Establishment of in vitro Cultures of Tapinanthus bangwensis (Engler and K. Krause) Danser and the Effects of Sugars on Growth

Culturing of organs in vitro has been successfully employedin studies on morphogenesis and nutritional requirements ofparasitic and semi-paraaitic angiosperms. Tapinanthus bangwensis,a semi-parasite, has been successfully cultured on chemicallydefined media. By and large the parasite will thrive well ina medium of mineral salts and sucrose at its optimal concentration(4 per cent). However, the parasite is able to metabolize awide range of sugars most of which show similar concentrationoptima Although the growth in vivo was simulated in vitro inthe early stages, it was found that in the later stages growthin vitro was much slower than growth in vivo. The growth differencesobserved in the different media may reflect some of the physiologicaldifferences that are responsible for the selective nature ofthe parasite's development and establishment on different hosts     

Mature Tissue and Crop Canopy Respiratory Characteristics of Rye, Triticale and Wheat

Crop dry matter and its chemical composition, together withcanopy and mature tissue respiration rates were measure at equivalentgrowth stages and temperatures for spring and winter rye, triticaleand wheat crops grown under irrigated field conditions. Canopyrespiration was partitioned into growth and maintenance respirationusing information from the chemical composition analysis ofthe crop biomass. Rates of dry matter accumulation early inthe growing season were significantly greater for rye cropsin comparison to triticale and wheat. However, when dry matterwas measured at similar ontogenetic stages, the productivityadvantage of the rye crop was no longer evident. Nevertheless,canopy respiration rates per unit ground area were significantlylower for rye than wheat over all temperatures and growth stages.Intergeneric differences in the respiration rates of matureleaf and stem tissues were consistent with those measured atcanopy scales. Differences in the chemical composition of thebiomass among genera were minimal, and insufficient to accountfor differences in canopy respiration due to synthesis respirationrequirement. Estimates of biomass maintenance requirements appearto be significantly lower for rye than wheat when calculatedat similar temperatures and ontogenetic stages. The maintenancecoefficient (m) depended on stage of development, suggestingthat m will decline earlier chronologically for rye than wheat,which implies that greater carbon retention is another aspectcontributing to the higher early-season crop growth rates ofspring and winter rye. Considering the lower respiration ratesof mature stems relative to leaves, the dependence of m on stem:leafratio was suggested as a useful approach to modelling ontogeneticeffects on maintenance respiration.Copyright 1993, 1999 AcademicPress Rye, triticale, wheat, dry matter, growth and maintenance respiration     

The Culture of Immature Pea Embryos

Pea embryos of a range of developmental stages were culturedin a defined medium in vitro for up to 16 days. The criticalfactor for successful culture was the osmotic pressure of themedium; for the stages studied this was provided by the incorporationof 18 per cent sucrose in the medium. The growth of embryosof a range of genotypes was compared; small seeded genotypescould grow at comparable rates in vitro to those attained invivo. The amount of protein synthesized in vitro was similarto that attained in vivo, whereas slightly higher and lowerlevels of starch and DNA respectively were attained in vitro.The roles of intrinsic and extrinsic factors in regulating embryogrowth were studied by comparing the growth in culture of embryosof different genotypes and of hybrid embryos derived from reciprocalcrosses. embryo culture, pea embryos, hybrid embryos, osmotic pressure     

Embryo Rescue in Wide Crosses in Arachis. 2. Embryo Development in Cultured Peg Tips of Arachis hypogaea

Embryo rescue techniques in Arachis are potentially importantfor recovering interspecific hybrids which have the propensityto abort. Pegs are commonly produced in interspecific crosses,but either they fail to reach the soil because growth is arrested,or pods are produced but embryo development is never re-initiated.Peg tips, with the ovule and embryo, of A. hypogaea L. cv. ‘NC6’, were used to determine whether peg tips can be usedas nurse tissue for in vitro culture of embryos. Tissues werecollected 1, 2, 3 and 4 d after self-pollination, after whichpeg meristems were removed from half the pegs, and culturedon five media combinations. Continued reproductive developmentwas observed for embryos cultured at all four collection days;however, the highest frequency of growth was observed in 1-d-oldtissues. Evidence is presented that meristematic activity mayrestrict embryo growth in the 2- to 4-d-old embryos and, oncethe sequence of events is initiated to slow embryo growth, itis not easily reversed in vitro. Achievements of embryo growthto multicellular, globular stages (stages 1–1 or 1–2)encourage the development of methods to recover very young embryosthrough tissue-culture techniques. Embryo culture, morphology, interspecific hybridization, Arachis hypogaea, comparative light and scanning electron microscopy, peanuts, groundnuts     

