The copepod genus Oncaea (Poecilostomatoidea) from the Lebanon: taxonomic and ecological observations

Eighteen species of the genus Oncaea, four of them polymorphic,have been collected from the inshore and offshore waters ofthe Lebanon. Three species are new additions to the Mediterraneanfaunal list, O.shmelevi, O.pumilis and O.rufa. The males ofthree poorly described species, O.bathyalis, O.ovalis and O.similis,the female of O.shmelevi and both sexes of O.tenella are redescribed.Oncaea media and O.mediterranea were the two most common representativesof the genus in the study area. Oncaea were most abundant inDecember and January and between March and May; they were mainlymesopelagic and oceanic. Many of the species recorded here havecosmopolitan distributions; some of the smaller ones are lesswell-known, but may prove in time to be as widespread as thelarger taxa.     

Shoot Anatomy of Three Bulbous Species of Oxalis

The shoots of Oxalis latifolia, O. corymbosa and O. oxypteraare comprised of underground bulbs which send out stolons withapical and lateral bulbs. The external scales of the bulbs formthe base of the leaves; an adnation of the stipules to the petioleoccurs as well. In O. oxyptera the bulb shows primitive charactersand can be considered a rhizome-shaped bulb. Incipient secondarygrowth and schizo-lysigenous secretory cavities are described.An ascending evolutionary sequence of O. oxyptera, O. latifoliaand O. corymbosa is proposed based on the vegetative system. Oxalis spp., Oxalidaceae, shoot anatomy, bulb, stolons     

九种蝗虫核型似近系数的聚类分析研究

应用核型似近系数聚类分析方法,研究了小稻蝗Oxya hyla intricata、山稻蝗O.Agav-isa、上海稻蝗O.Shanghaiensis无齿稻蝗O.Adentata、中华稻蝗O.Chisensis、日本稻蝗O.Japonica、短额负蝗Atractomorpha sinensis、奇异负蝗A.Pergrina和日本蚱Tetrix japonica等9种蝗虫的亲缘关系。结果显示,9种蝗虫分为3类：稻蝗,负蝗和蚱。6种稻蝗之间的核型似近系数(λ)在0.961～0.5695之间,2种负蝗的λ＝0.5867,日本蚱与这8种蝗虫的λ在0.5318～.0322。聚类图直观地反映出它们的亲缘关系与形态分类学的分类结果相一致。从9种蝗虫 的核型演化上看,日本蚱是较原始的类型,负蝗分化也较早,而稻蝗则是较进化的类型。     

Microsporogenesis in some Triploid Dactylorchid Hybrids

During meiosis in naturally occurring triploid hybrids betweenthe diploid Orchis fuchsii Druce (2n = 4O) and the two tetraploids,O. purpurella Steph. and O. praetermissa Druce (2n = 8O), thereis a regular formation of 20 bivalents and 20 bivalents. Sincethe two tetraploid species themselves show typical ‘diploid’behaviour in synapsis and fertility, they are considered tobe allopolyploids, and the hybrid pairing to be allosyndetic.The implication is therefore that both tetraploids are amphidiploidsof which O. fuchsii has been one progenitor. It is suggestedthat varieties of the polytypic diploid O. latifolia L. sec.Pugsl. may have been the other progenitors. A feature of interestin the microsporogenesis of both parents and hybrids is theclose synchronization of nuclear events in the pollen massulae,which behave as physiological units throughout meiosis and pollen-mitosis.In the triploids, although numerous dysploid nuclei are produced,none dies prematurely, probably because of mutual compensationwithin what is, in effect, a common cytoplasmic matrix.     

Variations in the Contents and Kinetic Properties of Ribulose-1,5-bisphosphate Carboxylases among Rice Species

The K_m(CO₂) ancl V_max of ribulose 1,5-bisphosphate (RuBP) carboxylaseand its protein ratio to total soluble protein from Oryza speciesincluding cultivars (25 varieties) and wild types (11 species,21 strains) were surveyed. Their variabilities among cultivarsof O. sativa were very small. The averages of the K_m(CO₂) andV_max values and the ratio of carboxylase to soluble protein,and their standard errors were 10.2?1.0µM, 1.72?0.13units.mg^–1(pH 8.0 and 25?C) and 52?2%, respectively. However, some differencesseemed to exist based on genome constitution in the Oryza genus.RuBP carboxylases from the species with the A^gA^g genome, O.graberrima and O. breviligulate, exhibited low K_m(CO₂) values(8.0?0.8 µM). High V_max was associated with the CC genome,O. eichingeri and O. officinalis (2.08?0.15 units.mg^–1).A higher ratio of RuBP carboxylase protein to soluble proteinwas found for the AA genome, O. sativa and O. perennis. (Received September 24, 1986; Accepted April 15, 1987)     

