Studies of grain production in Sorghum bicolor (L. Moench). VI.* Profiles of photosynthesis, illuminance and foliage arrangement. 4. Profiles of Photosynthesis, Illuminance and Foliage Arrangement

1976 ◽  
Vol 27 (1) ◽  
pp. 35 ◽  
Author(s):  
KS Fischer ◽  
GL Wilson
Keyword(s):  
Leaf Surface ◽  
Canopy Structure ◽  
Light Extinction ◽  
Grain Production ◽  
Area Index ◽  
14Co2 Uptake ◽  
Total Light ◽  
Intercepted Radiation ◽  
Density Population ◽  
Sorghum Bicolor L

Grain sorghum was grown at two population densities in the field, and photosynthetic rates compared at noon. Profiles of photosynthesis were established by combining measurements of 12CO2 exchange and 14CO2 uptake. Canopy structure and light penetration were measured. Factors responsible for the superiority of the higher density population were evaluated. Photosynthesis–radiation responses of leaves were similar between the populations and there was little difference in total light interception. The high density population had leaves which were more vertically displayed, more uniformly dispersed, smaller in both length and width, and distributed over a greater height of canopy. Light was therefore more uniformly distributed down the profile, and coefficients of light extinction were lower. Associated with this was a higher leaf area index. The overall consequence was the distribution of intercepted radiation over a larger leaf surface, at a lower illuminance and therefore a higher efficiency of photosynthetic conversion, resulting in greater total photosynthesis. ___________________ ** Part V, Aust. J. Agric. Res., 26: 31 (1975).

Comparing nondestructive measures of forage structure and phytomass

2000 ◽  
Vol 80 (3) ◽  
pp. 565-573 ◽  
Author(s):  
B. E. Olson ◽  
R. T. Wallander ◽  
J. M. Beaver
Keyword(s):  
Radiative Transfer ◽  
Leaf Area ◽  
Canopy Structure ◽  
Plant Canopy ◽  
Native Range ◽  
Area Index ◽  
Crested Wheatgrass ◽  
Canopy Volume ◽  
Peak Standing Crop ◽  
Intercepted Radiation

Nondestructive radiative transfer and canopy volume methods were compared with the destructive hand-clipping method to determine forage structure and phytomass. On a native range site, fifteen 1-m2 circular plots were located at each of five microsites. On a crested wheatgrass site, thirty 1-m2 plots were located in grazed and in ungrazed areas. At peak standing crop, all plots were measured with a LI-COR Plant Canopy Analyzer to determine leaf area index (LAI), diffuse non-intercepted radiation (DNIR), and mean tilt angle (MTA) of leaves. Then, plants within plots were measured with a ruler to determine volume. Finally, all phytomass within plots was harvested. At the native range site, plant volume was related with LAI and DNIR on four of five microsites. Phytomass was related with LAI and DNIR on two microsites. At the crested wheatgrass site, volume and phytomass were related with LAI, DNIR, and MTA on grazed plots. Only phytomass was related with LAI and DNIR on ungrazed plots. The Plant Canopy Analyzer measures canopy structure and phytomass; it is fast, and its data are transferred directly to a computer. Measuring plant volume is inexpensive and requires minimal training. Determining phytomass by clipping is accurate and requires minimal training, but it is time-consuming and destructive. Key words: Leaf area, canopy, volume, phytomass, radiative transfer

scholarly journals Breeding strategies for soybean canopy structure optimization in dry regions

2021 ◽  
Vol 186 (2) ◽  
pp. 24-30
Author(s):  
V.E. Rosenzweig ◽  
◽  
D.V. Goloenko ◽  
Keyword(s):  
Leaf Area ◽  
Leaf Surface ◽  
Effective Means ◽  
Canopy Structure ◽  
Leaf Size ◽  
Leaf Number ◽  
Width Ratio ◽  
Area Index ◽  
Trifoliate Leaf ◽  
Soybean Canopy

Water supply is one of the key factors limiting soybean yield. Coming from the monsoon climate region, soybean lacks effective means of leaf surface growth restriction and is prone to produce excessive leaf area that leads to undesirable transpiration increase. Reducing branching rate and, correspondingly, leaf number per plant is usually proposed to decrease leaf area. However, as far as branching ability is generally a useful trait contributing to yield stability, we have undertaken a search for possible alternative ways of leaf area reduction. Soybean canopy structure was studied in our germplasm nursery in Kursk region. We have updated an express method of soybean trifoliate leaf surface calculation. A regression index for soybean trifoliate leaf surface by central leaflet length and width product characterizes leaflet shape and depends from its length to width ratio. In the sampling studied, trifoliate leaf surface varied from 79 to 150sq. cm. Leaf area index (LAI) varied from 4.0 to 8.6 sq. m/sq. m, with optimal LAI equal to 6.0 sq. m/sq. m. Excessive LAI (over 7.7 sq. m/sq. m) decreased yield by 20 %. Optimal LAI may be achieved by various combinations of leaf size and leaf number per plant. Lines possessing good branching rate but remaining within optimal LAI values due to small leaf size were revealed. Thus, lamina size reduction may be proposed as an alternative breeding direction to solve a conflict of bushy plant type and drought tolerance.

