Leaf Movements in Sicklepod (Cassia obtusifolia) in Relation to Herbicide Response

Weed Science ◽  
1980 ◽  
Vol 28 (5) ◽  
pp. 551-556 ◽  
Author(s):  
Gary W. Kraatz ◽  
Robert N. Andersen
Keyword(s):  
Leaf Area ◽  
Cloud Cover ◽  
Leaf Surface ◽  
Early Morning ◽  
Rhythmic Movements ◽  
Cassia Obtusifolia ◽  
Leaf Movements ◽  
Late Evening ◽  
Highly Correlated ◽  
Over The Top

Sicklepod (Cassia obtusifoliaL.) leaves and leaflets changed their orientation throughout 24-h periods. These endogenously controlled rhythmic movements resulted in dramatic changes in the percent projected leaf area (PPLA), the leaf area observed from directly above and expressed as a percentage of the total actual leaf area. The PPLA of sicklepod varied more than seven-fold throughout a 24-h period, being greatest during the day and least at night. Control of sicklepod with linuron [3-(3,4-dichlorophenyl)-1-methoxy-1-methylurea] applied postemergence at intervals throughout 24-h periods was greater from daytime applications than from late evening, night, and early morning applications. Percent control was highly correlated with PPLA, suggesting that rhythmic leaf movements and the resulting change in PPLA could be an important factor in determining the efficacy of postemergence herbicide applications on sicklepod by altering the area of the leaf surface most likely to intercept and retain herbicide spray from an over-the-top application. In addition to endogenously controlled leaf movements, we observed leaf movements caused by simulated cloud cover (80% shading). Shading increased the PPLA of sicklepod, suggesting that more leaf surface might be exposed to an over-the-top spray during cloudy periods than during sunny periods.

The Relation Between Leaf Production and Wood Weight in First-Year Root Sprouts of Two Populus Clones

1972 ◽  
Vol 2 (2) ◽  
pp. 98-104 ◽  
Author(s):  
Philip R. Larson ◽  
J. G. Isebrands
Keyword(s):  
Leaf Area ◽  
Leaf Surface ◽  
Dry Weight ◽  
First Year ◽  
Leaf Production ◽  
Leaf Surface Area ◽  
Highly Correlated ◽  
The Relationship ◽  
Non Destructive ◽  
Leaf Dry Weight

The relationship between leaf production and wood production in two clones of Populus grown for 1 year under intensive culture was investigated. Wood weight at any one stem position was highly correlated with the cumulative leaf area above that position. About one-half the total stem weight was bark, but the bark/wood ratio decreased with increasing leaf area. Wood specific gravity in creased from stem top to stem base, with mid-stem values of about 0.35. Leaf surface area and leaf dry weight were highly correlated with leaf lamina length; the latter therefore provides an easily measured, non-destructive estimate of photosynthesizing leaf surface. Marked clonal differences existed in all parameters measured.

scholarly journals Protein Supplementation and Grazing Behavior for Cows on Differing Late-Season Rangeland Grazing Systems

Animals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 3219
Author(s):  
James E. Sprinkle ◽  
Joseph K. Sagers ◽  
John B. Hall ◽  
Melinda J. Ellison ◽  
Joel V. Yelich ◽  
...  
Keyword(s):  
Early Morning ◽  
Protein Supplementation ◽  
Grazing Behavior ◽  
Late Season ◽  
Bite Rate ◽  
Measured Time ◽  
Late Evening ◽  
Grazing Systems ◽  
Time Periods ◽  
Walking Time

The objective was to determine if low- or high-residual feed intake (LRFI or HRFI, n = 24 for each) Hereford × Angus cows on continuously or rotationally grazed rangeland altered their grazing behavior when provided a protein supplement in late autumn. Treatments included continuously grazed, control (CCON, n = 12); continuously grazed, supplemented (CTRT, n = 12); rotationally grazed, control (RCON, n = 12); and rotationally grazed, supplemented pastures (RTRT, n = 12). Cows in each treatment had grazing time (GT), resting time (RT), and walking time (WLK) measured for 2 years with accelerometers. Bite rate (BR) was also measured. Time distributions of GT and RT differed by year (p < 0.05), being influenced by colder temperatures in 2016. Cattle in 2016 spent more time grazing during early morning and late evening (p < 0.05) and rested more during the day (p < 0.05). In 2017, cattle in the CCON treatment walked more (p < 0.05) during early morning time periods than did the CTRT cattle, indicative of search grazing. All supplemented cattle had greater BR (p < 0.05) than control cattle in 2017. Cattle with increased nutritional demands alter grazing behavior in a compensatory fashion when grazing late-season rangelands.

