scholarly journals New approaches to the action of silicon to enable the cultivation of Panicum maximum in soil with water restriction

Author(s):  
Juan Ricardo Rocha ◽  
Renato Mello Prado ◽  
Marisa Cássia Piccolo

Abstract Climate change increases the occurrence of droughts, decreasing the production of tropical forages through the induction of physiological stress. Si is expected to broaden the limit from physiological stress of forages grown under water restriction, which may come from an improvement in the stoichiometric homeostasis of Si with N and C, favoring physiological aspects. This study assessed whether Si supply via fertigation improves physiological aspects and the water content in the plant by means of an antioxidant defense system and changes in the C:N:Si stoichiometry during the regrowth of two cultivars of Panicum maximum grown under two soil water regimes (70 and 40% of the soil’s water retention capacity). The forages studied are sensitive to water deficit without silicon supply. The application of Si via fertigation attenuated the water deficit, favoring plant growth by stabilizing the stoichiometric homeostasis C:N and C:Si, which are responsible for increasing the plant capacity of converting accumulated C in dry mass, favoring the water content of the plant tissue and the photosynthetic efficiency. This study highlights the importance of the physiological function of Si, and effects on the stoichiometry of C and N, which are neglected in most research on forages grown under water restriction.

2023 ◽  
Vol 83 ◽  
Author(s):  
E. M. M. Bartieres ◽  
D. M. Dresch ◽  
L. C. Reis ◽  
Z. V. Pereira ◽  
R. M. Mussury ◽  
...  

Abstract The objective of this study was to evaluate the activity of antioxidant enzymes, the functioning of the photosystem II and quality of C. xanthocarpa seedlings cultivated under intermittent water deficit and shading levels and the influence of shading on recovery potential after suspension of the stress conditions. The seedlings were subjected to three levels of shading (0, 30, and 70%), six periods of evaluation (start: 0 days; 1st and 2nd photosynthesis zero: 1st and 2nd P0; 1st and 2nd recovery: 1stand 2nd REC; and END), and two forms of irrigation (control: periodically irrigated to maintain 70% substrate water retention capacity, and intermittent irrigation: suspension of irrigation). The plants subjected to intermittent irrigation conditions at 0% shading showed a reduction in water potential (Ψw) and potential quantum efficiency of photosystem II (Fv/Fm) and maximum efficiency of the photochemical process (Fv/F0) and an increase in basal quantum production of the non-photochemical processes (F0/Fm). Superoxide dismutase (SOD) activity was higher in the leaves than in the roots. The C. xanthocarpa is a species sensitive to water deficit but presents strategies to adapt to an environment under temporary water restriction, which are more temporary are most efficient under shading. The seedlings with water deficit at all levels of shading exhibited higher protective antioxidant activity and lower quality at 0% shading. The shading minimizes prevents permanent damage to the photosystem II and after the re-irrigation, the evaluated characteristics showed recovery with respect to the control group, except POD and SOD activities in the leaves.


2020 ◽  
Vol 19 ◽  
pp. 10
Author(s):  
DANIELLE REZENDE VILELA ◽  
NATHALIA REZENDE RIBEIRO ◽  
HELOISA OLIVEIRA DOS SANTOS ◽  
ÉDILA VILELA RESENDE VON PINHO ◽  
RENATO COELHO DE CASTRO VASCONCELLOS ◽  
...  

Seed size may affect the initial development of seedlings, especially under adverse conditions such as water deficit. The objective of this study was to characterize the influence of seed size on traits presented by maize seedlings under contrasting conditions of water availability. The experiment was conducted with a tolerant line (L91), a non-tolerant line (L57), and with the F2 resulting from the cross between those lines. The seeds were classified with the use of round-hole sieves and those retained on sieves of sizes 22, 20 and 18/64” were used. The seeds were sown in trays containing sand and, in order to simulate water deficit, the water retention capacity was adjusted to 10% (stress) and 70% (control). Four replications were used, with 25 seeds per treatment, which were stored in a growth chamber at 25 ºC for 7 days. Then the number of seminal roots, length of root and shoot, and their weights (fresh, dry and total) were evaluated. The seed size directly influences the development of maize seedlings, when subjected to water restriction, regardless of whether they are lines or F2. In this case, the larger-size sieves (22 and 20) were superior when compared with the size 18. In the early stages, the L57 was more tolerant to water restriction when compared with L91.


