Ion Regulation in the Organs of Casuarina Species Differing in Salt Tolerance

Distribution of Na+, Cl-, K+, Ca2+ and Mg2+ was studied in individual organs of two highly tolerant and one moderately tolerant species of Casuarina. The highly tolerant species (C. equisetifolia and C. glauca) accumulated little Na+ and Cl- in their shoots and the concentrations of Na+ and Cl- decreased from old to young growing needles. The concentrations of Na+ and Cl- were much higher in shoots of the moderately tolerant species (C. cunninghamiana) and a concentration gradient between old and young needles was not observed. The same pattern of distribution of Cl- in C. equisetifolia was found in seedlings exposed to both short term (13 days at 100 mol m-3 NaCl in solution culture), and long term (6 months at 250 mol m-3 NaCl in sand culture) salinisation. The three species showed little difference in their root ion concentrations. A time sequence experiment of Cl- uptake indicated that the better exclusion of Cl- from the shoots of C. equisetifolia than C. cunninghamiana was due to a lower rate of Cl- uptake and lower net transport into the shoot rather than to its retention in the roots, or reabsorption at the proximal root or hypocotyl.

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Structural and Compositional Responses to Thinning over 50 Years in Moist Forest of the Northern Rocky Mountains

Forest Science ◽

10.1093/forsci/fxz025 ◽

2019 ◽

Vol 65 (5) ◽

pp. 626-636

Author(s):

Chenchen Shen ◽

Andrew S Nelson ◽

Terrie B Jain ◽

Meghan B Foard ◽

Russell T Graham

Keyword(s):

Stand Density ◽

Growth And Yield ◽

Short Term ◽

Mixed Forests ◽

Northern Rocky Mountains ◽

Tolerant Species ◽

Moist Forest ◽

Shade Tolerant Species ◽

Northern Idaho

Abstract A thinning study was established in 1967 in moist mixed forests on the Priest River Experimental Forest in northern Idaho, USA. The study design included three thinning intensities: low, moderate, and high intensity (1,976, 988, and 494 trees ha–1). This study examined short-term (11 years) and long-term (50 years) thinning effects on residual stand characteristics, growth, and yield. Since regeneration may occur after thinning, understory change was also addressed. Thinning decreased stand density immediately but improved the growth of residual trees. Shade-tolerant species were favored in all the thinnings and dominated 50 years after thinning. Unthinned stands had higher total and merchantable volume than all thinned stands both 11 years and 50 years post treatment. Regeneration and nontree vegetation richness increased shortly after thinning, whereas nontree vegetation cover decreased sharply 50 years after treatment. The stands developed into multistrata forests with shade-tolerant species in both the overstory and understory. This is contrary to current thinning practice favoring shade-intolerant species, but demonstrates the resilience of moist Northern Rockies forests to partial overstory disturbances. In this study, thinning favoring shade-tolerant species in these mixed forests has a more significant effect on forest structure dynamics than timber production.

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Drought Adaptation Confers Short-Term but Not Long-Term Salt Tolerance in Cocksfoot, Dactylis glomerata

International Journal of Botany ◽

10.3923/ijb.2008.283.289 ◽

2008 ◽

Vol 4 (3) ◽

pp. 283-289 ◽

Cited By ~ 1

Author(s):

Ahmad Abdol Zadeh ◽

Kazuto Shima ◽

Erik J. Veneklaas ◽

Kyozo Chiba

Keyword(s):

Salt Tolerance ◽

Dactylis Glomerata ◽

Drought Adaptation ◽

Short Term

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Changes in Species Abundances with Short-Term and Long-Term Nitrogen Addition are Mediated by Stoichiometric Homeostasis

10.21203/rs.3.rs-250958/v1 ◽

2021 ◽

Author(s):

Tian Yang ◽

Min Long ◽

Melinda D. Smith ◽

Qian Gu ◽

Yadong Yang ◽

...

