Effect of water stress on the phasic development of annual Medicago species

1976 ◽  
Vol 27 (2) ◽  
pp. 227 ◽  
Author(s):  
NM Clarkson ◽  
JS Russell
Keyword(s):  
Water Stress ◽  
Life Span ◽  
Mean Delay ◽  
Severe Water Stress ◽  
Eastern Australia ◽  
The Mean ◽  
Annual Medics ◽  
Annual Medicago ◽  
Delayed Flowering ◽  
Medicago Species

Although annual medics (Medicago spp.) grow and persist in subtropical eastern Australia, their growth in the field is greatly affected by water stress, which can occur at any time after germination. To study this effect in some detail, the phasic development of six annual Medicago cultivars was measured under four water regimes in a glasshouse. Stress was varied by allowing the soil to dehydrate to different degrees before rewetting, the cycles being repeated continuously. Water stress delayed flowering in all medics except M. scutellata, the mean delay being 14 days. Corresponding delays occurred in the onset of pod production. In contrast the later stages of phasic development were accelerated in some species. Both the length of flowering and life span of the M. truncatula cultivars were significantly reduced by water stress. In the case of cv. Jemalong, severe water stress reduced its length of flowering by 53 days and its life span by 27 days. These results suggest that annual medics have no mechanisms for evading dry seasonal conditions by earlier flowering, but once flowering has begun phasic development is accelerated in some species by water stress. The implications of this study for the interpretation and prediction of field behaviour of annual medics are that water stress can affect phasic development mainly through a delay in flowering. However, the effects appear to be small compared with those due to vernalization, photoperiod and temperature.

Effect of rotation and cultivation systems on establishment and persistence of annual medics

1989 ◽  
Vol 29 (2) ◽  
pp. 183 ◽  
Author(s):  
EJ Crawford ◽  
BG Nankivell
Keyword(s):  
Lower Proportion ◽  
The Other ◽  
Annual Plant ◽  
Plant Populations ◽  
The Third ◽  
Permanent Pasture ◽  
Seed Reserves ◽  
Annual Medics ◽  
Annual Medicago ◽  
Medicago Species

The persistence and annual and seasonal regeneration of 3 annual Medicago species, M. rugosa cv. Paragosa, M. scutellata cv. Robinson and M. truncatula cvv. Cyprus and Jemalong, were compared between 1978 and 1985 over 3 rotation systems, permanent pasture (R1); pasture, barley, pasture, barley repeated (R2) and pasture, fallow, wheat, barley, repeated (R3). Ploughing practices adopted for the various rotations affected persistence and regeneration. Not all ofthe seed that was produced in 1978 produced seedlings. A much lower proportion of the seed reserve of cv. Paragosa produced seedlings compared with cv. Robinson and cvv. Cyprus and Jemalong. The poorer re-establishment of cv. Paragosa could have been due to its more permeable seed compared with the other cultivars. Seed reserves persisted for a maximum of 7 years. Annual re-establishment was greater for all cultivars under the system of permanent pasture than under either the pasture, barley or the pasture, fallow, wheat, barley rotations which disturbed the soil. Unlike the other cultivars, germination and establishment rates of cv. Robinson were low following the first autumn rains in all years. Germination of this cultivar usually occurred from June to November following a delayed breakdown in hardseededness. It also responded to cultivation so that with the exception of R2 in 1980, the highest annual plant populations in R2 and R3 were in the cropping and/or fallowing phases rather than the pasture phases. Although cv. Paragosa produced the highest seed yield in the year of sowing, its reserves were exhausted by the third year in all rotations, whereas the harder seeded cultivars maintained adequate seed reserves to enable good plant re-establishment in the sixth year under all rotations, except in the continuous pasture rotation, where seed reserves of cv. Robinson were exhausted by the fifth year. Cultivation and consequent pod burial in the 2 cropping rotations preserved seeds longer than did the continuous pasture system. Jemalong maintained higher (P< 0.05) seed reserves than cvv. Cyprus and Robinson in the sixth year.

