、生物学特性测量分析研究,得出结论:达里湖鲫鱼属均匀生长型,其种群的繁殖能力也较强,但种群年龄结构不合理,应增加人工放流量和减少捕捞量.合理的捕捞规格为体长大于19.67cm,体重大于214.5g.     

Environmental characteristics and distribution of macrobenthos in a mudflat of the west coast of Korea (Yellow Sea)

The spatio-temporal changes of environmental factors and the distribution patterns of macrobenthos were investigated on an intertidal mudflat near Panweol on the west coast of Korea. Temperatures of the surface sediments and salinities of the intertitial water were highest in summer and lowest in winter, while water content of the sediment was lowest in summer and highest in winter. Hourly variations of sediment temperature, water content and interstitial salinity during the daytime depended largely upon both the timing of ebb tide and daylight intensity.Temperature, water content and interstitial salinity showed a marked variation with sediment depth. Temperatures decreased sharply from the surface to 10 or 15 cm depth, and below this depth they were nearly constant, except in summer. Water content and interstitial salinity underwent a rapid decline in this upper layer and began to rise from this depth. From the high tide mark toward the main tidal channel, water content increased but salinity decreased. The sand fraction increased with the decrease of clay content toward the main tidal channel. This tidal flat could be divided into two zones: the “upper intertidal zone” and the “lower intertidal zone”, based on the spatial differences of the water content, interstitial salinity and grain-size composition in the surface sediment.There were three distinct zones of macrobenthos. The upper intertidal zone was dominated by burrowing deposit feeders, such as Ilyoplax dentimerosa, Helice tridens sheni, Cleistostoma dilatatum and Perinereis vancaurica tetradentata. The middle intertidal zone was characterized by other burrowing deposit feeders, such as Ilyoplax pingi, Macrophthalmus japonicus and Periserrula leucophryna. And the lower intertidal zone was dominated by suspension feeders represented by Laonome tridentata and Potamocorbula amurensis. Each zone was named after these characteristic species.Although the species composition of the upper intertidal community was different from that of the middle intertidal, the way of living and the feeding behaviour of the species occurring in these two zones were very similar. But the lower intertidal zone showed a characteristic community structure differing not only in species composition but also in ways of living and feeding of the species. Some sets of environmental factors are considered to explain the zonation. Water content of the sediment and interstitial salinity will be the main factors causing the observed zonation.     

达里湖东北雅罗鱼受精卵在不同水体中的孵化试验

在赤峰市克什克腾旗达里诺尔渔场进行了达里湖东北雅罗鱼(华子鱼)受精卵在不同水体中的孵化试验及其鱼苗成活试验,试验表明:华子鱼受精卵在鄂尔多斯市柒盖淖水体中能够孵化且鱼苗成活良好,为达里湖华子鱼向内蒙古部分盐碱水域移植提供了科学依据。     

Changes in growth of plaice Pleuronectes platessa L. and sole Solea solea (L.) in the North Sea

The changes in growth of plaice and sole between 1957 and 1988, as estimated from samples of the commercial fishery and pre-recruit surveys, were analysed in order to study possible density dependent effects. Indices of potentially competitive biomasses of plaice and sole, based on Lloyd's index of mean crowding, were estimated from the average spatial distribution of various age groups during the summer growing period and from the population age structure as estimated by virtual population analysis.Growth of all age groups of sole increased in the 1960s and was stable in the 1970s and 1980s. In plaice only age groups 1 to 3 showed a similar increase in the 1960s, whereas the growth of 1-year-old plaice tended to decrease in the 1980s. Growth did not show a negative correlation with mean crowding, except in age group 1 of plaice and in age group 3+ of sole. It is concluded that these negative correlations do not provide unequivocal evidence for density dependent growth in plaice and sole, since they could equally well be caused by parallel but unrelated trends in time of one or more other factors. The simultaneous increase in growth in the 1960s of age groups of sole and plaice in the southern North Sea, and the absence of such an increase in age groups in the central North Sea, suggests that food availability must have increased in the Southern North Sea. This inference is supported by several macrobenthos studies. Whether the reduced growth of 1-group plaice in the 1980s, when recruitment was well above the average level, is caused by density dependent growth or to a reduced food availability remains an open question.     

