保水剂对冬小麦土壤水分和光合生理特征的影响

 为探明保水剂施用对冬小麦不同生育期的土壤水分、叶片相对含水量及光合生理等的作用,采用保水剂大田试验,研究分析了冬小麦不同生育时期保水剂对土壤水分动态变化、叶片相对含水量及光合特征等的影响。结果表明:1)从返青期到孕穗期,随保水剂用量的增加,020cm土壤含水量显著提高,且2040 cm土壤水分均提高,其基本表现为:60 kg/hm2>90 kg/hm2>30kg/hm2>对照。2)叶片相对含水量表现为:拔节期,随保水剂用量的增加,叶片相对含水量降低,但均显著高于对照（P0.05）,但均显著高于对照（P<0.05）。3)冬小麦各生育期的光合生理特征表现为:用量为60kg/hm2的光合速率、蒸腾速率及叶片水分利用效率均相对最高,而30和90kg/hm2保水剂用量结果各异,但均显著高于对照（P<0.05）。综上所述,保水剂显著提高了冬小麦各生育期的土壤水分、叶片相对含水量及其光合速率、蒸腾速率及水分利用效率等,且以60kg/hm2保水剂用量的效果为佳。     

Influence of nitrogen fertilization on yield and phenolic compounds in wheat grains (Triticum aestivum L. ssp. aestivum)

Nitrogen (N) is an important plant nutrient and is crucial for the plant growth and grain yield formation of field crops such as wheat (Triticum aestivum L. ssp. aestivum). However, little is known about the influence of N on secondary metabolites in wheat grains which are supposed to be beneficial for human health due to their antioxidant potentials. Therefore, we investigated the influence of N fertilization on plant growth and yield performance of winter wheat, as well as on total phenolic concentration, antioxidant capacity, and the accumulation of (in)soluble phenolic acids in wheat grains during the grain‐filling phase. It was found that ferulic acid was the predominant phenolic acid in wheat grains. As expected, higher amounts of N fertilizer led to increasing grain yields, whereas the concentration of soluble ferulic acid decreased. In contrast, insoluble bound ferulic acid, total phenolic content, and antioxidant capacity were not affected by the N treatment. Insoluble phenolic compounds seemed to be less susceptible to variations in N supply.     

Effect of wheat (Triticum aestivum) roots on mineralization rates of soil organic matter

Summary Two different soils were amended with ¹⁴C-labelled plant material and incubated under controlled laboratory conditions for 2 years. Half the samples were cropped with wheat (Triticum aestivum) 10 times in succession. At flowering, the wheat was harvested and the roots removed from the soil, and a new crop was started. Thus, the soil was continuously occupied by predominantly active root systems. The remaining samples were maintained without plants under the same conditions. The aim of the experiment was to study the effects of active roots on C-mineralization rates during different stages of decomposition and during long-term incubation. During the first 200 days, corresponding to the active decomposition stages, the roots weakly reduced ¹⁴C mineralization. With a lower level of decomposition, when more than 60% of the initial 14C was mineralized and when the available nutrients were markedly exhausted by plant uptake, the roots stimulated 14C mineralization.[/ p]     

黄土旱塬长期施肥对小麦连作土壤养分和水分的影响

利用长期定位实验,在黄土高原旱地研究不同施肥下小麦连作22年后土壤养分及水分的变化状况,为合理利用水肥资源提供参考.在对照(CK)、单施氮肥(N)、单施磷肥(P)、单施有机肥(M)、氮磷化肥配施(NP)、氮磷化肥与有机肥配施( NPM)6个不同长期施肥处理中,测定耕层(0～20 cm)土壤的基础养分和土壤剖面(0～30...     

Determining critical limit of boron in soil for wheat (Triticum aestivum L.)

Abstract

Critical values of boron (B) for wheat nutrition in soil and plant were determined through a pot experiment with twenty-one surface soils of Alluvial flood plain and Red-latertic belt comprising three major soil orders (Entisols, Alfisols, Inceptisols) with four levels of boron. Application of boron significantly increased the dry matter yield as well as uptake of B by plants. Critical concentration of hot calcium chloride (CaCl₂) extractable B in soil for wheat was found to be 0.53?mg?kg^?1. The critical plant B concentration varied with growth stages and values were 7.4?mg?kg^?1 at panicle initiation and 4.18?mg?kg^?1 at maturity, respectively. The findings of this investigation also recommend the application of 2?kg?B^?1?ha^?1 for ensuring B sufficiency to wheat in Indo-gangetic alluvial and Red-Lateritic soils.     