Annual Medicago species in Morocco. I. Species and their abundance

1992 ◽  
Vol 43 (3) ◽  
pp. 739 ◽  
Author(s):  
M Bounejmate ◽  
PE Beale ◽  
AD Robson
Keyword(s):  
Seed Yield ◽  
Genetic Erosion ◽  
Soil Surface ◽  
Annual Medics ◽  
Annual Medicago ◽  
Medicago Species ◽  
Collection Sites

An ecogeographic survey of the distribution of annual medics in Morocco was conducted in 1988 by sampling 161 sites within six agricultural zones. At each site all medic pods lying on the soil surface were collected from five quadrats placed at random. Of the 18 medic species reported to occur in Morocco, only 11 were recorded in 1988. M. polymorpha and M. truncatula were the most frequent. Thirty-five sites had no medics in quadrats and 15 sites had no medics in the near vicinity. The average seed yield for all collection sites was 12.6 kg ha-1. Nearly 60% of the sites yielded less than 20 kg ha-1. More than 50 kg seed ha-1 was recorded at less than 10% sites. Maximum seed yield at any site was only of 169 kg ha-1. Results suggest that genetic erosion is occurring but occasional sites can be found where medics are abundant.

Influence of Platelet Membrane Sialic Acid and Platelet-Associated IgG on Ageing and Sequestration of Blood Platelets in Baboons

1993 ◽  
Vol 70 (04) ◽  
pp. 676-680 ◽  
Author(s):  
H F Kotzé ◽  
V van Wyk ◽  
P N Badenhorst ◽  
A du P Heyns ◽  
J P Roodt ◽  
...  
Keyword(s):  
Sialic Acid ◽  
Life Span ◽  
Blood Platelets ◽  
Senescent Cell ◽  
Platelet Membrane ◽  
Antigen Complex ◽  
The Mean ◽  
Aggregation Of Platelets

SummaryPlatelets were isolated from blood of baboons and treated with neuraminidase to remove platelet membrane sialic acid, a process which artificially ages the platelets. The platelets were then labelled with 111In and their mean life span, in vivo distribution and sites of Sequestration were measured. The effect of removal of sialic acid on the attachment of immunoglobulin to platelets were investigated and related to the Sequestration of the platelets by the spleen, liver, and bone marrow. Removal of sialic acid by neuraminidase did not affect the aggregation of platelets by agonists in vitro, nor their sites of Sequestration. The removal of 0.51 (median, range 0.01 to 2.10) nmol sialic acid/108 platelets shortened their life span by 75 h (median, range 0 to 132) h (n = 19, p <0.001), and there was an exponential correlation between the shortening of the mean platelet life span and the amount of sialic acid removed. The increase in platelet-associated IgG was 0.112 (median, range 0.007 to 0.309) fg/platelet (n = 25, p <0.001) after 0.79 (median, range 0.00 to 6.70) nmol sialic acid/108 platelets was removed (p <0.001). There was an exponential correlation between the shortening of mean platelet life span after the removal of sialic acid and the increase in platelet-associated IgG. The results suggest that platelet membrane sialic acid influences ageing of circulating platelets, and that the loss of sialic acid may have exposed a senescent cell antigen that binds IgG on the platelet membrane. The antibody-antigen complex may then provide a signal to the macrophages that the platelet is old, and can be phagocytosed and destroyed.

Elimination of three doses of gentamicin over three consecutive days using a polyacrylonitrile-derived filter: An in vitro assessment

2021 ◽  
pp. 039139882110322
Author(s):  
Frédéric J Baud ◽  
Vanessa Seif ◽  
Pascal Houzé ◽  
Jean-Herlé Raphalen ◽  
Benoît Pilmis ◽  
...  
Keyword(s):  
Life Span ◽  
Bolus Dose ◽  
Central Compartment ◽  
Daily Session ◽  
Progressive Decrease ◽  
Time Dependency ◽  
Study Results ◽  
In Vitro Assessment ◽  
The Mean

