scholarly journals The effect of UV-B radiation on plant growth and development

2011 ◽  
Vol 49 (No. 3) ◽  
pp. 135-140 ◽  
Author(s):  
K. Zuk-Golaszewska ◽  
M.K. Upadhyaya ◽  
J. Golaszewski

In the experiment conducted in the greenhouse, the different doses of UV-B radiation applied to the two species Avena fatua and Setaria viridis induced changes in leaf and plant morphology. It was a decrease of plant height, fresh mass of leaves, shoots and roots as well as leaf area. Besides, it caused the leaf curling in both of the species. The significant differences between Avena fatua and Setaria viridis in the studied traits were mainly due to the tillering ability of the species. The content of chlorophyll varied considerably. The average values of leaf greenness (SPAD units) for oats were about 43 while for green foxtail 32, respectively. U-VB did not reduce leaf weight ratio, shoot dry matter, shoot to root ratio and leaf area ratio.

Author(s):  
Muhammad Zeeshan Mehmood ◽  
Ghulam Qadir ◽  
Obaid Afzal ◽  
Atta Mohi Ud Din ◽  
Muhammad Ali Raza ◽  
...  

AbstractSeveral biotic and abiotic stresses significantly decrease the biomass accumulation and seed yield of sesame crops under rainfed areas. However, plant growth regulators (such as Paclobutrazol) can improve the total dry matter and seed production of the sesame crop. The effects of the paclobutrazol application on dry matter accumulation and seed yield had not been studied before in sesame under rainfed conditions. Therefore, a two-year field study during 2018 and 2019 was conducted with key objectives to assess the impacts of paclobutrazol on leaf greenness, leaf area, total dry matter production and partitioning, seed shattering, and seed yield of sesame. Two sesame cultivars (TS-5 and TS-3) were treated with four paclobutrazol concentrations (P0 = Control, P1 = 100 mg L−1, P2 = 200 mg L−1, P3 = 300 mg L−1). The experiment was executed in RCBD-factorial design with three replications. Compared with P0, treatment P3 improved the leaf greenness of sesame by 17%, 38%, and 60% at 45, 85, and 125 days after sowing, respectively. However, P3 treatment decreased the leaf area of sesame by 14% and 20% at 45 and 85 days after sowing than P0, respectively. Compared with P0, treatment P3 increased the leaf area by 46% at 125 days after sowing. On average, treatment P3 also improved the total biomass production by 21% and partitioning in roots, stems, leaves, capsules, and seeds by 23%, 19%, 23%, 22%, and 40%, respectively, in the whole growing seasons as compared to P0. Moreover, under P3 treatment, sesame attained the highest seed yield and lowest seed shattering by 27% and 30%, respectively, compared to P0. This study indicated that by applying the paclobutrazol concentration at the rate of 300 mg L−1 in sesame, the leaf greenness, leaf areas, biomass accumulation, partitioning, seed yield, and shatter resistance could be improved. Thus, the optimum paclobutrazol level could enhance the dry matter accumulation and seed production capacity of sesame by decreasing shattering losses under rainfed conditions.


1997 ◽  
Vol 48 (1) ◽  
pp. 111 ◽  
Author(s):  
D. K. Singh ◽  
P. W. G. Sale

A glasshouse experiment was carried out to determine how an increasing P supply influences the growth and survival of white clover plants subjected to a range of defoliation frequencies. Treatments involved the factorial combination of P application rate (0, 30, 90, and 180 mg/pot) to a P-deficient Krasnozem soil and defoliation frequency (1, 2, or 4 defoliations over 36 days). The survival of P-deficient plants was threatened by the most frequent defoliation; their leaf area declined owing to a reduction in leaf number and individual leaf size with each successive defoliation. Increasing the P supply to 180 mg/pot reversed this downward trend as the high P plants were able to maintain leaf area by increasing leaf size and number. Increasing the frequency from 1 to 4 defoliations over the 36 days also changed the form of the leaf dry matter response to added P, from an asymptotic to a linear response. The P requirement of white clover for maximum leaf yield therefore increased under frequent defoliation. This effect was also apparent for a range of morphological measurements including stolon elongation rate, leaf area, root mass, leaf number, and stolon number, where the magnitude of the P response was consistently greater for frequently defoliated plants. Exceptions included stolon mass, which responded more to P addition under infrequent defoliation.