Metabolite profiling of wheat grains (Triticum aestivum L.) from organic and conventional agriculture

In some European community countries up to 8% of the agricultural area is managed organically. The aim was to obtain a metabolite profile for wheat (Triticum aestivum L.) grains grown under comparable organic and conventional conditions. These conditions cannot be found in plant material originating from different farms or from products purchased in supermarkets. Wheat grains from a long-term biodynamic, bioorganic, and conventional farming system from the harvest 2003 from Switzerland were analyzed. The presented data show that using a high throughput GC-MS technique, it was possible to determine relative levels of a set of 52 different metabolites including amino acids, organic acids, sugars, sugar alcohols, sugar phosphates, and nucleotides from wheat grains. Within the metabolites from all field trials, there was at the most a 50% reduction comparing highest and lowest mean values. The statistical analysis of the data shows that the metabolite status of the wheat grain from organic and mineralic farming did not differ in concentrations of 44 metabolites. This result indicates no impact or a small impact of the different farming systems. In consequence, we did not detect extreme differences in metabolite composition and quality of wheat grains.     

Influence of inorganic fertilizers and organic amendments on soil organic matter and soil microbial properties under tropical conditions

 Soil organic matter level, mineralizable C and N, microbial biomass C and dehydrogenase, urease and alkaline phosphatase activities were studied in soils from a field experiment under a pearl millet-wheat cropping sequence receiving inorganic fertilizers and a combination of inorganic fertilizers and organic amendments for the last 11 years. The amounts of soil organic matter and mineralizable C and N increased with the application of inorganic fertilizers. However, there were greater increases of these parameters when farmyard manure, wheat straw or Sesbania bispinosa green manure was applied along with inorganic fertilizers. Microbial biomass C increased from 147 mg kg^–1 soil in unfertilized soil to 423 mg kg^–1 soil in soil amended with wheat straw and inorganic fertilizers. The urease and alkaline phosphatase activities of soils increased significantly with a combination of inorganic fertilizers and organic amendments. The results indicate that soil organic matter level and soil microbial activities, vital for the nutrient turnover and long-term productivity of the soil, are enhanced by use of organic amendments along with inorganic fertilizers. Received: 6 May 1998     

Kinetics of carotenoids degradation during the storage of einkorn (Triticum monococcum L. ssp. monococcum) and bread wheat (Triticum aestivum L. ssp. aestivum) flours

To evaluate the effect of storage temperature, the degradation kinetics of carotenoids in wholemeal and white flour of einkorn cv. Monlis and bread wheat cv. Serio, stored at -20, 5, 20, 30, and 38 degrees C, was assessed by normal-phase high-performance liquid chromatography. In Monlis, the carotenoids content (8.1 and 9.8 mg/kg for wholemeal and white flour, respectively) was 8-fold higher than in Serio (1.0 and 1.1 mg/kg). Only lutein and zeaxanthin were detected in bread wheat, while significant quantities of (alpha and beta)-carotene and beta-cryptoxanthin were observed in einkorn. Carotenoids degradation was influenced by temperature and time, following first-order kinetics. The degradation rate was similar in wholemeal and white flour; however, loss of lutein and total carotenoids was faster in Serio than in Monlis. The activation energy E(a) ranged from 35.2 to 52.5 kJ/mol. Temperatures not exceeding 20 degrees C better preserve carotenoids content and are recommended for long-term storage.     

Ion chromatographic determination of the decomposition products of tecnazene solution irradiated by ultraviolet light: inorganic and organic anions.

Ion chromatographic (IC) methods using sodium hydroxide and methanol gradients were used for the determination of small inorganic and organic anions as decomposition products of a tecnazene solution in water irradiated by UV light. After 60 min of UV irradiation, >99% of the tecnazene was decomposed, and 11 organic and 3 inorganic anions were identified and quantified. A fourth inorganic anion, carbonate, was not quantified due to likely losses as carbon dioxide. The final content of chloride, total nitrogen, and total carbon released from the saturated tecnazene solution after 60 min of UV irradiation were 108, 85, and 38%, respectively. These results suggest that other products rich in carbon and/or nitrogen (such as phenolic compounds and nitrobenzenes) were formed during the UV irradiation of the tecnazene solution. The results obtained indicate several decomposition pathways of tecnazene in water solutions, for example, ring opening reactions, dechlorination, and replacement of the ring nitro group. The determination of nonionic decomposition products from the latter two possibilities is the subject of further study.     