Introduction: Adsorption of gentamicin in a polyacrylonitrile filter was previously evidenced in a session lasting 6 h using the NeckEpur model. We extended the study over three consecutive days to mimic the 72-h life span of a filter. Methods: Prismaflex® monitor and ST150® filter were used in the continuous diafiltration (CDF) mode at a 2.5 L/h flowrate. The daily session started with a 6-h session of CDF. Thereafter, the 5-L central compartment was changed using a bag free of gentamicin to assess gentamicin release over the following 18 h. Experiments were repeated on Day 2 and stopped at the end of the 6-h session of CDF on Day 3. The experiment was performed in duplicate. Results: At a 2.5 L/h diafiltration flowrate, the mean daily clearances of gentamicin were 5.5, 4.0, and 3.3 L/h, respectively. The mean diafiltration and adsorption ratios in the daily elimination of gentamicin were 32/68%, 58/42%, and 88/12%, respectively. During days 1 and 2, the mean amount of gentamicin released from the ST150® filter were 14 and 34 mg, respectively. Conclusion: The pharmacokinetics of gentamicin over 3 days is strongly altered by adsorption in the same filter with a progressive decrease of elimination by adsorption, suggesting saturation of the filter. One limitation of our study results from the mode of administration using a bolus dose instead of an infusion over 30 min. Adsorption adds a clearance to those of diafiltration. The time-dependency of gentamicin clearance precludes using a constant dosage regimen over the filter’s life span.

scholarly journals Physiological and Yield Responses of Green-Shelled Beans (Phaseolus vulgaris L.) Grown under Restricted Irrigation

Agronomy ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 562
Author(s):  
Karen Campos ◽  
Andrés R. Schwember ◽  
Daniel Machado ◽  
Mónica Ozores-Hampton ◽  
Pilar M. Gil
Keyword(s):  
Water Stress ◽  
Deficit Irrigation ◽  
Pot Experiment ◽  
Water Restriction ◽  
One Pot ◽  
Dry Land ◽  
Severe Water Stress ◽  
The Face ◽  
Use Efficiency ◽  
Yield Responses

Common bean is an important crop, consumed as green-shelled bean in several countries. In Chile, green-shelled beans are cultivated often as a dry land crop, vulnerable to drought. The objective of this study was to characterize the hydric and productive responses of four green-shelled bean genotypes subjected to deficit irrigation in order to outline production strategies in the face of increasing water scarcity. Two experiments were evaluated: one pot experiment with three irrigation treatments, supplying 100% of the crop evapotranspiration (ETc) (T100), 50% (T50), and 30% (T30); and an open field experiment with two treatments: 100% (I100) and 40% of ETc (I40). Treatments were applied during reproductive stage in determinate cultivars and vegetative stage in indeterminate plants. Severe water restriction (T30 and I40) in both experiments showed a significant decrease in stomatal conductances, as well as biomass and number of grains per pod; I40 treatment also showed a reduction in chlorophyll fluorescence. Water use efficiency (WUE) was higher under water stress in field (I40), but lower on the T30 treatment from the pot experiment. Determinate cultivars showed 22.7% higher of 100-seed weight compared to indeterminate type, and, thus, higher tolerance to drought. Our results indicate that severe water stress is highly harmful in terms of yield, and a moderate controlled deficit irrigation plus the use of determinate genotypes may be a strategy for producing green-shelled bean successfully under a drought scenario.

Hand Infections: An Audit of 160 Infections Treated in an Accident and Emergency Department

1993 ◽  
Vol 18 (1) ◽  
pp. 115-118 ◽  
Author(s):  
J. STEVENSON ◽  
I. W. R. ANDERSON
Keyword(s):  
Emergency Department ◽  
Complete Resolution ◽  
Wound Care ◽  
Duration Of Treatment ◽  
Mean Delay ◽  
Accident And Emergency ◽  
Accident And Emergency Department ◽  
The Mean ◽  
Careful Assessment

160 consecutive hand infections presented to an Accident and Emergency department over a four-month period. All but one were treated solely on an out-patient basis. The mean delay to presentation was three days, the mean duration of treatment was six days. Follow-up to complete resolution was achieved in 89% of cases. No patients were treated with parenteral antibiotics. The need for careful assessment, early aggressive surgery, and meticulous attention to the principles of wound care by experienced clinicians is emphasized.

scholarly journals Complex Regional Pain Syndrome: Current Practice Management and Referral Trends in a Closed Healthcare System

