An analysis of seed development in Pisum sativum XIX. Effect of mutant alleles at the r and rb loci on starch grain size and on the content and composition of starch in developing pea seeds

The effects of mutant alleles at the r and rb loci on starchgrain size and the levels of starch and amylose in developingpea (Pisum sativum L.) seeds have been examined. Four lines,near-isogenic except for genes at these loci, have been usedto show that both mutations reduce levels of starch throughoutembryo development and reduce levels still further when combinedin the ‘double mutant’. The reduction in starchcontent was due, at least in part, to a reduction in starchgranule size. Although the proportion of starch in mature embryoswas similar in the rrRbRb and RRrbrb lines, the starch contentdiffered between these two lines during development, as a percentageof embryo dry weight. This difference was due to a reductionin the absolute growth of the embryo caused by the rb mutation.Lines homozygous for the mutant r allele with either wild-type(RbRb) or mutant (rbrb) alleles at the rb locus contained increasedproportions of amylose in their starch throughout development,due to a reduced production of amylopectin. The presence ofthe rb mutation, however, also reduced the amount of amylosein relation to the reduction in total starch levels. Mutantalleles at both loci also reduced starch levels in the testaduring development, the reduction due to rb being more extreme.Reciprocal crosses showed a maternal effect of the rb mutationon final seed size and on the absolute amount of starch in theembryo. Key words: Pisum sativum L., seed, starch, development, mutant     

Evolution of insect eye development: first insights from fruit fly, grasshopper and flour beetle

The molecular genetic dissection of Drosophila eye developmentled to the exciting discovery of a surprisingly large panelof genes and gene activities, which are functionally conservedacross phyla. Little effort has yet been made towards pinpointingnon-conserved gene functions in the developing Drosophila eye.This neglects the fact that Drosophila visual system developmentis a highly derived process. The comparative analysis of Drosophilaeye development within insects can be expected to enhance resolutionand accuracy of between phyla comparisons of eye development,and to reveal molecular developmental changes that facilitatedthe evolutionary transition from hemimetabolous to holometabolousinsect development. Here we review aspects of early Drosophilaeye development, which are likely to have diverged from thesituation in more primitive insects, as indicated by resultsfrom work in the flour beetle Tribolium castaneum and the grasshopperSchistocerca americana.     

Structure and Development of Stomata in Some Leptosporangiate Ferns

The structure and development of stomata are described for 17species of leptosporangiate ferns. In these species the maturestomata are anomocytic, diacytic, Pyrrosia(applied), tetracytic,suspended, or floating type. Stomata are present on both surfacesof floating as well as sub merged leaves of Azolla and Marsilea.In a few species twin stomata, arrested development, and persistentstomatal initials are present Floating stomata result from disintegrationof the anticlinal suspending wall in Pleopeltis, and by detachmentand displacement in Azolla pinnata. The development of stomatais haplocheilic, syndetocheilic, or syndetohaplocheilic. InCyathea spinulosa the guard cell nuclei divide amitoticallyand the resulting two daughter nuclei occupy the opposite polesof the guard cells     

Genetic and Photoperiodic Control of the Relative Rates of Reproductive and Vegetative Development in Peas

The rates of leaf and flower production were determined in peas(Pisum sativum L.) of genotypes e sn hr (line 13), E Sn hr (line60), and E Sn Hr (line G2), to assess the role of the interactionof alleles Sn and Hr with photoperiod in development. The ratesat which flowers at successive nodes opened (AR) and leavesat successive nodes unfolded (PR) were constant. The AR wasfaster than the PR so that successive flowers opened at nodescloser to the apical bud. The rate at which this occurred wasindependent of photoperiod in line 13 but was slightly or markedlyslower in short days (SD) than long days (LD) in lines 60 andG2, respectively. The opening of flowers closer to the apicalbud of G2 peas in SD was so slow as to not be visually apparentduring the time of this study. The number of nodes between thefirst open flower and the apical bud was unaffected by photoperiodin line 13 but was greater in SD than LD in lines 60 and G2.The daylength effects are photoperiodic, since development ofG2 peas in LD with respect to the parameters measured was unaffectedby light intensity. It is concluded that photoperiod and theE Sn allele combination control the rate of reproductive developmentrelative to vegetative development in peas. The effects of ESn are magnified by the presence of the Hr allele. The constantrates of development measured are not consistent with declineof Sn allele expression with age. Delay of the rate of reproductivedevelopment relative to vegetative development correlated withdelay of apical senescence, suggesting that these processesare related. Pisum sativum, genotypes, photoperiod, flowering, reproductive development, vegetative development, senescence     