气候变暖对春小麦籽粒痕量元素利用率的影响

为了回答温度升高是否会改变痕量元素在士壤中的溶解性,以及作物对痕量元素的生物利用率,在人工气候室模拟未来气候变化温度升高背景下,对种植在不同温度处理的3种春小麦,测定了籽粒中Cd,Cu,Fe和Zn含量.结果发现温度升高引起了土壤中Cd,Cu,Fe和Zn溶解性的显著变化,也显著地影响小麦籽粒中Cd,Cu,Fe和Zn的生物利用率.最高升温3℃处理使西旱1号、2号和3号小麦籽粒中Cd浓度相比对照分别下降43.4％、11.1％和13.4％,Cu浓度相比对照处理分别下降了30.4％、25.1％和10.8％.但Fe和Zn的情况却不同,1℃和2℃升温处理使西旱1号籽粒中Zn浓度比对照处理分别增加了28.9％和35.8％.根据未来气候变化两北地区温度升高1.9℃,估计到2050年,小麦籽粒中的质量分数范围分别在Cd(0.59-0.65)、Cu(5.91-7.64)、Zn(63.73-69.41)和Fe(185.23-202.70) mg/kg.     

Availability of soil and fertilizer nitrogen to wheat (Triticum aestivum L.) following rice-straw amendment

Summary A pot experiment was conducted to study the N availability to wheat and the loss of ¹⁵N-labelled fertilizer N as affected by the rate of rice-straw applied. The availability of soil N was also studied. The straw was incorporated in the soil 2 or 4 weeks before a sowing of wheat and allowed to decompose at a moisture content of 60% or 200% of the water-holding capacity. The wheat plants were harvested at maturity and the roots, straw, and grains were analysed for total N and ¹⁵N. The soil was analysed for total N and ¹⁵N after the harvest to determine the recovery of fertilizer N in the soil-plant system and assess its loss. The dry matter and N yields of wheat were significantly retarded in the soil amended with rice straw. The availability of soil N to wheat was significantly reduced due to the straw application, particularly at high moisture levels during pre-incubation, and was assumed to cause a reduction in the dry matter and N yields of wheat. A significant correlation (r=0.89) was observed between the uptake of soil N and the dry matter yield of wheat with different treatments. In unamended soil 31.44% of the fertilizer N was taken up by the wheat plants while 41.08% of fertilizer N was lost. The plant recovery of fertilizer N from the amended soil averaged 30.78% and the losses averaged 45.55%     

Effects of aluminum on the growth and element composition of 20 winter cultivars of Triticum aestivum L. (wheat) grown in solution culture

Seedlings of twenty cultivars of Triticum aestivum L. differing in tolerance to aluminum (Al) were grown with Al (74 uM, 2.0 mg L^‐1 ) and without Al at pH 4.5 to examine the effect of Al on the element composition of leaf and root tissues of juvenile plants. Treatment with Al reduced concentrations of Mg and Mn and increased concentrations of Al, P, Ca, and Fe in roots. Treatment with Al reduced concentrations of P, Ca, Mg, Fe, and Mn in leaves. Concentrations of Mg, Fe, and Mn in leaves were in the range considered to be deficient.

Cultivars differed in the effect of Al on element composition. Concentrations of Ca, Mg, Fe, and Mn in leaves of the 20 cultlvars grown with Al were positively correlated with cultivar tolerance to Al as measured by relative root yield. The variance, however, was relatively high. Leaf P concentrations of seedlings grown with Al were not significantly correlated with tolerance to Al. Differences among cultivars in the effect of Al on element, composition were not likely a primary cause of differential tolerance to Al, but Al‐induced element deficiencies may have a secondary effect on the yield of cultivars grown on sub‐lethal, Al‐toxic substrates.     

