Plant population studies on peanut (Arachis hypogaea L.) in subtropical Australia. 3. Growth and water use during a terminal drought stress

1992 ◽  
Vol 32 (2) ◽  
pp. 197 ◽  
Author(s):  
GC Wright ◽  
MJ Bell
Keyword(s):  
Water Use ◽  
Reproductive Potential ◽  
Plant Population ◽  
High Density ◽  
Low Density ◽  
Crop Water ◽  
Water Deficits ◽  
Pod Yield ◽  
Terminal Drought ◽  
Terminal Drought Stress

Two peanut cultivars of different botanical type (Virginia and Spanish) were grown at 3 plant population densities (40000, 120000 and 240000 plants/ha) and relied solely on stored soil water in a deep kraznozem soil for water requirements. Protracted crop water deficits occurred from flowering to maturity. Plant population influenced both the temporal and spatial patterns of water use, with high density crops extracting water from lower depths sooner than low density crops. Higher water use prior to early podfilling in high density crops was associated with more rapid leaf area development. Reproductive development was strongly influenced by plant population density, with more pods per m2 in low than in high density crops. Lower leaf water potential and individual leaf photosynthetic rates in the middle of the day during the pegging and early podding phase suggested that high crop water deficits had lowered assimilate availability and reduced reproductive potential in high, compared with low, density crops. The results indicate that there is scope for increasing pod yield when peanut is growing solely on stored water, by reducing plant population. The timing of water use, as distinct from the amount of water used, was the major determinant of pod yield.

Plant population studies on peanut (Arachis hypogaea L.) in subtropical Australia. 2. Water-limited conditions

1992 ◽  
Vol 32 (2) ◽  
pp. 189 ◽  
Author(s):  
GC Wright ◽  
MJ Bell
Keyword(s):  
Population Density ◽  
Soil Water ◽  
Water Availability ◽  
Plant Population ◽  
Yield Response ◽  
Crop Water ◽  
Water Deficits ◽  
Pod Yield ◽  
Arachis Hypogaea L ◽  
Plant Population Density

The effects of plant population density on total dry matter (TDM) production, and on pod and kernel yields, of 2 peanut (Arachis hypogaea L.) cultivars (Virginia and Spanish) were investigated under a range of contrasting soil water availability regimes. Protracted crop water deficits were applied to each plant population density treatment in 3 experiments: (i) from planting until the early pod-filling phase (DSWF, dry start, wet finish); (ii) during the pod-filling to maturity phase (WSDF, wet start, dry finish); (iii) from flowering to maturity (TS, terminal stress). Crop water deficits of varying timing and severity were shown to modify substantially the effect of plant population on yield response compared with that observed under well-watered conditions. In most cases, TDM was maximised at the lowest density (40000 Plants/ha). In the WSDF and DSWF experiments, significant cultivar x plant population interactions for pod yield were found. The Spanish cultivar, McCubbin, showed strong pod yield response to S30000 plants/ha, while the Virginia cultivar, Early Bunch, did not respond to increases in plant population above 40000 plants/ha. These differing responses were probably associated with cultivar differences in branching pattern. Under extreme water stress situations where crops were forced to rely solely on soil water reserves (TS), pod yields were highest at the lowest plant population density and declined rapidly as plant population increased. The Gardner and Gardner (1983) model provided a useful framework to characterise the plant population-pod yield response under reduced water availability. The assumptions that both partitioning of dry matter to pods and the hypothetical minimum plant size capable of producing pods were crop constants, irrespective of crop water deficits experienced, were shown to be invalid. These constants may, however, be linearly related to water availability. Relationships relating these parameters to an index of crop or soil water status may improve the predictive capability of the model under water-limited conditions.