Roles of the Af and Tl Genes in Pea Leaf Morphogenesis: Shoot Ontogeny and Leaf Development in the Heterozygotes

The wildtype leaf blade of Pisum sativum possesses proximalleaflets and distal tendrils, which may be altered by two recessivemutations that affect pinna morphology, afila (afaf) and tendrilless(tltl). Using morphological observations and SEM, the variationin leaf forms along the plant axis and leaf development werecharacterized for plants heterozygous at the Af and/or Tl loci.The Af and Tl genes interacted to affect many characteristicsof shoot ontogeny, including rate changes in leaf blade lengthand complexity increases, as well as time to flowering. TheAf gene retarded early vegetative development and acceleratedthe time to flowering. The leaf phenotypes of these heterozygousgenotypes were specified mainly by changes in the timing ofmajor developmental events. The data support the hypothesesthat both genes are heterochronic in nature and that the pealeaf blade consists of three genetically- and developmentally-determined regions: proximal, distal and terminal. Copyright2000 Annals of Botany Company Heterochrony, leaf development, shoot ontogeny, Pisum sativum L., garden pea, afila,tendrilless .     

Comparison of Embryo Development in Wild and Cultivated Arachis Species

Embryo development following selfing was investigated in twowild diploid peanut species, Arachis batizocoi Krap. et Greg.(coll. K 9484) (2n = 20) and A. duranensis Krap. et Greg. nom.nud. (coll. K 7988) (2n = 20), and one cultivated tetraploidspecies, A. hypogaea L. NC-Ac 18000 (2n = 40). Rates of pegelongation and sequences of embryo development for each specieswere compared. Peg elongation rates were similar for the twowild species, but for A. hypogaea it was only one-third to one-halfthat of the diploid species. Embryos in A. hypogaea showed slightlymore rapid cell division than in the wild species. The observedvariation in reproductive development between the wild and cultivatedspecies indicate that different control mechanisms may governdevelopment in the different species and may be at least partiallyresponsible for failure to produce viable interspecific hybridsat various ploidy levels. The observations are also importantfor determining the time at which embryos of different speciesof Arachis will reach the appropriate stage of development forsuccessful culture on an artificial medium during embryo rescueprocedures. Peanut, Arachis hypogaea, wild species, embryo, peg     

The Chloroplast and Leaf Developmental Mutant, pale cress, Exhibits Light-conditional Severity and Symptoms Characteristic of its ABA Deficiency

The PALE CRESS gene (PAC) is essential for proper chloroplastand leaf development in Arabidopsis thaliana. The ability ofpac mutants to accumulate significantly more chlorophyll whengrown in low light conditions than in high light conditionssuggests that carotenoid deficiency is at least partly responsiblefor premature cessation of chloroplast development. In additionto accumulation of low levels of chlorophyll and carotenoidpigments,pac mutants are abscisic acid (ABA) deficient and havecharacteristics which may be explained by this deficiency. Theseinclude reduced seed viability and, in enclosed growth conditions,increased leaf growth. Plants transformed with an antisensePAC construct often bear viviparous embryos which may be symptomaticof a deficiency in ABA. Since carotenoids are precursors ofABA, a role for PAC in carotenoid biosynthesis is further supported.The nuclear-encoded, chloroplast-localized PAC protein has beenimplicated in the maturation of plastid-encoded mRNAs. Thus,PAC may affect the abundance of one or more chloroplast proteinswhich function in the synthesis or stability of carotenoids.Using thePROLIFERA gene as a marker for cell division, it isshown that cell division profiles in the pac shoot apex aredisrupted. pac leaves are relatively normal in size and shapedespite the light intensity-induced variability of leaf celldefects. Copyright 2000 Annals of Botany Company Abscisic acid, carotenoid, chloroplast development, leaf development, organismal theory, PALE CRESS,PROLIFERA , vivipary     

