The effects of B and Ca treatments on root growth, nutrient localization and cell wall properties in wheat ( Triticum aestivum L.) plants with and without Al stress were investigated. Seedlings were grown hydroponically in a complete nutrient solution for 7 d and then treated with B (0, 40 μM), Ca (0, 2,500 μM), and Al (0, 100 μM) in a 500 μM CaCl2 solution for 8 d. The cell wall materials (CWM) were extracted with a phenol: acetic acid: water (2:1:1 w/v/v) solution and used for subsequent pectin extraction with trans -1,2-diami-nocyclohexane- N,N,N,N -tetraacetic acid (CDTA) and Na2CO3 solutions. Boron, Ca, and B + Ca treatments enhanced root growth by 19.5, 15.2, and 27.2%, respectively, compared to the control (pH 4.5). Calcium and B+Ca treatments enhanced root growth with Al stress by 43 and 54%, respectively, while B did not exert any effect. The amounts of CWM and pectin per unit of root fresh weight increased by Al treatment, whereas the Ca and B+Ca treatments slightly reduced the contents of these components. Seventy-four percent of total B, 69% of total Ca, and 85% of total Al were located in the cell wall in the B, Ca, and Al treatments, respectively and 32% of total B, 33% of total Ca, and 33% of total Al were located in the CDTA-soluble and Na2CO3-soluble pectin fractions. A more conspicuous localization of B was observed in the presence of Al. Aluminum treatment markedly decreased the Ca content in the cell wall as well as pectin fractions, mainly in the case of the CDTA-soluble pectin fraction. Boron + Ca treatment decreased the Al content in the cell wall and pectin fractions compared to the Ca treatment alone in the presence of Al. It is concluded that the B+Ca treatment enhanced root growth and, B and Ca uptake, and helped to maintain a normal B and Ca metabolism in the cell walls even in the presence of Al. 相似文献
Limited information is available on the grazing management principles of forage rape (Brassica napus L.), particularly in relation to grazing height and intensity and the impact of these on dry-matter (DM) yield and nutritive value. A glasshouse study was undertaken to investigate the effect of three defoliation heights (plant height at harvest; DH: 40, 70 and 90 cm; L, M and H DH respectively) and three defoliation intensities (height at which plants were cut; DI: 5, 20 and 35 cm of residual height; H, M and L DI respectively) on forage rape (cv Goliath) yield and nutritive value at two harvests (harvest 1, H1 and harvest 2, H2), and the impact of nitrogen (N) and water soluble carbohydrate (WSC) reserves on regrowth. Increasing DH from L to H increased estimated total DM yield (H1 plus H2) from 0.5 to 4.6 t DM/ha but DI did not affect yield. Dry-matter yield was optimized at 90 cm DH, but greater nutritive value was achieved by harvesting at lower levels of DH. Despite high in vitro DM digestibility (IVDMD; 852–889 g/kg), harvesting at 90 cm DH could not meet the protein requirement of lactating dairy cows and harvesting at lower levels risks nitrate poisoning. Our results indicate the optimum DH may be between 70 and 90 cm DH, and 20 and 35 cm DI, which requires further studies. 相似文献
Paddy and Water Environment - Repairs of concrete irrigation channels in Japan are guided to a large extent by the degree to which their walls have degraded over decades of use. Current methods of... 相似文献
A pot experiment was conducted to evaluate the efficiency of farm yard manure (FYM) and lime (calcium carbonate) on reducing the uptake of Cd by rice in two Cd contaminated soils of Chittagong. The effects of farm yard manure, lime and farm yard manure mixed with lime (FYM + Lime) on rice (Oryza sativa L.) growth, Cd uptake by rice and 0.1 N HC1 extractable Cd in soil were investigated. Results showed that addition of lime and farm yard manure mixed with lime significantly decreased 0.1 N HCl extractable Cd in the city sewage soil. Application of farm yard manure significantly decreased Cd concentration in rice in the city sewage soil. Lime and farm yard manure mixed with lime significantly reduced Cd concentration in rice m both the contaminated soils. Lime was more efficient than farm yard manure in reducing the uptake of Cd by rice. 相似文献
An experiment was carried out to evaluate fermented soybean meal and squid by‐product blend (1:1) (FP) as replacement of fishmeal (FM) for Japanese flounder, Paralichthys olivaceus. Five isocaloric (19 kJ g?1) diets were prepared by replacing 0 (FP0), 12 (FP12), 24 (FP24), 36 (FP36) and 48% (FP48) FM protein with FP. Triplicate groups of juveniles (mean weight of 3.9 g) were delivered the test diets for 8 weeks in a flow‐through sea water system. The results showed that there were no significant differences (P >0.05) among the growth rates of fish fed FP0, FP12, FP24 and FP36 diets. Growth and nutrient utilization parameters were significantly reduced in fish fed FP48 diet. Although, whole body proximate composition of fish were not significantly affected by the dietary treatments compared to the control; methionine and phenylalanine contents were significantly decreased in FP48 group. Protein retention was also significantly decreased in the similar group of fish. Dietary treatments did not alter most of the plasma metabolites, while some of the health parameters were improved in the replacement groups. Results suggested that FP is a potential candidate for alternative protein ingredient in aquafeed and can replace 36% FM protein in the diet of Japanese flounder. 相似文献