scholarly journals Modelos alométricos na determinação da área foliar de Bauhinia monandra Kurz

2016 ◽  
Vol 7 (3) ◽  
pp. 415
Author(s):  
Edilson Romais Schmildt ◽  
Omar Schmildt ◽  
Rodrigo Sobreira Alexandre ◽  
Adriano Alves Fernandes ◽  
Marcio Paulo Czepak
Keyword(s):  
Mathematical Models ◽  
Leaf Area ◽  
Linear Model ◽  
Potential Model ◽  
Leaf Surface ◽  
Linear Quadratic ◽  
Potential Models ◽  
Independent Variables ◽  
Model Based ◽  
Area Determination

The aim of this study was to evaluate the efficiency of the adjustment of mathematical models for determining Bauhinia monandra leaf area using the length and/or width of the leaves as independent variables. Leaves from plants with three years were used to the estimative of equations in linear, quadratic and potential models. The validation from the estimated leaf area as a function of the observed leaf area showed that the linear model based on the product of length and width of the largest leaf surface is the model that best fits. However, the leaf area determination can be represented by using only the length or width of the leaves with little loss of accuracy. A representation that better estimates Bauhinia monandra leaf area with easy application is the potential model in which xi represents the length of one of the symmetrical leaf lobes.

scholarly journals Life near a city: activity pattern of Golden Jackal Canis aureus Linnaeus, 1758 (Mammalia: Carnivora: Canidae) in a habitat adjoining Bhubaneswar, India

2021 ◽  
Vol 13 (9) ◽  
pp. 19363-19366
Author(s):  
Subrat Debata
Keyword(s):  
Activity Pattern ◽  
Prey Species ◽  
Early Morning ◽  
Golden Jackal ◽  
Eastern India ◽  
Present Study Area ◽  
Late Evening ◽  
Reduced Activity ◽  
Second Peak ◽  
Intense Heat

Activity pattern of the Golden Jackal was studied by camera trapping survey in an urban influenced protected habitat in Odisha, eastern India from January to April 2019. A total of 552 independent photos of Golden Jackals were obtained from 771 trap nights. Although Golden Jackals were active throughout the day, they showed two major peaks in activity; the first peak during late evening after sunset, and the second peak during early morning until sunrise. The reduced activity of Golden Jackal during day time in the present study area might be due to less movement of prey species, intense heat, and heavy human traffic.

A simple and low-cost method for leaf area measurement of detached leaves

1997 ◽  
Vol 33 (01) ◽  
pp. 65-72 ◽  
Author(s):  
J. T. Korva ◽  
G. A. Forbes
Keyword(s):  
Solanum Tuberosum ◽  
Leaf Area ◽  
Low Cost ◽  
Electronic Equipment ◽  
New Method ◽  
Area Measurement ◽  
Water Spray ◽  
Spray Method ◽  
Detached Leaves ◽  
Highly Correlated

A technique for leaf area measurement utilizing water spray as an inexpensive substitute for electronic equipment was developed and tested with leaves of potato (Solanum tuberosum L.). The leaf areas measured by the spray method were highly correlated with those measured by an electronic area meter. Measurements of leaf area obtained by the spray method were significantly more highly correlated with those obtained by the area meter than were the measurements of dry weights. The main advantages of the new method are precision, accuracy and immediate results at a low cost.