Changes in plant response to NaCl during development of rice (Oryza sativa L.) varieties differing in salinity resistance

The effects of NaCl stress on growth and development of rice{Oryza sativa L.) were studied and compared in varieties ofvarious origins. During the vegetative stage, tall indica landraces(Nona Bokra, Buhra Rata, Panwell, and Pokkali) appeared to beresistant throughout while in japonica varieties (I Kong Pao(IKP) and Tainung 67) and elite breeding lines (IR 4630, IR2153 and IR 31785), resistance fluctuated. Panwell, which wasthe only indica variety evaluated during the reproductive stage,also expressed salt resistance during booting, heading and grainmaturation while varieties with the greatest variability insalt stress response during the vegetative phase (IR 4630, IR31785 and IKP) also showed the greatest variability during reproductivedevelopment. Thus, varietal levels of resistance to salinityat different growth stages are not necessarily interdependentcharacteristics. Variability in salt resistance of differentgenotypes during the vegetative and reproductive phases of developmentwas not correlated to their mean level of relative resistance. There was an ontogenic evolution of salt resistance and theyoung seedling stage appeared to be the most sensitive to NaCIduring vegetative growth. Nevertheless, short- and middle termeffects of stress have to be distinguished for each genotypesince some varieties showed better growth during the secondweek of stress than during the first, whilst others showed anopposite trend. Moreover, even at specific stages of development,plant responses to NaCI were quite variable according to thecriterion used to quantify salinity resistance. The identificationof genotypes resistant to NaCI at specific developmental stagesis essential to improve the understanding of the effects ofsalt stress upon phenology and to elaborate further breedingprogrammes. Key words: Rice, Oryza sativa L., salt resistance, NaCl, phenology     

Effects of food quality on individual growth and development in the freshwater copepod Boeckella triarticulata

To quantify the demographic effects of food quality, and specificallyof the ‘poorquality’ cyanobecterium Anabaena flos-aquae,we reared individual Boeckella triarticulata (Copepoda, Calanoida)on two diets (monospecific Cryptomom sp. versus mixed Cryptomonas-Anabanmadiets) and quantified individual growth and developmental trajectoriesby examining exuviae produced at each molt, from hatching tomaturity. Size at molting was less variable among individuals,within and between diets, than age. Food quality had significanteffects on male sizes at molting and on stage-specific dailygrowth rates of both sexes; these effects were strongest duringlate naupliar and all copepodite stages Tke med Cryptomonas-Anabaenadiet significantly slowed development, particularly of copepoditestages. As a consequence of these effects, individuals raisedon the mixed diet were smaller and older at maturity. Withina given diet, individual differences explained much, if notmost, of the variation exhibited in growth and development.By following growth and development of a large number of individualsthroughout their Life cycles, we show that individual femalesproduce variable offspring, indicative of a bet-hedging life-historystrategy, and that B.triarticulata (like other calanoids) cangrow, develop and survive on diets that include ‘poorquality’ cyanobacteria. ¹Present address: Department of Biological Sciences, Universityof Rhode Island, Kingston, RI 02881, USA     

