scholarly journals Infrared thermometry to schedule irrigation of common bean

2004 ◽  
Vol 39 (2) ◽  
pp. 113-121 ◽  
Author(s):  
Francisco de Almeida Lobo ◽  
Marco Antonio Oliva ◽  
Morethson Resende ◽  
Nei Fernandes Lopes ◽  
Moacyr Maestri
Keyword(s):  
Growth Rate ◽  
Common Bean ◽  
Leaf Area ◽  
Relative Growth Rate ◽  
Linear Correlation ◽  
Canopy Temperature ◽  
Mean Value ◽  
Relative Growth ◽  
Infrared Thermometry ◽  
Significant Linear Correlation

The objective of this work was to determine the critical irrigation time for common bean (Phaseolus vulgaris L. cv. Carioca) using infrared thermometry. Five treatments were analyzed. Canopy temperature differences between plants and a well-watered control about 1, 2, 3, 4, and 5±0.5ºC were tested. Physiological variables and plant growth were analyzed to establish the best time to irrigate. There was a significant linear correlation between the index and stomatal resistance, transpiration rate, and leaf water potential. Although significant linear correlation between the index and mean values of total dry matter, absolute growth rate, and leaf area index was found, no correlation was found with other growth index like relative growth rate, net assimilation rate, and leaf area ratio. Plants irrigated when their canopy temperature was 3±0.5ºC above the control had their relative growth rate mean value increased up to 59.7%, yielding 2,260.2 kg ha-1, with a reduction of 38.0% in the amount of water used. Plants irrigated when their canopy temperature was 4±0.5ºC yielded 1,907.6 kg ha-1, although their relative growth rate mean value was 4.0% below the control. These results show that the best moment to irrigate common bean is when their canopy temperature is between 3ºC and 4±0.5ºC above the control.

Low temperature effects on the growth of evening primrose (Oenothera spp.) rosettes

2004 ◽  
Vol 52 (1) ◽  
pp. 19-28
Author(s):  
A. F. Fieldsend
Keyword(s):  
Growth Rate ◽  
Leaf Area ◽  
Relative Growth Rate ◽  
Relative Rate ◽  
Field Trials ◽  
Effect Of Temperature ◽  
Relative Growth ◽  
Evening Primrose ◽  
Intermittent Exposure ◽  
Environment Experiment

In field crops of evening primrose (Oenothera spp.) the post-winter growth of rosettes is slow to re-start. The effect of temperature on the growth of rosettes was assessed in a controlled environment experiment. Relative growth rate was positively correlated with temperature, but in apparent contrast to the results from field trials, the rosettes grew at constant temperatures as low as 6.5ºC. However, following transfer to warmer temperatures an increase in relative growth rate did not occur until 7-10 days later, whilst a change to a cooler environment caused an immediate reduction in relative growth rate. Thus, it seems likely that growth is inhibited by intermittent exposure to temperatures of 0°C or below. Partitioning of biomass between root and shoot was independent of temperature, but at 6.5ºC the relative rate of leaf area increase was very low. Consequently, the specific leaf area was lower in rosettes growing at lower temperatures.

scholarly journals Growth Analysis of Wheat Using Machine Vision: Opportunities and Challenges

Sensors ◽  
2020 ◽  
Vol 20 (22) ◽  
pp. 6501
Author(s):  
Mohammad Ajlouni ◽  
Audrey Kruse ◽  
Jorge A. Condori-Apfata ◽  
Maria Valderrama Valencia ◽  
Chris Hoagland ◽  
...  
Keyword(s):  
Growth Rate ◽  
Machine Vision ◽  
Leaf Area ◽  
Relative Growth Rate ◽  
Growth Analysis ◽  
Growth Parameters ◽  
Dry Weight ◽  
Projected Area ◽  
Relative Growth ◽  
Leaf Dry Weight

Crop growth analysis is used for the assessment of crop yield potential and stress tolerance. Capturing continuous plant growth has been a goal since the early 20th century; however, this requires a large number of replicates and multiple destructive measurements. The use of machine vision techniques holds promise as a fast, reliable, and non-destructive method to analyze crop growth based on surrogates for plant traits and growth parameters. We used machine vision to infer plant size along with destructive measurements at multiple time points to analyze growth parameters of spring wheat genotypes. We measured side-projected area by machine vision and RGB imaging. Three traits, i.e., biomass (BIO), leaf dry weight (LDW), and leaf area (LA), were measured using low-throughput techniques. However, RGB imaging was used to produce side projected area (SPA) as the high throughput trait. Significant effects of time point and genotype on BIO, LDW, LA, and SPA were observed. SPA was a robust predictor of leaf area, leaf dry weight, and biomass. Relative growth rate estimated using SPA was a robust predictor of the relative growth rate measured using biomass and leaf dry weight. Large numbers of entries can be assessed by this method for genetic mapping projects to produce a continuous growth curve with fewer replicates.

scholarly journals Growth of the crabgrass species Digitaria ciliaris and Digitaria nuda