蠡湖鲢鳙鱼生长的研究

2009年9月,在蠡湖的水上明月、珍宝舫、美湖和鹿顶山用网具共进行了4次捕捞作业,鲢鱼的体重主要集中在6000－11000g范围内,年龄为3－5龄,鳙鱼的体重主要集中在7000－12000g范围内,年龄为3－5龄。鲢鱼的生长方程为 , ;鳙鱼的生长方程为 , ,蠡湖鲢鳙鱼生长速度最快的年龄段是3-5龄。本研究对蠡湖鲢鳙鱼的种群结构及其生长特性进行了调查,旨在为保护和科学利用其渔业资源提供依据。     

Some observations on the floral biology of the carrot (Daucus carota L.)

The production of carrot seed sometimes presents the problem of the occurrence of seedless umbels. During an investigation into the cause of this phenomenon, a number of floral-biological data have been collected which are valuable both for the seed production and breeding of this crop.

1. 1.
   The distribution of male flowers and bisexual flowers. Both in the wild carrot and in 2 cultivated varieties the tendency to produce male flowers was encountered. In all forms tested the percentage of male flowers was practically negligible in the main umbel and was found to increase regularly in umbels of higher order. There were, however, clear differences in the mean percentage between the forms tested. Presumably the tendency to produce male flowers is determined genetically, but it may also be affected by the environment.     
   
   

Studies on the reproductive biology of white yam (Dioscorea rotundata Poir.)

Summary Investigations were conducted on the identification and distribution of yam natural pollinators, flowering pattern and hybridization of white yam (Dioscorea rotundata Poir.) at the International Institute of Tropical Agriculture (IITA), Ibadan, Nigeria, in order to provide informations for producing hybrid seeds needed for vam genetic improvement.Insects belonging to the Coleoptera (48.0%), Diptera (20.4%), Hymenoptera (20.0%), Hemiptera (5.8%), and Thysanoptera (5.8%) were caught around yam plants and presumed to be pollinators: they entered open-receptive-flowers and their presence on yam plants coincided with the duration of the flowering period.Studies on the flowering pattern revealed that: (i) Male and female clones differed in their periods of flower initiation as well as the flowering duration; (ii) Seed production and conventional breeding methods are feasible if staggered planting, water and soil fertility could be managed to ensure that flowering periods of males and females nick and also extend flowering.Artificial pollinations within white yam and between white yam and yellow yam (D. cayenensis Lam) using the camel hair brush method were successful, but resulted in a relatively low fruit set (31.8% maximum). This method was more effective than natural pollination (19.2%) and can thus supplement it for the production of hybrid seeds for introducing genetic variation in yam breeding populations.     

The importance of estuaries in life histories of flatfish species on the Southern Coast of Africa

This paper reviews the ecology of flatfish species associated with estuaries in southern Africa. Information from estuarine and coastal studies carried out in this region over the past 25 years indicates that only 4 of the 56 flatfish species occurring in the region utilize estuaries during part of their life histories. The suitability of estuaries and their role as nursery grounds for juvenile flatfish is assessed in terms of the proportion of the life cycle that each species spends within estuarine systems. Biological data on Pseudorhombus arsius, Bothus pantherinus, Heteromycteris capensis and Solea bleekeri extracted from broad based estuarine studies in the warm temperate and subtropical regions of southern Africa are presented in support of the thesis that in the absence of calm, shallow, turbid, marine shelf areas, juveniles of these species utilize estuaries as nursery grounds.     

RFLP/AFLP mapping of a brown planthopper (Nilaparvata lugens Stål) resistance gene Bph1 in rice

We have constructed a linkage map of the rice brown planthopper (BPH)resistance gene, Bph1. RFLP and AFLP markers were selected by thebulked segregant analysis and used in the mapping study of 262 F₂sthat were derived from a cross of `Tsukushibare', a susceptible japonica cultivar, and `Norin-PL3', an authentic japonicaBph1-introgression line. Twenty markers were mapped within a 28.9-cMregion containing the Bph1 locus on the long arm of rice chromosome12. Combining the result of segregation analysis of BPH resistance by themass seedling test and that of the markers, the Bph1 locus wasmapped within a 5.8-cM region between two flanking markers. The closestAFLP markers, em5814N and em2802N, was at 2.7 cM proximal to theBph1 locus. Together with the previously constructed high-resolutionmap of bph2 locating the locus at ca. 10 cM proximal to the Bph1 locus, this improved version of the linkage map would facilitatepyramiding these two important BPH resistance genes.     