Diurnal gross photosynthetic patterns and potential seasonal CO2 assimilation in Cladonia stellaris and Cladonia rangiferina

1983 ◽  
Vol 61 (3) ◽  
pp. 642-655 ◽  
Author(s):  
Thomas J. Moser ◽  
Thomas H. Nash III ◽  
Steven O. Link
Keyword(s):  
Photosynthetic Activity ◽  
Growing Season ◽  
Early Morning ◽  
Co2 Assimilation ◽  
Atmospheric Moisture ◽  
Growing Seasons ◽  
Late Evening ◽  
Summer Rain ◽  
Cladonia Rangiferina

The daily, in situ gross photosynthetic patterns of Cladonia stellaris (Opiz.) Pouz. & Vězda. and Cladonia rangiferina (L.) Wigg. were monitored during portions of the 1977, 1978, and 1979 growing seasons at Anaktuvuk Pass, Alaska. Photosynthetic activity in both species closely paralleled atmospheric moisture status, where peak photosynthetic rates were attained during or following sporadic summer rain. In addition, thallus absorption of moisture during extended periods of high atmospheric water vapor content gave rise to short periods of minimal photosynthetic activity. During late evening and early morning hours moistened thalli exhibited minimal or no photosynthetic activity, coinciding with consistent attenuation in solar radiation during these periods. Photosynthetic activity was not homogeneous throughout the thallus. The greatest activity occurred in the apical regions and decreased progressively into the basal regions. The apical 10-mm regions of C. stellaris and C. rangiferina thalli accounted for approximately 50% of their photosynthetic capabilities. The potential gross CO2 assimilation of the apical 10-mm regions over 72 days of the 1978 growing season was estimated at approximately 35 g CO2∙m−2 and 16 g CO2∙m−2 for C. stellaris and C. rangiferina, respectively.

Rhythmic Leaf Movements of Some Common Weeds

Weed Science ◽  
1979 ◽  
Vol 27 (4) ◽  
pp. 401-415 ◽  
Author(s):  
Robert N. Andersen ◽  
Willard L. Koukkari
Keyword(s):  
Chenopodium Album ◽  
Continuous Light ◽  
Datura Stramonium ◽  
Amaranthus Retroflexus ◽  
Rhythmic Pattern ◽  
Weed Species ◽  
Rhythmic Movements ◽  
Wild Mustard ◽  
Dark Regime ◽  
Leaf Movements

In growth chamber studies, we measured the movement of cotyledons and leaves or leaflets in seedlings of nine weed species to determine: the magnitude of movement, whether movements followed a rhythmic pattern, and if rhythmic movements were endogenously controlled. Seedlings were always entrained under a 15-h light:9-h dark regime. Measurements were made at 3-h intervals for 3 to 4 days under four light regimes: alternating 15-h light:9-h dark; continuous light; one 15-h light:9-h dark span, followed by continuous light; and a 15-h light:9-h dark regime, in which the dark span was advanced 9 h (phase shift) when measurements were begun. No clearly defined pattern of leaf movement was found in wild mustard [Brassica kaber(DC.) L. C. Wheeler var.pinnatifida(Stokes) L. C. Wheeler]. Daily rhythmic leaf movements that did not appear to be endogenously controlled were found in redroot pigweed (Amaranthus retroflexusL.) and black nightshade (Solanum nigrumL.). Circadian rhythmic leaf movements that appeared to be under endogenous control were found in jimson-weed (Datura stramoniumL.), common lambsquarters (Chenopodium albumL.), common cocklebur (Xanthium pensylvanicumWallr.), prickly sida (Sida spinosaL.), sicklepod (Cassia obtusifoliaL.), and coffee senna (Cassia occidentalisL.).

Effect of FWD Testing Position on Modulus of Subgrade Reaction

2014 ◽  
Vol 518 ◽  
pp. 53-59 ◽  
Author(s):  
S.N. Shoukry ◽  
G.W. William ◽  
M.Y. Riad ◽  
J.C. Prucz
Keyword(s):  
Temperature Gradient ◽  
Early Morning ◽  
Slab Thickness ◽  
Positive Temperature ◽  
Falling Weight Deflectometer ◽  
Subgrade Reaction ◽  
K Value ◽  
Modulus Of Subgrade Reaction ◽  
Late Evening ◽  
Falling Weight

