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;     

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。     

模拟水分胁迫对不同种源麻楝种子萌发能力的影响

以麻楝6个种源种子为试验材料,用不同浓度的聚乙二醇(PEG)溶液模拟干旱胁迫,探讨干旱胁迫对种子发芽率、发芽势、发芽指数、活力指数以及幼苗苗高和胚根长及根苗比的影响,为麻楝的引种和推广种植提供依据。结果显示:(1)不同水势胁迫处理均降低了麻楝种子的发芽率和发芽势,当水势为-0.40MPa时延缓了种子萌发进程;种子的发芽率、发芽势、发芽指数和活力指数均随干旱胁迫强度的增加呈明显下降的趋势;当胁迫水势为-0.86MPa时,干旱胁迫处理的种子在试验结束时仍未能萌发,即-0.86MPa是麻楝种子萌发的临界水势。(2)当胁迫水势高于-0.40MPa时,麻楝幼苗的胚根长度与对照组差异不显著且长于对照组,说明高于-0.40MPa的水势有利于麻楝种子胚根的生长;麻楝幼苗苗高生长则是随着PEG浓度的升高而逐渐减缓。(3)适当的干旱胁迫可以增大各种源麻楝幼苗根苗比,且在胁迫水势高于-0.20MPa时都达到最大值。研究表明,麻楝种子具有一定的抗干旱胁迫的萌发能力,并以来自缅甸的Khin Aye Pale和泰国的Phu Wiang材料较强,来源于中国三亚和马来西亚Ulu Tranan的较弱。     

Respiratory electron transport system (ETS) activity in Spanish reservoirs: relationships with nutrients and seston

We examined the relationship between potential respiration rates,as measured by electron transport system (ETS) activity, standardizedat a defined temperature (ETS2O). and nutrients and sestonicparticles in a set of 101 Spanish reservoirs spannin a widerange of limnological characteristics. ETS activity ranged from0.009 to 31 31 µmol e^- 1^–1 h^–1 Among the nutrients,it was significantly correlated only with phosphorus, and onlyduring the stratification period. During this period, the bestregressor of ETS2O was the concentration of chlorophyll a (Chla),whereas during the mixing period the best regressor was particulateorganic nitrogen (PON), suggesting a greater contribution ofnon-algal sestonic particles to total metabolism. Both the meanETS20:PON ratio and the mean Chla:PON ratio increased systematicallywith increasing PON, indicating a lower relative contnbutionof detrital particles to total seston as trophic state increased.In contrast, the mean ETS20:Chla ratio was constant across therange of Chla. Vertical profiles of ETS2O. Chla and PON weremore coherent during the stratification period. when subsurfaceand metalimnetic peaks were frequent, than during the mixingperiod.     

ENDOSYMBIONTS OF DREISSENA POLYMORPHA IN IRELAND: EVIDENCE FOR THE INTRODUCTION OF ADULT MUSSELS

Although zebra mussels (Dreissena polymorpha) have invaded watersacross Europe for over 200 years, they colonized Ireland onlywithin the past decade. To test the hypothesis that Irelandwas colonized by adult D. polymorpha, we examined mussels fromdifferent sites along the Lower Shannon River system in Irelandfor the presence of host specific and generalist endosymbionts.Withinthe mantle cavity and/or associated with zebra mussel tissueswe found species specific-ciliates (Conchophthirus acuminatusand Ophryoglena hemophaga) and generalist symbionts (the ciliateAncistrumina limnica, nematodes, oligochaetes and chironomids).We found a significant difference in the prevalence of symbiontsamong sites, but all mussels at all sites harboured one specialistspecies C. acuminatus, and all of the mussels at three of thefour sites also had the second specialist, O. hemophaga. Thus,with the introduction of D. polymorpha into Ireland, at leasttwo additional species, their host-specific symbionts C. acuminatusand O. hemophaga, have also been introduced. The presence ofthese symbionts in Ireland supports the hypothesis that adultzebra mussels were introduced into Ireland, rather than larvalstages. This contrasts with the introduction of zebra musselsto North America, where adult zebra mussels are devoid of host-specificsymbionts. (Received 8 June 2005; accepted 7 November 2005)     

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.     

