bluuebunny/crossref_metadata_2025_split huggingface dataset:
Secondary dormancy (skotodormancy) in seeds of lettuce (Lactuca sativa cv. Grand Rapids) and its release by light, gibberellic acid and benzyladenine
Authors: BEWLEY J. DEREK 
Published: April 2006

AbstractLettuce seeds (Lactuca sativa L. cv. Grand Rapids) imbibed in darkness at supra‐optimal temperatures (23 ± 1°C) develop a secondary dormancy, termed skotodormancy. The seeds first lose their ability to be promoted to germinate by gibberellic acid, and then lose their ability to be promoted by red light. A combination of red light and gibberellic acid will break skotodormancy for longer than either alone, but red light and benzyladenine together are much more effective. Desiccation of skotodormant seeds does not diminish their dormancy. Embryos dissected from skotodormant seeds will germinate, and are as capable of radicle expansion in the osmoticum polyethylene glycol as are newly‐imbibed seeds. Hence skotodormancy is a whole seed dormancy and does not reside within the embryo as an inherent block to germination processes, but as an inability to respond to the stimulation of red light or to hormone.
Cadmium cytotoxicity and variation in nuclear content of DNA in Euglena gracilis
Authors: BONALY J. , BARIAUD A. , DURET S. , MESTRE J. C. 
Published: April 2006

AbstractCultures of Euglena gracilis (strain Z from French CNRS collection) can be made cadmium resistant if grown in a medium with 5x10‐4M cadmium chloride. This resistance is reflected by the appearance of a second exponential growth phase. The development of this resistance was studied at the cellular level by determining the relative content of DNA at different stages of the cell cycle in an asynchronously grown culture. The culture was followed until the second, cadmium resistant, growth phase had reached its stationary state.During the first exponential growth phase, cells were mostly in the late period of DNA synthesis (stage S of the cell cycle), or in the gap preceding mitosis (stage G2 of the cell cycle). In addition, some cells contained high multiples of the normal amount of DNA. In the beginning of the second exponential growth phase, a few cells were again in G1 (the post mitotic stage of the cell cycle preceding DNA synthesis). These G1 cells were predominant at the end of the second growth period. During the second stationary phase the DNA content of the cadmium treated cells was similar to the stationary phase of the control culture. Cells had stopped growing in G1 with an unreplicated genome. The implications of these data are discussed.
Hormonal factors controlling the initiation and development of lateral roots
Authors: WIGHTMAN FRANK , SCHNEIDER ELNORA A. , THIMANN KENNETH V. 
Published: April 2006

AbstractThe decapitated primary root of 3‐day‐old Alaska pea seedlings has been used as a test system to determine the activities on lateral root formation of six auxins, six cytokinins and several other naturally‐occurring compounds. Their effects were assessed on (1) the initiation of lateral root primordia, (2) the emergence of visible lateral roots, and (3) the elongation of these laterals.All the auxins, at the optimum concentration of 10‐4M, promoted the initiation of lateral root primordia, and all except 3‐indolylpropionic acid inhibited the elongation of the resulting lateral roots. Their effects on the emergence of laterals were small and varied. All the cytokinins, at 10‐6M and above, inhibited both the initiation and the emergence of lateral roots, zeatin being the most powerful inhibitor. The emergence process was about twice as sensitive as the initiation of primordia to the presence of cytokinins. The cytokinin ribosides were generally less active than the free bases. Abscisic acid and xanthoxin inhibited both emergence and elongation, the concentration for 50% decrease of emergence being about 10‐4M. Gibberellic acid had little clear effect on any of the three criteria. Nicotinic acid and thiamine at 10‐3M promoted both the initiation of primordia and their emergence: pyridoxal phosphate stimulated both emergence and elongation but did not influence the initiation of primordia. Adenine and guanine had little effect but decreased root elongation some 25%.The strong inhibiting effect of the cytokinins may well be the basis for the marked inhibition exerted by the root‐tip on lateral root formation, while the promoting effects of auxins may explain the previously observed promotion of lateral root formation by the young shoot and cotyledons.
The effect of salinity on lipid composition and on activity of Ca2+‐ and Mg2+‐stimulated ATPases in salt‐sensitive and salt‐tolerant Plantago species
Authors: ERDEI LÁSZLÓ , STUIVER BEP (C.E.E.) , KUIPER PIETER J. C. 
Published: April 2006

