禾谷类作物的小孢子培养

分析了小孢子培养的研究进展,并综述了禾谷类作物小孢子的培养方法。     

Residual Effect of Copper and Zinc from Fertilizers on Plant Concentration,Phytotoxicity, and Crop Yield Response

Abstract

To avoid toxicity resulting in reduced crop yields and/or phytotoxic symptoms on the foliage, information on the residual effect of micronutrient fertilization after periods of application is desirable. This article includes discussion on the micronutrients copper (Cu) and zinc (Zn), because they are essential and are of concern from plant and animal standpoints. In general, no detrimental effects in yield reduction or phytotoxicity were noted from Cu applications of up to 50 kg Cu ha^?1 to barley (Hordeum vulgare L.) and wheat (Triticum aestivum L.). Barley was an exception where 50 kg Cu ha^?1 decreased yield by about 12% in the first‐year crop. The Cu levels in plants did not exceed 9 mg kg^?1. Studies showed that Zn applications of 50 kg ha^?1 for 2 years in succession and the resulting crop tissue Zn levels as high as 105 mg kg^?1 did not cause any phytotoxicity in cereals. The results of this study suggest that cereals can tolerate high levels of Cu and Zn.     

Phytosterol,Squalene, Tocopherol Content and Fatty Acid Profile of Selected Seeds,Grains, and Legumes

The unsaponifiable lipid fraction of plant-based foods is a potential source of bioactive components such as phytosterols, squalene, and tocopherols. The objective of the present study was to determine the levels of phytosterols, and squalene, as well as tocopherols (α and β + γ) in selected grains, seeds, and legumes. The method comprised acid hydrolysis and lipid extraction followed by alkaline saponification, prior to analysis by HPLC. In addition, the fatty acid profile of the foods was determined via total lipid extraction, fatty acid derivitisation and GC analysis. In general, β-sitosterol was the most prevalent phytosterol, ranging in concentration from 24.9 mg/100 g in pumpkin seed to 191.4 mg/100 g in peas. Squalene identified in all foods examined in this study, was particularly abundant in pumpkin seed (89.0 mg/100 g). The sum of α- and β+ γ-tocopherols ranged from 0.1 mg/100 g in rye to 15.9 mg/100 g in pumpkin seeds. Total oil content ranged from 0.9% (w/w) in butter beans to 42.3% (w/w) in pumpkin seed and the type of fat, in all foods examined, was predominantly unsaturated. In conclusion, seeds, grains, and legumes are a rich natural source of phytosterols. Additionally, they contain noticeable amounts of squalene and tocopherols, and in general, their fatty acid profile is favorable.     

An improved method for rapid quantitative analysis of the insoluble dietary fiber in common cereals and some sorts of beans

An improved rapid analysis for determining the content of insoluble dietary fiber (IDF) in common cereals and some sorts of beans is described in this paper. The procedure includes starch gelatinization in water bath for 20 min at 100 °C and 2.5% (w/w) α-amylase hydrolyzed reaction followed by neutral detergent wash and acetone extraction. Compared with 1.5 h for filtration (estimated) and 18 h for the enzymatic hydrolysis required by the typical American Association of Cereal Chemists (AACC) method, the filtration and enzymatic treatment procedures in the improved method was completed within 15 min and 1.5 h, respectively. The length of time for the filtration and the enzymatic hydrolysis for the improved method was significantly shortened from 19.5 h (AACC method) to 1.75 h. In addition, orthogonal array design (OAD) has been applied to optimize parameters of the improved method. The recovery yield of microcrystalline cellulose was 97.75% (w/w), in agreement with the result obtained using the typical AACC method, demonstrating the reliability of the improved method. Furthermore, several common cereals and beans were employed to validate the accuracy and universality of this improved method.     

Estimation of genetic diversity of self-fertilizing cereal cultivars based on genotype-environment interactions

Summary A method is proposed for the estimation of genetic diversity in a range of cultivars, based on the analysis of the genotype-environment interactions. The degree of similarity or diversity between each pair of genotypes in an array is estimated by the correlation over a range of environments of their respective deviations from the mean yield of all genotypes in each environment. An example is given, using data from spring barley trials conducted in UK.     

Estimating nitrogen transfer by foliar 15N-labelling in legume – non-legume associations

We examined the basis for estimating the transfer of legume N to companion cereals or grasses in intercropping or pature systems using the foliar ¹⁵N-labelling technique. Published data from three pot experiments were used to illustrate different methods for estimating N transfer. Yield-dependent and yield-independent methods based on measurement of the ¹⁵N enrichment of the whole legume biomass at harvest overestimate N transfer. Estimates of N transfer using a yield-independent method based on the ¹⁵N enrichment of the legume roots at harvest were inconsistent with estimates based on the isotopic composition of the whole plant. We propose a new mathematical concept for estimating the transfer of legume N based on measurement of the ‘mean pool abundance’ of the legume biomass during the period of N transfer. Received: 7 January 1996     

Agro‐ecological classification and spatial demarcation of Western Europe: Results of an EU‐funded research programme

The paper presents a hierarchic system of agro‐environmental classification of regions and landscapes. At the highest level are agro‐climatic regions (AKR). Allocating soil data, these units are broken down to soil‐climatic regions (Boden‐Klima Regionen, BKR). The next level is defined by geological data, topography “typical patterns of land uses”; and results in landscape types (LT). The AKR are used to define the intensification level and the energy surplus of agro production. The BKR allow specific analysis of impacts to environment factors of farm production systems. In the LT, specific targets for sustainable production and landscape rehabilitation are developed. The results are proposals to refine European agro‐policy towards more environmentally oriented schemes. The data is also valid to control the positive environmental effects of farmers adaptation of schemes.     