2012 ◽  
Vol 30 (2) ◽  
pp. 317-325 ◽  
Author(s):  
R.C. Souza ◽  
A.C. Dias ◽  
M.R.A. Figueiredo ◽  
F.E.B. Obara ◽  
P.J Christoffoleti
Keyword(s):  
Growth Rate ◽  
Leaf Area ◽  
Relative Growth Rate ◽  
Dry Matter ◽  
Area Ratio ◽  
Leaf Area Ratio ◽  
Leaf Number ◽  
Relative Growth ◽  
Absolute Growth Rate ◽  
Absolute Growth

The aim of this research paper was to compare the growth of D. ciliaris and D. nuda crabgrass species under non-competitive conditions. To this end, two experiments were conducted, one from March - July 2010 and the other from February - June 2011. The experimental design of both trials was completely randomized making a factorial (2 seasons x 2 species crabgrass x 12 evaluation periods) with four replications. Assessments began at 15 days after sowing (DAS), and repeated weekly until 92 DAS. The variables evaluated were total dry matter (roots+leaves+stems), leaf area, leaf number and tiller. The results were submitted to analysis of variance and the absolute growth rate, relative growth rate and leaf area ratio were calculated using the means, which were adjusted regression models. The crabgrass species were significantly different in leaf area, leaf number, tiller number and dry matter per plant. D. ciliaris for all variables was statistically higher than D. nuda. Regarding the speed at which the growth of the species occurred, the absolute growth rate and relative growth rate of D. ciliaris was also greater than D. nuda. In addition, D. ciliaris also had a lower leaf area ratio indicating greater efficiency in converting light energy into carbohydrates. It can be concluded that D. ciliaris has a higher growth rate in conditions where there is no limitation of nutrients and water availability in relation to D. nuda, mainly due to D. ciliaris have greater leaf area, number of leaves and dry matter accumulation per plant.

scholarly journals Components of relative growth rate and nitrogen productivity of Brussels sprouts and leeks grown at two widely differing light intensities

1996 ◽  
Vol 44 (1) ◽  
pp. 21-29 ◽  
Author(s):  
A. Van Der Werf ◽  
C.T. Enserink ◽  
A.L. Smit ◽  
R. Booij
Keyword(s):  
Growth Rate ◽  
Leaf Area ◽  
Relative Growth Rate ◽  
Biomass Production ◽  
Field Experiments ◽  
Growth Chamber ◽  
Brussels Sprouts ◽  
Relative Growth ◽  
Unit Leaf ◽  
Growth Chamber Studies

Young vegetative Brussels sprout and leek plants were grown in a growth chamber at a light intensity of 550 micro mol m-2 s-1 or at only 20% of that intensity. In both light treatments, Brussels sprouts had a relative growth rate (RGR) ~90% higher than that of leeks, which was mainly explained by a higher leaf area ratio (LAR; msuperscript 2/kg plant). Only minor differences in the physiological component (net assimilation rate) were observed between the 2 species within a light treatment. The higher LAR of Brussels sprouts was mainly explained by higher specific leaf area. Brussels sprouts had a higher rate of biomass production per unit internal N (N productivity) than leeks. This was mainly explained by a higher allocation of N to leaves and a higher rate of biomass production per unit leaf N. It is suggested that the higher biomass production per unit of N taken up in Brussels sprouts than leeks as observed in the field is explained by higher N productivity. The results obtained from the growth chamber studies are discussed in relation to field experiments and data from the literature.

scholarly journals Leaf and Stem Traits are Linked to Liana Growth Rate in a Subtropical Cloud Forest

Forests ◽  
2020 ◽  
Vol 11 (10) ◽  
pp. 1120
Author(s):  
Xiao-Long Bai ◽  
Yun-Bing Zhang ◽  
Qi Liu ◽  
Yang-Si-Ding Wang ◽  
Da Yang ◽  
...  
Keyword(s):  
Growth Rate ◽  
Leaf Area ◽  
Relative Growth Rate ◽  
Cloud Forest ◽  
High Elevation ◽  
Growth Patterns ◽  
Relative Growth ◽  
Leaf Vein ◽  
Vein Density ◽  
Leaf Vein Density

There is accumulating evidence that the abundance and biomass of lianas are increasing with global climate change in the Neotropics. However, our knowledge of growth–trait relationships among lianas is surprisingly rare. Here, we monitored the relative growth rate of 2860 individuals from seven deciduous and four evergreen liana species in a 20 ha subtropical cloud forest dynamics plot at high elevation (2472–2628 m a.s.l.) in southwest China. We linked the relative growth rate of lianas with nine leaf traits associated with leaf morphology, nutrient concentrations, and water hydraulic capacity as indicated by leaf vein density, and five stem wood traits related to stem water transport capacity and wood density. Our results showed that deciduous lianas have higher relative growth rates than their evergreen counterparts. Across all lianas studied, the relative growth rate was positively correlated with the leaf area and specific leaf area, but negatively correlated with leaf dry matter content. The relative growth rate of lianas was strongly correlated with nitrogen concentration after excluding the legume liana species. The relative growth rate was decoupled from leaf phosphorus and potassium concentrations, leaf vein density, and stem vessel traits across all lianas investigated. For four evergreen lianas, there were positive associations of the relative growth rate with the leaf thickness and diameter of the largest vessels. This study is the first to illustrate the relationships of liana growth with leaf and stem traits in the high-elevation subtropical cloud forest. More studies from diverse forest ecosystems are needed to comprehensively understand the mechanism underlying liana growth patterns.

