The Effect of Reduced Light Intensity on Grass Weeds

Weed Science ◽  
2017 ◽  
Vol 65 (5) ◽  
pp. 603-613 ◽  
Author(s):  
Muhammad Yasin ◽  
Eva Rosenqvist ◽  
Christian Andreasen
Keyword(s):  
Light Intensity ◽  
Plant Height ◽  
Dry Matter ◽  
Photochemical Efficiency ◽  
Grass Species ◽  
Weed Species ◽  
Annual Bluegrass ◽  
Light Levels ◽  
Number Of Leaves ◽  
Reduced Light

The effect of reduced light intensity on the growth and development of three common grass weeds, blackgrass, silky windgrass, and annual bluegrass, was studied. Two identical greenhouse experiments displaced in time were performed with six light levels aiming at 0%, 20%, 50%, 80%, 90%, and 95% shade corresponding to a mean daily light integral (DLI) of 12.4, 9.63, 7.13, 2.74, 0.95, and 0.69 mol m−2d−1in experiment 1 and 21.2, 18.0, 10.7, 3.71, 1.64, 1.20 mol m−2d−1in experiment 2. Climate screens of acrylic fabric were used to create the light levels. A DLI of 0.69 to 3.71 mol m−2d−1substantially reduced the plant height, the number of leaves, leaf chlorophyll content index, stomatal conductance, maximum photochemical efficiency of photosystem II, and dry matter of blackgrass. It also reduced plant height, the number of leaves, and dry matter and delayed flowering of windgrass and annual bluegrass. Annual bluegrass reacted most rapidly when light levels increased from the lowest levels by producing more leaves. DLI thresholds for blooming were estimated to be about 7.13 mol m−2d−1for windgrass and 1.64 mol m−2d−1for annual bluegrass. Annual bluegrass was able to bloom and sustain biomass even at a DLI of 1.64 mol m−2d−1. This ability may contribute to an explanation of why annual bluegrass is among the most common weed species in highly competitive and well-fertilized crops even though it is much smaller than the two other grass species.

Growth of Amaranthus Hybridus (African Spinach) under diffferent Daylight Intensities in the Dry Season in Southern Nigeria

1987 ◽  
Vol 23 (2) ◽  
pp. 193-200 ◽  
Author(s):  
J. M. O. Eze
Keyword(s):  
Light Intensity ◽  
Biochemical Parameters ◽  
Dry Matter ◽  
Maximum Growth ◽  
Area Ratio ◽  
Dry Matter Accumulation ◽  
Amaranthus Hybridus ◽  
Maximum Accumulation ◽  
Southern Nigeria ◽  
Reduced Light

SummaryThe growth of Amaranthus hybridus under different daylight intensities was assessed in terms of physical, morphological and biochemical parameters. Maximum growth in many respects was achieved at about 70% of full daylight. However, full daylight favoured chlorophyll stability and maximum accumulation of total dry matter, carbohydrate, chlorophyll and ascorbic acid. The leaf area ratio increased uniformly with decrease in light intensity. Ageing was accelerated by full daylight. Reduced light intensity reduced dry matter accumulation in the roots more than in the stems or leaves.

scholarly journals Effects of Photosynthetic Activity Radiation (PAR) on Green Mustard Plant Growth (Brassica rapa var. parachinensis L.)

2019 ◽  
Vol 20 (1) ◽  
pp. 19
Author(s):  
Ni Nyoman Ratini ◽  
I Wayan Supardi ◽  
Yuli Nurfadhillah
Keyword(s):  
Growth Rate ◽  
Light Intensity ◽  
Plant Height ◽  
Photosynthetic Activity ◽  
Plant Biomass ◽  
Vegetative Phase ◽  
Active Radiation ◽  
Blue Filter ◽  
Mustard Plant ◽  
Number Of Leaves

A research on the effect of photosynthetic active radiation (PAR) on the growth of green mustard plants has been conducted. The radiation source used is sunlight. Samples have been grouped as a sample which treated by red filter (P1), by orange filter (P2), by purple filter (P3), by green filter (P4), by blue filter (P5) and a sample without filter as a control (P0). Each sample consisted of four plants. The planting was carried out using polybags with compost media. Observations were made from the nursery phase to the slow vegetative phase (day 3rd, when all plants had grown shoots until day 63rd of the harvest). Parameters measured include light intensity, plant height and number of leaves. Measurement is done every three days. Also it measured plant biomass on the last day of observation (63rd day). The results showed that the intensity of each sample had an impact on the harvest. The best growth rate is obtained in P2, both in the nursery phase and fast vegetative phase i.e. 0.119 cm/day and 0.194 cm/day, respectively. While the highest growth rate was obtained in the P3 sample, namely the slow vegetative phase (0.035 cm/day). Overall the best planting results were obtained in P2 samples with plant height of 23.18 cm, number of leaves of 12 strands and plant biomass of 33.56 g.