Response of canopy structure, light interception and grain yield to plant density in maize

2018 ◽  
Vol 156 (6) ◽  
pp. 785-794 ◽  
Author(s):  
J. Li ◽  
R. Z. Xie ◽  
K. R. Wang ◽  
P. Hou ◽  
B. Ming ◽  
...  
Keyword(s):  
Grain Yield ◽  
Leaf Area ◽  
Plant Density ◽  
Canopy Structure ◽  
Light Extinction ◽  
Area Index ◽  
Light Extinction Coefficient ◽  
Modern Maize ◽  
The Difference ◽  
Structure Light

AbstractGood canopy structure is essential for optimal maize (Zea mays L.) production. However, creating appropriate maize canopy structure can be difficult, because the characteristics of individual plants are altered by changes in plant age, density and interactions with neighbouring plants. The objective of the current study was to find a reliable method for building good maize canopy structure by analysing changes in canopy structure, light distribution and grain yield (GY). A modern maize cultivar (ZhengDan958) was planted at 12 densities ranging from 1.5 to 18 plants/m2 at two field locations in Xinjiang, China. At the silking stage (R1), plant and ear height increased with plant density as well as leaf area index (LAI), whereas leaf area per plant decreased logarithmically. The fraction of light intercepted by the plant (F) increased with increasing plant density, but the light extinction coefficient (K) decreased linearly from 0.61 to 0.39. Taking the optimum value of F (95%) as an example, and using measured values of K for each plant density at R1 and the equation from Beer's law, the corresponding (theoretical) LAI for each plant density was calculated and optimum plant density (9.72 plants/m2) obtained by calculating the difference between theoretical LAIs and actual observations. Further analysis showed that plant density ranging from 10.64 to 11.55 plants/m2 yielded a stable GY range. Therefore, taking into account the persistence time for maximum LAI, the plant density required to obtain an ideal GY maize canopy structure should be increased by 10–18% from 9.72 plants/m2.

Roughness measurements of nonlinear optical polymer films by scanning tunneling microscopy

1989 ◽  
Vol 47 ◽  
pp. 22-23
Author(s):  
I. H. Musselman ◽  
R.-T. Chen ◽  
P. E. Russell
Keyword(s):  
Surface Roughness ◽  
Scanning Tunneling Microscopy ◽  
Nonlinear Optical ◽  
Polymer Surface ◽  
Light Extinction ◽  
Scanning Tunneling ◽  
Silicon Substrates ◽  
Tunneling Microscopy ◽  
Optical Polymer ◽  
Total Light

Scanning tunneling microscopy (STM) has been used to characterize the surface roughness of nonlinear optical (NLO) polymers. A review of STM of polymer surfaces is included in this volume. The NLO polymers are instrumental in the development of electrooptical waveguide devices, the most fundamental of which is the modulator. The most common modulator design is the Mach Zehnder interferometer, in which the input light is split into two legs and then recombined into a common output within the two dimensional waveguide. A π phase retardation, resulting in total light extinction at the output of the interferometer, can be achieved by changing the refractive index of one leg with respect to the other using the electrooptic effect. For best device performance, it is essential that the NLO polymer exhibit minimal surface roughness in order to reduce light scattering. Scanning tunneling microscopy, with its high lateral and vertical resolution, is capable of quantifying the NLO polymer surface roughness induced by processing. Results are presented below in which STM was used to measure the surface roughness of films produced by spin-coating NLO-active polymers onto silicon substrates.

scholarly journals A Plant Process Economic Model for Weed Management Decisions in Irrigated Onion

1999 ◽  
Vol 124 (1) ◽  
pp. 99-105 ◽  
Author(s):  
Claudio M. Dunan ◽  
Philip Westra ◽  
Frank D. Moore
Keyword(s):  
Leaf Area ◽  
Plant Density ◽  
Light Extinction ◽  
Species Number ◽  
Yield Reduction ◽  
Weed Species ◽  
Early Application ◽  
Area Index ◽  
Variable Approach ◽  
Number Of Leaves