This paper discusses the variation of the Modulus of subgrade reaction (k) backcalculated from slab deflection basins, interactive with the location of the Falling Weight Deflectometer (FWD) load pulse, and curling of slabs due to daily temperature variations. The k-value was calculated following the AASHTO design guides procedures, while deflection basins were recorded at an interval of 3 to 4 hours along the day on an instrumented concrete pavement test section in West Virginia. The state of deformation of the slabs are continuously monitored, through dowel bar bending measurements and records of the temperature gradient profiles through the slab thickness, as well as joint openings every 20 minutes. The results indicated that the backcalculated k-values are greatly affected by the positive temperature gradient, and the least variation in (k) was found in the slab center. In order to minimize errors in back-calculations of k-values, it is recommended to perform the FWD test for recording deflection basins in the interior of the slab during late evening or in the early morning.

scholarly journals Using the conservative nature of fresh leaf surface density to measure foliar area

2014 ◽  
Vol 28 (4) ◽  
pp. 413-421
Author(s):  
Omar S. Castillo ◽  
Esther M. Zaragoza ◽  
Carlos J. Alvarado ◽  
Maria G. Barrera ◽  
Nabanita Dasgupta-Schubert
Keyword(s):  
Image Analysis ◽  
Leaf Area ◽  
Digital Image ◽  
Surface Density ◽  
Digital Image Analysis ◽  
Leaf Surface ◽  
Area Measurement ◽  
Fresh Leaf ◽  
The Masses

Abstract For a herbaceous species, the inverse of the fresh leaf surface density, the Hughes constant, is nearly conserved. We apply the Hughes constant to develop an absolute method of leafarea measurement that requires no regression fits, prior calibrations or oven-drying. The Hughes constant was determined in situ using a known geometry and weights of a sub-set obtained from the fresh leaves whose areas are desired. Subsequently, the leaf-areas (at any desired stratification level), were derived by utilizing the Hughes constant and the masses of the fresh leaves. The proof of concept was established for leaf-discs of the plants Mandevilla splendens and Spathiphyllum wallisii. The conservativeness of the Hughes constant over individual leaf-zones and different leaftypes from the leaves of each species was quantitatively validated. Using the globally averaged Hughes constant for each species, the leaf-area of these and additional co-species plants, were obtained. The leaf-area-measurement-by-mass was cross-checked with standard digital image analysis. There were no statistically significant differences between the leaf-area-measurement-by-mass and the digital image analysis measured leaf-areas and the linear correlation between the two methods was very good. Leaf-areameasurement- by-mass was found to be rapid and simple with accuracies comparable to the digital image analysis method. The greatly reduced cost of leaf-area-measurement-by-mass could be beneficial for small agri-businesses in developing countries.

Predicting the effects of hardwood competition on red pine seedling growth

1992 ◽  
Vol 22 (10) ◽  
pp. 1510-1515 ◽  
Author(s):  
Alan S. White ◽  
Katherine J. Elliott
Keyword(s):  
Leaf Area ◽  
Seedling Growth ◽  
Negative Impact ◽  
Ground Level ◽  
Red Pine ◽  
Area Index ◽  
Clear Cut ◽  
Site Characteristics ◽  
Early Effects ◽  
Highly Correlated

Pin cherry (Prunuspensylvanica L.f.) and striped maple (Acerpensylvanicum L.) are potentially important competitors of red pine (Pinusresinosa Ait.) planted on recently clear-cut hardwood sites. By experimentally manipulating initial competitor densities on 2.0-m2 plots, we were able to quantify and compare the effects of competitor species on red pine seedlings 2 years after planting on two sites in western Maine. Various measures of competitor biomass and leaf area index (LAI) were highly correlated; thus, we used LAI to quantify competitor abundance. On the site with poorer growth for both competitors and red pine, the only red pine variable significantly correlated with competitor LAI was specific leaf area (SLA) of current needles. On the site with better growth for all species, various measures of red pine biomass as well as diameter at ground level and SLA were significantly correlated with competitor LAI. Seedling height was not significantly correlated with competitor LAI at either site. Although there were no significant differences between competitor species in terms of their effect per unit of LAI, pin cherry tended to achieve much higher LAI (and biomass) than did striped maple and thus had a greater negative impact on red pine seedling growth. We conclude that general predictions of the early effects of competition under field conditions are possible, but that the strength of the relationships may be influenced by the extent to which microsite factors and site characteristics are incorporated.

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