Biochemical Changes Associated with Zygotic Pine Embryo Development

Johnson, M. A., Carlson, J. A., Conkey, J. H. and Noland, T.L. 1987. Biochemical changes associated with zygotic pine embryodevelopment.—J. exp. Bot. 38: 518–524. At intervals during the period from pre-fertilization to nearmaturation, pine (Pinus resinosa Ait. and Pinus strobus L.)ovules were analysed for several biochemical constituents, andthe results were expressed on a fresh weight basis. Lipid accumulatedin parallel with the growth of the developing seeds. Solubleprotein also accumulated but only in the initial stages of development.ATP content peaked approximately 2 weeks after fertilization,followed about one week later by the energy charge; these peakswere associated with maximal growth stages of the developingembryos. Likewise, peaks of glutathione (GSH) and ascorbic acid(AA), two water-soluble reductants, preceded or coincided withthe ATP maximum. At late stages of seed development, dissectionof the more mature ovules into embryos and gametophytes foranalysis revealed that the ATP, GSH, and AA were more concentratedin the embryonic tissue. On the other hand, this segregationshowed that virtually no proanthocyanidin was located in thedeveloping embryos proper, although they contained other reductants,some of which were probably phenolics. Also, general stainingwith reagents for phenolics and thiols indicated that the formeroccurred primarily in non-embryonic tissue, whereas GSH wasin the embryo per se. These findings are consistent with rolesfor ATP, GSH, and AA in the growth and development of zygoticpine embryos; however, it would appear that lipid and proteinare being stored for subsequent germination events and thatmuch of the phenolic component is segregated from the developingembryo. Key words: Pine, embryogenesis, biochemistry     

RNA and Protein Synthesis in Germinating Pine Pollen

The results of autoradiographic experiments demonstrate that,as with the pollen of most other species, both the generativeand vegetative nuclei of Loblolly Pine (Pinus taeda) activelyengage in RNA synthesis from the very early stages of pollengermination. Unlike most other species, however, this newlysynthesized RNA includes rRNA. Evidence is provided for theimportance of this newly synthesized RNA in the process of continuedpollen tube growth. One and two-dimensional gel electrophoretic analysis revealsa number of both qualitative and quantitative differences amongthe proteins synthesized during the early stages of germinationand the later stages of pollen tube growth. One of the mostnotable of these is a 36 kD protein, the synthesis of whichpredominates during the later stages of pollen germination.A similar pattern of 36 kD protein synthesis is observed whenmRNA extracted from pollen at each of these stages is translatedin vitro. Key words: Pinus, pollen tube growth     

Growth of Lettuce, Onion, and Red Beet. 1. Growth Analysis, Light Interception, and Radiation Use Efficiency

A field experiment was carried out to analyse the growth oflettuce, onion and red beet in terms of: (a) canopy architecture,radiation interception and absorption; (b) efficiency of conversionof absorbed radiation into biomass; and (c) dry matter partitioning.Growth analysis, total solar radiation interception, PAR interceptionand absorption by the crop canopy, ground cover, maintenancerespiration of onion bulbs and red beet storage roots were measured.Models for different leaf angle distribution and ground coverwere used to simulate light transmission by the crop canopy. The three crops are shown to have contrasting growth patternsfrom both a morphological and a physiological point of view.Lettuce showed very high light interception and growth afterthe early growth stages but, throughout the growth cycle, thisleafy crop showed the lowest radiation use efficiency due tothe respirational cost of the high leaf area. Onion showed alower early relative growth rate than lettuce and red beet.This was due partly to the low light interception per unit leafarea in the later stages of growth and partly to the low initialradiation use efficiency compared with the other two crops.On the other hand, thanks to more uniform distribution of theradiation inside the canopy, to the earlier termination of leafdevelopment and to the very low level of bulb respiration, onionshowed high radiation use efficiency and was able to producea large amount of dry matter. Red beet leaf posture and canopystructure resulted in high light interception and absorption.Its radiation use efficiency was lower than that of onion, partlyperhaps because of the more adverse distribution of the interceptedradiation fluxes within the canopy and partly because of thehigh respiration cost of a continuous dry-matter allocationto the leaves. However, this crop can accumulate a very largeamount of dry matter as leaf blade development and storage rootgrowth can both continue almost indefinitely, providing continuouslyavailable sinks. Ground cover gave a good estimate of the PAR interception onlyat low values of light interception but, in general, it underestimatedPAR interception in all three crops. Ratios between attenuationcoefficients established by considering PAR or total solar radiationand LAI or ground cover were calculated. Lettuce,Lactuca sativa L. var.crispa ; onion,Allium cepa L.; red beet; Beta vulgaris L. var.conditiva ; growth analysis; light interception and absorption; canopy architecture; ground cover; radiation use efficiency; maintenance respiration rate; dry matter distribution     

Stigma-surface Esterase Activity and Stigma Receptivity in Some Taxa Characterized by Wet Stigmas