2020 ◽  
Vol 202 (11) ◽  
pp. 2-13
Author(s):  
Svetlana Denisova ◽  
Antonina Reut

Abstract. Purpose. Study of the effect of anti-stress adaptogens on the water regime of some varieties of chrysanthemum in the conditions of the Bashkir Pre-Urals. Methodology and methods. The analysis of indicators of water regime is based on the method of artificial wilting (V. N. Tarenkov, L. N. Ivanova) and the method of saturation of plant samples (V. P. Moiseev, N. P. Reshetskiy). Plants were processed once, and samples were taken in three terms. Calculations were carried out by standard methods using statistical packages of the Microsoft Excel 2003 and the Agros 2.13. Results. The dynamics of indicators of the water regime during the treatment with the preparations “Gumi-20” and “Oberig” is analyzed. An assessment of the total water content, water retention capacity, daily moisture loss and water deficit of ten varieties of chrysanthemum bred by the South-Ural Botanical Garden-Institute of UFRC RAS (SUBGI UFRC RAS) in the period under study is given. Studies have shown that varieties of chrysanthemum in the Bashkir Ural under the same soil-climatic and agrotechnical conditions had the following indicators: total water content ‒ 69.4–86.9 %, water-holding capacity ‒ 25.6–53.8 %, daily moisture loss ‒ 17.2–61.0 %, water deficit ‒ 10.9–13.2 %. The use of anti-stress adaptogens did not have a significant effect on the parameters of the water regime, or their effect was variety-specific. As a result of the correlation-regression analysis, inverse relationships were revealed between the indicators of water deficit and the total water content, as well as between the daily water loss and water retention capacity. Scientific novelty. For the first time, the water regime of varieties of chrysanthemum of the SUBGI UFRC RAS selection was studied, the dependences of the water regime indicators were revealed, and the assessment of the expediency of using anti-stress adaptogens for certain varieties in the conditions of the Bashkir Pre-Urals was given.


Author(s):  
Jéssica Cezar Cassol ◽  
Sidinei José Lopes ◽  
Sylvio Henrique Bidel Dornelles ◽  
Mariane Peripolli ◽  
Luciane Almeri Tabaldi

Silicon is an enzyme stimulator that promotes signaling for the production of antioxidant, osmoprotective compounds and attenuates interference in photosynthesis in rice plants subjected to water deficit. The aim of this study was to evaluate the possible effects of silicon as a stress reliever in rice plants grown from seeds treated with dietholate under of water deficit conditions. The experimental design was fully randomized with three replicates, 144 experimental units consisting of pots containing 4.4 pounds soil, and a 3x2x2x4 factorial arrangement: three soil water conditions (50% and 100% of soil water retention capacity and water blade of 5.0 cm); two cultivars (IRGA 424 RI and Guri INTA CL); two sources of Si (sodium and potassium metasilicate); and four Si rates (0; 4.0; 8.0 and 16 g L-1). Silicon boosted stomatal density; induced an increase in the maximum photochemical efficiency of photosystem II (PSII) under both water deficit and optimal conditions, boosting photosynthesis; and increased effective quantum yield of PSII and levels of total dry mass. Thus, silicon attenuated the effects of water deficit in plants grown from seeds treated with dietholate.