Changes in o-Diphenol Oxidase During Fibre Development in Cotton

Quantitative and electrophoretic changes in o-diphenol oxidase(o-diphenol: O₂ oxidoreductase, E.C. 1 10,3.1) were studiedduring the entire period of cotton (Gossypium arboreum L. cv.Sanjay) fibre development. A significant increase in o-diphenoloxidase activity was recorded during the fibre initiation phaseand it is suggested that a shift in redox balance towards oxidationmay play an important role in fibre initiation. Low o-diphenoloxidase activity during elongation and its high activity duringthe phase of secondary thickening, together with isoenzyme patterns,suggest an important role of this enzyme in cotton fibre development.The role of o-diphenol oxidase in relation to auxin turnoverand redox balance is discussed. Gossypium arboreum, cotton, fibre development, o-diphenol oxidase, redox balance, auxin turnover     

The Rate of Morphogenesis of Embryos and Seeds in Four Species of Grain Legumes

Comparative embryo development has been studied histologicallyin Lupinus albus, Lupinus mutabilis, Vicia faba, Pisum sativumand Latkyrus latifolius. The detailed histology of the stagesof embryo formation up to the early differentiation of tissuesof the seed is reported. The rate of embryogenesis has beentimed through 15 stages of development from anthesis and comparativerates of tissue formation established between the species. Themain observation was the slow rate of morphogenesis of embryosand seeds in Lupinus albus in comparison with the very rapidrate observed in Pisum sativum. A long period at the globularembryo stage, when embryo morphogenesis was inactive contributedto the extended development time of embryos and seeds in Lupinusalbus. Slow differentiation of reproductive tissues in L. albusdetermines late maturity in seeds and pods. Lupinus albus, white lupin, L. mutabilis, tarwi, Vicia faba, faba bean, Pisum sativum, pea, Lathyrus latifolius, everlasting pea, embryo development     

Anther Culture of Lolium temulentum, Festuca pratensis and Lolium x Festuca Hybrids. II. Anther and Pollen Development In Vivo and In Vitro

The various pathways of pollen development were investigatedin cultured anthers of Lolium temulentum, Festuca pratensisand the L. multiflorum x F. pratensis hybrid ‘Elmet’.In all three, development from the vegetative cell was the predominantpathway of pollen callus development. However, there were characteristicdifferences in the behaviour of the generative cell. In L. temulentumit remained attached to the pollen wall and degenerated, whereasin F. pratensis it divided. In ‘Elmet’ it detachedfrom the pollen wall and remained undivided. Both polarizedand unpolarized partitioned calluses were observed. Developmentof the fusion product of the vegetative and generative nucleiwere also observed in anthers of L. temulentum. Anomalous grainswere not found to be major source of pollen calluses. Sections of anthers of L. temulentum were used to investigatethe origin of S pollen grains, the small pale-staining grainswhich denote pollen dimorphism. Such grains form out of contactwith the tapetum and are therefore determined before or duringmeiosis (i.e. before harvest of anthers for culture). Sectionswere also used to demonstrate the influence of the durationof pretreatment on the development of the middle layer of theanther wall. Festuca pratensis, Lolium temulentum, Lolium x Festuca, anther culture, haploid, microspore, pollen     

Pelagic growth and colony division of Gloeotrichia echinulata in Lake Erken

Gloeotrichia echinulata colony development was monitored inLake Erken, Sweden and studied in enclosure experiments. Significantcolonial division did not occur in mesh bags, although the abundanceof the pelagic population in the lake increased during the experimentalperiods. On the basis of these findings, it is suggested thatcirculation of G. echinulata to deeper nutrient rich water supportspelagic growth. In support of this, a large part of the buoyantG. echinulata colonies in Lake Erken was found at several metersdepth. In an experiment with nutrient additions, the only treatmentthat favoured G. echinulata development was additions of phosphate,nitrate and iron. Trace element additions had a negative effecton the development of G. echinulata. On the basis of these findings,the nutritional requirements of G. echinulata are discussed.     

Seed Epidermis Development and Histochemistry in Solanum melongena L. and S. violaceum Ort.