The Rest Period of RhododendronFlower Buds I. EFFECT OF THE BUD SCALES ON THE ONSET AND DURATION OF REST

Shortly after flower differentiation, Rhododendron flower developmentis interrupted by a rest period. The results reported here showthat the onset and duration of rest depended upon the presenceof the flower bud scales. When the scales were removed beforethe onset of rest, the flowers continued to elongate and attainedanthesis. Intact buds stopped growing and remained in rest forat least four months. Scale removal after the onset of restterminated the rest period, though there was a lag phase beforethe flowers began to elongate. The duration of the lag phasewas related to the time of scale removal. The scales preventedflower development in situ, on detached stems and in vitro.Theresults further show that the rest period of each flower budwas independent of the rest period of adjacent flower buds andthat the resting terminal flower buds correlatively inhibitedthe growth of the lateral vegetative apices. The correlativeinhibition was eliminated by removing the terminal flower budor by breaking the rest period of the flower bud.     

INVESTIGATIONS ON AUXIN-GIBBERELLIN INTERACTION ON THE PHOTOTROPISM OF HELIANTHUS ANNUUS HYPOCOTYL

On applying IAA-GB and IAA-NAA mixtures to the hypocotyls ofHelianthus annuus, the plants showed an increase and a decrease,respectively, in their phototropic response compared with thecontrol treated with IAA-H₂O only. In the in vitro experimentsit was observed that the illumination (with 1,500 lux light,lasting for 24 hr) caused photoinactivation of IAA in the mixturesof IAA-H₂O, IAA-GB and IAA-NAA by 50%, 24% and 0%, respectively.In the presence of 0.01% riboflavin as a photosensitizer inthe same mixtures, the degree of photodestruction of IAA causedby the same illumination was 92%, 97% and 86%, respectively. The stronger positive phototropism in the IAA-GB treated hypocotylwas accounted for by the situation that on the illuminated sidethe photo-inactivation of IAA was accelerated by GB, while onthe shaded side IAA and GB acted synergistically. On the otherhand, the weaker phototropism in the IAA-NAA treated hypocotylwas explained as due to a partial inhibition of photoinactivationof IAA by NAA. (Received October 6, 1962; )     

A COMPARISON OF THE LIFE CYCLES OF THE SLUGS DEROCERAS RETICULATUM (MULLER) AND ARION INTERMEDIUS NORMAND ON PERMANENT PASTURE

Life cycles of the slugs Deroceras reticulatum and Arion intermediuswere compared over a four-year period on permanent pasture nearOvingham, Northumberland. Both species were semelparous, theirlife cycles taking about one year. D. reticulatum, unlike A.intermedius and other species, had two overlapping generationsthat laid their eggs in late spring and autumn respectivelyand also had one instead of two immature phases in its lifecycle. The pattern and rates of growth for the immature phasesin the life cycle of A. intermedius differed markedly from thosedescribed under laboratory conditions. Growth in the infantilephase was delayed in the field by low winter temperatures whilesecond stage growth was usually delayed in late spring by dryconditions. The life cycle of A. intermedius appears to be synchronisedby seasonal changes in photoperiod, unlike that of D. reticulatum.Growth in D. reticulatum continued throughout the winter monthsexcept under exceptionally cold conditions and was not usuallydelayed by dry conditions in spring. The size of hermaphroditegland relative to body weight in D. reticulatum reached a maximumin mature-unmated slugs and then became progressively smalleras the slug approached the post-reproductive stage which wasrelatively brief. Exceptionally dry conditions in 1962 delayedthe development of the hermaphrodite gland, the maximum sizereached was significantly reduced and fewer eggs were laid. (Received 17 September 1987; accepted 2 January 1988)     

The Rest Period of Rhododendron Flower Buds: II. STUDIES ON THE REST PERIOD IN TISSUE 3IN SITU

Shortly after the onset of rest in Rhododendron flower buds,the buds were transferred to a tissue-culture medium. The resultsreported here show that the rest period in culture was identicalto the rest period of buds in situ. In both environments theduration of rest and the frequnency distribution of elongationof the buds were the same. Histograms of bud development againsttime were bimodal, with about 20 per cent of the buds elongatingduring the second peak. In culture, the rest period was notaffected by changes in pH, temperature, or the addition of nutrientsalts. The results further show that the duration of the rest periodof each bud was independent of the time of the onset of rest.Buds that were supplied with either indol-3yl-acetic acid orgibberellic acid in culture or in situ remained in rest. Onlya low temperature treatment had a rest-breaking influence.     