scholarly journals Growth of marandu palisadegrass subjected to strategies of intermittent stocking

2009 ◽  
Vol 66 (6) ◽  
pp. 733-741 ◽  
Author(s):  
Alessandra Aparecida Giacomini ◽  
Sila Carneiro da Silva ◽  
Daniel Oliveira de Lucena Sarmento ◽  
Cauê Varesqui Zeferino ◽  
Salim Jacaúna Souza Júnior ◽  
...  
Keyword(s):  
Growth Rate ◽  
Leaf Area ◽  
Relative Growth Rate ◽  
Weight Ratio ◽  
Crop Growth ◽  
Net Assimilation Rate ◽  
Assimilation Rate ◽  
Relative Growth ◽  
Crop Growth Rate ◽  
Net Assimilation

Grazing strategies alter sward leaf area patterns of growth, affecting herbage accumulation and utilisation. The objective of this experiment was to evaluate the growth of marandu palisadegrass (Brachiaria brizantha cv. Marandu) swards subjected to strategies of intermittent stocking. The experiment was carried out in Piracicaba, São Paulo, Brazil, from October/2004 to September/2005. Swards were grazed at 95 and 100% canopy light interception (LI) to post-grazing heights of 10 and 15 cm, following a 2 × 2 factorial arrangement with four replications in a randomised complete block design. The response variables evaluated were: crop growth rate, relative growth rate, net assimilation rate, leaf area ratio and leaf weight ratio. In early and late spring, the highest crop growth rate was recorded for treatment 95/15 (11.2 and 10.1 g m-2 day-1, respectively), along with high values of net assimilation rate (4.4 and 6.9 g m-2 day-1, respectively), leaf area ratio (0.0095 and 0.0103 m-2 g-1, respectively) and leaf weight ratio (0.56 and 0.56 g g-1, respectively). To compensate reductions in net assimilation rate plants made some morphological and physiological adjustments increasing leaf area and leaf weight ratio. Relative growth rate and net assimilation rate were 26 and 50% higher, respectively, on swards grazed at 95% than at 100% LI. In early spring treatments 100/10 and 95/15 resulted in the highest relative growth rate (0.086 and 0.059 g m-2 day-1, respectively). Treatment 95/15 resulted in the most favourable pattern of growth (crop growth rate, relative growth rate, net assimilation rate), particularly during the transition period between winter and spring.

scholarly journals Analysis of cassava growth at different harvest times and planting densities

2019 ◽  
Vol 40 (1) ◽  
pp. 113
Author(s):  
Eli Carlos de Oliveira ◽  
Luiz Henrique Campos de Almeida ◽  
Claudemir Zucareli ◽  
Teresa Losada Valle ◽  
José Roberto Pinto de Souza ◽  
...  
Keyword(s):  
Growth Rate ◽  
Leaf Area ◽  
Relative Growth Rate ◽  
Dry Mass ◽  
Area Ratio ◽  
Plant Population ◽  
Leaf Area Ratio ◽  
Primary Data ◽  
Population Densities ◽  
Relative Growth

Vegetative canopy architecture, and plant population density, has a direct influence on the growth and production of crops. The objective of this study was to evaluate the growth of four cassava cultivars of contrasting canopies, in four population densities, during two vegetative cycles. A randomized complete block design was used in a subdivided plot scheme, with two replications, with the population densities in the plots and harvesting times in the subplots. ‘Branca de Santa Catarina’ (BSC), ‘IAC 13’, ‘IAC 14-18’ and ‘Fibra’ were collected every four months, beginning at 120 and ending at 720 days after planting (DAP). Primary data on dry matter and leaf area were calculated. The total dry mass (Wt), leaf area ratio (La), leaf area index (L), relative growth rate (Rw), and net assimilation rate (Ea) were calculated based on the primary data. All cultivars accumulated more total dry mass (Wt) at lower planting densities. The plants reached a higher leaf area ratio (La) 120 days after planting. In the second vegetative cycle, the four cultivars, independently of the population, presented a reduction of assimilate translocation to the leaves. Relative growth rate (Rw) of the cultivars varied strongly with the plant population only in the second cycle. ‘IAC 14-18’ showed greater dependence on spacing, and ‘Fibra’ less dependence. Growth (Rw) and assimilatory (Ea) rates decreased at the end of the first cycle, then increased slowly until the end of the second cycle of vegetation.

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