AbstractLipid composition of the roots and the shoot of the salt‐sensitive Plantago media L., the salt‐tolerant P. maritima L. and the less salt‐tolerant P. coronopus L. was followed under saline conditions. In the roots of P. media the level of phospho‐, galacto‐ and sulpholipids decreased strongly with increased NaCl concentration, indicating decreased control of permeability of the root cell membranes. In the roots of the two salt‐tolerant species the level of most lipid classes was maintained or even raised up to 75 mM NaCl, and a decrease was noted only at higher NaCl concentrations. In P. maritima, a species from relatively nutrient‐rich habitats, decreased lipid levels in the roots and shoot were observed with increasing salinity in combination with a low nutrient availability. The Ca2+‐ and Mg2+‐stimulated ATPase activities of the microsomal fraction of the roots of P. maritima was decreased at a salinity level in excess of 150 mM, while in P. coronopus they were decreased at all NaCl levels tested. The obtained results are discussed as part of the adaptation of the species to salinity.
Some effects of humidity on the light reaction of photosynthesis in the lichens Cladonia impexa and Collema flaccidium
Authors: SIGFRIDSSON BJÖRN 
Published: April 2006

AbstractLuminescence and fluorescence were measured at different relative humidities in the lichen Cladonia impexa Harm. Both parameters showed a constant value at relative humidities lower than 80%: thereafter they increased. Low relative humidity was found to decrease energy transfer from chlorophyll b to chlorophyll a. inhibit electron transport, lower electron holding capacity on the reduced side of photosystem two and impair far‐red‐induced afterglow, reflecting photophosphorylation. In Collema flaccidium Ach. Ach. energy transfer from the accessory pigments phycocyanin and phycoerythrin to chlorophyll a was only possible at high relative humidity. The results are interpreted as due to conformational changes caused by changed water content in the lichen.
Variation in Phenotype and Chromosome Number of Plants Regenerated from Protoplasts of Dihaploid and Tetraploid Potato
Authors: Sref Ramulu K. , Dijkhuis P. , Roest S. , Bokelmann G. S. , de Groot B. 
Published: April 2006

AbstractAn investigation was made on the origin and basis of somaclonal variation in potato. Plants were regenerated from protoplasts of dihaploid and tetraploid potato, and the degree of variation in phenotype and chromosome number was analysed. All the regenerants from dihaploid potato showed variation in chromosome number, while only part of these varied in plant morphology. In tetraploid potato, 60 % of the regenerants showed variation in chromosome number, all of which exhibited phenotypic changes. The data suggest that the explant source and the initial ploidy level of the genotype play an important role in influencing the degree of somaclonal variation.
Diallel Analysis of Grain Yield in Barley Using Doubled‐Haploid Lines*
Authors: Choo T. M. , Kotecha A. , Reinbergs E. , Song L. S. P. , Ffjer S. O. 
Published: April 2006

AbstractGrain yields of seven barley cultivars (Hordeum vulgareL.) and 398 doubled‐haploid lines derived from their diallel crosses were evaluated in hill plots at two locations in Ontario. Additive × additive epistasis and linkage disequilibrium were detected in the seven cultivars. Additive × additive genetic variance was significantly greater than zero but additive genetic variance was not significantly greater than zero. The narrow‐sense heritability on the basis of line means was intermediate (0.33). It was predicted that 13.1% yield improvement could be realized in the next recurrent selection cycle using the doubled‐haploid method.
Comparison of Spring Barley Lines Produced by Single Seed Descent, Pedigree Inbreeding and Doubled Haploidy
Authors: Powell W. , Caligari P. D. S. , Thomas W. T. B. 
Published: April 2006

