Architecture et stratégies adaptatives des rejets de recépage du Buddleia variabilis

1989 ◽  
Vol 67 (9) ◽  
pp. 2646-2654
Author(s):  
R. Phelouzat ◽  
P. Levacher ◽  
Y. Chabot-Jacquety
Keyword(s):  
Seed Production ◽  
Leaf Production ◽  
Pronounced Increase ◽  
Strong Energy ◽  
Median Zone

Cutting down close the stalks of Buddleia in February has resulted in an immediate development of populations of offshoots. Most of them would flower before the year was out. All of them, even those that remained vegetative, branched out and the branching showed mesotonous dominance. This was expressed, in the median zone, as a more pronounced increase in length of only one of the two branches at each node (stronger branch) rather than as an increase in leaf production. Reproductive branches are strong energy consumers; actually, they combine r strategy (seed production) with K strategy (pronounced cauline growth for space occupancy). Vegetative branches, weak energy consumers on which, however, leaves are particularly abundant, might serve as suppliers of metabolites. A nutritional equilibrium is perhaps achieved in a similar manner at the level of the stumps by the division of physiological roles between vegetative and reproductive offshoots. [Journal translation]

Responses of nitre goosefoot (Chenopodium nitrariaceum) to simulated rainfall and depth and duration of experimental flooding

2019 ◽  
Vol 70 (4) ◽  
pp. 493
Author(s):  
William Higgisson ◽  
Sue Briggs ◽  
Fiona Dyer
Keyword(s):  
Seed Production ◽  
New South ◽  
New South Wales ◽  
Simulated Rainfall ◽  
Leaf Production ◽  
South Wales ◽  
Murray Darling Basin ◽  
Flooded Areas ◽  
Water Depths

Nitre goosefoot (Chenopodium nitrariaceum (F.Muell.) is a woody shrub that occurs at the edges of floodplains and other intermittently flooded areas across the Murray–Darling Basin. No studies have been conducted on the hydrological requirements of nitre goosefoot, and the species is not considered in watering requirements of floodplain species of the Murray–Darling Basin. This study investigated the effects of simulated rainfall and depth and duration of experimental flooding on mortality, leaf production, biomass and seed production of nitre goosefoot. Nitre goosefoot plants were grown from seeds collected near Hillston, New South Wales, Australia. The plants were subjected to the following 14 hydrological treatments: dry (no water applied), rainfall (simulating rainfall conditions at Hillston) and 12 combinations of three water depths (10cm, 50cm, 75cm) with four durations of inundation (5 days, 10 days, 20 days, 40 days). The study found that nitre goosefoot plants survived flooding, providing plants were not totally submerged, leaf production increased during flooding and after drawdown, and leaf production, biomass and seeding were highest under shallow flooding for approximately 1 month. The results of the study allow the hydrological requirements of nitre goosefoot to be considered in environmental watering programs.

scholarly journals Climatic sensitivity of species’ vegetative and reproductive phenology in a Hawaiian montane wet forest

2019 ◽  
Author(s):  
Stephanie Pau ◽  
Susan Cordell ◽  
Rebecca Ostertag ◽  
Lawren Sack ◽  
Faith Inman-Narahari
Keyword(s):  
Climate Change ◽  
Seed Production ◽  
Climatic Factors ◽  
Leaf Phenology ◽  
Effect Of Temperature ◽  
Future Climate Change ◽  
Reproductive Phenology ◽  
Metrosideros Polymorpha ◽  
Leaf Production ◽  
The Impact

ABSTRACTUnderstanding the way tropical tree phenology (i.e., the timing and amount of seed and leaf production) responds to climate is vital for predicting how climate change may alter ecological functioning of tropical forests. We examined the effects of temperature, rainfall, and photosynthetically active radiation (PAR) on seed and leaf phenology in a montane wet forest on Hawaiʻi using monthly data collected over ∼6 years. We expected that species’ phenologies were more sensitive to temperature and PAR than to rainfall at this wet tropical site because rainfall is not limiting. Seed production declined with increasing temperatures for two foundational species in Hawaiian forests (Acacia koa and Metrosideros polymorpha). Seed production also declined with rainfall for two species, and greater PAR for one species. One species showed relatively flat responses to climate. Community-level leaf phenology was not strongly seasonal. Unlike seed phenology, we found no effect of temperature on leaf phenology. However, leaf fall increased with rainfall. Climatic factors explained a low to moderate proportion of variance for both seed and leaf litterfall, thus the impact of future climate change on this forest will depend on how climate change interacts with other factors such as daylength, biotic, and/or evolutionary constraints. Our results nonetheless provide insight into how climate change may differentially affect different species with potential consequences for shifts in species distributions and community composition.

