scholarly journals Productivity and morphological composition of Xaraés palisade grass under three light intensities

2019 ◽  
Vol 40 (6) ◽  
pp. 2749
Author(s):  
Vinicius Carreteiro Gomes ◽  
Juliana da Silva Barros ◽  
Paulo Roberto de Lima Meirelles ◽  
Ciniro Costa ◽  
Erikelly Aline Ribeiro de Santana ◽  
...  
Keyword(s):  
Light Intensity ◽  
Accumulation Rate ◽  
Area Index ◽  
Light Reduction ◽  
Production Studies ◽  
Light Production ◽  
Light Intensities ◽  
Dead Material ◽  
Urochloa Brizantha ◽  
Artificial Shading

The adaptation of Urochloa brizantha to Brazilian ecosystems and the use of artificial shading in low light production studies are important tools to obtain productive responses and to know the behavior of plants when used in integration with arboreal components. The experiment was conducted at the FMVZ - UNESP in Botucatu city, São Paulo state, Brazil. The study aimed to evaluate the yield of U. brizantha (syn Brachiaria brizantha) cv. Xaraés (Xaraés palisade grass) under three light intensities and four cuts. The experimental design was a randomized block with three treatments (natural luminosity, 30% light reduction, and 60% light reduction), three replicates and four cuts. The following morphological components were determined: leaf area index (LAI), forage accumulation rate (FAR), total forage mass (TFM), stem yield (SY), leaf yield (LY), and dead material yield (DMY). Light intensity influenced grass productivity, and the best performance was reached under 60% shading, which had higher values of TFM, LY, SY, LAI, and FAR if compared to natural luminosity. Thus, a reduction of 60% in light intensity showed to be the most productive and the best alternative under those conditions.

scholarly journals Intensive Production and Management of Marandu Palisadegrass (Urochloa brizantha ‘Marandu’) Accelerates Leaf Turnover but Does Not Change Herbage Mass

Agronomy ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1846
Author(s):  
Fernando Ongaratto ◽  
Marcia Helena Machado da Rocha Fernandes ◽  
Erick Escobar Dallantonia ◽  
Lais de Oliveira Lima ◽  
Guilherme Alves do Val ◽  
...  
Keyword(s):  
Production Systems ◽  
Accumulation Rate ◽  
Canopy Structure ◽  
Leaf Lifespan ◽  
Randomized Design ◽  
Leaf Turnover ◽  
Dead Material ◽  
Urochloa Brizantha ◽  
Leaf Appearance ◽  
Stocking Rates

Pasture intensification through higher stocking rates, nitrogen fertilization and intensified grazing management in beef cattle production optimizes pasture use by increasing the forage harvested. We aimed to assess its effects on the morphogenesis and canopy structure of Urochloa brizantha ‘Marandu’ (marandu palisadegrass) pastures. The treatments consisted of marandu palisadegrass pastures managed under continuous stocking and a canopy height of 25 cm, with different levels of intensification: extensive, semi-intensive, and intensive systems N-fertilized with 0 kg, 75 kg, and 150 kg N ha−1 year−1, respectively, as ammonium nitrate (32% of N), with four replicates (paddocks) in a completely randomized design. Phyllochron (9.8 days) and leaf lifespan (34.7 days) were shorter in intensified pastures, whereas herbage mass was similar among treatments. Extensive pastures had a higher proportion of senescent material; thus, more intensive systems showed higher proportions of leaves and stems, although the leaves-to-stem ratio remained similar across production systems. The defoliation interval was lower in intensive (14.4 days) and higher in extensive (18.7 days) treatments. Thus, pasture intensification accelerates leaf appearance, decreases leaf lifespan, shortens the tiller defoliation interval and increased herbage accumulation rate but does not change herbage mass. The extensive system produces excessive forage losses due to dead material.