Author(s):  
Anthony S. R. Juo ◽  
Kathrin Franzluebbers

Allophanic soils are dark-colored young soils derived mainly from volcanic ash. These soils typically have a low bulk density (< 0.9 Mg/m3), a high water retention capacity (100% by weight at field capacity), and contain predominantly allophanes, imogolite, halloysite, and amorphous Al silicates in the clay fraction. These soils are found in small, restricted areas with volcanic activity. Worldwide, there are about 120 million ha of allophanic soils, which is about 1% of the Earth's ice-free land surface. In tropical regions, allophanic soils are among the most productive and intensively used agricultural soils. They occur in the Philippines, Indonesia, Papua New Guinea, the Caribbean and South Pacific islands, East Africa, Central America, and the Andean rim of South America. Allophanic soils are primarily Andisols and andic Inceptisols, Entisols, Mollisols, and Alfisols according to the Soil Taxonomy classification. Allophanic soils generally have a dark-colored surface soil, slippery or greasy consistency, a predominantly crumb and granular structure, and a low bulk density ranging from 0.3 to 0.8 Mg/m3. Although allophanic soils are apparently well-drained, they still have a very high water content many days after rain. When the soil is pressed between fingers, it gives a plastic, greasy, but non-sticky sensation of a silty or loamy texture. When dry, the soil loses its greasiness and becomes friable and powdery. The low bulk density of allophanic soils is closely related to the high soil porosity. For example, moderately weathered allophanic soils typically have a total porosity of 78%, with macro-, meso-, and micropores occupying 13%, 33%, and 32%, respectively. Water retained in the mesopores is readily available for plant uptake. Water retained in the micropores is held strongly by soil particles and is not readily available for plant use. The macropores provide soil aeration and facilitate water infiltration. The high water retention capacity is also associated with the high soil porosity. In allophanic soils formed under a humid climate, especially those containing large amounts of allophane, the moisture content at field capacity can be as high as 300%, calculated on a weight basis. Such extremely high values of water content seem misleading.


2018 ◽  
Vol 10 (5) ◽  
pp. 338
Author(s):  
Ronan C. Colombo ◽  
Adriane M. de Assis ◽  
Vanessa Favetta ◽  
Lilian Y. Yamamoto ◽  
Sergio R. Roberto

Lychee (Litchi chinensis Sonn.) propagation by cuttings is a promising alternative in commercial production of seedlings, since it is an easy procedure, in addition to enabling the standardization in the field and the reduction in production costs. Therefore the objective of this work was to evaluate ‘Bengal’ lychee cuttings rooting, collected in spring and summer, using different concentrations of indolebutyric acid (IBA) and substrates. The experimental design was completely randomized, in a 3 × 3 factorial arrangement, with 5 replications and 10 cuttings per plot, and the following factors were adopted: IBA concentrations (0; 1,000 and 2,000 mg L-1) and types of substrates (carbonized rice husk, vermiculite medium granules and coconut fiber). At 140 days, the following variables were evaluated: cuttings survival; leaf maintenance; cuttings unrooted with calli; cuttings rooted; roots number per cutting; root length and root dry mass. In addition, the pH, electrical conductivity, density and water retention capacity of the substrates were evaluated. There was no difference in IBA concentrations applied in both evaluated periods. However, in the spring, the carbonized rice husk provided highest mean for the measured variables. On the other hand, in the summer, the rooting percentage presented a lower average in all substrates (< 1%), independent of the IBA concentrations. It was concluded that the ‘Bengal’ lychee propagation by cutting can be carried out in the spring, using carbonized rice husk as substrate, without IBA.


2018 ◽  
Vol 50 ◽  
pp. 01011
Author(s):  
Joan Rossello ◽  
José M. Escalona ◽  
Josep Cifre ◽  
Jaume Vadell ◽  
Hipólito Medrano

Under the conditions of the semi-arid Mediterranean climate, soil depth and water retention capacity are the most important characteristics of the soil related to the quality of the wines. The availability of water will mark the development of the vines and the development and maturity of the grape. The characterization and agronomic evaluation of the soil has been carried out from the excavation of 38 soil pits in the main wine growing areas of Mallorca. Cambisols are the most predominant soil typology followed by Cambisols, Regosols and Luvisols. The water classification of the soils has been made according to the maximum water availability (useful water) in 2 m of soil (mm water / 2 m soil). The proposed levels are: very low (<120 mm), low (120-180 mm), Medium (180-240 mm), High (240-300 mm) and Very high> 300 (mm). The most abundant soil type we find that 47% have high soil water availability, 27% very high, 14% normal and 14% low. Establishing an area based on available water content is a tool that allows us to adjust the selection of the most suitable grape varieties in each soil, thus taking advantage more efficiently of the potential of each type of grape.