Andean beans (Phaseolus vulgaris L.) with resistance to the angular leaf spot pathogen (Phaeoisariopsis griseola) in southern and eastern Africa

Common beans (Phaseolus vulgaris) are separated into two distinct groups: Andean and Middle American. We identified CAL 143 as the first Andean bean with resistance to angular leaf spot disease caused by Phaeoisariopsis griseola. Angular leaf spot is the most widespread and economically important bean disease in southern and eastern Africa, and it is especially severe on the extensively grown Andean beans. Cal 143 was resistant in Malawi, South Africa, Tanzania, and Zambia, but it was susceptible in Uganda. This was attributed to the presence of races of P. griseola in Uganda not present in the other countries. We identified two additional Andean bean lines, AND 277 and AND 279, with resistance to angular leaf spot in Malawi. We also characterized the virulence diversity of 15 isolates of P. griseola from southern and eastern Africa into nine different races. Five of six isolates from Malawi and two of seven from Uganda, obtained from large-seeded Andean beans, were characterized into four different races considered Andean. These were compatible only or mostly with large-seeded Andean cultivars. The other eight isolates from Uganda, Malawi, and the Democratic Republic of Congo, obtained from a small- or medium-seeded Middle American beans, were characterized into five different Middle American races. These were compatible with Middle American and Andean cultivars. CAL 143 was resistant or intermediate under greenhouse conditions to all but one of the same 15 isolates from southern and eastern Africa, but it was susceptible to an isolate from Uganda obtained from a medium-seeded Middle American bean. This revised version was published online in July 2006 with corrections to the Cover Date.     

A contribution to the classification of evergreen azalea cultivars located in the Lake Maggiore area (Italy) by means of AFLP markers

The amplified fragment length polymorphism (AFLP) technique was employed to assess the genetic conformity within a gene pool of evergreen azaleas. Ninety-three genotypes grown in historical gardens and nurseries of the Lake Maggiore area (Northern Italy), locally classified in the groups Indica, Japonica and Amoena, 44 reference cultivars of the four more or less universally recognized groups Belgian, Hirado, Kurume and Satsuki, and 40 species and species accessions that most concurred in the origin of the reference groups were included. Aims of the study were to define the genetic profiles of the Italian accessions and to provide useful information for their classification and pedigree reconstruction. Ordination analyses were used to evaluate if the AFLP technique can be applied to establish phylogenetic relationships and to investigate the DNA-based relatedness within the Italian gene pool and between the latter and the reference one. The results regarding the Italian accessions were compared with morphological data by means of Mantel’s test. Assignment tests both on the level of the groups and on individual plant level for the reference and Italian genotypes were applied to further evaluate the relatedness of the groups or individual accessions. Results demonstrated that the AFLP technique together with morphological characterization can contribute to depict the phylogeny of the evergreen azalea. Comparing the reference and Italian genotypes, conclusions about the classification of the evergreen azalea cultivars located in the Lake Maggiore area were drawn.     

油菜应用的研究进展

油菜作为世界范围内主要的油料作物，其油主要食用，其饼粕主要饲用，近年来人们对油菜的品质不断改良并且菜籽油也大量应用于化工，能源领域，转基因油菜也用来生可降解塑料的原油和生产昂贵的多肽，蛋白等药物，由地油菜用途的不断拓展，对其研究也不断深入。笔者对油菜产量，质量的提高，抗病性的加强，工业用油的开发等方面的应用研究作以综述。     

The mutagenic effect of ethylene imine (EI) on the tomato

Air-dry tomato seeds were treated with an ethylene imine dilution series. Most sterile M₁-plants can be detected morphologically at an early stage. Few of the morphological deviants proved to be fertile. Both with regard to M₁ ^- and to M₂ ^- growing space the highest concentration leaving fertiles (0.25%) was the most efficient. At this dose the rate of mutation which can be scored on young M₂-plants, reached a value of 1.04 per M₂-family. A small shortage of M₂-families with 1 mutation is suggested by different tests. This may be due to penetrance heterogeneity. The spectrum of chlorophyll mutations changes with the EI concentration, a significantly smaller proportion of chlorodefectios (albinas, etc.) being found at higher concentrations.