Weed Science ◽  
1977 ◽  
Vol 25 (5) ◽  
pp. 382-385 ◽  
Author(s):  
B.G. Todd ◽  
E.H. Stobbe

The selectivity of {2-[4-(2′,4′-dichlorophenoxy) phenoxy] methyl propionate}, (hereinafter referred to as dichlofop methyl), among wheat (Triticum aestivumL. ‘Neepawa’), barley (Hordeum vulgareL. ‘Bonanza’), wild oat (Avena fatuaL.), and green foxtail (Setaria viridis(L.) Beauv.) was investigated. On an ED50basis, barley, wild oat, and green foxtail were 2, 190, and 1,090 times more sensitive, respectively, to foliar-applied dichlofop methyl at the two-leaf stage than was wheat. Selectivity decreased with increasing maturity of the plant material with the ratio of selectivity between barley and wild oat decreasing from 55 at the two-leaf stage to three at the four-leaf-plus-one-tiller stage. Greater spray retention and more rapid penetration of dichlofop methyl partially explained the susceptibility of green foxtail, but did not explain selectivity between wheat, wild oat, and barley. Root uptake of14C-dichlofop methyl by the four species was proportional to the amount of solution absorbed during the treatment period and to the concentration of dichlofop methyl in the treatment solution but was not related to species sensitivity to this herbicide.


2021 ◽  
Vol 53 (2) ◽  
pp. 64-70
Author(s):  
Raphael Elias Da Silva Colla ◽  
Sebastião Ferreira de Lima ◽  
Eduardo Vendruscolo ◽  
Vinicius Andrade Secco ◽  
Gabriel Luiz Piati ◽  
...  

The largest corn yeld in Brazil is currently in the second harvest, which is the most susceptible period to climatic adversities occurring during the cycle. Thus, introducing beneficial elements for maintaining the adequate development of the plant can help producers in obtaining greater kernel yields. Among studied elements, nicotinamide has potential use since it is associated with accumulating secondary metabolites and manifesting defence metabolism in plants. The objective of this work was to evaluate the influence of nicotinamide applied in different doses (only once or in instalments) on the biometric and productive characteristics of corn. The treatments were composed by the number of nicotinamide applications (one or two) and five doses (0, 50, 100, 150 and 200 mg L-1). Plant diameter, plant height, ear insertion height, leaf area and dry matter, yield and 100-kernel mass were evaluated. It was found that doses close to 100 mg L-1 resulted in increases in vegetative and reproductive development, regardless of the number of applications. In this way, foliar nicotinamide application positively influences the biometric and productive characteristics of second crop corn. Highlights The use of nicotinamide in corn plants improves its growth, yield components and grain yield. A single application of nicotinamide during vegetative stage V3 at a dose of 100 mg L-1 is sufficient to increase the leaf area of corn plants. Corn grain yield can be increased by 12.6% with a single application of nicotinamide. There was no need for two applications of nicotinamide in corn crop.


Weed Science ◽  
1984 ◽  
Vol 32 (6) ◽  
pp. 774-780 ◽  
Author(s):  
Carol J. Bubar ◽  
Ian N. Morrison

The growth of green foxtail (Setaria viridisL. Beauv. ♯3SETVI) and yellow foxtail [S. lutescens(Weigel.) Hubb. ♯ SETLU] in full sunlight, under 55 and 73% shade and within a wheat (Triticum aestivumL. ‘Neepawa’) stand, was compared in field experiments conducted over 3 yr. Shade resulted in a proportionately greater reduction in tiller number of yellow foxtail than of green foxtail. Plants growing in full sunlight produced up to five times more tillers than those growing in the crop. Averaged over the 3 yr, the two shade treatments reduced dry-matter accumulation of both species by 40% or more. The dry weight of plants within the crop was only about one-eighth of that of plants grown in full sunlight. Under both shade treatments and in the crop, yellow foxtail was consistently taller than green foxtail. Nevertheless, no differences in dry weight occurred between species under either shade treatment or in the crop. The results indicate that neither of the two species is distinctly more shade tolerant than the other, nor better adapted to compete with wheat.