INTERACTIONS BETWEEN SOIL BACTERIA AND THE MOLLUSCAN ALIMENTARY TRACT

The alimentary tract is a major site of interaction betweenan animal's ecosystem and its physiology. It may be intermittentlyor permanently populated by microorganisms from its environmentthat could be beneficial or pathogenic in their influence. Thebacterial populations of the snail (H. aspersa) and the woodlouse(O. asellus) have therefore been estimated in terms of colonyforming units. gm body weight^–1. The bacteria in the snailappear to be similar to those found in soil and show wide resistanceto antibiotics. The main types are gram negative rods tentativelyidentified as belonging to Pseudomonas, Xanthomonas, Acinobacter,Vibrio and Enterobacteriaceae. Some gram positive and endosporeforming bacteria of Bacillus, Staphylococcus and Micrococcusspp were also present. The numbers of bacteria increase towardsthe posterior of the alimentary tract although the numbers inthe digestive gland are more constant. An artificial diet is described that can be used to feed snailsand study the effects of known amounts of additives. When starvedor kept under clean conditions the bacterial population of thesnail gut falls and the thickness of the alimentary tract decreases.All the indications are that the bacteria in the alimentarytract of the snail are indiscriminately accumulated from thenatural environment and are transient populations. (Received 7 June 1989; accepted 24 July 1989)     

AGE, GROWTH AND MATURATION OF THE SQUID ENOPLOTEUTHIS LEPTURA (OEGOPSIDA: ENOPLOTEUTHIDAE) FROM THE CENTRAL-EAST ATLANTIC

Fifty-nine specimens of the tropical epipelagic eno-ploteuthidEnoplotcuthis leptura were collected in the central-east Atlanticbetween 1986–1988. Statoliths were extracted from allspecimens (mantle length (ML) 4.1–92 mm) and processedunder the statolith ageing technique. The characteristic featureof statolith morphology in E. leptura is a sculpture of therostrum, which is covered by numerous tiny spines and knobs.In the ground statolith it was possible to distinguish fourmain growth zones consisting of narrow growth increments likethose in other squids studied. Allometric growth of statolithsversus ML is negative. E. leptura is a short-lived squid witha half-year life span. Growth rates of E. leptura are high atjuvenile stage (instantaneous rate of growth (G) of body weight(BW) 0.04–0.06). An early maturation of males (at age45–60 days) and females (at 80–90 days) causes asharp decrease of somatic growth of E. leptura, and mature squidhave low growth rates (G of BW - 0.OO3-O.0O5). Spawning takesplace between January and September with two peaks: in Januaryand in June-July. (Received 22 November 1992; accepted 15 February 1993)     

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)     

TWO LIGHT REACTIONS IN THE PHOTOPERIODIC CONTROL OF FLOWERING OF LEMNA PERPUSILLA AND L. GIBBA

The effects of light quality on the photoperiodic control inthe flowering of a SD duckweed, Lemna perpusilla strain 6746,and a LD duckweed, L. gibba strain G3, were investigated withspecial reference to the interaction between R and B or FR lights. In the diurnal alternation of R or G light and dark periods,L. perpusilla responded as a SDP, but in that of B or FR lightit was almost daylength-indifferent. On the other hand, L. gibbaresponded as a LDP under B, R or FR light, although the criticallight length was altered by the light quality. In the diurnal alternation of R and B or FR light periods containingno dark period, L. perpusilla flowered with the shortening ofthe optimal and critical R light lengths, compared with theplant exposed to that of R light and dark period. The floweringresponse of L. gibba to the R light length showed double peaks,that is, the first peak at the R duration less than 9 hours,and the second at the R duration longer than 9 hours. The firstpeak corresponds to the optimal R light length in L. perpusilla. Under the CL with a mixture of R and B or FR lights, the floweringand frond production were influenced by the intensity ratioof two light given. In both plants, the optimal ratio of B toR or FR to R for the flowering was always greater than thatfor the frond production. It is suggested that the B or FR light interacts with the Rlight in the photoperiodic process in the plants and this interactionbetween the R and B or FR lights should be of importance forobtaining a better understanding of photoperiodism. (Received August 28, 1965; )     

PATTERNS OF REPRODUCTION IN THREE SANDY BEACH WHELKS OF THE GENUS BULLIA GRIFFITH

The breeding cycles of two species of sandy beach whelk (Bulliadigitalis and B. pura) are presented and compared with a thirdspecies (B. rhodostoma). In all three species, egg maturationand copulation occur in spring while summer marks the depositionand spawning of egg capsules. B. digitalis and B. pura migrateoffshore to lay their eggs, the juveniles of both species restrictingthemselves to beyond the breaker zone. Newly hatched snailsof B. rhodostoma appear in the intertidal towards late summer.The discovery of a penis-like structure on females of B. rhodostomais investigated. The pseudopenis was also found on B. pura butnever on B. digitalis. The possibility of a sex-change was eliminatedon the histological investigation of the gonads of a range ofsnails and the examination of sex-ratios over a period of fivemonths. General trends in reproductive behaviour are also discussed. (Received 18 March 1984;     