Seasonal alteration in sward height of Marandu palisade grass (Brachiaria brizantha) pastures managed by continuous grazing interferes with forage production

2020 ◽  
Vol 71 (3) ◽  
pp. 285 ◽  
Author(s):  
Suleize Terra ◽  
Flávia Maria de Andrade Gimenes ◽  
Alessandra Aparecida Giacomini ◽  
Luciana Gerdes ◽  
Marisa Xavier Manço ◽  
...  
Keyword(s):  
Accumulation Rate ◽  
Cold Season ◽  
Forage Production ◽  
Brachiaria Brizantha ◽  
Sward Height ◽  
Continuous Grazing ◽  
Dead Material ◽  
Hot Season ◽  
Urochloa Brizantha ◽  
The Stability

Changes in sward height of pastures managed by continuous grazing according to climatic seasonality may alter tillering and forage production. In order to evaluate the feasibility of seasonal alteration in sward height of Marandu palisade grass pastures (Brachiaria brizantha (Hochst. ex A.Rich.) R.D. Webster; syn. Urochloa brizantha (A.Rich.) Stapf) under continuous grazing management, we studied two constant sward heights (15 cm and 30 cm), and one height that was initiated at 30 cm, reduced to 15 cm in June (dry and cold season) and returned to 30 cm in December (wet and hot season) (30–15–30 cm). Pastures managed at 30–15–30 cm had a greater tiller appearance rate (22 tillers/100 tillers.30 days) than those maintained at 15 cm and 30 cm (16 and 17 tillers/100 tillers.30 days, respectively). In the 30–15–30 cm pastures, a lower accumulation rate of dead material was observed during the dry and cold season (June–August), which resulted in a higher leaf and lower dead material accumulation rate during the second growth season (wet and hot season, December–January). Planned reduction in sward height during the cold season can be used safely because it permits better seasonal distribution and utilisation of forage production without compromising the stability of Marandu palisade grass pastures.

scholarly journals Sward Structure and Herbage Accumulation of Massai Guineagrass Pastures Managed According to Pre-Grazing Heights, in the Northeast of Brazil

2017 ◽  
Vol 9 (4) ◽  
pp. 155 ◽  
Author(s):  
João Virgínio Emerenciano Neto ◽  
Gelson Dos Santos Difante ◽  
Angela Maria Quintão Lana ◽  
Nathália Rafaela Fidelis Campos ◽  
Emmanuel Lievio de Lima Veras ◽  
...  
Keyword(s):  
Dry Matter ◽  
Accumulation Rate ◽  
Mineral Matter ◽  
Panicum Maximum ◽  
Height Measurement ◽  
Area Index ◽  
Sward Height ◽  
Dead Material ◽  
Positive Effect ◽  
Potential Tool

The forage sward height measurement is a practical and potential tool for grazing management. Thus, the objective of this study was to evaluate the structure of pasture and forage accumulation related to sward pre-grazing height of Panicum maximum cv. Massai, before being grazed by sheep. The study was conducted in the Federal University of Rio Grande do Norte, Macaíba, Brazil. The treatments were the pre-grazing sward heights at: 35, 40, 45 and 50 cm. The post-grazing height was 15 cm for all treatments. The interaction between the pre-grazing sward heights and grazing cycles was only statistically significant for light interception (LI) and leaf area index (LAI). The LI had linear and positive effect to the pre-grazing heights in only one of three grazing cycles, with approximately 1% increase in LI for each centimeter grown in the sward. The total forage mass had linear regression, every centimeter increased in height, there was a correspondent dry matter (DM) increase of 187 kg ha-1 in forage mass. There was a linear response between leaf blade mass and dead material with sward height. The post-grazing lowest LI was 29.42% at 42.05 cm high. The lowest amount of LI was 29.42% at 42.05 cm high. The minimum LAI was 0.69. The top DM and mineral matter (MM) accumulation rate were linear and had 58.32 and 20.46 kg ha-1 day-1 MS, respectively. Massai guineagrass grazed by sheep must be handled between 35 and 40 cm high at pre-grazing when associated with post-grazing height of 15 cm.

NET CARBON DIOXIDE EXCHANGE RATES IN PHASEOLUS VULGARIS L. AS INFLUENCED BY TEMPERATURE, LIGHT INTENSITY, LEAF AREA INDEX, AND AGE OF PLANT

1964 ◽  
Vol 42 (4) ◽  
pp. 393-401
Author(s):  
Douglas P. Ormrod
Keyword(s):  
Carbon Dioxide ◽  
Phaseolus Vulgaris ◽  
Light Intensity ◽  
Exchange Rates ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Planting Density ◽  
Carbon Dioxide Exchange ◽  
Area Index ◽  
Light Intensities

Plants of Phaseolus vulgaris were grown under controlled conditions for 10 to 60 days and then transferred to light intensities of from 0 to 12,000 ft-c at temperatures of 4 to 38 °C for measurement of net carbon dioxide exchange by means of an infrared analyzer. The net carbon dioxide exchange was not markedly influenced by temperature at higher light intensities, particularly with older plants and the greater planting density, but was strikingly influenced by temperature in darkness or low light intensity. The leaf area index affected the rate at which the maximum net carbon dioxide exchange rates were attained. The compensation point increased with aging and with denser planting. The net assimilation decreased at the onset of fruiting. Several features of the experimental method are discussed.

scholarly journals How does the sward condition in late winter influence the Marandu palisade grass (Urochloa brizantha cv. Marandu) structure during spring and summer?