2011 ◽  
Vol 68 (2) ◽  
pp. 191-199 ◽  
Author(s):  
María Teresa Castellanos ◽  
María Jesús Cabello ◽  
María del Carmen Cartagena ◽  
Ana María Tarquis ◽  
Augusto Arce ◽  
...  

Nitrogen (N) is an important nutrient for melon (Cucumis melo L.) production. However there is scanty information about the amount necessary to maintain an appropriate balance between growth and yield. Melon vegetative organs must develop sufficiently to intercept light and accumulate water and nutrients but it is also important to obtain a large reproductive-vegetative dry weight ratio to maximize the fruit yield. We evaluated the influence of different N amounts on the growth, production of dry matter and fruit yield of a melon 'Piel de sapo' type. A three-year field experiment was carried out from May to September. Melons were subjected to an irrigation depth of 100% crop evapotranspiration and to 11 N fertilization rates, ranging 11 to 393 kg ha-1 in the three years. The dry matter production of leaves and stems increased as the N amount increased. The dry matter of the whole plant was affected similarly, while the fruit dry matter decreased as the N amount was increased above 112, 93 and 95 kg ha-1, in 2005, 2006 and 2007, respectively. The maximum Leaf Area Index (LAI), 3.1, was obtained at 393 kg ha-1 of N. The lowest N supply reduced the fruit yield by 21%, while the highest increased the vegetative growth, LAI and Leaf Area Duration (LAD), but reduced yield by 24% relative to the N93 treatment. Excessive applications of N increase vegetative growth at the expense of reproductive growth. For this melon type, rates about 90-100 kg ha-1 of N are sufficient for adequate plant growth, development and maximum production. To obtain fruit yield close to the maximum, the leaf N concentration at the end of the crop cycle should be higher than 19.5 g kg-1.


Revista CERES ◽  
2016 ◽  
Vol 63 (1) ◽  
pp. 16-24 ◽  
Author(s):  
Deborah Amorim Martins ◽  
Adriano Jakelaitis ◽  
Isabella Sichierski Cardoso ◽  
Alan Carlos Costa ◽  
Juliana de Fátima Sales

ABSTRACT Sorghum arundinaceum (Desv.) Stapf is a weed that belongs to the Poaceae family and is widespread throughout Brazil. Despite the frequent occurrence, infesting cultivated areas, there is little research concerning the biology and physiology of this species. The objective of this research was to evaluate the growth, carbon partitioning and physiological characteristics of the weed Sorghum arundinaceum in greenhouse. Plants were collected at regular intervals of seven days, from 22 to 113 days after transplanting (DAT). In each sample, we determined plant height, root volume, leaf area and dry matter, and subsequently we perfomed the growth analysis, we have determined the dry matter partitioning among organs, the accumulation of dry matter, the specific leaf area, the relative growth rate and leaf weight ratio. At 36, 78 and 113 DAT, the photosynthetic and transpiration rates, stomatal conductance, CO2 concentration and chlorophyll fluorescence were evaluated. The Sorghum arundinaceum reached 1.91 in height, with slow initial growth and allocated much of the biomass in the roots. The photosynthetic rate and the maximum quantum yield of FSII are similar throughout the growth cycle. At maturity the Sorghum arundinaceum presents higher values of transpiration rate, stomatal conductance and non-photochemical quenching coefficient (NPQ).