An Enzymic Basis for Pathogenic Specificity in Ophiobolus graminis

Avenacin, the glucosidic inhibitor present in oat roots, isacted on by a specific glucosidase produced by Ophiobolus-graminisvar. avenae, which destroys biological activity, as does hydrolysiswith 0.1 N. HCl. Neither O. graminis itself nor any other fungustested produces this enzyme. It is suggested that the resistanceof oats to O. graminis and its susceptibility to var. avenaedepend on an inhibitor-inactivating enzyme complex, and thisis compared with the antibiotic-inactivating enzyme complexfound in penicillin-producing moulds and resistant penicillinase-producingbacterial strains; such a complex may be concerned in othercases of pathogenic specificity. The way in which a varietyof O. graminis pathogenic to oats may have arisen is discussed.     

阿维菌素对南方小花蝽抑制烟蚜的影响

在室内分别测定了阿维菌素类杀虫剂1% 9512-1乳油和虫螨克对南方小花蝽Orius similis的毒力,研究了无阿维菌素介入后南方小花蝽对烟蚜Myzus persicae捕食效应所受的影响,结果表明：阿维菌素类杀虫剂对南方小花蝽具有一定毒力,不同虫态对阿维菌素的敏感性有差异,卵的敏感性明显低于若虫和成虫;不同的阿维菌素类药剂对南方小花蝽的毒力存在差异,9512-1对南方小花蝽卵、若虫及成虫的LC_５０依次为11.2743±3.8613、2.6584±1.2139、2.4508±1.3266 mg·L^-１,虫螨克则为10.8699±3.7653、6.4422±2.8596、6.4738±3.0124 mg·L^-１;阿维菌素显著降低了南方小花蝽对烟蚜的捕食量和捕食能力,也降低了同种个体间的竞争能力;阿维菌素对南方小花蝽若虫的发育速率有显著的抑制作用,但对发育速率与取食量的线性关系无明显影响,而且对存活个体成虫期的产卵量无显著影响。     

THE BIOLOGY OF THE NORTHEASTERN PACIFIC TURRIDAE II. OENOPOTA

The habitat, diet, some reproductive and mortality factors forseveral shallow-water species of the boreal turrid genus Oenopotafrom the Puget Sound region were determined. All fed exclusivelyon tubicolous polychaetes. Oenopota fidicula was a dietary andhabitat generalise Oenopota elegans eats Schistocomus hiltoniand lives in areas of shell fragments. Oenopota excunata eatsTharyx multifilis and is a habitat generalist. Oenopota tabulataappears to be a dietary generalist, but lives only on or nearrocks. The widely-distributed species, O. levidensis, eats spionidpolychaetes, primarily Polydora species, or Owenia fusiformis,and is a habitat generalist. Feeding frequencies are low asare population densities; although O. levidensis sometimes exceeds15 animals m^–2. Crabs are major predators upon turridsin some areas, but mortality causes are generally obscure. Spawningwas observed in four species, but only O. elegans and O. levidensishad viable larvae. Development takes 13–15 weeks, 6–7weeks in a capsule and 6–7 weeks as planktonic veligers.There are no nurse eggs. Settling was not observed. ^*Present mailing address: Bamfield Marine Station Bamfield,B.C. VOR 1B0 CANADA (Received 30 May 1982;     

Two new Oncaea species (Copepoda: Poecilostomatoida) from the Red Sea

Two new Oncaea species, O.umerus and O.hawii, are describedfrom females taken in the central Red Sea. They are closelyrelated to each other and to a group of Oncaea similis-likespecies, whose morphological characteristics are reviewed forcomparison.     