scholarly journals Effect of Planting Date and Gibberellic Acid on the Growth and Yield of Garlic

2010 ◽  
pp. 132-140 ◽  
Author(s):  
MA Islam ◽  
MH Reza ◽  
SMAHM Kamal ◽  
MA Wazed ◽  
KM Islam
Keyword(s):  
Gibberellic Acid ◽  
Plant Height ◽  
Dry Matter ◽  
Dry Weight ◽  
Planting Date ◽  
Growth And Yield ◽  
Planting Time ◽  
Local Cultivar ◽  
Number Of Leaves ◽  
Bulb Yield

An experiment was conducted with a local cultivar of garlic to study the effects of planting date and gibberellic acid on the growth and yield of garlic at the field laboratory of the Department of Crop Botany, Bangladesh Agricultural University, Mymensingh during November 2001 to April 2002. Early planting influenced the plant height, leaf number, bulb diameter and total dry matter. With the delay in planting time starting from November 7, the yield was chronologically reduced in later plantings. Significantly the highest bulb yield (2.67 t/ha) was recorded when planting was done on November 7 and lowest yield (0.92 t/ha) was obtained from December 22 planted crop. Bulb yield was higher in control plants than those of GA3 treated plants. The interaction effects of planting date and different concentrations of GA3 differed significantly in respect of plant height, number of leaves, bulb diameter and dry weight of roots, leaves and bulbs and yield of garlic.

scholarly journals Assimilate partitioning and phytotoxicity in soybean plants treated with herbicides

1996 ◽  
Vol 14 (1) ◽  
pp. 48-54 ◽  
Author(s):  
Ricardo A. Marenco ◽  
Nei F. Lopes
Keyword(s):  
Plant Height ◽  
Dry Matter ◽  
Growth Stage ◽  
Plant Part ◽  
Dry Matter Accumulation ◽  
Assimilate Partitioning ◽  
Developing Seeds ◽  
Number Of Leaves ◽  
Stems And Leaves ◽  
Soybean Plants

To investigate the effects of trifluralin, chlorimuron and clomazone on morphology and assimilate partitioning during soybean development, plants were grown in a greenhouse and sampled at 14-day intervals. Clomazone reduced stem and leaf dry matter accumulation at 14 days after emergence (DAE), while trifluralin and chlorimuron reduced plant part dry matter accumulation up to 28 DAE. The number of leaves, plant height, mass and number of pods and seeds, and the shoot/root ratio were not influenced by the herbicides. Roots, stems and leaves were the preferred sinks up to the R2 growth stage, while pods and developing seeds became the preferred sinks later. This order was not altered by the herbicides.

scholarly journals ALTERNATIVE SUBSTRATES FOR PRODUCTION OF YELLOW PASSION FRUIT SEEDLINGS

2020 ◽  
Vol 7 (1) ◽  
pp. 43-48
Author(s):  
Eduardo Santana Aires ◽  
Carlos Alberto Aragão ◽  
Itala Laiane Silva Gomes ◽  
Gilmário Noberto de Souza ◽  
Isa Gabriela Vieira de Andrade
Keyword(s):  
Plant Height ◽  
Dry Matter ◽  
Passion Fruit ◽  
Dry Matter Accumulation ◽  
Alternative Substrates ◽  
Randomized Design ◽  
Length Width ◽  
Number Of Leaves ◽  
Completely Randomized Design ◽  
Yellow Passion Fruit

This study aimed to evaluate different substrates to produce yellow passion fruit seedlings. For this purpose, an experiment was carried out in a greenhouse, from April to June 2016. A completely randomized design with five replications, in a 6 x 5 factorial scheme was used. The first factor was the alternative substrates (poultry, cattle and equine manure, sugarcane and coconut bagasse, and Organomais compost). The second factor was the replacement levels to the commercial substrate of Plantmax® (100:0, 75:25, 50:50, 25:75, 0:100). The seedling evaluation was carried out 42 days after sowing. The following variables were analyzed: length, width, and the number of leaves; plant height and shoot dry matter. A significant effect (P0.05) for the interaction between the factors was verified. The addition of 60% cattle manure and Organomais to the commercial substrate Plantmax® promoted greater length, width, and the number of leaves, plant height, and shoot dry matter accumulation in the yellow passion fruit seedlings.