Effect of irrigation interval and plant population on growth, yield and water use of soybeans in a semi-arid environment

1978 ◽  
Vol 18 (91) ◽  
pp. 276 ◽  
Author(s):  
JA Thompson
Keyword(s):  
Water Use ◽  
Seed Yield ◽  
Growth Yield ◽  
Arid Environment ◽  
Plant Population ◽  
Plant Performance ◽  
Crop Water ◽  
Plant Populations ◽  
Irrigation Interval ◽  
Reduced Water

The influence of irrigation interval and plant population on seed yield, yield components and water use of soybeans was examined. Plant populations of 12,20 and 28 plants m-2 were furrow irrigated at irrigation intervals of 70 mm and 140 mm of estimated evapotranspiration. Although 12 plants m-2 yielded significantly less than 28 plant m-2, plant population had little influence on plant performance or on water use. Any effect was small when compared with the effect of irrigation interval. Highly significant differences were recorded between the two irrigation intervals. Extending the irrigation interval to 140 mm reduced seed yield by 1286 kg ha-1 or 34 per cent. The drop in yield resulted principally from a substantial decrease in the number of pods per plant. There was little effect on protein and oil content of the seed. Crop water use at the 70 mm interval was 786 mm or 75 per cent of pan evaporation. Although the 140 mm interval reduced water use by 15 per cent, production of seed and protein was less efficient. Peak demand for soil moisture coincided with the end of flowering-early pod fill period.

scholarly journals Exploratory Factorial for Nutrient and Water Use in Liquid Culture Micropropagation of Diploid and Tetraploid Daylily (Hemerocallis sp.)

HortScience ◽  
2005 ◽  
Vol 40 (4) ◽  
pp. 1107A-1107
Author(s):  
Jeffrey Adelberg ◽  
Maria Delgado ◽  
Jeffery Tomkins
Keyword(s):  
Water Use ◽  
Plant Density ◽  
Media Use ◽  
Dry Weight ◽  
Optimal Growth ◽  
Plant Size ◽  
High Density ◽  
Low Density ◽  
High Density Culture ◽  
Sugar Levels

Two tetraploid and two diploid varieties of daylily were micropropagated on a shaker in MS liquid medium containing high and low sugar levels (3% and 6% sucrose), 2 BA levels (0.32 and 3.2 μm), at two densities (57 and 171 explants/L), in the presence (0.32 μm) and absence of ancymidol. Biomass and media use were partitioned for the four genotypes and 32 cultural conditions with three replications (4 × 2 × 2 × 2 × 2 × 3). Genotype greatly effected f resh weight, dry weight, media, sugar and water use, but ploidy had little effect. Vessels at high density (171 explants/L) produced 1.8× more fresh weight, 1.4× more dry weight, used 1.6× more media and sugar than low density (57 explants/L). Plants from low density were 1.7× larger, 2× greater dry weight, and used 2× more sugar and media, than from high-density culture (per explant). Doubling the initial sugar level increased dry weight and sugar use 1.3×. There was a linear relation between sugar residual and percentage of dry weight (R2 = 0.55, P < 0.0001), where a 1% increase in °Brix raised percentage of dry weight 1.8 units over the range of 9% to 22%. Ancymidol and BA had less effect on plant size, sugar and media use than genotype or plant density. Greenhouse survival was reduced by including ancymidol (90% to 30%) and increased BA concentration (85% to 35%). Lab plant density and initial sugar concentration had no apparent effect on greenhouse growth. `Barbara Mitchell' had greatest mass, used more sugar and media than the other varieties, yet had least greenhouse growth. Nutrient use with `Barbara Mitchell' was linearly correlated (R2>80%) to lab growth for seven of 12 ions. P and Fe supply was inadequate to support optimal growth, as indicated by low residual in media (>1% of MS formulation).

Quantitative defect studies in semiconductor TEM samples prepared by low angle ion milling

1995 ◽  
Vol 53 ◽  
pp. 512-513
Author(s):  
L. Mulestagno ◽  
J.C. Holzer ◽  
P. Fraundorf
Keyword(s):  
Sample Preparation ◽  
Milling Time ◽  
High Density ◽  
Low Density ◽  
Ion Milling ◽  
High Quality ◽  
Variable Angle ◽  
Major Disadvantage ◽  
Induced Defects

Due to the wealth of information, both analytical and structural that can be obtained from it TEM always has been a favorite tool for the analysis of process-induced defects in semiconductor wafers. The only major disadvantage has always been, that the volume under study in the TEM is relatively small, making it difficult to locate low density defects, and sample preparation is a somewhat lengthy procedure. This problem has been somewhat alleviated by the availability of efficient low angle milling.Using a PIPS® variable angle ion -mill, manufactured by Gatan, we have been consistently obtaining planar specimens with a high quality thin area in excess of 5 × 104 μm2 in about half an hour (milling time), which has made it possible to locate defects at lower densities, or, for defects of relatively high density, obtain information which is statistically more significant (table 1).