Photoconversion of a Water-Soluble Chlorophyll Protein from Chenopodium Album: Resonance Raman and Fourier Transform Infrared Study of Protein and Pigment Structures

A water-soluble Chl a/b-protein complex, CP668, from Chenopodiumalbum converts to another form of protein complex, CP743, uponlight illumination. Structural changes of pigments and proteinsupon photoconversion were studied using resonance Raman (RR)and Fourier transform infrared (FTIR) spectroscopies. RR spectraof CP668 and CP743 and a light-induced FTIR difference spectrumshowed that the macrocyle C=C bands of Chl a in CP668 considerablychanged upon conversion to the pigment (not chemically identifiedyet) in CP743. The C=C band pattern of the RR spectrum of CP743was similar to that of bacteriochlorophyll a, suggesting thatthe conjugated system of the CP743 pigment resembles a bacteriochlorinring. Judging from the C=O frequencies, the 13¹-keto C=O groupsof Chl a and b in CP668 are free from hydrogen bonding, whereasthe 13²-ester C=O groups of both Chl a and b and the 7-formylC=O of Chl b in CP668 are hydrogen bonded. Upon conversion toCP743, interactions of the 13¹-keto and 13²-ester C=O groupswere basically unaffected, demonstrating no drastic changesaround these C=O groups. FTIR spectra in the amide I' regionof CP668 and CP743 in D₂O buffer showed a peak at 1,633 cm^–1,which represents a major component of ß-sheet conformation.Second-derivative spectra of the amide I' bands as well as alight-induced FTIR difference spectrum suggested that drasticchange in the protein conformation does not occur upon photoconversion. (Received November 1, 1998; Accepted December 24, 1998)     

Egg trading in the simultaneously hermaphroditic polychaete worm Ophryotrocha gracilis (Huth)

Ophryotrocha gracilis (Huth 1934) is a simultaneously hermaphroditicpolychaete worm with external fertilization and a brief protandrousphase. The mating system of this species seems to meet conditionsleading to the establishment of egg-trading behavior. Experimentsshowed that mating occurs in pairs composed of two simultaneoushermaphrodites; sex roles are sequentially alternated and self-fertilizationis avoided. Egg reciprocation is kept evolutionarily stableby laying eggs in multiple, small-sized egg clutches and reducingthe reproductive success of pairs in which one of the two partnersdoes not reciprocate egg exchange. The frequency of ovigeroushermaphrodites in mass cultures of O. gracilis is about 50".Such a high mate availability preadapts hermaphrodites of O.gracilis to change partners very frequently and to reduce investmentin parental care, contrary to what is observed in another egg-trading,simultaneously hermaphroditic species, O. diadema. Laboratorypopulations of O. diadema have a frequency of only 17% ovigeroushermaphrodites     

Two new species of Oncaea (Copepoda: Poecilostomatoida) from the Red Sea and a redescription of O. atlantica Shmeleva

Two new species of planlctonic copepods are described: Oncaearufa and O. platysetosa. The former is characterised by thelong setae of the fifth leg, the latter by the numerous modifiedsetae on the appendages and caudal rami. Oncaea atlantica whichis closely related to O. platysetosa, is redescribed from newmaterial, also collected in the central and northern Red Sea.     

Growth Delay and Intracellular Changes in Chlorella ellipsoidea C-27 as a Result of Deuteration

The effects of deuterium (D) on Chlorella ellipsoidea C-27 wereinvestigated. Cells grown in a medium prepared with deuteriumoxide (D₂O) showed pronounced delays in cell growth and division;the length of a cell cycle in medium with 100 mol% D₂O was morethan 5 times longer than that in medium prepared in H₂O Thedelay caused by D₂O was not overcome by either indoleaceticacid or kinetin. The biological and ultrastractural characteristicsof deuterated .Chlorella (D-Chlorella) cells were examined.The responses of D-Chlorella to cell wall-digesting enzymesdid not differ from those of normal (H-Chlorella) cells. D-Chlorellacells were enlarged, and cellular components, such as proteins,nucleic acids, lipids and ATP, were present in larger quantitiesthan those in H-cells. The chloroplast of D-Chlorella was enlarged,but the levels of component photosynthetic pigments were significantlyreduced. By contrast, mitochondria of D-Chlorella were smallerthan those of H-cells. These changes in levels of cellular componentsand in the sizes of organelles seem to be unique to deuteration. (Received May 13, 1992; Accepted July 28, 1992)     

The foraging behavior of granivorous rodents and short-term apparent competition among seeds