Structure, development and histochemistry of the seed epidermiswere studied inSolanum melongena L. andS. violaceum Ort. usinglight and scanning electron microscopy. The epidermal cellsat the endosperm mother cell stage of ovule development hadthickened outer periclinal walls, consisting of two layers,a thin inner layer, and a thick outer layer. The latter whichstained positively for pectic substances became further thickenedduring the course of seed development; more so inS. melongena.The inner layer of the outer periclinal wall also was thickenedby depositions of cellulose but remained comparatively thin.The development of the inner periclinal and anticlinal wallstook place by the uneven deposition of concentric layers. Thesesecondary wall thickenings which appeared as pyramids in transversesection stained for cellulose, lignin and pectin. Further unevensecondary thickenings near the outer part of the anticlinalwalls resulted in the formation of projections which were hair-or ribbon-like in appearance. InS. melongena, these projectionsprogressed only a short distance from the anticlinal wall. InS.violaceum, on the other hand, they grew much longer formingstriations on the inside of the outer periclinal wall. InS.melongena, partial removal of the outer periclinal wall by enzymeetching exposed to surface view a beaded appearance of the cellboundaries. Complete erosion of the outer periclinal wall revealedthe hair-like projections of the underlying anticlinal walls.InS. violaceum, enzyme treatment exposed the striations whichformed bridge-like structures over the curves in the anticlinalwalls. Solanum melongena ; Solanum violaceum; seed epidermis; seed structure; seed development; cell wall histochemistry; cell wall projections; cell wall striations     

Laboratory studies on the larval growth and development of Nyctiphanes capensis (Euphausiacea)

Larvae of Nyctiphanes capensis Hansen were reared in the laboratoryunder different trophic conditions (i.e., algal, animal andmixed diets) from the second calyptopis stage to the first juvenilestage. It is demonstrated that diet is important in determininggrowth rates and development of the larvae. The highest growthrates were achieved on diets of Artemia nauplii mixed with eitherthe flagellate Tetraselmis or Pseudodiaptomus nauplii. Poorerdietary conditions such as with the diatom Phaeodactylum yieldedslower growth rates where additional moults were needed to completefurcilia development. Under favourable trophic conditions theintermoult period was 4–6 days and was not age dependent.Three dominant pathways of pleopod development were found inhealthy individuals.     

Effects on Growth and Development of Individual Chromosomes from Slow-growing Lophopyrum elongatum Love when Incorporated into Bread Wheat (Triticum aestivum L.)

Aspects of growth and development were evaluated in the fast-developingannual Triticum aestivum L. ‘Chinese Spring’, theslow-developing perennial Lophopyrum elongatum Löve, theiramphiploid, and chromosome addition and substitution lines ofL. elongatum into ‘Chinese Spring’. Relative growthrates (RGR) of shoots of L. elongatum and the amphiploid werelower than those of ‘Chinese Spring’ (34 and 13%respectively) and main stem development was also slower. Therewas no difference in shoot RGR of any of the chromosome additionor substitution lines and that of ‘Chinese Spring’when assessed between Haun stages 2.0 and 5.0. In contrast,several aspects of plant development were observed to differin the chromosome addition and substitution lines. SubstitutingE genome chromosomes (with the exceptions of 3E and 4E) forD genome chromosomes, or adding E genome chromosomes, slowedthe rate of main stem development, at least up to Haun stage5.0. Despite these differences in the rate of main stem development,the appearance of adventitious roots commenced at approximatelyHaun stage 2.0 in all genotypes. However, the numbers of adventitiousroots and tillers at the 5.0 Haun stage differed between someof the lines when compared to ‘Chinese Spring’.Although incorporation of some L. elongatum chromosomes alteredaspects of plant development, all lines showed more similarityto bread wheat than to L. elongatum, reflecting, in part, thegreater genetic contribution made by bread wheat to these lines.Copyright 2001 Annals of Botany Company Adventitious roots, chromosome addition and substitution lines, Haun stage, Lophopyrum elongatum, relative growth rate (RGR), Triticum aestivum(wheat)     