Cereal complex carbohydrates and their contribution to human health

Population studies have shown that whole grain consumption is associated with diminished risk of serious, diet-related diseases, which are major problems in wealthy industrialised economies and are emerging in developing countries with greater affluence. These conditions include coronary heart disease, certain cancers (especially of the large bowel), inflammatory bowel disease and disordered laxation. Carbohydrates are important contributors to the health benefits of whole grains. Insoluble non-starch polysaccharides (NSP, major components of dietary fibre) are effective laxatives. Soluble NSP (especially mixed-link β-glucans) lower plasma cholesterol and so can reduce heart disease risk but the effect is inconsistent. Processing seems to be an important contributor to this variability and other grain components may be involved. However, starch not digested in the small intestine (resistant starch, RS) appears to be as important as NSP to large bowel function. Dietary analysis suggests that some populations (e.g. native Africans) at low risk of diet-related disease through consumption of unrefined cereals may actually have relatively low fibre intakes. While NSP are effective faecal bulking agents, they are fermented to a very variable extent by the large bowel microflora. In contrast, RS seems to act largely through the short chain fatty acids (SCFA) produced by these bacteria. One SCFA (butyrate) appears to be particularly effective in promoting large bowel function and RS fermentation appears to favour butyrate production. Animal studies show that dietary RS lowers diet-induced colonocyte genetic damage and chemically-induced large bowel cancer which correlates with increased butyrate. These effects could contribute to a lower risk of cancer and ulcerative colitis in the long term. Cereal grain oligosaccharide (OS) may also function as prebiotics and increase the levels of beneficial bacteria in the large bowel. Understanding the relationships between NSP, RS and OS and large bowel health will be facilitated by the advent of new molecular technologies to identify the bacterial species involved. The potential for improvements in public health is considerable.     

Effect of proccesing on dietary fiber content of cereals and pulses

Total dietary fiber (TDF), insoluble dietary fiber (IDF) and soluble dietary fiber (SDF) content of rice, wheat, sorghum, maize, ragi, bajra, whole grains of pigeonpea, chickpea, green gram and lentil as well as their dehusked split dhals were analyzed. Cereals except rice flours were made into chapati (unleavened bread), while rice and dhals were cooked in a pressure cooker. After the processing, IDF and SDF contents of these foods were also analyzed. Among the cereals, rice had the lowest TDF (4.1%) and wheat had the highest (12.5%). TDF content of whole pulses ranged from 15.8% in lentil to 28.3% in chickpea. IDF as % of TDF constituted 85 to 89% in whole pulses. Dehusking of pulses into dhals decreased the TDF and IDF contents significantly. Among the dhals, green gram dhal had the lowest (8.2%, 6.5%) and chickpea dhal (15.3%, 12.7%) had the highest TDF and IDF contents, respectively. Processing of cereals had no effect on their TDF and IDF contents, rith the exception of ragi, where a significant increase in TDF and IDF was observed. Cooking of dhals brought about a significant increase in their TDF and IDF contents.     

Alkylresorcinol composition allows the differentiation of Triticum spp. having different degrees of ploidy

Total alkylresorcinol (AR) content and homologue composition were assessed in whole grain flours of 15 varieties each of bread wheat, durum, spelt, emmer, and einkorn grown in four different environments. Bread wheat (761 ± 92 μg/g DM) and spelt (743 ± 57 μg/g) belonging to the hexaploid species showed higher AR concentrations than the tetraploid durum (654 ± 48 μg/g, p < 0.05), while the concentrations found in the diploid einkorn (737 ± 91 μg/g) and the tetraploid emmer (697 ± 94 μg/g) did not significantly differ from the other species. The AR content showed a remarkable heritability and, thus, seemed to be mainly determined by genetic factors. If ARs were assumed to be deposited within a specific AR-rich layer of the kernel, AR levels of all varieties would easily surpass their minimal inhibitory concentrations against fungal pathogens within this barrier layer. Although the AR carrying a C21:0 side chain was the main homologue in all species, the levels of all AR homologues and their relative composition significantly differed between hexaploid (bread wheat and spelt), tetraploid (durum and emmer) and diploid (einkorn) species. Consequently, a clear-cut differentiation of Triticum species and derived whole grain flours according to their degrees of ploidy was established based on concentrations of saturated C₁₇-, C₁₉-, C₂₁-, C₂₃-, and C₂₅-substituted ARs.