The foraging behavior of a predator species is thought to bethe cause of short-term apparent competition among those preyspecies that share the predator. Short-term apparent competitionis the negative indirect effect that one prey species has onanother prey species via its effects on predator foraging behavior.In theory, the density-dependent foraging behavior of granivorousrodents and their preference for certain seeds are capable of inducing short-term apparent competition among seed species.In this study, I examined the foraging behavior of two heteromyidrodent species (family Heteromyidae), Merriam's kangaroo rats(Dipodomys merriami) and little pocket mice (Perognathus longimembris).In one experiment I tested the preferences of both rodent speciesfor the seeds of eight plant species. Both rodent species exhibiteddistinct but variable preferences for some seeds and avoidanceof others. However, the differences in preference appearedto have only an occasional effect on the strength of the short-term apparent competition detected in a field experiment. In anotherexperiment, I found that captive individuals of both rodentspecies had approximately equal foraging effort (i.e., timespent foraging) in patches that contained a highly preferredseed type (Oryzopsis hymenoides) regardless of seed density and the presence of a less preferred seed type (Astragalus cicer)in the patches. The rodents also harvested a large proportionof O. hymenoides seeds regardless of initial seed density;this precluded a negative indirect effect of A. cicer on O.hymenoides. But there was a negative indirect effect of O.hymenoides on A. cicer caused by rodents having a lower foragingeffort in patches that only contained A. cicer seeds than inpatches that contained A. cicer and O. hymenoides seeds. Theindirect interaction between O. hymenoides and A. cicer thusrepresented a case of short-term apparent competition thatwas non-reciprocal. Most importantly, it was caused by theforaging behavior of the rodents.     

Vegetative Reproduction as Related to Biomechanics, Morphology and Anatomy of Four Cholla Cactus Species in the Sonoran Desert

Vegetative reproduction via the rooting of detached stem segments(joints) is well recognized for certain cylindropuntias (chollas).This mode of reproduction was characterized in the field forOpuntia acanthocarpa, O. bigelovii, O. echinocarpa and O. ramosissimain the northwestern Sonoran Desert and the southern Mojave Desertand related to the following: (1) morphology of terminal jointsand their junctions; (2) the biomechanics and anatomy of terminaljoint junctions; and (3) the rooting of detached terminal joints.Species that typically reproduce vegetatively were hypothesizedto possess mechanically weak terminal joint junctions and terminaljoints with high rooting abilities. In general, resistance tofailure of terminal joint junctions depended on the diameterof the junction, with larger diameters providing greater resistanceto mechanical failure. Junction strength also depended on thepresence or absence of fibres and the amount of parenchyma cellsper cross-sectional area. Rooting ability appeared to dependon joint diameter, which determines the amount of stored carbohydratesand water. Of the four species, only O. bigelovii showed evidenceof vegetative reproduction in the field and was also the onlyspecies that had both relatively weak junctions and joints witha high rooting ability. Furthermore, joints of O. bigeloviihad the most spines per tubercle area, which increases the chancethat their spines will catch on a passing vertebrate, allowingfor greater joint dispersal. Copyright 2001 Annals of BotanyCompany Biomechanics, Cactaceae, Cholla, libriform fibres, Opuntia, vascular tracheids, vessel elements     

Isolation, Culture, and Plant Regeneration of Protoplasts of Two Shrubby Oxalis Species from South America

Protoplasts were successfully isolated from internodal callustissues of both Oxalis glaucifolia and O. rhombeo-ovata whenthey were digested in a solution containing 0.1% (w/v) MacerozymeR-10, 0.5% (w/v) cellulase Onozuka R-10 and 0.3 mmol m^–3sucrose. Protoplasts proliferated to give cell colonies on Gamborget al.'s B5 medium supplemented with 0.3 mmol m^–3 mannitol,0.5 mg dm^–32, 4-D, and 2.0 mg dm^–3 kinetin. Calluswas produced upon transfer of cell colonies to Murashige andSkoog medium containing 2.0 mg dm^–3 l-naphthaleneaceticacid (NAA) and 0.1 mg dm^–3 kinetin for O. glaucifolia,or with 5.0 mg dm^–3 NAA and 0.5 mg dm^–3 6-benzylaminopurine,for O. rhombeo-ovata. Plants were regenerated from O. glaucifoliaprotoplasts on a medium containing 0.1 mg dm–3 NAA, 1.0mg dm^–3 kinetin and 1.0 mg dm^–3 gibberellic acid,but only vascular nodules were differentiated by O. rhombeo-ovataprotoplast-derived calli. Key words: Tissue culture, protoplasts, plant regeneration, Oxalis spp     