A simulation model was built as a decision aid for management of five weed species in direct seeded irrigated onion (Allium cepa L.). The model uses the state variable approach and simulations are driven by temperature and sunlight as photosynthetically active radiation (PAR). It predicts yield reduction caused by competition for PAR according to the ratio of crop leaf area index (LAI) to weed LAI and respective light extinction coefficients (k). Input variables are plant density by species and average number of leaves by species. Number of leaves per plant is used by the model to provide an estimate of initial leaf area per plant. The model calculates initial species LAIs by multiplying species density times average leaf area per plant. The model accurately describes competitive interactions, taking into account respective plant densities, time of emergence, and time of weed removal. It permits economic evaluation of management factors such as handweeding, chemical weed control, herbicide phytotoxicity due to early application, and control of weed flushes during the season. The model is also used to evaluate mechanisms of plant competition for sunlight. In a sensitivity analysis, onion yield loss was more sensitive to weed PAR interception than to PAR use efficiency, the latter a species-dependent constant in the model.

scholarly journals Influence of mineral fertilizers on morphometric parameters of Melissa officinalis in the Republic of Mordovia

2019 ◽  
pp. 45-48
Author(s):  
Ilya Alexandrovich Khapugin
Keyword(s):  
Leaf Area Index ◽  
Leaf Surface ◽  
Shoot Formation ◽  
Meteorological Conditions ◽  
Morphometric Parameters ◽  
Mineral Fertilizers ◽  
Melissa Officinalis ◽  
Area Index ◽  
Maximum Value ◽  
The Republic

The influence of mineral fertilizers on morphometric parameters of Melissa officinalis (Melissa officinalis L.) was studied. It is shown that the morphometric indicators changed depending on the meteorological conditions and the types of mineral fertilizers. The most active shoot formation was observed on the variant with the use of phosphorus-potassium fertilizers. The maximum value of the leaf surface index (leaf area index – LAI) of Melissa officinalis plants was recorded in 2017 on the variant with the use of nitrogen-potassium mineral fertilizers.    

Studies of grain production in Sorghum bicolor (L. Moench). IV.* Some effects of increasing and decreasing photosynthesis at different stages of the plant's development on the storage capacity of the inflorescence

1975 ◽  
Vol 26 (1) ◽  
pp. 25 ◽  
Author(s):  
KS Fischer ◽  
GL Wilson
Keyword(s):  
Storage Capacity ◽  
Developmental Stages ◽  
Light Transmission ◽  
Plant Competition ◽  
Grain Filling ◽  
Floral Initiation ◽  
Grain Production ◽  
Grain Number ◽  
Plant Parts ◽  
Sorghum Bicolor L

Sorghum plants (cv. RS610) grown in field stands at two population densities were manipulated to increase the supply of assimilates (by removing neighbouring plants) at one of three developmental stages—10-15 days after floral initiation, 1 week prior to three-quarters anthesis, and 1 week after three-quarters anthesis. Post-initiation exposure increased the number of grains per inflorescence 1.8-fold and 3.5-fold in medium and high density populations respectively, but had relatively less effect on grain size. Higher grain number resulted largely from more grains per secondary branch in the lower part of the inflorescence. Neither of the post-heading exposure treatments influenced grain number, but the higher supply of assimilates resulted in larger grains at both densities. Differences at one density only between yield characteristics of plants exposed at the two times provide evidence of inter-plant competition for assimilates to the extent that the potential size of the grain may be affected. Shading (10% light transmission) of plants grown in a glasshouse, whether for 1 week at anthesis or during grain filling, reduced grain yield at maturity by the same amount as the immediate reduction at the end of the shading period. The experiment was unable to demonstrate changes in the potential size of grains resulting from the loss of assimilates at anthesis. There was substantial compensation for the loss by translocation from other plant parts. *Part III, Aust. J. Agric. Res., 26: 11 (1975).

Corrigendum - Growth and productivity of irrigated Sorghum bicolor (L. Moench) in Northern Australia. II. Low solar altitude as a possible constraint to productivity in the tropical dry season

1984 ◽  
Vol 35 (2) ◽  
pp. 229
Author(s):  
MA Foale ◽  
GL Wilson ◽  
DB Coates ◽  
KP Haydock
Keyword(s):  
Solar Radiation ◽  
Canopy Structure ◽  
Dry Season ◽  
High Density ◽  
Light Penetration ◽  
Northern Australia ◽  
Growth Study ◽  
Altitude Effect ◽  
Solar Altitude ◽  
Sorghum Bicolor L

A growth study was carried out during the dry season on irrigated grain sorghum cultivar NK 300F at latitude 16�S. in northern Australia. The apparent efficiency of the canopy in the photosynthetic conversion of solar radiation increased progressively in high density stands between June and September, while low density stands showed no change. An hypothesis is advanced that the rise in canopy efficiency was due to increasing solar altitude combining with a suitable canopy structure at high density to give increased light penetration into the canopy. A parameter named weighted mean solar altitude (WMSA) is used in conjunction with noon solar altitude (NSA) to assist in the interpretation of published models of light penetration. This solar altitude effect, if verified by further work, would lower the expectations, based on mean daily solar radiation, for dry season yield of irrigated sorghum and possibly other cereals in the semi-arid tropics.