1991 ◽  
Vol 71 (3) ◽  
pp. 821-829 ◽  
Author(s):  
K. N. Harker ◽  
P. A. O'Sullivan

Field experiments were conducted at the Lacombe Research Station to determine the influence of growth stage on the control of wild oat (Avena fatua L.) and Tartary buckwheat (Fagopyrum tartaricum (L.) Gaertn.) with imazamethabenz in wheat (Triticum aestivum L.). In greenhouse experiments, the effct of imazamethabenz on canola (Brassica campestris L.) or green foxtail (Setaria viridis L. Beauv.) at two growth stages was also studied. Canola and wild oat were highly susceptible, Tartary buckwheat was somewhat less susceptible, and green foxtail was rather tolerant to imazamethabenz. Imazamethabenz was much more effective on early growth stages of wild oat (2 leaf) and Tartary buckwheat (1–2 leaf), whereas the control of canola and the suppression of green foxtail was much less dependent on growth stage. Linear regression equations were developed to describe the response of the above species to the imazamethabenz treatments. Key words: AC 222, 293; phenology; regression; Setaria viridis; Fagopyrum tartaricum; Avena fatua


1977 ◽  
Vol 57 (2) ◽  
pp. 479-484 ◽  
Author(s):  
J. R. MOYER ◽  
R. D. DRYDEN

Tank mixtures of solution nitrogen, triallate [S-(2,3,3-trichloroallyl)diisopropyl-thiocarbamate] and/or trifluralin [α,α,α,-trifluro-2, 6-dinitro-N, N-dipropyl-p-toluidine] were evaluated for the control of wild oats (Avena fatua L.) and/or green foxtail (Setaria viridis (L.) Beauv.). The response of wheat (Triticum aestivum L.) cv. Neepawa to solution nitrogen applied alone or in combination with triallate and/or trifluralin were evaluated. Good control of wild oats and green foxtail was obtained with a tank mixture of solution nitrogen, trifluralin at 1.38 kg/ha, and triallate at 1.65 kg/ha. Tank mixtures of triallate at 1.65 kg/ha with solution nitrogen controlled wild oats. Trifluralin at 1.38 kg/ha with solution nitrogen controlled wild oats and green foxtail. Control of green foxtail and wild oats resulted in increased wheat yields, higher nitrogen content in wheat grain, and a more efficient use of applied nitrogen fertilizer. The response of wheat to nitrogen was similar when nitrogen was applied in tank mixes with herbicides or with water to hand-weeded plots.


1979 ◽  
Vol 59 (2) ◽  
pp. 383-389 ◽  
Author(s):  
J. R. MOYER ◽  
R. D. DRYDEN

Twelve weed control treatments recommended for corn (Zea mays L.) in the dryland areas of Western Canada were compared over a 3-yr period from 1975 to 1977. Corn yields were similar after treatment with atrazine (2-chloro-4-ethylamino-6-(isopropylamino)-s-triazine) alone, plus cultivation, or plus butylate (S-ethyl di-diisobutylthiocarbamate), or EPTC (S-ethyl dipropylthiocarbamate) plus R25788 (N,N-diallyl-2,2-dichloroacetamide). Wild oats (Avena fatua L.) were consistently controlled by atrazine or by EPTC plus R25788 applied and incorporated before seeding. Postemergence applications of atrazine plus oil also effectively controlled wild oats. Butylate was not as effective as atrazine or EPTC plus R25788 in the control of wild oats. EPTC plus R25788 and butylate consistently controlled green foxtail (Setaria viridis (L.) Beauv.) while atrazine effectively controlled green foxtail only in 1976 when rainfall was above normal during the period of green foxtail emergence and initial growth. Broad-leaved weeds were controlled by atrazine with all methods of application. The preplant incorporation of atrazine plus butylate and the postemergence application of atrazine plus oil in a band over the row followed by interrow cultivation consistently controlled all weeds. Wild oats and broad-leaved weeds greatly reduced corn yields whereas green foxtail did not compete strongly with corn. Green foxtail was present only in the unweeded and atrazine treatments and, in those treatments, its ability to compete with corn may have been reduced by either wild oats or atrazine, respectively.


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