Effects of three prostaglandins (i.e., prostanoids) and one of its precursors, arachidonic acid, were examined on the melanophores of the fish Labeo rohita (Ham.). PGE1, PGE2, PGF2α and arachidonic acid elicit a concentration-related dispersion in the fish melanophores. In vitro analysis of melanophores was performed through incubation of the isolated fish scales in different agonists and antagonists solutions. Dispersal effect of prostanoids may be mediated directly through the typical receptors or indirectly through release of neurotransmitter substance(s) from the melanophore nerve endings. Denervation of fish melanophores rendered them insensitive to prostanoid (PGF2α). Propranolol and verapamil completely inhibited the dispersal effects of PGF2α; theophylline and indomethacine blocked the effects of higher concentrations of PGF2α. During dispersing influence of PGF2α, a free flux of Ca2+ ions was required and the indirectly released substance(s) from melanophore nerve endings would be the catecholamines of adrenergic and purinergic in nature. 相似文献
This study investigated the effects of sodium alginate supplementation on gut microbiota composition, health parameters, growth performances and growth‐related gene expression of Malaysian mahseer. Five test diets were formulated by supplementing 0%, 0.1%, 0.2%, 0.4% and 0.8% sodium alginate. Triplicate groups of juvenile Tor tambroides (2.19 ± 0.05 g) were stocked in 15 aquaria (20 individuals per aquarium) and fed at 3.0% body weight per day for 60 days. PCoA and UPGMA analysis showed that gut bacterial community were more convergence in higher sodium alginate‐supplemented diets. The percentage of Porphyromonadaceae, Bacteroides, Plesiomonas and Shewanella were substantially higher and Aeromonas, Entomoplasmatales and Prevotellaceae were drastically lower in higher sodium alginate (0.2%–0.8%) diets. Sodium alginate supplementation (≥0.2%) significantly improved the haematocrit value and respiratory burst activity of T. tambroides. Growth performances and feed utilization were significantly higher in 0.2%–0.4% sodium alginate‐supplemented diets. The increased growth rate of T. tambroides was governed by both hyperplastic and hypertrophic muscle growth. Real‐time PCR data demonstrated that most of the growth‐related genes were significantly upregulated in 0.2%–0.4% sodium alginate‐supplemented diet. Finally, it can be concluded that sodium alginate should be supplemented at 2 g/kg in practical fish feed formulation. 相似文献
A 70‐day growth trail was conducted to investigate the effects of inclusion of high levels of meat and bone meal (MBM) and protein concentrate (PC) on growth, digestibility and economic performances of climbing perch, Anabas testudineus. Four isonitrogenous diets were formulated by lowering the level of dietary fishmeal protein at 0 (D1, control), 70 (D2), 85 (D3) and 100% (D4) with a mixture of MBM and PC protein (1:1). Triplicate groups of 300 fish (mean weight of 0.80 g) stocked in each 40 m2 pond and fed the respective test diets. A digestibility trial was conducted after the growth trial in indoor glass aquarium. The result showed that growth parameters were significantly decreased (P < 0.05) with fishmeal replacement levels. However, significant differences were not found in feed conversion ratio and survival of fish. No difference was also found in protein efficiency ratio among D1, D2 and D3. Similar to growth parameters, total fish production was highest in D1, intermediate in D2 and D3; and lowest in D4. Apparent digestibility coefficients of dry matter, protein and lipid were highest (P < 0.05) in D1 and lowest in D4. The economic analysis revealed that the benefit cost ratio was ranked by D3 (1.81), D2 (1.71), D1 (1.66) and D4 (1.46) respectively. Upon considering the overall performances and unavailability of finite protein sources, it can be concluded that 70–85% fishmeal could be replaced with a mixture of MBM and PC (1:1) in practical diets for climbing perch. 相似文献
Humic substances, which are integral components of total organic carbon (TOC), influence soil quality. The study aimed to investigate whether humic and non-humic fractions exhibit early, consistent, and measurable changes and affect TOC sensitivity and storage in a tropical sandy loam soils amended with corn cob biochar.
Materials and methods
There were four treatments with four replicates established in a randomized complete block design. Composite soil samples were taken from plots without biochar (CT), from plots incorporated with 15 t biochar ha?1 (BC-15), and 30 t biochar ha?1 without or with phosphate fertilizer (BC-30 and BC-30+P). The TOC, and humin, humic acid (HA), and fulvic acid (HA) fractions of soil organic carbon were determined for each treatment. The optical densities (400–700 nm) were measured on the soil-free extracts by spectrophotometry; the densities measured at 465 and 665 nm were used to calculate the E465/E665 ratios.
Results and discussion
The BC-30 and BC-30+P plots recorded the highest TOC, humin, humic acid (HA), and fulvic acid (FA) contents with respect to the lowest in the CT. The total exchangeable carbon stratification was significantly higher in all the biochar-treated plots relative to the CT. Spectral analysis showed higher values of E465/E665 (5.02 and 5.15) in the CT and BC-15-treated soils, respectively, compared with the BC-30 and BC-30+P-amended soils with E465/E665 ratios of 2.76 and 2.98, respectively.
Conclusions
Corn cob biochar applied to a tropical sandy loam:
? increased the concentrations of HA and FA and led to increased stratification of TOC, with a stronger effect on HA compared with FA;
? significantly lowered E465/E665 at the high biochar application rate of 30 t ha?1, implying the dominance of high molecular weight humic acid-like substances, and increased degree of aromaticity of the TOC.