scholarly journals The Impacts of Growth and Environmental Parameters on Solar-Induced Chlorophyll Fluorescence at Seasonal and Diurnal Scales

2019 ◽  
Vol 11 (17) ◽  
pp. 2002
Author(s):  
Leizhen Liu ◽  
Wenhui Zhao ◽  
Jianjun Wu ◽  
Shasha Liu ◽  
Yanguo Teng ◽  
...  
Keyword(s):  
Chlorophyll Fluorescence ◽  
Water Stress ◽  
Growth Parameters ◽  
Pearson Correlation ◽  
Canopy Structure ◽  
Principal Component ◽  
Environmental Parameters ◽  
Area Index ◽  
Relationship Of ◽  
The Impact

Solar-induced chlorophyll fluorescence (SIF) is considered to be a potential indicator of photosynthesis. However, the impact of growth and environmental parameters on SIF at different time-scales remains unclear, which has greatly restricted the application of SIF in detecting photosynthesis variations. Thus, in this study, the impact of growth and environmental parameters on SIF was thoroughly clarified. Here, continuous time series of canopy SIF (760 nm, F760) over wheat and maize was measured based on an automated spectroscopy system. Meanwhile, field measurements of growth and environmental parameters were also collected using commercial-grade devices. Relationships of these parameters with F760, apparent SIF (F760/solar radiance, AF760), and SIF yield (F760/canopy radiance of 685 nm, Fy760) were analyzed using principal component analysis (PCA) and Pearson correlation to reveal their impacts on SIF. Results showed that F760 at seasonal and diurnal scales were mainly driven by solar radiation (SWR), leaf area index (LAI), chlorophyll content (Chl), mean leaf inclination angle (MTA), and relative water content (RWC). Other environmental parameters, including air temperature (Ta), relative humidity (Rh), vapor pressure deficit (VPD), and soil moisture (SM), contribute less to the variation of seasonal or diurnal F760. AF760 and Fy760 are likely to be less dependent on Ta, Rh, and VPD due to the removal of the impact from SWR, but an enhanced relationship of AF760 (and Fy760) with SM was observed, particularly under water stress. Compared with F760, wheat AF760 was better correlated to LAI and RWC as expected, while maize AF760 did not show an enhanced relationship with all growth parameters, probably due to its complicated canopy structure. The relationship of wheat Fy760 with canopy structure parameters was further reduced, except for maize measurements. Furthermore, SM-induced water stress and phenological stages should be taken into consideration when we interpret the seasonal and diurnal patterns of SIF since they were closely related to photosynthesis and plant growth (e.g., LAI in our study). To our knowledge, this is the first exploration of the impacts of growth and environmental parameters on SIF based on continuous ground measurements, not only at a seasonal scale but also at a diurnal scale. Our results could provide deep insight into the variation of SIF signals and also promote the further application of SIF in the health assessments of terrestrial ecosystems.

A comparison of barley cultivars with different leaf inclinations

1972 ◽  
Vol 23 (6) ◽  
pp. 945 ◽  
Author(s):  
JF Angus ◽  
R Jones ◽  
JH Wilson
Keyword(s):  
Dry Matter ◽  
Canopy Structure ◽  
The Other ◽  
Dry Matter Production ◽  
Visible Radiation ◽  
Area Index ◽  
Assimilation Chamber ◽  
Barley Cultivars ◽  
Matter Production ◽  
Erect Leaf

Under conditions of adequate moisture an erect-leaf barley cultivar, Lenta, responded to an increase in density (resulting from doubling of the sowing rate) with increases in dry matter production and in grain yield, whereas the cultivar Research, which has long lax leaves, responded with decreases in dry matter production and yield. In a study of canopy structure and its effects on light interception and utilization, it was found that in Research, with a leaf area index (LAI) of 6.1, the leaves were concentrated near the canopy surface and a relatively small proportion of the above-crop light penetrated through this layer. The net crop photosynthesis of this canopy (measured in a field assimilation chamber) was 3.8 g CO2/m2.hr when visible radiation was 313 W/m2. With Lenta (LAI 7.0) on the other hand, leaves were concentrated in the middle layers of the canopy and the light was more evenly distributed throughout the canopy. The net crop photosynthesis with the same radiation as for Research was 4.3 g CO2/m2.hr. The relative rates of photosynthesis at various levels in the canopies were determined by introducing 14CO2 into the assimilation chambers enclosing the cultivars and observing where the 14C was fixed. With Research most of it was localized near the canopy surface while with Lenta most of it was near the centre of the canopy. Of the 14CO2 taken up, 7 % was fixed in the leaf sheaths of Research and 12% in those of Lenta.

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