Developmental changes in the germinability, desiccation tolerance, hardseededness, and longevity of individual seeds of Trifolium ambiguum

Background and Aims: Using two parental clones of outcrossing Trifolium ambiguum as a potential model system, we examined how during seed development the maternal parent, number of seeds per pod, seed position within the pod, and pod position within the inflorescence influenced individual seed fresh weight, dry weight, water content, germinability, desiccation tolerance, hardseededness, and subsequent longevity of individual seeds. Methods: Near simultaneous, manual reciprocal crosses were carried out between clonal lines for two experiments. Infructescences were harvested at intervals during seed development. Each individual seed was weighed and then used to determine dry weight or one of the physiological behaviour traits. Key Results: Whilst population mass maturity was reached at 33–36 days after pollination (DAP), seed-to-seed variation in maximum seed dry weight, when it was achieved, and when maturation drying commenced, was considerable. Individual seeds acquired germinability between 14 and 44 DAP, desiccation tolerance between 30 and 40 DAP, and the capability to become hardseeded between 30 and 47 DAP. The time for viability to fall to 50 % (p50) at 60 % relative humidity and 45 °C increased between 36 and 56 DAP, when the seed coats of most individuals had become dark orange, but declined thereafter. Individual seed f. wt at harvest did not correlate with air-dry storage survival period. Analysing survival data for cohorts of seeds reduced the standard deviation of the normal distribution of seed deaths in time, but no sub-population showed complete uniformity of survival period. Conclusions: Variation in individual seed behaviours within a developing population is inherent and inevitable. In this outbreeder, there is significant variation in seed longevity which appears dependent on embryo genotype with little effect of maternal genotype or architectural factors

Increases in the longevity of desiccation-phase developing rice seeds: response to high temperature drying depends on harvest moisture content

• Background and Aims Earlier studies have suggested that the drying conditions routinely used by genebanks may not be optimal for subsequent seed longevity. The aim of this study was to compare the effect of hot-air drying with low temperature drying on subsequent seed longevity for 20 diverse rice accessions and to consider how factors related to seed production history might influence the results. • Methods Seeds were produced according to normal regeneration procedures at IRRI. They were harvested at different times (harvest date and days after anthesis (DAA), once for each accession) and dried either in a drying room (DR; 15% RH, 15°C), or in a flat-bed heated-air batch dryer (BD; 45°C, 8 h d-1) for up to 6 daily cycles followed by drying in the DR. Relative longevity was assessed by storage at 10.9% moisture content (m.c.) and 45°C. • Key Results Initial drying in the BD resulted in significantly greater longevity compared with the DR for 14 accessions (seed lots): the period of time for viability to fall to 50% for seeds dried in the BD as a percentage of that for seeds dried throughout in the DR varied between 1.3 and 372.2% for these 14 accessions. The seed lots that responded the most were harvested earlier in the season and at higher moisture content. Drying in the BD did not reduce subsequent longevity compared with DR drying for any of the remaining accessions. • Conclusions Seeds harvested at a m.c. where, according to the moisture desorption isotherm, they could still be metabolically active (>16.2%), may be in the first stage of the post-mass maturity, desiccation phase of seed development and able to increase longevity in response to hot-air drying. The genebank standards regarding seed drying for rice and, perhaps, for other tropical species should be reconsidered

The S-Cycle performance matrix : supporting comprehensive sustainability performance evaluation of technical systems

The work reported in this paper consolidates and rationalises disparate evaluation methods in a novel, generic framework to support the selection of comprehensive material/energetic sustainability performance indicators (SPIs) for technical systems. The S-Cycle Performance Matrix (S-CPMatrix) is comprised of 6 generic sustainability goals, 11 SPI archetypes, and 23 corresponding metrics identified from a model of technical system sustainability (the S-Cycle). The matrix was evaluated by interpreting and classifying 324 indicators currently applied to evaluate technical system sustainability performance in the literature, with 94.1% found to be fully classifiable with respect to the matrix following several refinements. The remaining 5.9% suggested additional SPI archetypes and a goal that were not initially identified. The matrix is intended to support decision makers in meeting three criteria for comprehensiveness identified from the literature: (C1) inclusion of indicators measuring performance at all relevant scales; (C2) inclusion of efficiency and effectiveness indicators; and (C3) coverage of all system sustainability goals. It may be applied to different systems in conjunction with different evaluation methods, thereby contributing to more consistent guidance on the selection of comprehensive SPIs for technical systems. In addition to industrial evaluation and comparison with existing evaluation methods, four avenues for future research were identified: (i) use of the S-CPMatrix to support systems comparison/benchmarking; (ii) further investigation of unsupported metrics; (iii) the nature and measurement of contaminants; and (iv) the comprehensiveness of SPI sets currently used in sustainability performance evaluation of technical systems

High-temperature stress during drying improves subsequent rice (Oryza sativa L.) seed longevity

