scholarly journals Understanding the genetic and physiological basis of transpiration efficiency in Australian wheat

2020 ◽  
Author(s):  
◽  
Andrew Lincoln Fletcher
Keyword(s):  
Transpiration Efficiency ◽  
Physiological Basis ◽  
Australian Wheat

On the extent of genetic variation for transpiration efficiency in sorghum

1997 ◽  
Vol 48 (5) ◽  
pp. 649 ◽  
Author(s):  
Graeme L. Hammer ◽  
Graham D. Farquhar ◽  
Ian J. Broad
Keyword(s):  
Genetic Variation ◽  
Carbon Isotope ◽  
Carbon Isotope Discrimination ◽  
Selection Index ◽  
Leaf Tissue ◽  
Transpiration Efficiency ◽  
Significant Finding ◽  
Physiological Basis ◽  
Isotope Discrimination ◽  
Accepted Standard

A glasshouse study examined 49 diverse sorghum lines for variation in transpiration efficiency. Three of the 49 lines grown were Sorghum spp. native to Australia; one was the major weed Johnson grass (Sorghum halepense), and the remaining 45 lines were cultivars of Sorghum bicolor. All plants were grown under non-limiting water and nutrient conditions using a semi-automatic pot watering system designed to facilitate accurate measurement of water use. Plants were harvested 56–58 days after sowing and dry weights of plant parts were determined. Transpiration efficiency differed signficantly among cultivars. The 3 Australian native sorghums had much lower transpiration efficiency than the other 46 cultivars, which ranged from 7·7 to 6·0 g/kg. For the 46 diverse cultivars, the ratio of range in transpiration efficiency to its l.s.d. was 2·0, which was similar to that found among more adapted cultivars in a previous study. This is a significant finding as it suggests that there is likely to be little pay-off from pursuing screening of unadapted material for increased variation in transpiration efficiency. It is necessary, however, also to examine absolute levels of transpiration efficiency to determine whether increased levels have been found. The cultivar with greatest transpiration efficiency in this study (IS9710) had a value 9% greater (P < 0·05) than the accepted standard for adapted sorghum cultivars. The potential impact of such an increase in transpiration efficiency warrants continued effort to capture it. Transpiration efficiency has been related theoretically and experimentally to the degree of carbon isotope discrimination in leaf tissue in sorghum, which thus offers a relatively simple selection index. In this study, the variation in transpiration efficiency was not related simply to carbon isotope discrimination. Significant associations of transpiration efficiency with ash content and indices of photosynthetic capacity were found. However, the associations were not strong. These results suggest that a simple screening technique could not be based on any of the measures or indices analysed in this study. A better understanding of the physiological basis of the observed genetic differences in transpiration efficiency may assist in developing reliable selection indices. It was concluded that the potential value of the improvement in transpiration efficiency over the accepted standard and the degree of genetic variation found warrant further study on this subject. It was suggested that screening for genetic variation under water-limiting conditions may provide useful insights and should be pursued.

scholarly journals Mesophyll conductance in two cultivars of wheat (Triticum aestivum) grown in glacial to super-elevated [CO2]

2020 ◽  
Author(s):  
Eisrat Jahan ◽  
Peter C. Thomson ◽  
David T. Tissue
Keyword(s):  
Environmental Conditions ◽  
Mesophyll Conductance ◽  
Specific Mechanism ◽  
Physiological Basis ◽  
Breeding Programs ◽  
Cultivar Selection ◽  
Australian Wheat ◽  
Use Efficiency ◽  
Selection For

AbstractMesophyll conductance (gm) is an important factor limiting photosynthesis. However, gm response to long-term growth in variable [CO2] is not well understood, particularly in crop plants. Here, we grew two cultivars of wheat (Halberd and Cranbrook), known to differ in gm under current environmental conditions, in four [CO2] treatments: glacial (180 μmol mol−1), pre-industrial (280 μmol mol−1), current ambient (450 μmol mol−1) and super-elevated (1000 μmol mol−1) in well-watered and moderate water limitation conditions, to develop an evolutionary and future climate perspective on gm control of photosynthesis and water use efficiency (WUE). In the two wheat genotypes, gm increased with rising [CO2] from glacial to ambient [CO2], but declined at super-elevated [CO2]; however, the specific mechanism of gm response to [CO2] remains unclear. Although gm and gm/gsc (mesophyll conductance/stomatal conductance) were strongly associated with the variability of A and WUE, we found that plants with higher gm may increase A without increasing gsc, which increased WUE. These results may be useful to inform plant breeding programs and cultivar selection for Australian wheat under future environmental conditions.HighlightMesophyll conductance increased with increasing [CO2] from glacial to ambient CO2 levels, then declined at super-elevated CO2 for both well-watered and water-limited treatments. These responses of mesophyll conductance with varying [CO2] have a physiological basis.