2020 ◽  
Vol 8 (3) ◽  
pp. 167-176
Author(s):  
Manoel E.R. Santos ◽  
Bruno H.R. Carvalho ◽  
Flávia O.S. Van Cleef ◽  
Gabriel O. Rocha ◽  
Henrique C.R. Nogueira ◽  
...  
Keyword(s):  
Plant Growth ◽  
Structural Characteristics ◽  
Late Winter ◽  
Animal Performance ◽  
Area Index ◽  
Dead Material ◽  
Grazing Period ◽  
Urochloa Brizantha ◽  
Favorable Structure ◽  
Animal Consumption

Height and mowing of a sward in late winter can change its structure during the subsequent spring and summer seasons, which influences plant growth and animal performance. This work was conducted to evaluate the structural characteristics of Urochloa brizantha (syn. Brachiaria brizantha) cv. Marandu (marandu palisadegrass) during spring and summer in relation to the following sward conditions in late winter: short (15 cm), medium (23 cm), tall (31 cm) and tall (31 cm)/mowed to 8 cm. Stages of the grazing period (beginning, middle and end) in spring and summer were considered measures repeated over time. Leaf area index was lower in the tall pasture than in the other pastures and was lower at the beginning than at the end of the grazing period. Dead material mass was highest in the tall pasture, intermediate in the short and medium pastures and lowest in the tall/mowed pasture. Live stem mass was higher at the end than at the beginning and middle of the grazing period of the short, medium and tall/mowed pastures, contrary to that observed in the tall sward. At the end of the grazing period, tiller number did not vary among pastures. The tall pasture in late winter presents a limiting structure to animal consumption. Short and tall/mowed pastures in late winter show a favorable structure for forage plant growth and, probably, animal performance.

scholarly journals Effect of artificial shading on growth and morphogenesis of rauvolfia serpentina benth. Ex. Kurz and r. Tetraphylla L.

1970 ◽  
Vol 18 ◽  
pp. 21-26
Author(s):  
MP Trivedi ◽  
Rachna Kumari
Keyword(s):  
Light Intensity ◽  
Leaf Area ◽  
Weight Ratio ◽  
Dry Weight ◽  
Rauvolfia Serpentina ◽  
Light Regimes ◽  
Light Intensities ◽  
Partial Shade ◽  
Net Assimilation ◽  
Artificial Shading

Context: Plants behaviour is greatly influenced by light intensity, quality and photoperiods. Rauvolfia serpentina Benth. ex. Kurz and R. tetraphylla L. grow well during April to September with longer daylength and maximum light intensity. Growth of both the species continues during rest months with slow rate. From their overall performance in their normal habitat R. serpentina seems to appear that it can tolerate some shading as against R. tetraphylla.   Objective: To study the growth behaviour of R. serpentina and R. tetraphylla under three different light intensities i.e. full open sun, partial shade and shade in a glasshouse.   Materials and Methods: Experiments were done on three light regimes measured with the help of luxmeter, i.e. full light under natural condition with 100% light under netted cloth cover with 90% and diffused light under muslin cloth with 70% Seedlings were raised in earthenware pots. The harvesting was started after 2 weeks after transference of the plants to their appropriate light intensities. The performance of species was judged with respect to mean dry weight accumulation, leaf area increase, relative growth rate, leaf area ratio, specific leaf area, leaf weight ratio, net assimilation rate and α.   Results: In both species dry weight and leaf area increased steadily in successive harvests but R. serpentina and R. tetraphylla appear to behave differently in their response to different light regimes. R. serpentina grows well in partial shade and full light as against R. tetraphylla which does well in full light than in partial shade. R. serpentina always maintained an edge over R. tetraphylla.   Conclusion: Both species showed the value of α more than one in most regimes. It means that they are morphogenetically well balanced and are ready for flowering. Keywords: Artificial shading; Growth; Morphogenesis; Rauvolfia serpentine; R. tetraphylla. DOI: http://dx.doi.org/10.3329/jbs.v18i0.8770 JBS 2010; 18(0): 21-26

scholarly journals Productive characteristics of the grass Digitaria umfolozi subjected to defoliation frequencies