Post-harvest drying prolongs seed survival in air-dry storage; previous research showed benefit from drying moist rice seeds at temperatures greater than recommended for genebanks (5-20°C). The aim of this study was to determine whether there is a temperature limit for safely drying rice seeds, and to explore whether the benefit to longevity is caused by high-temperature stress or continued seed development. Seeds of two rice varieties were harvested at different stages of development and dried initially either over silica gel, or intermittently (8 h d-1) or continuously (24 h d-1) over MgCl2 at temperatures between 15 and 60°C for up to 3 d. Seeds dried more rapidly the warmer the temperature. Subsequent seed longevity in hermetic storage (45°C with 60% equilibrium RH) was substantially improved by increase in drying temperature up to 45°C in both cultivars, and also with further increase from 45 to 60°C in cv. ‘Macassane’. The benefit of high-temperature drying to subsequent longevity tended to diminish the later the stage of development at seed harvest. Intermittent or continuous drying at high temperatures provided broadly similar improvements to longevity, but with the greatest improvements detected in a few treatment combinations with continuous drying. Heated-air drying of rice seeds harvested before maturity improved their subsequent storage longevity by more than that which occurred during subsequent development in planta, which may have resulted from the triggering of protection mechanisms in response to high-temperature stress

Downward shortwave surface irradiance from 17 sites for the FIRE/SRB Wisconsin experiment

A field experiment was conducted in Wisconsin during Oct. to Nov. 1986 for purposes of both intensive cirrus cloud measurments and SRB algorithm validation activities. The cirrus cloud measurements were part of the FIRE. Tables are presented which show data from 17 sites in the First ISCCP (International Satellite Cloud Climatology Project) Regional Experiment/Surface Radiation Budget (FIRE/SRB) Wisconsin experiment region. A discussion of intercomparison results and calibration inconsistencies is also included

Weighing the Milky Way

We describe an experiment to measure the mass of the Milky Way galaxy. The experiment is based on calculated light travel times along orthogonal directions in the Schwarzschild metric of the Galactic center. We show that the difference is proportional to the Galactic mass. We apply the result to light travel times in a 10cm Michelson type interferometer located on Earth. The mass of the Galactic center is shown to contribute 10^-6 to the flat space component of the metric. An experiment is proposed to measure the effect.Comment: 10 pages, 1 figur

Late Miocene to early Pliocene stratigraphic record in northern Taranaki Basin: Condensed sedimentation ahead of Northern Graben extension and progradation of the modern continental margin

The middle Pliocene-Pleistocene progradation of the Giant Foresets Formation in Taranaki Basin built up the modern continental margin offshore from western North Island. The late Miocene to early Pliocene interval preceding this progradation was characterised in northern Taranaki Basin by the accumulation of hemipelagic mudstone (Manganui Formation), volcaniclastic sediments (Mohakatino Formation), and marl (Ariki Formation), all at bathyal depths. The Manganui Formation has generally featureless wireline log signatures and moderate to low amplitude seismic reflection characteristics. Mohakatino Formation is characterised by a sharp decrease in the GR log value at its base, a blocky GR log motif reflecting sandstone packets, and erratic resistivity logs. Seismic profiles show bold laterally continuous reflectors. The Ariki Formation has a distinctive barrel-shaped to blocky GR log motif. This signature is mirrored by the SP log and often by an increase in resistivity values through this interval. The Ariki Formation comprises (calcareous) marl made up of abundant planktic foraminifera, is 109 m thick in Ariki-1, and accumulated over parts of the Western Stable Platform and beneath the fill of the Northern Graben. It indicates condensed sedimentation reflecting the distance of the northern region from the contemporary continental margin to the south

The use of politics by Disraeli the novelist and the use of the novel by Disraeli the politician: a study of reciprocity

Disraeli's fame as a politician is well recognised: his Premier-ship under Queen Victoria and his Parliamentary duels wit^ Peel and Gladstone, amongst others, are established in history. But, with the exception perhaps of Coningsby and Sybil, his novels are net well known, even to students of literature, This thesis seeks to redress the balance, by showing that Disraeli's career as a whole was shaped as much by him literary nature as by his political ambitions. So it is a mistake to argue that should have confined himself to one pursuit or to the other; because both were psychologically essential to him - two ambitions exerting a reciprocal influence on each other. In some instances these 'two natures' can be accused of diluting his energies, but as a rule their interaction was a dynamic which prevented introverted and self-defeating absorption in one of them. So, although Disraeli never achieved great fame as a novelist, he actually wrote more successfully after entering Parliament, than before. And this was not entirely due to the interest aroused in a politician taking his experiences into print. In themselves, the tone of his works became less self-concerned, and the style sharper: less self-conscious and ponderous. The early novels were too autobiographical and introverted: they lacked an objective outside of themselves, and political issues were to provide this. Coningsby and Sybil, written in the heat of frustrated political ambition, veered to the opposite and polemical extreme. They were rooted in the active world of politicians and political struggles, and read at times like Parliamentary reports or speeches rather than novels. The basic elements of most novels: an historical/social contest, a meaningful structuring or commenting upon it, and a suitable 'plot', are certainly present, but mot always satisfactorily integrated. Nevertheless, Disraeli's position in polities gave him some unique advantages of access to, and familiarity with, the world of government. Thus in time he learnt to incorporate his perspective on the political world into more balanced works: Lothair and Endymion. Without the challenge of presenting political subjects, however, his writing would probably have tailed off into irrelevant and self-indulgent autobiography. Conversely, although Disraeli wrote few novels after entering Parliament, considering the length of his career, he still acknowledged a debt to the literary side of his nature, in the policies and speeches he initiated. Some of his moves were to fulfil the apparently wild prophecies of the earlier novels with almost uncanny fidelity. And he retained a dramatic self-consciousness and a symbolic sense, even after adopting the sober dress and impassive manner of the Conservative leader. Whether one calls his approach romantic, or spiritual, or simply sentimental, the novelist in Disraeli was borne out in a number of acts which seem to have come not from the committee-room, bat from the pages of his quixotic romances