scholarly journals Interference of soybean and corn with Chloris distichophylla

2013 ◽  
Vol 37 (4) ◽  
pp. 306-312 ◽  
Author(s):  
Alana Cristina Dorneles Wandscheer ◽  
Mauro Antônio Rizzardi
Keyword(s):  
Plant Height ◽  
Dry Matter ◽  
Total Density ◽  
Weed Species ◽  
Replacement Series ◽  
Crop Season ◽  
Crop Species ◽  
Agricultural Ecosystems ◽  
Corn Plants ◽  
The University

In nature, plants interact with each other and establish positive, negative, and neutral interference relationships. In agricultural ecosystems, crops are usually affected by competition with weeds, and the effects of this process are influenced by the plant population density and proportional abundance and by the species involved. The present study evaluates the competitive interactions of soybean and corn with Chloris distichophylla. Two experiments were conducted in a greenhouse belonging to the University of Passo Fundo during the 2011/12 crop season: one experiment involving corn and C. distichophylla and another involving soybean and C. distichophylla. The experimental units were plastic pots, and the treatments were based on a replacement series, with a constant total density of eight plants per pot. The treatments included five combinations of soybean or corn plants with the weed species (8:0, 6:2, 4:4, 2:6 and 0:8), corresponding to relative abundances of 100, 75, 50, 25 and 0% of the crop species (and the reverse for the weed species). Competitiveness was analyzed using replacement-series experiment diagrams and competitive indices. Total dry matter and plant height were the two variables analyzed. The competitive indices indicated that corn and soybean crops were more competitive than the weed. The plant height was not affected by competition between both the species.

scholarly journals Leaf Characteristics and Yield Performance of Mungbean (Vigna radiata L.) Varieties under Different Levels of Shading

2018 ◽  
Vol 15 (2) ◽  
pp. 40-51
Author(s):  
M A Hossain ◽  
M A Hasan ◽  
S Sikder ◽  
A K M M B Chowdhury
Keyword(s):  
Light Intensity ◽  
Grain Yield ◽  
Vigna Radiata ◽  
Dry Weight ◽  
Light Levels ◽  
Spongy Layer ◽  
Partial Shade ◽  
Shade Condition ◽  
Reduced Light ◽  
Leaf Dry Weight

An experiment was carried out to evaluate the leaf characteristics and yield performances of mungbean (Vigna radiata L.) under different light levels at the Crop Physiology and Ecology Research Field of Hajee Mohammad Danesh Science and Technology University, Dinajpur during March to June 2016. The experiment was laid out in a split plot design with three replications. Three light levels (L100 - 100 % light intensity, L75- 75 % light intensity and L50- 50% light intensity) were assigned in the main plots and four varieties (BARl Mung-6, BINA Mung-8, BINA Mung-5 and BU Mug-4) were assigned in subplots. Mosquito nets of different pore size were used for maintaining 75 and 50 percent light intensity. Leaf area was increased due to reduced light levels in all mugbean varieties but the increment was significant in BINA Mung-5 and BINA Mung-8 only at 75% light intensity at 40 days after sowing and only in BARI Mung-6 with L50 and BU Mug-4 with L75 and L50at 50 days after sowing. Due to reduced light levels, leaf dry weight was affected more in BINA Mung-5 and BU Mug- 4 than BARI Mung-6 and BINA Mung-8. Leaf thickness was reduced under shade in all the mungbean varieties, except in BU Mug-4 at 75% light intensity, and the reduction in leaf thickness was mainly due to the reduction in thickness of spongy layer. The palisade layer thickness was influenced insignificantly but spongy layer thickness was increased in BINA Mung-5 at 100% light intensity. The grain yields (t ha-1) of BARI Mung-6 and BINA Mung-8 remained stable under partial shade condition but the grain yield of BINA Mung-5 and BU Mug-4 was reduced drastically under partial shade condition. Higher leaf dry weight, number of pods plant-1, seeds pod-1, and heavier grains in BARI Mung-6 and BINA Mung-8 contributed to the higher grain yield plant-1 under partial shade condition than in BINA Mung-5 and BU Mug-4.The Agriculturists 2017; 15(2) 40-51

Effect of nitrogen and zinc on nodulation, growth and yield of cowpea (Vigna unguiculata)

2016 ◽  
Vol 39 (1) ◽  
Author(s):  
R. G. Upadhyay ◽  
Anita Singh
Keyword(s):  
Grain Yield ◽  
Plant Height ◽  
Dry Matter ◽  
Growth And Yield ◽  
Production Plant ◽  
Plant Seeds ◽  
Matter Production ◽  
Number Of Leaves ◽  
Four Levels ◽  
Number Of Branches