Keyword(s):

Leymus Chinensis ◽

Sand Culture ◽

Global Changes ◽

N Addition ◽

Short Term ◽

Starting Point ◽

Species Abundances ◽

N Enrichment ◽

Species Responses

Abstract Aims Increasing nitrogen (N) deposition altered plant communities globally, however the changes in species abundances with short-term vs. long-term N enrichment remains unclear. Stoichiometric homeostasis (H) is a key trait predictive of plant species dominance and species responses to short-term global changes. It is unknown whether N enrichment can alter H over time, thereby affecting species responses to long-term N addition. Methods Here we address these two knowledge gaps with three representative species in a long-term N addition experiment and a sand culture experiment. Results The abundance of Leymus chinensis decreased with short-term N addition, and increased with long-term N addition, while Chenopodium glaucum showed opposite pattern. Cleistogenes squarrosa was only favored by 1-year N addition, and depressed by two and more years of N addition. The H values of L. chinensis and C. glaucum decreased significantly with long-term N addition however did not change for C. squarrosa. Conclusion The decrease of H suggested the nutrients use strategy became more progressive, which mediated the responses of species abundances to short- and long-term N addition. We anticipate our research to be a starting point for explaining ecosystems function and process in response to global change from the perspective of species adaptability mediated by H.

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Salt Tolerance, Ion Relations and the Effect of Root Medium on the Response of Citrus to Salinity

Functional Plant Biology ◽

10.1071/pp9950101 ◽

1995 ◽

Vol 22 (1) ◽

pp. 101 ◽

Cited By ~ 56

Author(s):

R Storey

Keyword(s):

Salt Tolerance ◽

Root Morphology ◽

High Efficiency ◽

Solution Culture ◽

Sand Culture ◽

Fibrous Root ◽

Rangpur Lime ◽

Root Medium ◽

Ion Relations ◽

Uptake And Transport

This paper describes the ion relations of two citrus genotypes, Etrog citron (Citrus medica L.), a salt-sensitive genotype, and Rangpur lime (Citrus reticulata var. austera hybrid?), a salt-tolerant genotype, under conditions of high NaCl concentrations. Root morphology was modified by establishing seedlings for 6 months in solution or sand culture. When established in sand culture, both genotypes displayed a high efficiency, relative to plants established in solution culture, to exclude Na from leaves, but differed in their capacities to exclude Cl; this capacity was much lower in Etrog citron than Rangpur lime. The net Cl root to shoot transport rates over 7 weeks for Etrog citron and Rangpur lime, treated with 50 mol m-3 NaCl, were 0.25 and 0.07 μmol g-1 root FW h-1, respectively. The net transport rates of Cl in Etrog citron were 10 times those in Rangpur lime between weeks 4 and 7. In Rangpur lime Cl reached pseudo steady-state levels in root and leaf tissue by week 4, thereafter, the net Cl root to shoot transport rate of Rangpur lime decreased while the rates in Etrog citron increased. The accumulation of Na and Cl in leaves of Rangpur lime, in contrast to Etrog citron, was not affected by transpiration. The high salt tolerance of Rangpur lime appears to be associated with low rates of net uptake and transport of Cl, feedback control of net root to shoot transport by Cl levels in the shoot, a low interaction between water flow and Cl and Na fluxes, and a reduction in the leafiroot ratio in response to salinity. When plants were established in solution culture the pioneer roots became elongated and the normal development of the laterals into a fibrous root system was suppressed. Plants of both genotypes, previously established in solution culture and then treated with 50 mol m-3 NaCl, accumulated levels of Na and Cl in leaves up to 200-400 mol m-3. Under these conditions the rates of net Cl root to shoot transport over the 7 weeks were 0.53 and 0.56 μmol g-1 root FW h-1 for Etrog citron and Rangpur lime, respectively. These high rates of Cl uptake and transport were attributed to changes in root permeability and increases in passive ion fluxes. Keywords: citrus, root morphology, root medium, transpiration, Cl, Na, salt accumulation, salinity.

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Conceptual short-term memory (CSTM) supports core claims of Christiansen and Chater

Behavioral and Brain Sciences ◽

10.1017/s0140525x15000928 ◽

2016 ◽

Vol 39 ◽

Author(s):

Mary C. Potter

Keyword(s):

Working Memory ◽

Rapid Serial Visual Presentation ◽

Language Comprehension ◽

Short Term Memory ◽

Visual Presentation ◽

Long Term Memory ◽

Short Term ◽

Term Memory ◽

Use Of Knowledge

AbstractRapid serial visual presentation (RSVP) of words or pictured scenes provides evidence for a large-capacity conceptual short-term memory (CSTM) that momentarily provides rich associated material from long-term memory, permitting rapid chunking (Potter 1993; 2009; 2012). In perception of scenes as well as language comprehension, we make use of knowledge that briefly exceeds the supposed limits of working memory.