AbstractSamples of inbred lines of Hordeum vulgare produced by pedigree inbreeding, doubled haploidy and single seed descent have been compared for a range of agronomic characters. Differences between the means of the in bred s produced by single seed descent and pedigree breeding were due to differing levels of inbreeding. The present study confirmed chat recombinant inbred families which out‐perform the higher scoring parent may be produced by either method. Caution should, however, be exercised when simply inherited characters controlled by major genes are fixed in early generations. Differences between the doubled haploid and single seed descent samples for the character thousand grain weight were attributable to coupling linkages involving epistatic genes. The production and evaluation of random inbred lines should be considered as an alternative to pedigree methods of barley breeding.
Patterns of Diversity of Ethiopian Wheats (Triticum spp.) and a Gene Center for Quality Breeding
Authors: Negassa M. 
Published: April 2006

AbstractA collection consisting of 293 entries of tetraploid and hexaploid Ethiopian wheat was investigated for diversity of endosperm texture, seed color, kernel texture, flour color, gluten quality, seed size, and protein content. All characters, except gluten quality, showed high levels of diversity‐ Significant differences in protein content and gluten quality occurred among districts, and among provinces. Regional differences were also observed for seed size and flour color. The average estimate of diversity of these characters for Ethiopia was high (H̄= 0.77). Some of the characters showed clinal variations, and others, localized concentrations. Entries with combinations of good quality characters were observed, and their possible use as source materials in wheat breeding is discussed. A gene center for quality breeding was identified in Southern Ethiopia, and the participation of centers of diversity in the evaluation and utilization of genetic resources is considered as a very important tool in genetic conservation.
Potential for Incorporation of Early and Late Leafspot Resistance in Peanut*
Authors: Anderson W. F. , Wynne J. C. , Green C. C. 
Published: April 2006

AbstractA detached leaf technique was used to evaluate components of resistance to both early and late leafspot caused by Cercospora arachidicola Hori and Cercosporidium personatum (Berk, and Curt.) Deighton, respectively, for F2 plants of two peanut (Arachis hypogaea L.) crosses (FESR 5‐P2‐B1 /PI 269685 and PI 35068Q/GP‐NC 343), No negative correlations were obtained when comparing components of resistance to early leafspot with components of resistance to late leafspot, indicating that the resistances are inherited independently. A small number of F2 plants had greater partial resistance to both leafspots than their parents when evaluated by an index including percent necrotic area, latent period and sporulation. Broad sense heritabilities of resistance components were moderate to high (0.4 to 0.8) for the F2 populations. A visual sporulation rating scale was significantly correlated (0.8 to 0.9) with conidia per lesion and conidia per necrotic area. The data suggest that peanut cultivars resistant to both leafspots can be developed.
Autofertility and Bee Visitation in Winter and Spring Genotypes of Faba Beans (Vicia faba L.)
Authors: Stoddard F. L. 
Published: April 2006

AbstractDifferences in the expression of autofertility and in the evidence of attractiveness to bees were investigated in both autumn‐sown and spring‐sown faba beans. All six winter stocks and one spring stock expressed very little autofertility, with averages of only 10% of flowers and 7% of ovules fertilized when undisturbed. Three other spring stocks, including a closed‐flower population, were moderately autofertile, with 22% of flowers and 17% of ovules fertilized when undisturbed. The remaining two spring stocks, both English cultivars, expressed good autofertility, with 50% of undisturbed flowers and 44% of ovules fertilized. Current levels of autofertility in the winter and closed‐flower stocks were inadequate to allow the development of a desirable distribution of pods without substantial bee visitation. If levels of autofertility could be raised simply by selection within populations, then they should have been much higher in these stocks. Therefore, autofertile parents will probably have to be included in programmes for breeding cultivars with improved levels of auto fertility.The closed‐flower population received significantly less bee visitation than the other stocks in the spring trial. No variation in attractiveness to bees was found among the open‐flowered spring stocks, nor among the winter stocks.
Pollination, Fertilization and Seed Development in Inbred Lines and F1 Hybrids of Spring Faba Beans (Vicia faba L.)
Authors: Stoddard F. L. 
Published: April 2006