2017 ◽  
Vol 38 (1) ◽  
pp. 343 ◽  
Author(s):  
Helber Rodrigues Araujo ◽  
José Henrique de Albuquerque Rangel ◽  
Jailson Lara Fagundes ◽  
Evandro Neves Muniz ◽  
Daniel De Oliveira Santos ◽  
...  
Keyword(s):  
Protein Content ◽  
Crude Protein ◽  
Dry Matter ◽  
Accumulation Rate ◽  
Light Interception ◽  
Utilization Efficiency ◽  
Dry Matter Accumulation ◽  
Crude Protein Content ◽  
Area Index ◽  
Dead Material

An experiment was carried out to evaluate the dry matter production, total dry matter availability, daily dry matter accumulation rate, light interception, leaf area index, daily accumulation rate, dry matter availability of the morphological components (leaf blades, stems + sheaths and dead material), leaf/stem ratio, crude protein, neutral detergent fibre and acid detergent fibre of Faixa-Brancagrass under seven defoliation frequencies (14, 21, 28, 35, 42, 49, and 56 days). Longer defoliation frequencies reduced the percentage of leaf blades and increased the percentage of stems + sheaths. The defoliation frequency positively influenced the availability of leaf blades, stems + sheaths, dead material and total dry matter. In the range of 42 days of defoliation, light interception reached 95%. At frequencies of 14 and 21 days of defoliation, the crude protein content of the leaves was above 20%. The highest utilization efficiency of D. umfolozi grass is achieved when the forage is managed with cutting intervals of 40 to 46 days. Higher defoliation frequencies positively contribute to the increase in the number of total white band grass leaves and higher crude protein content of the leaf blades and stems + sheaths.

scholarly journals Growth and Yield of Okra (Abelmoschus esculentus Moench) as Influenced by Compost Application under Different Light Intensities

2015 ◽  
Vol 7 (2) ◽  
pp. 217-226 ◽  
Author(s):  
Victor A. DADA ◽  
Sifau A. ADEJUMO
Keyword(s):  
Light Intensity ◽  
Leaf Area ◽  
Abelmoschus Esculentus ◽  
Growth And Yield ◽  
Dry Matter Accumulation ◽  
Low Light ◽  
Light Reduction ◽  
Low Light Intensity ◽  
Light Intensities ◽  
Leaf Formation

Okra (Abelmoschus esculentus) is one of the popular vegetables, especially rich in iron, vitamins and other minerals. Poor soil fertility and inconsistent light intensity, due to unfavorable weather condition, reduce okra performance. Response of two okra varieties (‘NH47-4’ and ‘Clemson spine’) to different rates of compost (0, 5, 10 and 15 t/ha), under different light intensities (L0: control (no reduction) or 100% light intensity, L1: 33%, L2: 46% and L3: 76%, light reduction) were assessed in pot and field trials. The experimental design was a factorial experiment fitted in a randomized complete block design (RCBD). Data on growth and yield attributes were collected. The results showed that the reduction in light intensity (L3) increased the numbers of fruits and leaf area by 50 and 47% respectively on the field, but delayed flowering. High light intensity (L0) though enhanced leaf area formation and early flowering, but hastened leaf senescence and abscission. Compost generally increased growth rate, leaf area and dry matter accumulation of the two okra cultivars compared to control under varying light intensities. Compost at 15 t/ha performed better and increased fruit number by 66% on the field. Between the two cultivars, ‘Clemson spine’ responded better than ‘NH47-4’ plants in terms of yield. Low light intensity (76% light reduction) in combination with higher compost rate however enhanced prolonged fruiting and leaf formation in the two okra varieties. The application of compost at 15 t/ha is therefore recommended for optimum yield of okra under low light intensity.

scholarly journals Effect of chlorophyll biosynthesis-related genes on the leaf color in Hosta (Hosta plantaginea Aschers) and tobacco (Nicotiana tabacum L.)