How to Psychologically Minimize Scratching Impulses

2014 ◽  
Vol 222 (3) ◽  
pp. 140-147 ◽  
Author(s):  
Ariane Sölle ◽  
Theresa Bartholomäus ◽  
Margitta Worm ◽  
Regine Klinger
Keyword(s):  
Cognitive Processes ◽  
Placebo Effect ◽  
Psychological Factors ◽  
Pharmacological Treatments ◽  
Physiological Basis ◽  
Psychological Mechanisms ◽  
Physical Complaints ◽  
Factors Influencing ◽  
The Impact ◽  
Placebo Model

Research in recent years, especially in the analgesic field, has intensively studied the placebo effect and its mechanisms. It has been shown that physical complaints can be efficiently reduced via learning and cognitive processes (conditioning and expectancies). However, despite evidence demonstrating a large variety of physiological similarities between pain and itch, the possible transfer of the analgesic placebo model to itch has not yet been widely discussed in research. This review therefore aims at highlighting potential transfers of placebo mechanisms to itch processes by demonstrating the therapeutic issues in pharmacological treatments for pruritus on a physiological basis and by discussing the impact of psychological mechanisms and psychological factors influencing itch sensations.

SOYBEAN AND FLAX SELECTION METHODS

1970 ◽  
pp. 19-23
Author(s):  
V. М. Lukomets ◽  
S. V. Zelentsov
Keyword(s):  
High Resistance ◽  
Fungal Pathogens ◽  
Selection Process ◽  
Pathogenic Fungi ◽  
Cultivated Plants ◽  
Practical Implementation ◽  
Physiological Basis ◽  
Oil Crops ◽  
Soybean Genotypes ◽  
Genetically Determined

To improve the effectiveness of the soybeans and oil flax breeding, research to improve existing and develop new breeding methods are conducting in all-Russia Research institute of Oil Crops (Krasnodar). One of the improved methods for the soybean breeding, based on the use of sources of complexes of compensatory genes, is the CCG technology, which allows to create varieties with an increased yield of a heterotic level transmitted along the progeny for the entire life cycle of the variety. For the purpose of non-transgenic production of new traits, a theory of polyploid recombination of the genome (TPR) was formulated, which models the mechanism of the natural formation of polymorphism in the centers of origin of cultivated plants. On the basis of this theory, a method of breeding (TPR-technology) has been developed, which makes it possible to obtain recombinant reploids of soybeans and oil flax with an extended spectrum of traits. Of these reploids, the soybean lines with increased sucking force of the roots, providing high drought resistance, were distinguished; cold-resistant soybean lines, which stand in the phase of shoots of freezing to minus 5 °С; lines of oil flax with complete resistance to flax sickness of soil and high resistance to Fusarium; winter-hardy flax lines that withstand winter frosts down to minus 20–23 °С and ripen one and a half months earlier than spring sowings. Another original developed method is the ODCS-technology for isolating and selecting soybean genotypes with high resistance to fungal pathogens. The physiological basis of ODCS-technology is the blocking of osmotic nutrition of pathogenic fungi due to genetically determined increased osmotic pressure in the tissues of host plants. The practical implementation of CCG-, TPR- and ODKS-technologies in the selection process, allowed to create a whole series of soybean and oil flax varieties with improved or new traits.

Emotional processing and the autonomic nervous system: a comprehensive meta-analytic investigation

2018 ◽  
Author(s):  
Pedro Silva Moreira ◽  
Pedro Chaves ◽  
Nuno Dias ◽  
Patrício Costa ◽  
Pedro Rocha Almeida
Keyword(s):  
Nervous System ◽  
Autonomic Nervous System ◽  
Skin Conductance ◽  
Emotional Processing ◽  
Skin Conductance Level ◽  
The Body ◽  
Analytic Investigation ◽  
Physiological Basis ◽  
Autonomic Nervous ◽  
Conductance Level

Background: The search for autonomic correlates of emotional processing has been a matter of interest for the scientific community with the goal of identifying the physiological basis of emotion. Despite an extensive state-of-the-art exploring the correlates of emotion, there is no absolute consensus regarding how the body processes an affective state.Objectives: In this work, we aimed to aggregate the literature of psychophysiological studies in the context of emotional induction. Methods: For this purpose, we conducted a systematic review of the literature and a meta-analytic investigation, comparing different measures from the electrodermal, cardiovascular, respiratory and facial systems across emotional categories/dimensions. Two-hundred and ninety-one studies met the inclusion criteria and were quantitatively pooled in random-effects meta-analytic modelling. Results: Heart rate and skin conductance level were the most reported psychophysiological measures. Overall, there was a negligible differentiation between emotional categories with respect to the pooled estimates. Of note, considerable amount of between-studies’ heterogeneity was found in the meta-analytic aggregation. Self-reported ratings of emotional arousal were found to be associated with specific autonomic-nervous system (ANS) indices, particularly with the variation of the skin conductance level. Conclusions: Despite this clear association, there is still a considerable amount of unexplained variability that raises the need for more fine-grained analysis to be implemented in future research in this field.

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