Development of Axillary and Leaf-opposed Buds in Rattan Palms

Axillary vegetative buds are present in Calamus, Ceratolobus,and Plectocomiopsis. Two species of Daemonorops Sect. Piptospathaalso have axillary vegetative buds. All species of Daemonoropshave only displaced adnate axillary inflorescence buds. A singlebud is initiated in the axil of the first or second leaf primordiumin a way similar to that for axillary inflorescence buds. Themeristem is displaced during development on to the internodeabove and sometimes on to the base of the leaf above. Leaf-opposedvegetative buds occur in five species of Daemonorops Sect. Cymbospathaand in one species of Daemonorops Sect. Piptospatha. This typeof bud is initiated 180° away from the axil of the firstor second leaf primordium. It is not a displaced axillary bud,but does become adnate to the internode above like the axillarybuds. One or more leaves, transitional between juvenile andadult, on a shoot often subtend both types of buds. Myrialepishas leaf-opposed vegetative buds, but their development wasnot observed. Korthalsia has buds that are displaced about 130°from the leaf axil and are intermediate between the axillaryand the leaf-opposed condition. Other forms of vegetative budsare described: multiple buds in Plectocomia, aerial forkingin Korthalsia, and suckering from inflorescences and from aerialstems in Calamus. bud development, rattan palms, palm taxonomy, branching     

A Transgenic Mutant Defective in Cell Elongation and Cellular Organization during Both Root and Shoot Development in Lettuce, Lactuca sativa

A recessive mutation affecting both root and shoot developmentwas isolated from transformants of lettuce cv. Diana co-transformedwith maize Ac transposase and Ds. Mutant phenotype in the progenywas co-segregated with the T-DNA containing Ac transposase indicatingthat the mutation was caused by insertional mutagenesis. Mutationin this novel genetic locus, designated as ANORMAL ROOT ANDSHOOT (ARS), showed a dwarf phenotype with short thick roots,short hypocotyl and abnormal filamentous leaves without anyfurther reproductive development. The anatomical analysis revealedthat the ars mutant root phenotype is primarily due to the lackof cell elongation and to the abnormal increase in cell numberin the cortex region in the roots. ars mutants are able to initiatenormal leaf primodia, but, the cell elongation and cellularorganization of the developing leaf primodia is impaired andresults in sequentially abnormal development of the leaf. arsmutants also display photomorphogenic development in darknessby producing open cotyledons, developing vegetative leaves,and short hypocotyls. This suggests that the ARS gene may alsobe involved in the regulation of cell elongation in the hypocotylin the absence of light. Abnormal development in ars mutationscan not be normalized by exogenous application of phytohormonessuch as gibberellin and brassinosteroids, indicating that themutant is not impaired in the biosynthesis of these two hormones. (Received January 5, 1999; Accepted August 19, 1999)     

Variable Development and Cellular Patterning in the Epidermis of Ruscus hypoglossum

The general problem was the meaning of the variability of cellulardevelopment of the stomata-bearing epidermis of Ruscus hypoglossumin which 'immature stomata' occur, i.e. cells that have gonethrough part but not the final stages of stomatal development.The development of the epidermis was followed in vivo, by makingrepeated replicas of the same developing tissues using dentalimpression material. The development of stomata occurred overthe entire surface of large phyllodes and was not synchronous.The early development of future and 'immature stomata' couldnot be distinguished, neither by the form of the cells nor bythe timing of the initial, unequal divisions. The process ofstomatal development did not stop at any one, characteristicsstage. Statistical analyses indicated that the pattern of functionalstomata would have been less orderly if all stomatal initialshad developed into mature structures. The results suggest thatin Ruscus epidermal patterning occurs during, rather than preceding,stomatal development: many stomata are initiated, but they followa labile developmental program and cellular interactions selectthose that reach the mature functional state.Copyright 1993,1999 Academic Press Cellular patterns, epigenetic selection, immature stomata, Ruscus hypoglossum, spacing patterns, stomata, subsidiary cells, unequal divisions     

Lateral Root Anlage Development in Excised Roots of Vicia faba L., Pisum sativum L., Zea mays L. and Phaseolus vulgaris L.