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Jingying Zhang ◽  
Changhai Sui ◽  
Huimin Liu ◽  
Jinjiao Chen ◽  
Zhilin Han ◽  
...  
Keyword(s):  
Light Intensity ◽  
Antioxidant Capacity ◽  
Aminolevulinic Acid ◽  
Chlorophyll Biosynthesis ◽  
Expression Level ◽  
Virus Induced Gene Silencing ◽  
Leaf Color ◽  
Color Changes ◽  
Light Intensities ◽  
Structure Changes

Abstract Background ‘Regal Splendour’ (Hosta variety) is famous for its multi-color leaves, which are useful resources for exploring chloroplast development and color changes. The expressions of chlorophyll biosynthesis-related genes (HrHEMA, HrPOR and HrCAO) in Hosta have been demonstrated to be associated with leaf color. Herein, we isolated, sequenced, and analyzed HrHEMA, HrPOR and HrCAO genes. Subcellular localization was also performed to determine the location of the corresponding enzymes. After plasmid construction, virus-induced gene silencing (VIGS) was carried out to reduce the expressions of those genes. In addition, HrHEMA-, HrPOR- and HrCAO-overexpressing tobacco plants were made to verify the genes function. Changes of transgenic tobacco were recorded under 2000 lx, 6000 lx and 10,000 lx light intensity. Additionally, the contents of enzyme 5-aminolevulinic acid (5-ALA), porphobilinogen (PBG), chlorophyll a and b (Chla and Chlb), carotenoid (Cxc), superoxide dismutase (SOD), peroxidase (POD), malondialdehyde (MDA), proline (Pro) and catalase (CAT) under different light intensities were evaluated. Results The silencing of HrHEMA, HrPOR and HrCAO genes can induce leaf yellowing and chloroplast structure changes in Hosta. Specifically, leaves of Hosta with HrCAO silencing were the most affected, while those with HrPOR silencing were the least affected. Moreover, all three genes in tobacco were highly expressed, whereas no expression was detected in wild-type (WT). However, the sensitivities of the three genes to different light intensities were different. The highest expression level of HrHEMA and HrPOR was detected under 10,000 lx of illumination, while HrCAO showed the highest expression level under 6000 lx. Lastly, the 5-ALA, Chla, Cxc, SOD, POD, MDA, Pro and CAT contents in different transgenic tobaccos changed significantly under different light intensities. Conclusion The overexpression of these three genes in tobacco enhanced photosynthesis by accumulating chlorophyll content, but the influential level varied under different light intensities. Furthermore, HrHEMA-, HrPOR- and HrCAO- overexpressing in tobacco can enhance the antioxidant capacity of plants to cope with stress under higher light intensity. However, under lower light intensity, the antioxidant capacity was declined in HrHEMA-, HrPOR- and HrCAO- overexpressing tobaccos.

A laboratory study of vertical migration

1955 ◽  
Vol 144 (916) ◽  
pp. 329-354 ◽  
Keyword(s):  
Light Intensity ◽  
Vertical Migration ◽  
Time Course ◽  
Tap Water ◽  
Low Light ◽  
Overhead Light ◽  
Light Intensities ◽  
Orientation Response ◽  
Reduced Light ◽  
Characteristic Maximum

In a tank filled with a suspension of indian ink in tap water, a population of Daphnia magna will undergo a complete cycle of vertical migration when an overhead light source is cycli­cally varied in intensity. A ‘dawn rise’ to the surface at low intensity is followed by the descent of the animals to a characteristic maximum depth. The animals rise to the surface again as the light decreases, and finally show a typical midnight sinking. The light intensities at the level of the animals in this experiment are of the same order as those which have been reported in field observations; the time course of the movement also repeats the natural conditions in the field. The process is independent of the duration of the cycle and is related only to the variation in overhead light intensity. At low light intensity the movement of the animal is determined solely by positive photo-kinesis; the dawn rise is a manifestation of this, and is independent of the direction of the light. At high light intensities there is an orientation response which is superimposed upon an alternating positive (photokinetic) phase and a negative phase during which movement is inhibited. The fully oriented animal shows a special type of positive and negative phototaxis, moving towards the light at reduced light intensities and away from it when the light intensity is increased. In this condition it follows a zone of optimum light intensity with some exactness. Experiments show that an animal in this fully oriented condition will respond to the slow changes of intensity characteristic of the diurnal cycle, while being little affected by tran­sient changes of considerable magnitude.

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