Geophysics ◽  
2002 ◽  
Vol 67 (2) ◽  
pp. 536-545 ◽  
Author(s):  
Remke L. Van Dam ◽  
Wolfgang Schlager ◽  
Mark J. Dekkers ◽  
Johan A. Huisman

Iron oxides frequently occur as secondary precipitates in both modern and ancient sediments and may form bands or irregular patterns. We show from time-domain reflectometry (TDR) field studies that goethite iron-oxide precipitates significantly lower the electromagnetic wave velocity of sediments. Measured variations in magnetic permeability do not explain this decrease. The TDR measurements and a dielectric mixing model also show that neither electrical conductivity nor relative permittivity of the solid material are altered significantly by the iron-oxide material. From drying during all of the measurements, the amount of iron oxides appears to correlate with the volumetric water content, which is the result of differences in water retention capacity between goethite and quartz. These variations in water content control relative permittivity and explain the observed variation in electromagnetic wave velocity. Using 2-D synthetic radar sections, we show that the pattern of iron-oxide precipitation may have a profound influence on the GPR reflection configuration and can cause major difficulties in interpretation.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Lu Zhang ◽  
Jichang Han

Abstract The Mu Us sandy land in China’s Shaanxi Province faces a critical water shortage, with its aeolian sandy soil endangering the regional eco-environment. Here we investigated the effects of feldspathic sandstone on water retention in an aeolian sandy soil from the Mu Us sandy land. Feldspathic sandstone and aeolian sandy soil samples were mixed at different mass ratios of 0:1 (control), 1:5 (T1), 1:2 (T2), and 1:1 (T3). Soil-water characteristic curves were determined over low- to medium-suction (1–1000 kPa) and high-suction (1000–140 000 kPa) ranges, by centrifuge and water vapor equilibrium methods, respectively. Results showed that the addition of feldspathic sandstone modified the loose structure of the aeolian sandy soil mainly consisting of sand grains. The van Genuchten model described well the soil-water characteristic curves of all four experimental soils (R2-values > 0.97). Soil water content by treatment was ranked as T2 > T3 > T1 > control at the same low matric suction (1–5 kPa), but this shifted to T2 > T1 > T3 > control at the same medium- to high-suction (5–140 000 kPa). T2 soil had the largest saturated water content, with a relatively high water supply capacity. This soil (T2) also had the largest field capacity, total available water content, and permanent wilting coefficient, which were respectively 17.82%, 11.64%, and 23.11% higher than those of the control (P-values < 0.05). In conclusion, adding the feldspathic sandstone in an appropriate proportion (e.g., 33%) can considerably improve the water retention capacity of aeolian sandy soil in the study area.


2018 ◽  
Vol 15 (2) ◽  
pp. 163-175 ◽  
Author(s):  
JA Chowdhury ◽  
MA Karim ◽  
QA Khaliq ◽  
AU Ahmed ◽  
ATM MI Mondol

An experiment was conducted in a venyl house at the environmental stress site of Bangabandhu Sheikh Mujibur Rahman Agricultural University during September to December 2012 to know the internal water status under drought stress in soybean genotypes, viz. Shohag, BARI Soybean-6, BD2331 (relatively stress tolerant) and BGM2026 (susceptible). Drought (water) stress reduced the leaf water potential in all the genotypes though was more negative in tolerant genotypes than in susceptible ones. The lowest leaf water potential was obtained from BARI Soybean-6 (-1.58 MPa) and the highest in BGM2026 (-1.2 MPa). Relative water content (RWC) decreased remarkably in all the genotypes and reduction was more in susceptible than tolerant genotypes. At 8.00 am, RWC of stressed plants decreased by 9.58, 9.02, 8.90 and 13.90% in the genotype Shohag,, BARI Soybean-6, BD2331 and BGM2026 at vegetative stage, respectively. Drought stress decreased the exudation rate in all the genotypes of soybean and it was 24, 27, 22 and 12 mg h-1 in the genotype Shohag, BARI Soybean-6, BD2331 and BGM2026 at vegetative stage, respectively. Leaf temperatures in drought stressed plant were higher than in well-watered plants. Shohag, BARI Soybean-6, BD2331 and BGM2026 showed 4.7, 4.5 5.2 and 11.07% increase in leaf temperature due to water stress. At drought stressed treatment reduction in leaf water potential, relative water content, exudation rate and water retention capacity were noticed at the three growth stages in all the genotypes with a concurrent increase in leaf temperature. Genotypes BARI Soybean-6, Shohag and BD2331 showed considerably less reduction in relative water content, exudation rate and water retention capacity, high reduction in leaf water potential and less increase in leaf temperature during drought were considered as drought tolerant. However genotype BGM2026 showed considerably high reduction in relative water content, exudation rate and water retention capacity, low reduction in leaf water potential and high increase in leaf temperature was considered as drought susceptible.SAARC J. Agri., 15(2): 163-175 (2017)


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