The effect of plant density, harvest date and method on the yield of seed and components of yield of parsnip (Pastinaca sativa)

Experiments conducted over four years (1980–1983) with parsnip cv. Avonre-sister examined the effects of plant density, harvest date and method on seed yield and the components of yield. In 1980, using the root-to-seed method, the yield of seed increased by 50% for an increase in plant density from 5.6 to 35 plants m^-2; the maximum yield at the optimum harvest date was 3015 kg h^-1. In the other three years, using the seed-to-seed method, seed yield increased to a maximum with an increase in plant density from c. 1 to 10 plants m^-2 but at higher densities yields were lower. At c. 10 plants m^-2, seed yields were 1567, 4029 and 1040 kg ha^-1, in 1981, 1982 and 1983, respectively, when harvested at the optimum time. An increase in plant density increased the number of non-seeding plants in the population, reduced the number of umbels per plant and reduced the number of seeds per umbel. Mean seed weight was, in general, unaffected by plant density and so effects of density on yield reflected changes in seed numbers. Increasing the plant density increased the proportion of primary-umbel seed. Maximum yields of seed were obtained from crops harvested at a seed-moisture content of 50 to 70%, which occurred 46 ± 2·4 days after flowering. Delay in harvesting after this date led to a loss of yield of 33, 35, 139 and 32 kg ha^-1wk^-1 in 1980, 1981, 1982 and 1983, respectively. Plants cut, placed in the windrow to dry and then threshed gave similar yields to those harvested at the same time but dried in bins.     

The Polyunsaturated Fatty Acids of Marine Dinoflagellates

SYNOPSIS. Eight photosynthetic and one heterotrophic, marine dinoflagellates were cultured axenically in chemically defined media and their fatty acids characterized. Palmitic, octadecatetraenoic and docosahexaenoic were the most typical fatty acids. Photosynthetic forms also contained the polyunsaturates icosapentaenoic acid and α-linolenic acid, the latter as a relatively minor component. The galactolipids of one photosynthetic species, Glenodinium sp., were isolated and their fatty acids analyzed. Octadecatetraenoic acid was the predominant fatty acid, particularly of the monogalactosyl diglyceride fraction.
The relationship of these findings to the body of knowledge of the photosynthesis-associated lipids of eucaryotic microbes and to the ecology of polyunsaturated fatty acids in marine food chains is discussed.     

THE FINE STRUCTURE OF DIFFERENTIATING SPERMATOZOA AND SERTOLI CELLS IN THE GONAD OF THE POND SNAIL, LYMNAEA STAGNALIS

The fine structure has been examined, of spermatogonia, spermatocytes,early spermatids, late spermatids and early spermatozoa nestlingagainst Sertoli cells in the gonad of Lymnaea stagnalis. Changes in the Sertoli cells are linked with the phases of spermdifferentiation. Details on differentiation particularly ofthe head of the sperm, are presented. (Received 14 March 1981;     

Parsnip (Pastinaca sativa) seed production: effects of seed crop plant density, seed position on the mother plant, harvest date and method, and seed grading on embryo and seed size and seedling performance

Parsnip seeds from four years of seed production (1980–83) were used to examine the effects of position of the seed on the parent plant and several cultural factors on seed and embryo growth and seedling performance. Maximum seed dry weight was reached c. 50 days after flowering (DAF) but embryos continued to grow for a further 7–15 days. The coefficient of variation (C.V.) of seed weight fell from c. 35–40% at 40 DAF, to about 20–25% at maturity. The corresponding figures for C.V. of embryo length were 25–35% at the early harvest and 12–15% at maturity. The effects of seed position, plant density, harvest method, seed grading after harvest on seedling emergence and weight characters were small. Harvesting seeds c. 60 DAF gave, on average, 3.3 days earlier emergence, c. 3.6 days lower ‘spread’ of emergence time and c. 9% higher seedling emergence than harvesting 2 wk earlier. Late harvesting of the seed crop reduced the C.V. of seedling weight from 53 to 46%, on average, but there were variations in response from year to year. Seedling emergence and seedling weight characters were more closely related to embryo length than to seed weight characters.     

Synthesis of two distinct α-glucosidase activities in Bacillus licheniformis

When grown with maltose or starch as carbon source at 37°C, Bacillus licheniformis synthesized two α-glucosidases which could be resolved by polyacrylamide gel electrophoresis. One of these enzymes preferentially hydrolysed p -nitrophenyl-α-D-glucoside ( p NPG) and the other was inactive on p NPG but hydrolysed maltose (maltase). Only the maltase could be detected in induced cells grown at 50°C.     