Defoliation regrowth and dry matter partitioning in the two arid zone grasses, Aristida armata and Thyridolepis mitchelliana

1987 ◽  
Vol 38 (5) ◽  
pp. 881 ◽  
Author(s):  
RF Brown
Keyword(s):  
Seed Production ◽  
Dry Matter ◽  
Arid Zone ◽  
Plant Production ◽  
Pasture Management ◽  
Leaf Production ◽  
Dry Matter Partitioning ◽  
Intact Plants ◽  
Domestic Livestock ◽  
Total Plant

Plants of the desirable rangeland grass, Thyridolepis mitchelliana, and its undesirable companion, Aristida armata, were defoliated at various ages, and their subsequent regrowth and seed production compared with that of intact plants. Young plants of T. mitchelliana, but not A. armata, often failed to survive severe defoliation. Seed production by A. armata greatly exceeded that of T. mitchelliana and was much less affected by defoliation. In both defoliated and intact plants, the proportion of dry matter in inflorescences was several times greater for A. armata than T. mitchelliana, but the reverse occurred with leaf production. Root growth was little affected by defoliation, and there was no evidence of export of root material to support tops regrowth. Total plant production of both species was unaffected by the loss of half the tops, but was depressed by more severe defoliation. The differences between the two species in their reaction to defoliation seem sufficient to explain the displacement of T. mitchelliana by A. armata which followed the introduction of domestic livestock. Under grazing, A. armata is likely to have a reproductive advantage, and the implications of this for pasture management are examined.

Type II Solar Radio Bursts over Solar Cycle 21

1994 ◽  
Vol 144 ◽  
pp. 283-284
Author(s):  
G. Maris ◽  
E. Tifrea
Keyword(s):  
Solar Radio ◽  
Interplanetary Space ◽  
Impulsive Phase ◽  
Radio Bursts ◽  
Type Ii ◽  
Solar Radio Bursts ◽  
Strong Energy ◽  
Mass Ejection ◽  
Geophysical Effect ◽  
Radio Event

The type II solar radio bursts produced by a shock wave passing through the solar corona are one of the most frequently studied solar activity phenomena. The scientific interest in this type of phenomenon is due to the fact that the presence of this radio event in a solar flare is an almost certain indicator of a future geophysical effect. The origin of the shock waves which produce these bursts is not at all simple; besides the shocks which are generated as a result of a strong energy release during the impulsive phase of a flare, there are also the shocks generated by a coronal mass ejection or the shocks which appear in the interplanetary space due to the supplementary acceleration of the solar particles.

A Comparison of the Ultrastructural Morphology of Hepatic Necrosis in BDF1 Mice

1981 ◽  
Vol 39 ◽  
pp. 586-587
Author(s):  
Becky Jackson
Keyword(s):  
Endoplasmic Reticulum ◽  
Smooth Endoplasmic Reticulum ◽  
Preliminary Investigation ◽  
Hepatic Necrosis ◽  
Hepatic Tissue ◽  
Pronounced Increase ◽  
Glycogen Store ◽  
Ultrastructural Morphology ◽  
Mitochondrial Integrity ◽  
Glycogen Stores

Preliminary investigation has indicated similarity in hepatic ultrastructural morphology in nutritional deprivation, and cyanide induced hepatic necrosis. Analysis of hepatic tissue has indicated disruption of intracellular membranes, specifically, reduction in rough endoplasmic reticulum (RER) mitochondrial integrity, and glycogen stores. An increase in smooth endoplasmic reticulum (SER) portion was observed.To further investigate the apparent equivalence of necrotic morphology, ultrastructura1ly, BDF1 mice were subjected to senescence, nutritional deprevation, potassium cyanide (KCN) induced toxemia, and acetaminophen induced toxemia. Controls were utilized to ellucidate non-necrotic hepatocellular normals. U1trastructura1 investigation of controls (Fig. 1) shows densely granular RER, abundant glycogen stores, and morphologically normal mitochondria. Subjects with acetaminophen induced necrosis exhibit reduced normal RER with increased levels of dialated, vesicular RER in apparent conversion to SER (Fig. 2), loss of mitochondrial integrity, and glycogen store reduction. Senescent subjects exhibit a pronounced increase in SER and loss of glycogen store. (Fig. 3). Investigation of the senescent SER at high magnification (Fig. 5) indicates that the SER is arising from degranulating and vesiculating RER.

HES 200/0.5 Is not HES 200/0.5

1995 ◽  
Vol 74 (06) ◽  
pp. 1452-1456 ◽  
Author(s):  
Johannes Treib ◽  
Anton Haass ◽  
Gerhard Pindur ◽  
Ulrich T Seyfert ◽  
Wolfgang Treib ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Hydroxyethyl Starch ◽  
Clinical Relevance ◽  
Dilution Effect ◽  
Repeated Administration ◽  
Plasma Viscosity ◽  
Degree Of Substitution ◽  
Pronounced Increase ◽  
Large Molecules ◽  
Mean Molecular Weight