Scanning Electron Microscopic and Electrophoretic Observations on Barium Sulphate Used to Adsorb Clotting Factors

1975 ◽  
Vol 33 (02) ◽  
pp. 256-270
Author(s):  
R. M Howell ◽  
S. L. M Deacon
Keyword(s):  
Electron Microscopy ◽  
Factor Xa ◽  
Barium Sulphate ◽  
High Density ◽  
Low Density ◽  
Factor X ◽  
Clotting Factors ◽  
Electron Microscopic ◽  
Complementary Techniques ◽  
Scanning Electron

SummaryElectron microscopy and particle electrophoresis were found to be complementary techniques with which to complete the physical data from an earlier study on barium sulphates used to adsorb clotting factors from serum. The differences revealed by scanning electron microscopy (S. E. M.) in the physical shape of low and high density grades of barium sulphate particles appear to be of greater significance than charge as expressed by electrophoretic mobility, in determining whether or not precursor or preformed factor Xa is eluted.This conclusion was based on the finding that at pH values close to 7, where the adsorption from serum occurs, all samples with the exception of natural barytes were uncharged. However as the high-density, or soil-grade, was found by S. E. M. to consist of large solid crystals it was suggested that this shape might induce activation of factor X as a result of partial denaturation and consequent unfolding of the adsorbed protein. In contrast, uptake of protein into the centre of the porous aggregates revealed by S. E. M. pictures of low-density or X-ray grade barium sulphate may afford protection against denaturation and exposure of the enzyme site.The porous nature of particles of low-density barium sulphate compared with the solid crystalline forms of other grades accounts not only for its lower bulk density but also for its greater surface/gram ratio which is reflected by an ability to adsorb more protein from serum.Neither technique produced evidence from any of the samples to indicate the presence of stabilising agents sometimes used to coat particles in barium meals.

Physiological Response of Meadowfoam to Crop Water Deficits 1

1985 ◽  
Vol 77 (3) ◽  
pp. 422-426 ◽  
Author(s):  
C. H. Pearson ◽  
G. D. Jolliff
Keyword(s):  
Physiological Response ◽  
Crop Water ◽  
Water Deficits

scholarly journals Low-Temperature Mechanical Properties of High-Density and Low-Density Polyethylene and Their Blends

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1821
Author(s):  
Ildar I. Salakhov ◽  
Nadim M. Shaidullin ◽  
Anatoly E. Chalykh ◽  
Mikhail A. Matsko ◽  
Alexey V. Shapagin ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Low Temperature ◽  
Impact Strength ◽  
Relative Elongation ◽  
High Density ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Elongation At Break ◽  
Subzero Temperatures ◽  
Izod Impact

Low-temperature properties of high-density polyethylene (HDPE), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and their blends were studied. The analyzed low-temperature mechanical properties involve the deformation resistance and impact strength characteristics. HDPE is a bimodal ethylene/1-hexene copolymer; LDPE is a branched ethylene homopolymer containing short-chain branches of different length; LLDPE is a binary ethylene/1-butene copolymer and an ethylene/1-butene/1-hexene terpolymer. The samples of copolymers and their blends were studied by gel permeation chromatography (GPC), differential scanning calorimetry (DSC), 13С NMR spectroscopy, and dynamic mechanical analysis (DMA) using testing machines equipped with a cryochamber. It is proposed that such parameters as “relative elongation at break at −45 °C” and “Izod impact strength at −40 °C” are used instead of the ductile-to-brittle transition temperature to assess frost resistance properties because these parameters are more sensitive to deformation and impact at subzero temperatures for HDPE. LLDPE is shown to exhibit higher relative elongation at break at −45 °C and Izod impact strength at −20 ÷ 60 °C compared to those of LDPE. LLDPE terpolymer added to HDPE (at a content ≥ 25 wt.%) simultaneously increases flow properties and improves tensile properties of the blend at −45 °C. Changes in low-temperature properties as a function of molecular weight, MWD, crystallinity, and branch content were determined for HDPE, LLDPE, and their blends. The DMA data prove the resulting dependences. The reported findings allow one to understand and predict mechanical properties in the HDPE–LLDPE systems at subzero temperatures.

Sign in / Sign up

Export Citation Format

Share Document