THE INFLUENCE OF INGESTIVE CONDITIONING ON FOOD CHOICES IN THE LAND SNAIL HELIX ASPERSAMULLER (GASTROPODA: PULMONATA: STYLOMMATOPHORA)

An experiment of food choice in one-day-old naïve landsnail Helix aspersa Müller was carried out, involving threephases. First, a training period on a monophagous diet of leafdiscs of Taraxacum officinale or Urtica dioica was given for1, 5, 10, 15 or 30 days. The area of leaf discs consumed byeach snail during this stage was assessed. In the intermediatephase, the animals were not fed for 24hours. Finally, food choicewas tested over 24 hours, when animals could eat leaf discsof each species of plant usedfor training. A coefficient offood preference for Urtica dioica was calculated (UPC = areaof Vrtica leaf disc consumed/area of Urtica and Taraxacum discsof leaves consumed for 24 hours). The length of the training phase did not reduce the percentageof individuals preferring the plant previously consumed. Onthe contrary, after 15 days of monophagous diet, animals formerlyfed on Urtica showed a coefficient of food preference for Urticasignificantly higher than Taraxacum fed animals, and after 30days of training this phenomenon was more pronounced. Thus,during the choice test, snails ate more of the previously eatenplant leaf. Our experiment highlighted the feeding behaviourplasticity of H. aspersa. The significant correlation betweenthe area of Urtica eaten during the training phase and the coefficientof food preference for Urtica is discussed. (Received 10 April 1994; accepted 10 January 1995)     

INHIBITION OF OLFACTION IN THE MOTH HELIOTHIS VIRESCENS BY THE SULFHYDRYL REAGENT FLUORESCEIN MERCURIC ACETATE

A combined electrophysiological, behavioral, and biochemicalstudy was initiated to determine the effects of the sulfhydryl-specificreagent fluorescein mercuric acetate (FMA) on olfaction in thetobacco budworm moth Heliothis virescens. The electroantennogram(EAG) response to the standard odorant n-pentyl acetate showedboth a time and concentration dependent inhibition by FMA. Treatmentof insect antennae with 2.52 x 10^–5 M FMA for 2 min reducedthe EAG by 50%, while treatment for 17 min reduced the EAG by80%. Incubation of antennae for 7 min with 2.52 x 10^–6M FMA resulted in 30% inhibition, while incubation with 2.52x 10^–6 M FMA for 7 min resulted in 65% inhibition. Antennalgrooming behavior was inhibited by FMA in a similar time andconcentration dependent manner as the EAG. Regeneration of previouslyinhibited behavioral and EAG responses has been observed withina 24-hr period. The interaction of protein, obtained by sonicatingintact antennae in phosphate buffer, with FMA was monitoredfluorometrically. Successive additions of antennal sonicateto FMA resulted in stepwise decreases in fluorescence. Partialrecovery of fluorescence was obtained by addition of cysteineto the FMA-antennal sonicate solution. The polarization of theFMA-antennal sonicate fluorescence decreased upon addition ofcysteine. These data indicate that FMA is reacting with a relativelylarge antennal protein (s) by mercaptide linkage and blockingthe olfactory transduction process.     

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)     

THE ESTUARINE MUD SNAIL, NASSARIUS OBSOLETUS: ABNORMALITIES IN THE REPRODUCTIVE SYSTEM

Females of the dioecious snail Nassarius obsoletus may havethree male characteristics: a penis, a vas deferens, and theconvolution of a normally straight gonadial oviduct to resemblea stunted mimic of the vesicula seminalis in the male. The firstcharacteristic is the most common and the last is the leastcommon. Collectively these characteristics were called imposex.A system for evaluating its frequency of occurrence and intensityof expression was developed. The frequency and intensity ofimposex was similar among different age groupings of snails,though there may be a trend towards less imposex in juveniles.The differences in the frequency and intensity of imposex betweengroups of parasitized and unparasitized females were very small.In males the reduction of penis size due to parasites was muchlarger. This pattern ofimposition of male characteristics onfemales is a new syndrome which does not resemble reported formsof hermaphroditism or pseudohermaphroditism related to age orparasitism. ^*Current address: Community Health Program, Electric Power ResearchInstitute, P.O. Box 10412, Palo-Alto, California 94303, U.S.A. (Received 28 August 1979;     

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