SummaryThe plasma clearance of hydroxyethyl starch (HES) depends on the initial molecular weight and the degree of substitution. So far, little attention has been paid to the clinical relevance of the C2/C6 substitution ratio of hydroxyethyl starch.10 patients with cerebrovascular circulatory disturbance received hemodilution therapy for 10 days, consisting of 10% HES 200/0.5 (mean molecular weight 200 kD, degree of substitution 0.5) with a C2/C6 ratio of 13.4. A second group of 10 patients received a starch solution with identical initial molecular weight and degree of substitution but with a C2/C6 ratio of 5.7.After the administration of a single dose, no significant differences between the two groups were observed. After repeated administration, significant differences could be detected in hemorheology, coagulation and elimination (p<0.01). The larger C2/C6 ratio led to a higher intravascular mean molecular weight (95 vs. 84 kD), which in turn led to a higher increase in serum concentration during the therapy (14.7 vs.8.6 mg/ml). Hematocrit was lowered more (-30,5 vs. -23,5%) and plasma viscosity was increased more. There was also a more pronounced increase in partial thromboplastin time (+30% vs. +13%) and a factor of 2 larger decrease of factor VIII/von Willebrand factor-complex (p <0.01), which exceeded the dilution effect.The higher C2/C6 ratio of HES 200/0.5/13.4 slows down enzymatic degradation. After repeated administration of this starch, large molecules accumulate which are inefficiently degraded. The same effect has been observed after therapy with highly-substituted HES. This accumulation of large molecules leads to a beneficial longer lasting volume effect. The disadvantages include an increase in plasma viscosity and coagulation disturbances, which cannot be explained with the respective dilution effect alone. For these reasons, the C2/C6 ratio is of clinical relevance and should be included in the product labeling in the future.

Two-Stage Procedure for the Quantitative Determination of Autoprothrombin III Concentration and Some Applications

1967 ◽  
Vol 18 (01/02) ◽  
pp. 198-210 ◽  
Author(s):  
Ronald S Reno ◽  
Walter H Seegers
Keyword(s):  
Prothrombin Time ◽  
Factor Vii ◽  
Two Stage ◽  
Pronounced Increase ◽  
One Stage ◽  
Assay Procedure ◽  
Bovine Plasma ◽  
The One ◽  
Autoprothrombin C

SummaryA two-stage assay procedure was developed for the determination of the autoprothrombin C titre which can be developed from prothrombin or autoprothrombin III containing solutions. The proenzyme is activated by Russell’s viper venom and the autoprothrombin C activity that appears is measured by its ability to shorten the partial thromboplastin time of bovine plasma.Using the assay, the autoprothrombin C titre was determined in the plasma of several species, as well as the percentage of it remaining in the serum from blood clotted in glass test tubes. Much autoprothrombin III remains in human serum. With sufficient thromboplastin it was completely utilized. Plasma from selected patients with coagulation disorders was assayed and only Stuart plasma was abnormal. In so-called factor VII, IX, and P.T.A. deficiency the autoprothrombin C titre and thrombin titre that could be developed was normal. In one case (prethrombin irregularity) practically no thrombin titre developed but the amount of autoprothrombin C which generated was in the normal range.Dogs were treated with Dicumarol and the autoprothrombin C titre that could be developed from their plasmas decreased until only traces could be detected. This coincided with a lowering of the thrombin titre that could be developed and a prolongation of the one-stage prothrombin time. While the Dicumarol was acting, the dogs were given an infusion of purified bovine prothrombin and the levels of autoprothrombin C, thrombin and one-stage prothrombin time were followed for several hours. The tests became normal immediately after the infusion and then went back to preinfusion levels over a period of 24 hrs.In other dogs the effect of Dicumarol was reversed by giving vitamin K1 intravenously. The effect of the vitamin was noticed as early as 20 min after administration.In response to vitamin K the most pronounced increase was with that portion of the prothrombin molecule which yields thrombin. The proportion of that protein with respect to the precursor of autoprothrombin C increased during the first hour and then started to go down and after 3 hrs was equal to the proportion normally found in plasma.

Native Seed Production Manual for the Pacific Northwest

2016 ◽  
Vol 17 (2) ◽  
pp. 134-135
Author(s):  
Amy Bartow ◽  
Keyword(s):  
Pacific Northwest ◽  
Seed Production ◽  
Native Seed ◽  
The Pacific

Some insects affecting Penstemon seed production

2012 ◽  
Vol 13 (2) ◽  
pp. 107-111
Author(s):  
R. Hammon ◽  
M. Franklin
Keyword(s):  
Seed Production

PRIMING AS THE FACTOR OF INCREASE OF EFFICIENCY SEED PRODUCTION OF BIRDSFOOT TREFOIL

2020 ◽  
Author(s):  
Vladimir Zolotarev
Keyword(s):  
Seed Production ◽  
Characteristic Property ◽  
Seed Priming ◽  
Lotus Corniculatus ◽  
Birdsfoot Trefoil ◽  
Germination Energy ◽  
Field Germination

A characteristic property of legumes is the formation of hard-stone seeds. To use such seeds for sowing, it is necessary to carry out measures to increase their seeding indicators. The article provides an overview of methods of pre-sowing preparation of seeds, priming (Seed Priming). The harvest of Birdsfoot trefoil (Lotus corniculatus L.) can contain up to 90% or more hard-stone seeds. Mechanical priming of hard-stone seeds of Birdsfoot trefoil increases their germination energy and field germination.

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