AbstractWhen the flowers are not disturbed, the yield of F1 hybrids of faba beans normally exceeds that in their inbred parents. The basis of this “heterotic autofertility” was investigated by examining flowers for pollination and fertilization throughout the flowering season and assessing the distribution of seeds and pods on mature plants. Six inbred lines and seven of their F1 hybrids were grown without protection from bee visitation, and their autofertility was estimated’ by comparing their fertilization with that of cytoplasmic male‐sterile line. The first direct evidence was obtained that heterotic autofertility acts by increasing; the proportion of flowers which were pollinated and fertilized. The autofertility was not perfect, especially in a closed‐flower hybrid, as many ovules remained unfertilized. Several factors contributed to the number of seeds per pod in F1 hybrids, being superior to parental means: (1) more ovules per flower, (2) greater fertilization of the basal ovules, (3) reduced abortion of the apical ovules and (4) greater overall maturation ovules.
Changes in Several Traits of Oats Caused by Selection for Vegetative Growth Rate*
Authors: Gupta S. C. , Frey K. J. , Cox D. J. 
Published: April 2006

AbstractGrowth rate and harvest index are the primary components that cause variation in gram yield or oats it growth duration of the crop is fixed as it is in mid western USA. Because harvest index for oats in that region has been optimized 45 %, growth rate is the only remaining trait for improving grain yield.F2 derived oat lines from inter‐ (Avena sativa L. ×A. Sterilis L.) and intraspecific mating (among A. sativa cultivars) in F3 were selected for vegetative growth rate at maturity (GRM) with an intensity of 8.3%. Predicted genetic gain was 21.5% for GRM, and actual gain was 7%. Changes in grain, biological, and straw yields were higher than gains in GRM when expressed as percentages of the oat population means. Predicted genetic gains were very low for traits unrelated or negatively associated with GRM such as heading data and harvest index. This study suggests that indirect improvement can be made for gain, biological, and straw yields by selecting for GRM.
Heritability and Correlation Studies on Some Vegetative Traits in Nigerian Local White Onion, Allium cepa L.
Authors: Kadams A. M. , Nwasike C. C 
Published: April 2006

AbstractHeritability estimates for soluble solids, bulb firmness and bulb weight were carried out in two ways, namely, parent‐offspring regression and half‐sib family intra‐class correlation. Leaf characters were estimated only by half‐sib intra‐class correlations. For soluble solids the values were high (72% and 58% respectively), while the values for bulb weight And bulb firmness were low (20% and 39%, and 32%, and 33% respectively) using the two methods. Some high additive genetic correlations were observed between bulb firmness and length of longest leaf (rA= 0.830), bulb weight and leaf area of longest leaf (rA= 0.704).
Investigations on Seedling Vigour in Cashew (Anacardium occidentale L.)
Authors: Faluyi M. A. 
Published: April 2006

AbstractSeedlings from 27 open pollinated cas‐hew genotypes in two environments with five replications in each location were used to investigate the genetic, the environmental, and the nut size effects on cashew seedling vigour during the 12‐week pretransplantation period.Enviromental variances, genotype × environment interactions, and broadsense heritability values for the eight studied traits indicated that emergence percentage (L %) and seedling height (SH) were more reliable indices for seedling vigour, since they were more heritable and less influenced by the environment. Seedlings from large cashew nuts were consistently more vigorous than those from small nuts, probably because of the larger food reserve in the two cotyledons.
Callus Production and Plant Regeneration from Mature Embryos of Poa pratensis L.
Authors: Boyd L. A. , Dale P. J. 
Published: April 2006

AbstractPlant regeneration from callus cultures may provide a source ot somaclonal variation for the improvement ot the apomictic grass Poa pratensis L. It is first necessary to be able to induce callus and regenerate plants in this species at a high frequency. Variation was observed between 50 cutivars of Poa pratensis for callus induction and plant regeneration. Using the cultivars ‘Merion’ and ‘Victa’, three basal media were tested along with various media additives. Murashige and Skoog's basal medium with 0.2 mg 1−1 2,4‐dichlorophenoxyacetic acid, 0.1 mg 1−1 6‐benzylamanopurine, 100 mg 1−1 casein hydrolysate and 25 g 1−1 sucrose is considered to be a good medium for callus growth and plant regeneration. Embryo‐like structures were observed in the callus of some cultivars but plant regeneration appeared to be predominantly from shoot meristems on the callus surface. The majority of regenerated shoots were green, but chlorophyll deficient shoots were obtained from media containing coconut milk. Green plantlets could be transferred to soil without difficulty.
An Improved Culture Method of Mechanically Isolated Heterokaryons of Potato
Authors: Hein T. , Schieder O. 
Published: April 2006