Osteology ◽  
2020 ◽  
Vol 1 (1) ◽  
pp. 39-47
Author(s):  
Connor Zale ◽  
Joshua Hansen ◽  
Paul Ryan
Keyword(s):  
Pain Management ◽  
Pain Score ◽  
Complex Regional Pain Syndrome ◽  
Healthcare System ◽  
Pain Syndrome ◽  
Occupational Outcomes ◽  
Mean Delay ◽  
Significant Difference ◽  
The Mean ◽  
Over Time

Background: Complex regional pain syndrome (CRPS) is a neurologic condition that can present with severe pain and dysfunction. Delay in treatment adversely affects outcomes. The purpose of this study is to evaluate patient outcomes as they relate to the time from diagnosis to pain management referral once the diagnosis of CRPS has been made in a closed healthcare system. Methods: A retrospective record review from a closed healthcare system was utilized for CRPS cases from 2010–2019. Demographics, injury pattern, surgeries, pain score, treatment modalities, occupational outcomes, and time to pain management referral were recorded. Results: There were 26 cases of CRPS that met inclusion criteria. The mean time from diagnosis to treatment was 55 days. 16/26 (61.5%) were medically discharged from the military. 23/26 (88.5%) were unable to return to full duty due to CRPS. There was no significant difference in the reported pain scores over time regardless of treatment (p = 0.76). A linear regression demonstrated a significantly higher Visual Analog Scale Pain Score (VAS) over time in patients that were medically discharged (p = 0.022). Conclusions: The mean delay in referral to the pain service was 55 days. The majority of patients (88.5%) did not return to full duty secondary to the diagnosis of CRPS, and 61.5% of patients required medical separation from active duty. Due to the negative impact that the diagnosis of CRPS has on occupational outcomes with a mean delay in referral of 55 days, clinics and providers should set up referral criteria and establish early pain pathways for patients diagnosed with CRPS.

scholarly journals Change of Ascorbic Acid Level after Grafting of Tomato Seedlings

1999 ◽  
Vol 54 (9-10) ◽  
pp. 830-833 ◽  
Author(s):  
Akira Wadano ◽  
Mitsuharu Azeta ◽  
Shin-ichi Itotani ◽  
Ai Kanda ◽  
Toshio Iwaki ◽  
...  
Keyword(s):  
Ascorbic Acid ◽  
Water Stress ◽  
Ascorbate Peroxidase ◽  
Phosphate Buffer ◽  
Acid Level ◽  
Active Oxygen ◽  
Ascorbic Acid Level ◽  
Electrochemical Detector ◽  
Tomato Seedlings ◽  
Severe Water Stress

Grafting is an easy way to produce a new seedling, which can tolerate against various stresses. During the acclimation after grafting, however, the seedlings still suffer a severe water stress. It is well known that water stress produces active oxygen to oxidize ascorbic acid. The concentration of ascorbic acid in the leaves was analyzed by HPLC equipped with an electrochemical detector. The column used was SP-120-5-ODS-BP (DAISO, JAPAN) and elution was performed with 0.1 ᴍ phosphate buffer, pH 3.0. After grafting the seedlings were acclimated under a 6-hr light/dark regimen. The content of ascorbic acid increased gradually during 2 days compared with control. The ascorbate peroxidase showed about constant activity, so the increase of ascorbic acid may be due to its requirement to cure the grafting

RESPONSE OF PEAS TO ENVIRONMENT: IV. EFFECT OF FIVE SOIL WATER REGIMES ON GROWTH AND DEVELOPMENT OF PEAS

1968 ◽  
Vol 48 (2) ◽  
pp. 129-137 ◽  
Author(s):  
A. R. Maurer ◽  
H. F. Fletcher ◽  
D. P. Ormrod
Keyword(s):  
Water Stress ◽  
Soil Water ◽  
Growth And Development ◽  
Dry Matter ◽  
Fresh Weight ◽  
Water Regimes ◽  
Severe Water Stress ◽  
Water Conditions ◽  
Before And After ◽  
Soil Water Conditions

Pea plants growing in "weighing lysimeters" were subjected to five soil-water regimes to determine their response to varying conditions of soil water imposed at different stages of development. Plants subjected to a minimal water stress developed luxuriantly and continued to grow up to the harvest period. Pea yield and plant height were not reduced, but fresh weight and dry matter were less if irrigation was applied when soil water fell to 60% rather than 88% of that available. A severe water stress after blossom reduced pea yield, irrespective of soil-water conditions prior to blossom. Plants which had been given ample soil water before blossom wilted visibly when a severe stress was imposed in the post-blossom period, yet wilting did not occur in plants subjected to severe water stress both before and after blossom. Severe water stress prior to blossom did not cause a decrease in pea yield if ample soil moisture was made available after blossom.