Stigma-surface esterase activity and stigma receptivity througha sequence of developmental stages of the pistil have been studiedin four taxa characterized by having wet stigmas — Petuniahybrida, Nicotiana tabacum, Crinum defixum and Amaryllis vittata.The style is solid in the first two and hollow in the lattertwo taxa. In all the taxa, stigma—surface esterase couldbe detected in a thin surface layer (pellicle) from a very earlystage of pistil development, irrespective of the presence orabsence of the exudate. However, the taxa showed variation instigma receptivity. In Petunia and Nicotiana, stigmas from pistilsof all the stages supported pollen germination and tube growth.In Amaryllis and Crinum, stigmas of only the mature pistils,when the exudate is present on the stigma, supported normalpollen germination and tube growth. It is inferred that in taxacharacterized by a wet stigma and solid style, the factors requiredfor pollen germination are present from an early stage of pistildevelopment and the exudate per se is not involved in pollengermination. In taxa characterized by a wet stigma and hollowstyle, however, the pellicle does not carry the factors requiredfor pollen germination and tube growth; they appear to be presentin the exudate. Petunia hybrida Vilm, Nicotiana tabacum L., Crinum defixum, Ker-Gawl, Amaryllis vittata Ait., tobacco, pollination, pollen germination, stigmatic exudate, stigma receptivity, stigma-surface esterase, esterase activity     

Ultrastructure, Development and Secretion in the Nectary of Banana Flowers

The nectaries of Musa paradisiaca L. var. sapientum Kuntze werefound to secrete in addition to the sugar solution, a polysaccharidemucilage and a very electron dense, homogenous material whichwas apparently protein. The polysaccharide had already startedto appear outside the epithelial cells of the nectary at veryearly stages of nectary development. At somewhat later developmentalstages the very dense homogenous material appeared in the formof droplets between the plasmalemma and cell wall in massesin the nectary lumen. Nectar secretion started in flowers whenthe bract in the axil of which they occurred had just recoiled.The ER elements were dilated and formed vesicles and the Golgibodies were very active, at the stage of the nectar secretionand at stages preceding it, except at the stage just beforesecretion. In all stages of nectary development the dilatedER elements and most large Golgi vesicles contained fibrillarmaterial. It is suggested that both ER and the Golgi apparatusare involved in the secretion of the sugar solution and of thepolysaccharides. There was not enough evidence as to where inthe cell the very dense homogenous material is synthesized. A few developmental stages of the nectaries of the male flowersof the Dwarf Cavendish banana, which do not secrete nectar,were also studied. It was seen that at early stages of development,the ultra-structure of the nectary of this banana variety wassimilar to that of M. paradisiaca var. sapientum. However, theepithelial nectary cells of the Dwarf Cavendish banana disintegratedbefore maturation of the nectary. Musa paradisiaca L, banana, floral nectaries, ultrastructure     

'Vitrified' Dianthus--Teratomata in vitro due to Growth Factor Imbalance

Cultured shoot tips of Dianthus caryophyllus often develop asabnormal, ‘vitrified’ plants that have the characteristicsof teratomata: stable, unlimited development with fasciatedshoot apices, a bush habit, reduced stem elongation and succulentleaves. High concentrations of NAA in the culture medium increasedand benzylaminopurine decreased the proportion of shoot-tipsthat developed as abnormal plants. The requirements of abnormaland normal plants for continued development differed. Duringthe initial stages of development abnormal plants did not requireauxin and they were able to continue their growth in the absenceof roots. It is suggested that the abnormal plants are teratomata,similar to those induced by Crown Gall bacteria, and their inductionand abnormal traits could be due to imbalance of auxins andcytokinins. Dianthus caryophyllus L., carnation, abnormal plant growth, habituation, vitrification, teratoma (plant)     

Nucleic Acid Chemistry of the Ilyanassa Embryo

A morphological study of Ilyanassa embryogenesis was made fromsections of several stages and the nucleic acid content wasmeasured throughout the course of development. The kineticsof uptake and incorporation of radioactive precursors into RNAwas determined. The RNAs synthesized at different stages ofembryogenesis were fractionated by methylated albumin kieselguhrchromatography, and the polyadenylation of RNA during developmentwas measured. From these studies it was concluded that the Ilyanassa embryo,beginning with the 4-cell stage, synthesizes dRNA, rRNA, 4SRNA, and 5S RNA throughout all stages of development. The extensivesynthesis of dRNA and the higher proportion of RNAs polyadenylatedby the pregastrula embryo was considered to be of particularsignificance. The localization of nucleic acids and nucleic acid precursorsin the polar lobe and the effect of removing the polar lobeon nucleic synthesis was reviewed. Recent work on the ultrastructure of the Ilyanassa egg was reviewedin relation to the problem of ooplasmic segregation. The discoveryof a new cytoplasmic organelle in the Ilyanassa oocyte was reviewed.     