A pot experiment was conducted to determine the effect of zinc and nitrogen on growth, nodulation pattern and yield of cowpea. The treatments were four levels of nitrogen ( 0 , 10, 20 and 30 kg/ha) and four levels of zinc (0, 5, 10 and 15 kg/ha). Application of various levels of nitrogen significantly increased dry matter production/plant , plant height number of branches/ plant, effective nodules/ plant, total nodule / plant, effective nodules weight /plant, pods/plant , seeds/pod and grain yield. Similarly zinc significantly increased plant height, branches / plant, number of leaves/plant, dry matter /plant, effective nodules weight /plant and grain yield. There was no significant interaction between nitrogen and zinc on grain yield.

scholarly journals 018 EFFECTS OF ANCYMIDOL, PACLOBUTRAZOL, AND UNICONAZOLE ON GROWTH AND FLOWERING OF ACHIMENES cv HILDA UNDER TWO LIGHT LEVELS

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 430b-430
Author(s):  
J. C. Vlahos
Keyword(s):  
Plant Height ◽  
Light Level ◽  
The Other ◽  
Growth Retardants ◽  
Axillary Shoots ◽  
Full Sunlight ◽  
Foliar Sprays ◽  
Light Levels ◽  
Mode Of Application ◽  
Reduced Light

Plants of Achimenes cv Hilda were treated with foliar sprays of Ancymidol, Paclobutrazol and Uniconazole at 3 different concentrations each, and were placed in a greenhouse at 21°C under 2 light levels (0 and 40% light exclusion) for 12 weeks. Reduced light level decreased plant height, number of axillary shoots and flowers. The three growth retardants in any concentration, supressed development of axillary shoots and flowers. Ancymidol at 25 and 50 mg.1-1, Uniconazole at 5 mg.1-1 and Paclobutrazol at 25, 50 or 100 mg.1-1 decreased plant height and number of leaf whorls. Number of rhizomes was reduced by the 3 chemicals at the highest concentration only. Paclobutrazol was most effective than the other 2 growth retardants. Effects of treatments were more pronounced under shade rather than in full sunlight. Days to anthesis was not affected by any of the treatments except by Paclobutrazol at 100 mg.1-1. The use of these growth retardants in concentration and mode of application similar to those used in this study is not recommended for “Hilda” as height retardation significantly reduces number of flowers

scholarly journals Saline-sodic soil and organic matter addition in the cultivation of the colored cotton ‘BRS Topázio’

2016 ◽  
Vol 37 (2) ◽  
pp. 701
Author(s):  
Magaly Morgana Lopes da Costa ◽  
Reginaldo Gomes Nobre ◽  
Geovani Soares de Lima ◽  
Hans Raj Gheyi ◽  
Francisco Wesley Alves Pinheiro ◽  
...  
Keyword(s):  
Organic Matter ◽  
Leaf Area ◽  
Plant Height ◽  
Dry Matter ◽  
Block Design ◽  
Irrigation Management ◽  
Stem Diameter ◽  
Initial Growth ◽  
Exchangeable Sodium ◽  
Number Of Leaves

he prevailing climate of the semiarid region in the northeastern region of Brazil along with inadequate irrigation management, have caused the formation of halomorphic soils, which have hampered agricultural production and environmental sustainability of this region. Therefore, this study aimed to evaluate the emergence and initial growth of the cotton cultivar ‘BRS Topázio’ cultivated in soil with different levels of exchangeable sodium percentage (ESP) and concentrations of organic matter (OM) in a greenhouse from April to June 2014. The experiment was set in a randomized block design in a 5 × 4 factorial scheme, with three replicates, and the treatments consisted of five ESP levels (13.6, 22.4, 30.1, 39.0, and 48.0) and four OM concentrations (0, 5, 10, and 15% based on soil volume). Soils with an ESP ranging from 13.6 to 48.0 did not interfere with the emergence and number of leaves of cotton at 10 days after seeding (DAS). At 44 DAS, in the period preceding the flowering stage, ESPs ranging from 27 to 30 promoted greater plant height, stem diameter, and shoot fresh and dry matter. Increasing OM increased the emergence percentage and emergence speed index and, at 44 DAS, increased plant height, stem diameter, and shoot fresh and dry matter. Increasing OM mitigated the effect of the exchangeable sodium up to an ESP of 30 on the number of leaves, plant height, stem diameter, and leaf area at 10 DAS, and up to mean ESPs of 28.5 and 34.0 for the number of leaves and leaf area, respectively, at 44 DAS.

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