The development of lateral root primordia has been investigatedin excised roots of Vicia faba, Pisum sativum, Zea mays andPhaseolus vulgaris cultured in White's medium supplemented with2 per cent sucrose and compared with previously published dataon such development in primaries of the corresponding intactplants (control roots). Primordia were produced in each batchof excised roots over the 6 day culture period but at a lowerrate (number day^–1) than in the controls. Such primordia in cultured roots of Zea and Phaseolus completedtheir development and grew out as lateral roots over a periodsimilar in length to that found in the controls, but with acell number of only about 33 per cent of that attained at thetime of secondary emergence in the primaries of the latter roots.These lower cell numbers were at least partly a reflection ofincreases in mean cell doubling time over the period of anlagedevelopment investigated in the excised roots relative to thecorresponding values found in the controls. Primordia initiated in excised roots of Pisum and Vicia didnot complete their development in culture, i.e. no lateral rootsemerged and arrest took place with cell numbers of only 37 (Pisum)and 17 (Vicia) per cent of the numbers determined at the timeof secondary root emergence in the controls. Such arrested primordiahad few nuclei in S and none in mitosis. Moreover, at leastin Pisum, the frequency distribution of the relative DNA contentof the nuclei in the latter primordia approximated that foundin the apical meristem of primary roots following the establishmentof the stationary phase under conditions of carbohydrate starvation. It has also been demonstrated in the course of these investigationsthat lateral root primordium development in all four speciesis at least biphasic and possibly triphasic. Vicia faba L., broad bean, Pisum sativum L., garden pea, Zea mays L., maize, Phaseolus vulgaris L., dwarf bean, root primordia, anlage, cell doubling time, lateral root emergence     

The role of apical development around the time of leaf initiation in determining leaf width at maturity in wheat seedlings (Triticum aestivum L.) with impeded roots

High soil resistance to root penetration (measured as penetrometerresistance, R_s slows down leaf growth and reduces mature leafsize in wheat seedlings {Triticum aestivum L.). Underlying changesin the kinetics of cell partitioning and expansion and in thesize and organization of mature cells were reported in companionpapers (Beemster and Masle, 1996; Beemster et al., 1996). Inthe present study, the relationships between apex growth, primordiuminitiation and expansion were analysed for plants grown at contrastingR_s, focusing on a leaf whose whole development proceeded afterthe onset of root impedance (leaf 5). High R_s reduced the rates of apex and leaf development, butdid not appear to have immediate effects on the pattern of developmentof the newly initiated phytomers. During an initial short period,the rate of development of a leaf primordium and associatednode were related to plastochronic age, according to similarrelationships (slopes) at the two R_s. Effects on developmentalpatterns were first detected on phytomer radial expansion duringplastochron 2. The ontogenetic pattern of leaf elongation wasaffected later, during the next few plastochrons preceding leafemergence (‘post-primordial stage’). It is concludedthat a reduction in the number of formative divisions and inthe number of proliferative cells along the intercalary mer-istemreported earlier (Beemster and Masle, 1996; Beemster et al.,1996) is not related to the size of the apical dome at leafinitiation nor to the size and number of meristematic cellsinitially recruited to the leaf primordium, which were all unaffectedby R_s. Rather they are generated at the primordial and post-primordialstages. Key words: Wheat, apex development, leaf primodium development, mature leaf width, root impedance     

环境因子对角倍蚜秋迁蚜生殖和雌性蚜发育的影响

研究了环境因子对角倍蚜Schlechtendalia chinensis (Bell) 秋迁蚜生殖和雌性蚜发育的影响。温、湿度单因子试验表明,秋迁蚜在26℃和80%RH条件下有最大生殖量;温、湿度对秋迁蚜生殖量的影响均符合开口向下的二次抛物线变化趋势,极端温、湿度会导致生殖量的下降。采用三元一次正交组合设计,研究了环境温度（X₁）、湿度（X₂）和光照强度（X₃）三因子不同水平组合对雌性蚜发育的影响,表明温度是影响发育历期的主要因子,其次是光照强度,最后是湿度。因此,适当高温、强光照条件可以加快雌性蚜发育;而适当高湿条件可以降低雌性蚜的发育速率而延长其发育历期。在人工培育角倍蚜生产中,创造有利于秋迁蚜生殖的温、湿度条件可以使秋迁蚜产下较多的越冬侨蚜;在适当降低温度、增加湿度的阴暗条件下贮留雌性蚜可以适当延长其发育,以使角倍蚜与盐肤木在物候上达到最佳吻合。