Leaf Ecology of Pre-reproductive Ontogenetic Stages of the Palm TreeEuterpe edulisMart. (Arecaceae)

We studied leaves of 208 seedlings (S), infants (I) and juveniles(J) ofEuterpe edulis,randomly selected from plants in 1 ha ofswampy forest in SE Brazil. Each new leaf began extending afterthe complete development of the preceding leaf. The sequencesteps of leaf growth were emergence, linear growth while closed,opening of segments and logarithmic growth of the petiole. Averageleaf production rate (2.21 leaves per plant year^-1) did notvary among ontogenetic stages, conforming to a plastochronicrhythm. Average linear growth rate of the closed leaf was directlyrelated to average area of the open lamina. Herbivores attacked33.0% of all leaves giving rise to up to 10% loss of area andincluded damping-off-inducing suckers (7.1%), ordinary suckers(9.8%), chewers (5.4%), miners (2.7%) and multiple attacks (8.0%).These attacks varied among stages (S=22.4%, I=38.1%, J=33.3%),as did leaf mortality rates (S=26.5%, I=14.3% and J=0.0%). Unknownfactors were the main cause of leaf mortality (S=14.3%, I=7.1%).Not losing a leaf while a seedling and attaining a minimum leafarea in the infant stage were critical events for survival.Plants gained leaf area by not losing leaves while a seedling,by producing larger leaves with greater growth rates, and byaccumulating leaves with longer lifespans. The petiole can simulatean energetically cheaper branch, delimit a vital space aroundthe stem, favourably position the leaf lamina and substituteprovisionally for stem growth in height.Copyright 1999 Annalsof Botany Company Arecaceae,Euterpe edulis, herbivory, leaf ecology, leaf growth, leaf production, semideciduous forest, southeastern Brazil.     

Development of Meristems of Weigela florida Variety 'Bristol Ruby' Following Reproductive Induction in Long Days

Weigela florida variety ‘Bristol Ruby’ has longday requirements for its growth and, in general, for its flowering.Vegetative development, floral initiation and floral organogenesisare described using scanning electron microscopy during photoperiodictreatment in long days, under controlled conditions. Flowering of axillary buds of cuttings has been studied. Theapex of Weigela at the vegetative phase is characterized bya very small hollow meristem. After 9 long days, the meristemenlarges and, after 12 long days, early axillary buds are initiatedin the axils of the leaves, which become bracts. When the numberof long days was increased, flowers were initiated in the budson the induced branches; first at the proximal part of the branchwhere development afterwards slowed down, then on the medianparts of the branch where development was accelerated. Two bracteoles are differentiated soon after floral initiation;first initiation of the calyx required 18 long days. Petals,stamens and ovary were rapidly initiated after that. Weigelaflowers are clustered; the inflorescence ceased growth by abortionof the terminal meristem or by formation of a terminal flower.In axillary buds of the fifth node the formation of the clusterwas completed about 20 days after the beginning of floral induction. Weigela florida ‘Bristol Ruby’, scanning electron microscopic analysis, vegetative meristem, floral development stages, long days induction     

A Simple Phenological Model of Muskmelon Development

Utilizing information gathered in previous growth chamber andfield experiments, we developed a simple temperature-drivencrop phenology model of muskmelon (Cucumis melo L.) to helpcommercial growers time crop phenological events and predictharvest dates. The model quantifies vegetative development interms of main vine node numbers which allows the model to simulateeither a direct-seeded or a transplanted crop. The model operateson an hourly time-step but requires only daily weather dataand a few cultivar-specific parameters including plastochroninterval and thermal time requirements to reach six predefineddevelopmental stages. The model was tested against an independentdata set consisting of three muskmelon cultivars grown at fivetransplanting dates. Tests of the model indicate an averageability to predict main vine node numbers to within one to twonodes of observed values. Estimated harvest date predictionswere more variable than those for main vine node number butan average model accuracy of 1 to 3 d was obtained in modeltests with a data set used to construct the model. Proceduresfor calibrating the model for different cultivars, culturalpractices or environments are outlined. Copyright 0000 Cucumis melo L., cantaloupe, temperature, model, thermal time, plastochron interval, growth duration     