TRAINING NEEDS ASSESSMENT IN RESEARCH ETHICS EVALUATION AMONG RESEARCH ETHICS COMMITTEE MEMBERS IN THREE AFRICAN COUNTRIES: CAMEROON,MALI AND TANZANIA

Background: As actors with the key responsibility for the protection of human research participants, Research Ethics Committees (RECs) need to be competent and well‐resourced in order to fulfil their roles. Despite recent programs designed to strengthen RECs in Africa, much more needs to be accomplished before these committees can function optimally. Objective: To assess training needs for biomedical research ethics evaluation among targeted countries. Methods: Members of RECs operating in three targeted African countries were surveyed between August and November 2007. Before implementing the survey, ethical approvals were obtained from RECs in Switzerland, Cameroon, Mali and Tanzania. Data were collected using a semi‐structured questionnaire in English and in French. Results: A total of 74 respondents participated in the study. The participation rate was 68%. Seventy one percent of respondents reported having received some training in research ethics evaluation. This training was given by national institutions (31%) and international institutions (69%). Researchers and REC members were ranked as the top target audiences to be trained. Of 32 topics, the top five training priorities were: basic ethical principles, coverage of applicable laws and regulations, how to conduct ethics review, evaluating informed consent processes and the role of the REC. Conclusion: Although the majority of REC members in the targeted African countries had received training in ethics, they expressed a need for additional training. The results of this survey have been used to design a training program in research ethics evaluation that meets this need.     

Electronic nose evaluation of onion headspace volatiles and bulb quality as affected by nitrogen, sulphur and soil type

Edaphic factors affect the quality of onions (Allium cepa). Two experiments were carried out in the field and glasshouse to investigate the effects of N (field: 0,120 kg ha⁻¹; glasshouse: 0,108 kg ha⁻¹), S (field: 0, 20 kg ha⁻¹; glasshouse: 0, 4.35 kg ha⁻¹) and soil type (clay, sandy loam) on onion quality. A conducting polymer sensor electronic nose (E-nose) was used to classify onion headspace volatiles. Relative changes in the E-nose sensor resistance ratio (%dR/R) were reduced following N and S fertilisation. A 2D Principal Component Analysis (PCA) of the E-nose data sets accounted for c. 100% of the variations in onion headspace volatiles in both experiments. For the field experiment, E-nose data set clusters for headspace volatiles for no N-added onions overlapped (D²= 1.0) irrespective of S treatment. Headspace volatiles of N-fertilised onions for the glasshouse sandy loam also overlapped (D²=1.1) irrespective of S treatment as compared with distinct separations among clusters for the clay soil. N fertilisation significantly (P < 0.01) reduced onion bulb pyruvic acid concentration (flavour) in both experiments. S fertilisation increased pyruvic acid concentration significantly (P < 0.01) in the glasshouse experiment, especially for the clay soil, but had no effect on pyruvic acid concentration in the field. N and S fertilisation significantly (P < 0.01) increased lachrymatory potency (pungency), but reduced total soluble solids (TSS) content in the field experiment. In the glasshouse experiment, N and S had no effect on TSS. TSS content was increased on the clay by 1.2-fold as compared with the sandy loam. Onion tissue N: water-soluble SO₄²⁻ ratios of between five and eight were associated with greater %dR/R and pyruvic acid concentration values. N did not affect inner bulb tissue microbial load. In contrast, S fertilisation reduced inner bulb tissue microbial load by 80% in the field experiment and between 27% (sandy loam) and 92% (clay) in the glasshouse experiment. Overall, onion bulb quality discriminated by the E-nose responded to N, S and soil type treatments, and reflected their interactions. However, the conventional analytical and sensory measures of onion quality did not correlate with %dR/R.     

Do taxonomic divisions reflect genetic differentiation? A comparison of morphological and genetic data in Coenonympha tullia (Müller), Satyrinae

Historically, morphological variation has been used to classify many species (and subspecies) of Lepidoptera. However, some of this variation may be unsuitable for inferring the recent evolutionary history of populations. Genetic data provide an alternative. We examine the morphological and genetic variation within and between British subspecies of Coenonympha tullia (Müller 1764) to test the hypothesis that neutral genetic variation corresponds to morphological variation. We find that most morphological and genetic variation occurs within populations and that those populations designated as subspecies based on morphological characters are not necessarily most closely related for mitochondrial DNA or nuclear DNA (amplified fragment length polymorphisms and allozymes). Thus, the notion that wing spot variation reflects population isolation and therefore genetic differentiation does not hold. The present study highlights the need for genetic data where taxonomy may be based on environmentally plastic or locally adapted characters because such characters will not reflect the true population genetic history.  © 2009 The Linnean Society of London, Biological Journal of the Linnean Society , 2009, 97 , 314–327.     

Declaration of Taking Twice: The Fazendeville Community of the Lower Ninth Ward

The Fazendeville Village was a residential community founded during the Reconstruction era in 1867 on the land where the Battle of New Orleans (1815) was fought during the War of 1812 in what is now Chalmette, LA. The entire community was displaced and their homes were razed in 1964 to provide more land for the National Historical Park to commemorate the battle. Most of the residents moved to the Lower Ninth Ward in New Orleans and now, 42 years later, they are displaced again and their homes (those that are still standing) will be razed because of the devastation of Hurricanes Katrina and Rita and the floods. Previous research has proven that vernacular networks affect the exodus, return, recovery, and rebuilding of certain communities after traumatic situations. In this study, I suggest that in the Fazendeville community during past trauma, the maintenance of cultural livelihood was caused by communality, spirituality, and traditionality. In addition, I propose that these are also the vernacular networks that are catalyst for community renewal and empowerment—after hurricanes, floods, and historic displacement by the federal government. My ultimate goal is to transform ethnographies into a praxis capable of making the community present and not marginalized or excluded from history and the strategic plan for rebuilding New Orleans.