中国羽枝藻属新资料

1.山西羽枝藻 新种 图1:1—4 Cloniophora shanxiensis Y. J. Ling et S. L. Xie, sp. nov. Species affnis C. spicatae (Schmid.) Islam, sed primariis ramulis irregularibus alternatisvel oppositis, pyrenoidibus solitariis, ramuli cellulis apprime irregularibus differt. Thallo caespitoso, usque ad 5 cm longo; rhizoideis e filamenti cellulis basalibus angustis     

留兰香组织培养及快速繁殖条件的优化

以留兰香(Menthaspicata L.)茎尖为实验材料,对外植体消毒、不定芽增殖和试管苗移栽生根的最佳条件进行研究。结果表明,最佳外植体消毒方法为:用体积分数75%乙醇浸泡30s,再用1.0g·L-1HgCl2浸泡10min,培养7d后外植体生长状况良好。正交实验结果表明,在附加0.2mg·L-16-BA和0.02mg·L-1NAA的MS培养基中,留兰香不定芽的增殖倍数最高,试管苗生长状况最好。在含25mg·L-16-BA和50mg·L-1NAA的混合溶液中浸泡1h,移栽试管苗的生根率可达100%,且根较长。     

IDENTIFICATION OF CRYPTIC SPECIES IN THE LESSONIA NIGRESCENS COMPLEX (PHAEOPHYCEAE,LAMINARIALES)1

The kelp Lessonia nigrescens Bory is the most ecologically and economically important seaweed in rocky intertidal and shallow subtidal habitats along the temperate Pacific South American coasts. Recent molecular studies suggest the existence of two lineages, one (northern lineage) from 17° S to 30° S and a second (central lineage) from 29° S to 41° S. To identify and name these lineages we performed morphological, nomenclatural and field studies. Four external and three internal anatomical traits permitted a morphological separation of the two lineages. The internal structure of both lineages was different from the isolectotype of Lessonia nigrescens. It is therefore concluded that the name Lessonia nigrescens should not be used for the Chilean material. Chordaria spicata Suhr appears as the oldest available name for the central lineage, while Lessonia berteroana Montagne is the oldest name for the northern lineage. In both cases, the type material consisted of small‐sized, apical branches of larger plants. The new combination Lessonia spicata (Suhr) Santelices is proposed for the central lineage and we reinstate Lessonia berteroana for the northern lineage. Laminaria scissa Suhr is reduced to synonym of L. spicata. Representative specimens of Lessonia nigrescens were not found during new visits to its type locality in Cape Horn and along Chile. Future studies should verify the status of this species.     

Polyploidy: a missing link in the conversation about seed transfer of a commonly seeded native grass in western North America

The use of local, native plant materials is now common in restoration but testing for polyploidy in seed sources is not. Diversity in cytotypes across a landscape can pose special seed transfer challenges, because the methods used to determine genetically appropriate materials for seed transfer do not account for cytotypic variation. This lack of consideration may result in mixing cytotypes through revegetation, which could reduce long‐term population viability. We surveyed nine populations of a native bunchgrass, Pseudoroegneria spicata, in three EPA Level III Ecoregions in the western United States to determine the frequency of polyploidy, whether there are differences in traits (phenotype, fecundity, and mortality) among plants of different cytotypes, and whether cytotype frequency varies among ecoregions. We assessed trait variation over 2 years in a common garden and determined ploidy using flow cytometry. Polyploidy and mixed cytotype populations were common, and polyploids occurred in all ecoregions. Four of the nine populations were diploid. The other five had tetraploids present: three had only tetraploid individuals whereas two had mixed diploid/tetraploid cytotypes. There was significant variation in traits among cytotypes: plants from tetraploid populations were larger than diploid or mixed populations. The frequency and distribution of cytotypes make it likely that seed transfer in the study area will inadvertently mix diploid and polyploid cytotypes in this species. The increasing availability of flow cytometry may allow ploidy to be incorporated into native plant materials sourcing and seed transfer.     

Microsatellite markers isolated from saltgrass (Distichlis spicata)

Twelve polymorphic microsatellite DNA loci were isolated from saltgrass (Distichlis spicata) and optimized for future studies of its breeding system. The loci were screened for variability among 24 individuals from two populations. The primers amplified loci with numbers of alleles ranging from four to 14 per locus and polymorphic information content from 0.481 to 0.951. Observed heterozygosity varied from 0.227 to 0.958.     

Essential Oils with 1,2-Epoxy-p-menthane Derivatives from Mentha spicata Plants Growing Across the Island of Crete

The essential oil content and composition of Mentha splcata plants, collected from 11 localities, scattered across the island of Crete (S. Greece), have been studied. The qualitative and quantitative essential oil analyses by means of CC and GC-MS, have shown that these are characterized by a high quantity of trans-piperitone oxide and/or piperitenone oxide. The pattern of essential oil quantitative variation follows a NW→SE direction on Crete. Along this direction, the total essential oil content of the plants increased whereas, the essential oil components formed via the pathway leading to the formation of cis-piperitone oxide are gradually substituted by those leading to the formation of trans-piperitone oxide.     

Halophytic crops for cultivation at seawater salinity

Summary Several hundred halophytes from salt marshes and salt deserts of the world have been evaluated in our laboratory at various degrees of intensity, and a few have been selected for development as crops. The development of the cultivars and the basic biology of the plants is being studied in Delaware in the United States. Agronomic testing, feeding trials, and development of the best agronomic practices are taking place in the saline desert at the American University in Cairo research station in Sadat City. Our present efforts focus primarily on three forages, one grain, and one vegetable.Sporobolus virginicus cultivars for both hay and pasture are being tested. ADistichlis spicata cultivar for hay has been identified, andSpartina patens is being evaluated as a hay as well. Although we do not yet have the data for a full year's growth in Egypt, forage yields of these various cultivars, when harvested as hay crops, range to 6.9 or more tons per acre, depending on the salinity and other environmental conditions, and the crude protein content as indicated by the nitrogen content ranges from 6 to 10%. Cultivars having the most useful agronomic qualities have been identified and are being increased in quantity. The grain cropKosteletzkya virginica is a perennial, producing a seed which resembles millet; its whole seeds contain approximately 25% protein and 15% oil. The yields of one of our better cultivars are about 1460 kg/ha (1300 lb/acre) when grown under 25 salinity. The vegetableAtriplex triangularis (similar to spinach) has been under mass selection for four years; a cultivar has been identified and seed is now being increased for this species.     

Primary productivity of natural grass ecosystems of the tropics: A reappraisal

Studies of net primary production in four contrasting tropical grasslands show that when full account is taken of losses of plant organs above- and below-ground these ecosystems are far more productive than earlier suggested. Previous values have mainly been provided by the International Biological Programme (IBP), where estimates of production were based on a change in vegetation mass alone and would not necessarily have taken full account of organ losses and turnover. Calculation at three of our sites based on estblished methodology using changes in plant mass alone (i.e. that used by the International Biological Programme, IBP) proved to be serious underestimates of when acount was taken of losses simultaneously with measurement of change in plant mass. Accounting for the turnover of material at these three sites resulted in productivities up to five times higher than were obtained using the standard IBP procedure. An emergent C₄ grass stand at a fourth site in the Amazon achieved a productivity which approached the maximum recorded for agricultural crops. In this case, productivity values, when organ losses were taken into account, only slightly exceeded that obtained with IBP methods. The findings reported here have wider implications, in prediction of global carbon cycling, remote sensing of plant productivity and impact assessment of conversion to arable cropping systems.