The Sporulation of Penicillium notatum Westling in Submerged Liquid Culture: II. THE INITIAL SPORULATION PHASE

The initial sporulation time of Penicillium notatum Westlinggrown in shaken submerged culture inoculated with spores orvegetative mycelia is inversely proportional to the logarithmof the inoculum load, with a minimum time of 17.5 hours in theformer and 8 hours in the latter cultures. The development ofcultures is divisible into two stages. Firstly, there is a periodof vegetative growth, the duration of which depends on the inoculumload, after which the culture can be described as mature. Calciumis not required for the development of this maturity. Secondly,the cultures when mature develop phialides and spores if calciumis added to the medium. The development of phialides and thefirst spores takes 6 hours from the time of adding calcium andthis period is not influenced by the inoculum load of the culture.The medium from a mature culture promoted more rapid sporulationof vegetative mycelia placed in it than did a fresh medium,indicating the presence of a sporulation factor(s) in maturemedium. Similar activity was also demonstrated in media whichhad supported growth of any one of five other Penicillium speciesor Aspergillus niger. The nature of the sporulation factor isso far unknown.     

The duration of copepod life stages estimated from stage-frequency data

Current methods to determine the stage duration of copepodsfrom stage-frequency dataare often based on inappropriate distributionfunctions of the stage development time; they also lack a clearprobability model that describes the random noise in the data.This study aims to estimate the duration of copepod life stages,using an asymmetrical probability distribution function of developmenttime. Data on stage frequency were collected from cultured cohortsof Acartia clausi, Temora longicornis and Pseudocalanus elongatus.In addition, data from cultures of Calanoides carinatus andCalanus australis by Peterson and Painting (J. Plankton Res.,12, 283–293, 1990) were used. Following Landry(Limnol.Oceanogr., 20, 854–858, 1975), for each stage the numberof animals that did not yet pass that stage was plotted as afunction of time. A gamma distribution function appeared todescribe the expected proportion of these animals versus time.The number of animals is assumed to follow a binomial distributionand the model parameters are estimated by maximizing the likelihood.This method enables individuals with a retarded development,which are usually deleted from the data material, to be dealtwith. The median development time was estimated from the gammadistribution functions, from which the duration of the stageswas derived. Isochronal development was confirmed for most stages.However, the first feeding naupliar stage, as well as the lastcopepodite stage (CV), took longer in most species, whereasthe pre-feeding naupliar stages had a shorter duration, particularlyin P.elongatus. Differences betweensexes were not apparent.Contradicting results among cultures and with published resultsbyother workers suggest that part of the observed deviation fromnear-isochronal development may be due to the culture conditions.     

Variations in the Levels of cis- and trans-Ribosylzeatins and Other Minor Cytokinins during Development and Growth of Cones of the Hop Plant

The endogenous cytokinins in cones of the hop plant (Humuluslupulus L. cv. Shinshuwase) were identified by combined gaschromatography and selected ion current monitoring (GC-SIM)and high performance liquid chromatography as ribosyl-cis-zeatin,ribosyl-trans-zeatin, cis-zeatin, trans-zeatin and ribosyl-trans-zeatin-O-glucoside.The contents of these cytokinins in both fertilized and unfertilizedcones at various growth stages were determined using GC-SIMand/or bioassay. Based on these data, the rapid growth of thefertilized cone is attributed mainly to ribosyl-trans-zeatinwhich accumulates mostly in the seed. Ribosyl-cis-zeatin wasfound in both fertilized and unfertilized cones. In the latter,ribosyl-cis-zeatin was quantitatively a major cytokinin andseemed to cooperate with ribosyl-trans-zeatin and trans-zeatinin promoting the growth. (Received January 12, 1981; Accepted February 10, 1981)