AbstractFused protoplasts between different dihaploid genotype of potato were cultivated in small droplets of liquid medium. It was observed that divisions and sustained development of these protoplasts could only be achieved it they had contact via gas phase to other living cells. The factor being responsible for this effect could not be identified. Nevertheless it was possible under such a culture condition to regenerate somatic hybrid calli from heterokaryons of various fusion combinations of potato.
Substitution Analysis of Plant Regeneration from Callus Culture in Wheat
Authors: Galiba G. , Kovacs G. , Sutka J. 
Published: April 2006

AbstractThe genetic determination of the plant regeneration ability of tissue cultures arising from immature embryos was studied using a ‘Chinese Spring’/‘Cheyenne’ substitution series. Plant regeneration proved to be polygenically determined. In tile current experiment the chromosomes 7B, 7D and ID were found to be effective, although the possibility of other chromosome effects cannot be excluded.
Reinvestigation of the Architecture of the Vascular System within Racemes in Faba Beans
Authors: Ruckenbauer P. , Mollenkope K. 
Published: April 2006

AbstractA method is described which allows the visual demonstration of the vascular system of the receme of fava beans (Vicia faba L.). 150 recemes of plants of various breeding populations were investigated. It was possible to show the structure of the entire vascular system characteristic of faba bens. The existence of a system of completely independent vascular bundles (IVS), which according to GATES et al. (1983) might avoid the competition between flowers within a receme is though to be improbable.
Morphology, Cytology and Fertility of Avena sativa L. ×A. magna Murph. et Terrell Amphiploids
Authors: Premachandran M. N. , Choubey R. N. , Gupta S. K. 
Published: April 2006

AbstractThe genotypes of Avena sativa were crossed to A. magna Murph. et Terrell, from the sterile pentapliod F1 amphiploids were successfully developed after colchicine treatment. The C1 plants were observed for their morphology, cytology and fertility. These plants were characterized by longer and broader glumes, swollen pedicel attachment, pubescent lemmas, bold seeds and persistent spikelets. Other characters, viz., final plant height, rachis length, peduncle length and spikelets per panicle were intermediate. All plants hail the chromosome number 2n = 70 or close to. 7C. Due to stickiness of chromosomes, meiosis of only two decaploid plants could be studied in detail. The average chromosome Association was 1.3 I + 28.56 II + 1.4 III + 1.77 IV + 0.07 VI and 0.13 I + 28.7 II + 0.14 III + 2.09 IV + 0.59 VI; but in some cells up to 35 bivalents were observed. Seed set as well as pollen fertility and size exhibited great variation.
Tolerance of Triticum Species to Aluminum*
Authors: Berzonsky W. A. , Kimber G. 
Published: April 2006

AbstractA total of 523 accessions of 25 Triticum species were screened for tolerance of aluminum in solution. Only 22 accessions were identified with some root re growth following exposure w culture solutions containing 12 ppm aluminum. Interestingly, 15 of these 22 accessions were species with the Un genome (T. uniaristatum). The level of aluminum tolerance of none of these 22 accessions is as high as that of the cultivar ‘Atlas 66’.
Modification of Heterosis for Protein and Yield Components by Bean Common Mosaic Virus in Phaseolus vulgaris
Authors: Sarrafi A. , Ecochard R. 
Published: April 2006

AbstractThe effect of bean common mosaic virus on yield, yield components, and seed protein content was studied in tour bean cultivars and their F1 hybrids. The results of this experiment showed 3 significant decrease for yield in diseased plants; the 100 seed weight was also significantly reduced in one of the diseased varieties. The percentage of protein was increased m virus‐diseased plants: this increase was due to non‐protein nitrogen. Usually, the percentage of heterosis in virus‐diseased F1 hybrid of two susceptible varieties was decreased while in F1 hybrids of “susceptible × resistant” varieties it was increased. This study shows the danger of drawing conclusions in quantitative genetic studies then dealing with both diseased and healthy plants.