Effect of Potato-2 Medium on Anther Culture of Interspecific Rice Hybrids

The effect of two culture media, potato-2 and N₆ supplementedwith kinetin and either 2,4-dichlorophenoxyacetic acid (2,4-D)or -naphthalene acetic acid (NAA) on anther culture responseof two interspecific rice hybrids was studied. While calluscould be successfully induced and plants regenerated from theF₁ of O. saliva x O. rufipogon, the other hybrid, O. salivax O. longistaminala did not respond to the anther culture. Nevertheless,some success in callus induction was achieved when anthers froma few selected F₂ plants were cultured from the latter cross.No interaction effects between the media (potato-2, N₆ and growthhormones (2,4-D and NAA) for anther response to callusing wereobserved. Potato-2 medium proved to be superior to N₆ in termsof increased anther response, early callus induction, multiplecalli formation and also overall green plant regeneration Oryza saliva L., O. rufipogon Griff., O. longistaminata A. Chev. et Roehr, interspecific hybrid, anther culture, potato-2 medium, N₆ medium     

Photosynthesis and photorespiration in the genus Oryza

Photosynthetic gas exchange has been surveyed in 22 of the 23species currently placed in the genus Oryza and constitutingthe wild relatives of cultivated rice. Unimproved, wild germplasmof a number of species showed light-saturated assimilation ratesin atmospheric air at least as great as cultivars and elitebreeding material of the cultigen O. satlva. One of these specieswas O. australiensis, different accessions of which were significantly(P=0.001) superior in assimilation rate to the 0. satlva genotypestested, including representatives of the Indica, Japonica andJavanica subgroups. Amongst species, assimilation rate was correlatedpositively with light saturation and with carboxylation efficiency.The wild species fell into two distinct groupings accordingto whether they originated from sun or shade habitats, withthe higher assimilation rates being associated with the sunspecies. Assimilation rates were also higher in diploids thanin tetraploids and this was associated with the fact that allsun species are diploids and all tetraploids are shade species.The carbon dioxide compensation concentrations ranged from 28to 43µmol mol^–1 with the two lowest values (28 and32µmol mol^–1) coming from accessions of O. rufipogon.The mean value for the absolute quantum yield of photosynthesismeas ured on attached leaves was 0.060. There was a large rangein the activity of phosphoenolpyruvate (PEP) carboxylase witha number of species having rates several times those of C₃ species.Some species with the highest assimilation rates were assessedfor photorespiratory losses and these were generally around30% and similar to O. satlva cultivars. However, a range ofO. rufipogon accessions had photorespiration rates significantly(P=0.01) lower than the O. sativa genotypes tested. No speciesin the genus possessed C₄ photosynthetic metabolism though somedid overlap with compensation concentrations and phosphoenolpyruvatecarboxylase activities reported for C₃–C₄ intermediatespecies. The potential value of wild relatives to the improvementof cultivated rice is discussed. Key words: Oiyza, photorespiration, photosynthesis, rice, wild rice     

Oxidative Phosphorylation in Germinating Lettuce Seeds

The effect of thiourea and coumarin, in vivo and in vitro, onthe phosphorylating activity of lettuce mitochondria was investigated,as well as the effect of coumarin on the P/O ratio. It was shownthat both substances in vitro inhibit phosphorylation; whilein vivo coumarin inhibits but thiourea under certain circumstancesstimulates. Coumarin was also shown to decrease the P/O ratioand therefore may be considered as an uncoupler. The difficulties in considering these effects of the substancesas a primary mechanism controlling germination are pointed outand discussed.     

Sexual selection and condition dependence of courtship display in three species of horned dung beetles

Sexual selection has traditionally been divided into competitionover mates and mate choice. Currently, models of sexual selectionpredict that sexual traits are expressed in proportion to thecondition of their bearer. In horned beetles, male contestcompetition is well established, but studies on female preferencesare scarce. Here I present data on male mating success and condition dependence of courtship rate in three species of horn-dimorphicdung beetles, Onthophagus taurus, Onthophagus binodis, andOnthophagus australis. I found that in the absence of malecontest competition, mating success of O. taurus and O. australiswas unrelated to their horn length and body size, whereas inO. binodis horn size had a negative effect but body size hada positive effect on male mating success. Overall, in O. binodismajor morph males had greater mating success than minor morphmales. In all three species male mating success was affectedby courtship rate, and the courtship rate was condition dependent such that when males were manipulated to be in poor conditionthey had lower courtship rates than males that were manipulatedto be in good condition. My findings provide new insight intothe mating systems of horned dung beetles and support an importantassumption in indicator models of sexual selection.