The effect of soil-climate conditions on yielding parameters,chemical composition and baking quality of ancient wheat species Triticum monococcum L., Triticum dicoccum Schrank and Triticum spelt L. in comparison with modern Triticum aestivum L.

Triticum monococcum L., Triticum dicoccum Schrank and Triticum spelt L. nowadays offer an alternative to Triticum aestivum L. We analyzed grain and straw yield, yielding parameters, chemical composition and bakery quality of these species and compared them with modern T. aestivum at three sites with different soil-climate conditions. The average grain yield varied from 0.41 t ha^?1 (T. monococcum) to 5.17 t ha^?1 (T. aestivum), straw yield varied from 1.50 t ha^?1 (T. dicoccum) to 5.83 t ha^?1 (T. aestivum). The yielding parameters and chemical composition of the grain were significantly influenced by soil-climate conditions and wheat species. The highest average crude protein content was recorded in T. spelta (20.55%), while the lowest in T. aestivum (11.20%). The Zeleny’s sedimentation test ranged from 9.0 ml (T. monococcum) to 34.5 ml (T. aestivum) and the value of the Gluten index varied from 7.45 (T. dicoccum) to 89.75 (T. aestivum). According to the results, ancient wheat species provides lower grain and straw yields, higher protein content and mineral concentrations. Concentration of proteins and grain’s baking quality strongly depends on wheat species and soil-climate conditions.     

Fluctuations in bacterial populations on the root surface of wheat (Triticum aestivum L.) grown under different soil conditions

Summary Populations of several bacterial groups on the root surface of wheat and in root-free soil were investigated in volcanic ash soil and non-volcanic ash soil throughout a series of predetermined intervals. Over time, the populations changed similarly both on the root surface and in root-free soil. The numbers of total bacteria, fluorescent Pseudomonas spp., phosphate-solubilizing bacteria, and NH _inf+ ^sup4 -oxidizing bacteria, were consistently lower in the plots with volcanic ash soil than with nonvolcanic ash soil, but the numbers of cellulose-decomposing bacteria were opposite to those of the other groups. Superphosphate application improved the growth of wheat in the volvanic ash soil. It did not, however, bring about any significant changes in the bacterial populations among the volcanic ash soils supplemented with three different levels of superphosphate, though there were some variations with plant age.     

Influence of additional amino acids in growth of different wheat (Triticum aestivum L) genotypes

Abstract

Wheat is the main source of carbohydrates and amino acids consumed in the world. Amino acids and other physiological characters were determined in six wheat genotypes viz. IBWSN-1010, IBWSN -1025, TD-1, ESW-9525, Khirman and Chakwal-86 for pot experiment, to evaluate the response of genotypes under water stress at Nuclear Institute of Agriculture (NIA), Tandojam, Sindh, Pakistan, during 2018. Eight different physiological indices (Proline content, glycine-betaine, total sugars, total chlorophyll, nitrate reductase activity (NRA), potassium (K⁺) content, osmotic potential (OP) and relative water content (RWC)) were determined. The variance of analysis shows two-way interaction one with water stress [Control (normal four irrigations) and the other with terminal drought (Soaking dose) having significance at p?≤?0.05. It was observed that, ESW9525, IBWSN-1010 and IBWSN-1025 exhibited the tolerance followed by, Khirman and Chakwal-86 by maintaining their OP and accumulation of higher proline and glycine-betaine content. Whereas, moderate total soluble sugars were found in these genotypes. However, NRA increased in IBWSN-1010 enhancing tolerance under water stress.     

Effect of soil compaction by tractor traffic on soil structure, denitrification, and yield of wheat (Triticum aestivum L.)

In a field experiment with soil compaction by tractor traffic on a loam soil, the denitrification rate (using the C₂H₂ inhibition method), the soil structure, and the wheat yield were investigated. Tractor traffic on wet soil (> – 50 mbar matric potential) reduced the pore volume, doubled the percentage of large aggregates (> 20 mm), reduced the wheat yield by about 25%, and increased the N-loss through denitrification by a factor of 3–4. Neither of these parameters were affected by tractor traffic at low soil moisture content. The weight of the tractor (1800 kg vs 4800 kg) did not significantly alter the effect of compaction on the measured parameters. There was a factor of 2–6 between the measured denitrification rate in compacted and that in uncompacted soil, and this factor showed little dependence on the average activity level on each date of measurement. Accumulated values for the measured denitrification during 75 days (May 23-August 9) were 3–5 kg N ha^–1 in uncompacted soil and 15–20 kg N ha^–1 in soil which was compacted in wet condition.     