Single hyperspectral bands are highly sensitive to water stress in adult mandarin trees

2021 ◽  
Author(s):  
Pablo Berríos ◽  
Abdelmalek Temnani ◽  
Susana Zapata ◽  
Manuel Forcén ◽  
Sandra Martínez-Pedreño ◽  
...  
Keyword(s):  
Water Stress ◽  
Water Deficit ◽  
Phase Ii ◽  
Irrigation Water ◽  
Water Status ◽  
Irrigation Scheduling ◽  
Plant Water Status ◽  
Phase Iii ◽  
Plant Water ◽  
Severe Water Stress

&lt;p&gt;Mandarin is one of the most important Citrus cultivated in Spain and the sustainability of the crop is subject to a constant pressure for water resources among the productive sectors and to a high climatic demand conditions and low rainfall (about 250 mm per year). The availability of irrigation water in the Murcia Region is generally close to 3,500 m&lt;sup&gt;3&lt;/sup&gt; per ha and year, so it is only possible to satisfy 50 - 60% of the late mandarin ETc, which requires about 5,500 m&lt;sup&gt;3&lt;/sup&gt; per ha. For this reason, it is necessary to provide tools to farmers in order to control the water applied in each phenological phase without promoting levels of severe water stress to the crop that negatively affect the sustainability of farms located in semi-arid conditions. Stem water potential (SWP) is a plant water status indicator very sensitive to water deficit, although its measurement is manual, discontinuous and on a small-scale. &amp;#160;In this way, indicators measured on a larger scale are necessary to achieve integrating the water status of the crop throughout the farm. Thus, the aim of this study was to determine the sensitivity to water deficit of different hyperspectral single bands (HSB) and their relationship with the midday SWP in mandarin trees submitted to severe water stress in different phenological phases. Four different irrigation treatments were assessed: i) a control (CTL), irrigated at 100% of the ETc throughout the growing season to satisfy plant water requirements and three water stress treatments that were irrigated at 60% of ETc throughout the season &amp;#8211; corresponding to the real irrigation water availability &amp;#8211; except &amp;#160;during: ii) the end of phase I and beginning of phase II (IS IIa), iii) the first half of phase II (IS IIb) and iv) phase III of fruit growth (IS III), which irrigation was withheld until values of -1.8 MPa of SWP or a water stress integral of 60 MPa day&lt;sup&gt;-1&lt;/sup&gt;. When these threshold values were reached, the spectral reflectance values were measured between 350 and 2500 nm using a leaf level spectroradiometer to 20 mature and sunny leaves on 4 trees per treatment. Twenty-four HVI and HSB were calculated and a linear correlation was made between each of them with SWP, where the &amp;#961;940 and &amp;#961;1250 nm single bands reflectance presented r-Pearson values of -0.78** and -0.83***, respectively. Two linear regression curves fitting were made: SWP (MPa) = -11.05 &amp;#8729; &amp;#961;940 + 7.8014 (R&lt;sup&gt;2&lt;/sup&gt; =0.61) and SWP (MPa) = -13.043 &amp;#8729; &amp;#961;1250 + 8.9757 (R&lt;sup&gt;2&lt;/sup&gt; =0.69). These relationships were obtained with three different fruit diameters (35, 50 and 65 mm) and in a range between -0.7 and -1.6 MPa of SWP. Results obtained show the possibility of using these single bands in the detection of water stress in adult mandarin trees, and thus propose a sustainable and efficient irrigation scheduling by means of unmanned aerial vehicles equipped with sensors to carry out an automated control of the plant water status and with a suitable temporal and spatial scale to apply precision irrigation.&lt;/p&gt;

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