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Ultrastructural investigations of MDL 19,660-induced effects on the canine platelet and megakaryocyte

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100159412 ◽

1990 ◽

Vol 48 (3) ◽

pp. 374-375

Author(s):

D.E. Loudy ◽

J. Sprinkle-Cavallo ◽

J.T. Yarrington ◽

F.Y. Thompson ◽

J.P. Gibson

Keyword(s):

Antidepressant Drug ◽

Beagle Dogs ◽

Long Term Effects ◽

Short Term ◽

Platelet Counts ◽

Toxicological Studies ◽

Induced Aggregation ◽

Internal Architecture

Previous short term toxicological studies of one to two weeks duration have demonstrated that MDL 19,660 (5-(4-chlorophenyl)-2,4-dihydro-2,4-dimethyl-3Hl, 2,4-triazole-3-thione), an antidepressant drug, causes a dose-related thrombocytopenia in dogs. Platelet counts started to decline after two days of dosing with 30 mg/kg/day and continued to decrease to their lowest levels by 5-7 days. The loss in platelets was primarily of the small discoid subpopulation. In vitro studies have also indicated that MDL 19,660: does not spontaneously aggregate canine platelets and has moderate antiaggregating properties by inhibiting ADP-induced aggregation. The objectives of the present investigation of MDL 19,660 were to evaluate ultrastructurally long term effects on platelet internal architecture and changes in subpopulations of platelets and megakaryocytes.Nine male and nine female beagle dogs were divided equally into three groups and were administered orally 0, 15, or 30 mg/kg/day of MDL 19,660 for three months. Compared to a control platelet range of 353,000- 452,000/μl, a doserelated thrombocytopenia reached a maximum severity of an average of 135,000/μl for the 15 mg/kg/day dogs after two weeks and 81,000/μl for the 30 mg/kg/day dogs after one week.

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Comparison of Auditory, Language, Memory, and Attention Abilities in Children With and Without Listening Difficulties

American Journal of Audiology ◽

10.1044/2020_aja-20-00018 ◽

2020 ◽

Vol 29 (4) ◽

pp. 710-727

Author(s):

Beula M. Magimairaj ◽

Naveen K. Nagaraj ◽

Alexander V. Sergeev ◽

Natalie J. Benafield

Keyword(s):

Auditory Processing ◽

Short Term Memory ◽

Group Differences ◽

Long Term Memory ◽

Short Term ◽

Significant Group ◽

Term Memory ◽

Memory And Attention ◽

Speed And Accuracy

Objectives School-age children with and without parent-reported listening difficulties (LiD) were compared on auditory processing, language, memory, and attention abilities. The objective was to extend what is known so far in the literature about children with LiD by using multiple measures and selective novel measures across the above areas. Design Twenty-six children who were reported by their parents as having LiD and 26 age-matched typically developing children completed clinical tests of auditory processing and multiple measures of language, attention, and memory. All children had normal-range pure-tone hearing thresholds bilaterally. Group differences were examined. Results In addition to significantly poorer speech-perception-in-noise scores, children with LiD had reduced speed and accuracy of word retrieval from long-term memory, poorer short-term memory, sentence recall, and inferencing ability. Statistically significant group differences were of moderate effect size; however, standard test scores of children with LiD were not clinically poor. No statistically significant group differences were observed in attention, working memory capacity, vocabulary, and nonverbal IQ. Conclusions Mild signal-to-noise ratio loss, as reflected by the group mean of children with LiD, supported the children's functional listening problems. In addition, children's relative weakness in select areas of language performance, short-term memory, and long-term memory lexical retrieval speed and accuracy added to previous research on evidence-based areas that need to be evaluated in children with LiD who almost always have heterogenous profiles. Importantly, the functional difficulties faced by children with LiD in relation to their test results indicated, to some extent, that commonly used assessments may not be adequately capturing the children's listening challenges. Supplemental Material https://doi.org/10.23641/asha.12808607

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