Gram-positive bacterial flora on the root surface of wheat (Triticum aestivum L.) grown under different soil conditions

We identified 108 Gram-positive bacterial strains isolated from the root surface of wheat grown under different soil conditions. The strains were divided into four groups based on morphological and physiological characteristics, but most appeared to be coryneform. The taxonomic position of the various groups was verified by the guanine+cytosine DNA contents of the strains. In general, the ranges of these values agreed with those described for the respective taxonomic positions in the literature, with a few exceptions. With soil improvement the distribution of the various groups on the root surface changed, with the coryneform group becoming dominant. This group was further divided into five subgroups, according to cell wall components, cellulose-decomposition, and morphological characteristics, and were identified to genus level. The distribution of these subgroups on the root surface of wheat did not alter with soil improvement. The genus Arthrobacter, the dominant subgroup, predominated in every plot.     

Effects of genotype and weed control on the nutrient composition of winter spelt (Triticum aestivum ssp. spelta L.) and common wheat (Triticum aestivum ssp. vulgare)

The renaissance of spelt is associated with the development of alternative farming and a trend to maintain biodiversity. The present study carried out a comparison between two methods of weeding (mechanical and chemical) as well as a cereal cultivar influence on chemical composition of spelt and wheat. The research material was taken from field experiments carried out during three years. In order to assess the chemical composition, the following cereal cultivars were used: lines of winter spelt – STH 8 and STH 11 and a winter common wheat cv. Tonacja. In all cases, the overall protein content in spelt was significantly higher than in common wheat. Spelt grain is also richer in fats than common wheat. A visible tendency to higher concentration of raw fibre was observed when mechanical weeding was applied. Also, mechanical weeding as well as the variety significantly influenced β-glucan content. The study of the impact of a weeding method and a variety does not clearly show the direction of the amino acid content changes. The research indicates that there are ample opportunities to shape the level of nutrients, which decide about spelt grain application in the food industry through agronomic factors (methods of weeding and cultivar).     

Influence of soil solution Ca concentration on short-term K release and fixation of a loamy soil

The Ca concentration of the soil solution influences K plant nutrition by its influence on K concentration of the soil solution and on soil buffer power through ion exchange and K release or fixation. The effects of the imposed solution Ca concentration on the estimates of these parameters and on these two phenomena were studied on a loamy soil. Potassium sorption and desorption experiments were conducted for 16 h at five initial Ca concentrations (from 0 to 10^?1 M) and followed by the measurement of soil exchangeable K (ammonium acetate extraction). Soil K-Ca exchange properties and the contributions of exchangeable K and non-exchangeable K to K dynamics of the soil-solution system were estimated. The‘Ratio Law’ applied for the medium range of Ca concentrations, i.e. 10^?1 M to 10^?3 M. But, it failed for some experiments at small initial Ca concentrations (0 M and 10^?4 M). This failure went with a decrease of the number of sites of great affinity for K in K-Ca ion exchange and/or a decrease of the amount of K not in exchange equilibrium with Ca but extracted by M ammonium acetate. Release of K increased and fixation of K decreased when Ca concentration increased. The relation between the change in the amount of non-exchangeable K during the experiment and the initial constraint (ø) was curvilinear on the large range of ø investigated. But, this relation was independent of Ca concentration. The K concentration of the solution for which neither sorption of K by the soil nor desorption of K from the soil occurred decreased and the slope of the sorption-desorption curve at this K concentration increased when the solution Ca concentration decreased. These two parameters can be considered the K concentration of the soil solution of the soil and the buffer power of the soil, respectively, only if the initial Ca concentration imposed during the sorption-desorption experiments is close to the Ca concentration of the soil solution of the soil. A predictive model of the soil buffer power based on ion exchange and release-fixation properties is proposed. Despite some discrepancies at very low Ca concentrations (<0·5 mM Ca) when‘Ratio Law’did not apply the agreement between calculated and observed values was good. The model permits the correction of the experimentally obtained buffer power for the bias related to the great solution volume: soil weight ratio commonly used during the sorption-desorption experiments.