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1.
Little is known about Mg induced Ca deficiency in alkaline conditions, and the relationship between Mg induced Ca deficiency
and Na induced Ca deficiency. Dilute nutrient solutions (dominated by Mg) were used to investigate the effect of Ca activity
ratio (CAR) on the growth of mungbeans (Vigna radiata (L.) Wilczek cv. Emerald). At pH 9.0, root growth was reduced below a critical CAR of 0.050 (corresponding to 90% relative
root length). Root growth was found to be limited more in Mg solutions than had been previously observed for Na solutions.
Using a CAR equation modified with plasma membrane binding constants (to incorporate the differing antagonistic effects of
Mg and Na), new critical CAR values were calculated for both Na (0.56) and Mg (0.44) dominated solutions. This modified CAR
equation permits the calculation of CAR irrespective of the dominant salt present. 相似文献
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Peter M. Kopittke Enzo Lombi Brigid A. McKenna Peng Wang Erica Donner Richard I. Webb F. Pax C. Blamey Martin D. de Jonge David Paterson Daryl L. Howard Neal W. Menzies 《Physiologia plantarum》2013,147(4):453-464
The phytotoxicity of Mn is important globally due to its increased solubility in acid or waterlogged soils. Short‐term (≤24 h) solution culture studies with 150 µM Mn were conducted to investigate the in situ distribution and speciation of Mn in apical tissues of hydrated roots of cowpea [Vigna unguiculata (L.) Walp. cv. Red Caloona] using synchrotron‐based techniques. Accumulation of Mn was rapid; exposure to 150 µM Mn for only 5 min resulting in substantial Mn accumulation in the root cap and associated mucigel. The highest tissue concentrations of Mn were in the root cap, with linear combination fitting of the data suggesting that ≥80% of this Mn(II) was associated with citrate. Interestingly, although the primary site of Mn toxicity is typically the shoots, concentrations of Mn in the stele of the root were not noticeably higher than in the surrounding cortical tissues in the short‐term (≤24 h). The data provided here from the in situ analyses of hydrated roots exposed to excess Mn are, to our knowledge, the first of this type to be reported for Mn and provide important information regarding plant responses to high Mn in the rooting environment. 相似文献
4.
Mia Petljak Ludmil B. Alexandrov Jonathan S. Brammeld Stacey Price David C. Wedge Sebastian Grossmann Kevin J. Dawson Young Seok Ju Francesco Iorio Jose M.C. Tubio Ching Chiek Koh Ilias Georgakopoulos-Soares Bernardo Rodríguez–Martín Burçak Otlu Sarah O’Meara Adam P. Butler Andrew Menzies Shriram G. Bhosle Michael R. Stratton 《Cell》2019,176(6):1282-1294.e20
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Context-dependent memory: colour versus odour 总被引:1,自引:1,他引:1
An olfactory stimulus and a visual stimulus were employed in a context-
dependent memory study using a prose passage as the to-be-remembered item.
Ninety-five university students (aged 17-35 years) learned the passage of
prose in the presence of one of the stimuli and were then asked to recall
the passage with the original context either reinstated or not reinstated.
The results revealed a significant context-dependent memory effect for the
olfactory cue but not for the visual cue. They demonstrate support for the
effectiveness of odours as context cues and it is suggested that
context-dependent memory processes may underlie the formation and retrieval
of odour-evoked autobiographical memories.
相似文献
7.
A frequently desired outcome when rehabilitating Zn toxic sites in Australia is to establish a self-sustaining native ecosystem. Hence, it is important to understand the tolerance of Australian native plants to high concentrations of Zn. Very little is known about the responses of Australian native plants, and trees in particular, to toxic concentrations of Zn. Acacia holosericea, Eucalyptus camaldulensis and Melaleuca leucadendra plants were grown in dilute solution culture for 10 weeks. The seedlings (42 days old) were exposed to six Zn treatments viz., 0.5, 5, 10, 25, 50 and 100 M. The order of tolerance to toxic concentrations of Zn was E. camaldulensis> A. holosericea> M. leucadendra, the critical external concentrations being approximately 20, 12 and 1.5 M, respectively. Tissue Zn concentrations increased as solution Zn increased for all species. Root tissue concentrations were higher than shoot tissue concentrations at all solution Zn concentrations. The critical tissue Zn concentrations were approximately 85 and 110 g g–1 DM for M. leucadendra, 115 and 155 g g–1 DM for A. holosericea and 415 and 370 g g–1 DM for E. camaldulensis for the youngest fully expanded leaf and total shoots, respectively. The results from this paper provide the first comprehensive combination of growth responses, critical external concentrations, critical tissue concentrations and plant toxicity symptoms for three important Australian genera, viz., Eucalyptus, Acacia and Melaleuca, for use in the rehabilitation of potentially Zn toxic sites. 相似文献
8.
Ricardo Ewbank Steffen Rosangela Caetano Márcia Pinto Diogo Chaves Rossini Ferrari Mayara Bastos Sandra Teixeira de Abreu Dick Menzies Anete Trajman 《PloS one》2013,8(4)
Background
Latent tuberculosis infection (LTBI) is a reservoir for new TB cases. Isoniazid preventive therapy (IPT) reduces the risk of active TB by as much as 90%, but LTBI screening has limitations. Unlike tuberculin skin testing (TST), interferon-gamma release assays are not affected by BCG vaccination, and have been reported to be cost-effective in low-burden countries. The goal of this study was to perform a cost-effectiveness analysis from the health system perspective, comparing three strategies for LTBI diagnosis in TB contacts: tuberculin skin testing (TST), QuantiFERON®-TB Gold-in-Tube (QFT-GIT) and TST confirmed by QFT-GIT if positive (TST/QFT-GIT) in Brazil, a middle-income, high-burden country with universal BCG coverage.Methodology/Principal Findings
Costs for LTBI diagnosis and treatment of a hypothetical cohort of 1,000 adult immunocompetent close contacts were considered. The effectiveness measure employed was the number of averted TB cases in two years. Health system costs were US$ 105,096 for TST, US$ 121,054 for QFT-GIT and US$ 101,948 for TST/QFT-GIT; these strategies averted 6.56, 6.63 and 4.59 TB cases, respectively. The most cost-effective strategy was TST (US$ 16,021/averted case). The incremental cost-effectiveness ratio was US$ 227,977/averted TB case for QFT-GIT. TST/QFT-GIT was dominated.Conclusions
Unlike previous studies, TST was the most cost-effective strategy for averting new TB cases in the short term. QFT-GIT would be more cost-effective if its costs could be reduced to US$ 26.95, considering a TST specificity of 59% and US$ 18 considering a more realistic TST specificity of 80%. Nevertheless, with TST, 207.4 additional people per 1,000 will be prescribed IPT compared with QFT. 相似文献9.
10.