荞麦种子蛋白质组分分析

研究了不同品种荞麦种子中蛋白质组分情况，结果表明：养麦种子蛋白质主要由清蛋白、球蛋白、谷蛋白和醇溶蛋白构成。而不同类型蛋白质在总蛋白质中所占比例有明显差异，清蛋白是荞麦种子中的主要蛋白质，占总蛋白质含量的71．4％左右，其中以平荞最高。醇溶蛋白在荞麦种子总蛋白中所占比例较小，平均约为7．4％，榆养2号最高。球蛋白和谷蛋白所占比例非常接近，其中球蛋白平均约占9．1％，最高为日本大粒养。谷蛋白大约占总蛋白的12．1％，以京养1号最高。     

The use of grain protein deviation for identifying wheat cultivars with high grain protein concentration and yield

The relationship between grain protein concentration and grain yield in different cultivars of winter wheat was examined in a series of field experiments carried out over three years, in which 13, 12 and 8 cultivars were studied in each year, respectively. The plants were grown at sites located in Shropshire, west-central England, in years 1 and 2, and at three other locations in eastern England in year 3. Above ground plant samples were collected at an thesis and again at maturity, when they were separated into grain and straw, and analysed for dry matter and N content. Analysis of residuals from regression of grain protein concentration on grain yield (grain protein deviation, GPD) showed that some cultivars had a higher grain protein concentration than was predicted from grain yield alone. It was deduced that the capacity to accumulate a higher grain protein concentration than predicted from grain yield is under genetic control and thus may be improved through breeding. Other factors (weight of N accumulated in the biomass at anthesis, weight of N accumulated in the biomass between anthesis and maturity and the concentration of N remaining in the straw at maturity) were added step-wise into the regression to enable statistical analysis of their relative contributions to grain protein. High GPD may be achieved through increased N accumulation after anthesis, combined with efficient re-translocation of vegetative N reserves. The use of GPD provides a selection criteria in wheat breeding programs to screen for increased grain protein concentration without a concurrent grain yield reduction. This revised version was published online in August 2006 with corrections to the Cover Date.     

Remobilization of Nitrogen and Carbohydrate from Stems of Bread Wheat in Response to Heat Stress during Grain Filling

When wheat (Triticum aestivum L.) is grown under heat-stress conditions during grain filling, preanthesis stored total non-structural carbohydrates (TNC) and nitrogen (N) could serve as alternative source of assimilates. This study was performed to evaluate wheat genotypes for their ability to accumulate and remobilize TNC and N stored in their stem to support grain filling under heat stress. Eighteen genotypes were used for N remobilization study while nine of them were used for TNC remobilization study. They were grown in pots and placed in a vinyl house with the maximum temperature kept below 30 °C. Five days after anthesis (5DAA), half of the pots were taken to phytotrons where temperature was gradually increased and the maximum was set at 38 °C. Grain yield and grain weight decreased by about 35 % under heat stress. Significant differences were found among genotypes in percentage reduction in grain yield, grain weight, grain filling duration and harvest index because of heat stress. The N and TNC concentrations of the stem at 5DAA were significantly different among genotypes. Heat stress significantly reduced the N remobilization efficiency of most of genotypes. However, heat stress significantly increased TNC remobilization efficiency and significant variation were observed among genotypes. N remobilization efficiency across treatments significantly correlated with grain yield, grain weight, harvest index and grain filling duration. TNC at 5DAA negatively correlated with N at 5DAA and harvest index, but the TNC remobilization efficiency under heat stress positively correlated with mainstem grain yield, grain weight and harvest index. The rate of chlorophyll loss from flag leaf positively correlated with N and TNC remobilization efficiencies under heat stress suggesting a link between leaf senescence and remobilization efficiency. The results indicate that heat stress negatively affected grain yield, its components and N remobilization while it increased TNC remobilization because of the increasing demand for resources.     

以热量指数表示北疆棉区棉花延迟型冷害指标的研究

应用乌兰乌苏农业气象试验站棉花试验的生育期、产量及旬气温资料,计算出棉花不同播期和不同生长阶段的热量指数,研究分析不同播期棉花产量、霜前花率与棉花不同生长阶段的热量指数之间的关系发现:1)随播种期推后,棉花生长前期热量指数明显增加,而棉花生长后期的热量指数则呈现出明显的下降趋势。2)现蕾—开花阶段的热量满足状况很好,热量指数稳定。3)分期播种的单产与棉花生长后期的热量指数具有很好的线性关系,霜前花率也与棉花生长后期的热量指数关系密切,生长后期的热量指数变化对棉花品质的影响较产量更加敏感。4)以减产幅度为标准,在棉花开花期以前热量充足的情况下,后期生长热量指数低于64为一般延迟型冷害年指标,低于61.8为严重延迟型冷害年指标。5)以霜前花率为标准,在棉花开花期以前热量充足的情况下,后期生长热量指数低于 70.9 会出现一般冷害年,低于63.2,会出现严重冷害年。     

Vegetative protein and its relation to grain protein in high and low grain protein winter wheats

Summary Better understanding of the physiological and genetic basis of wheat grain protein will contribute to breeding efforts for this characteristic. This study provides information about plant protein distribution in high and low grain protein winter wheats (Triticum aestivum L.) at different growth stages and its relation to grain protein. Field experiments involved two winter wheats with high grain protein, Redwin and Lancota, and two with low grain protein, Centurk and Brule in two years. Protein content in the head, the upper three leaves, the first and second leaf, and the peduncle were estimated with Near Infrared Reflectance Spectrophotometer (NIR) at five growth stages. High protein cultivars had higher leaf protein at ripe and higher protein content in the heads at most growth stages than low grain protein cultivars. High protein cultivars had lower protein content in the peduncle than low protein cultivars at ripe. Correlation coefficients between plant-part protein and grain protein ranged from 0.48 to 0.87 for the heads, from –0.45 to –0.79 for the peduncle, and from 0.55 to 0.84 for the leaves. A combination of head, peduncle, and first leaf protein at heading was significantly related to grain protein (R²=0.71). Indirect selection for head, peduncle, and first leaf (flag leaf) protein at heading should result in increased grain protein. Recurrent selection for increased grain protein, with parent selectionbefore anthesis and hybridization should be successful.     

高温胁迫对番茄种子萌发的影响

当温度高于 2 5℃时 ,随温度上升 ,番茄种子活力下降 ;33℃时 ,种子的萌发在前 6d受到抑制 ,7d后萌发率上升 ;在35℃时 ,种子萌发几乎完全被抑制。在 30℃萌发的种子中 SOD和 POD活性较高 ,33℃萌发种子中的蛋白质含量较 2 5℃和30℃处理的高     

Karyotypic and electrophoretic studies on taro and its origin

Summary Karyotypes and electrophoretic pattern of 15 strains of taro were studied. Strains collected from the northeast India hill state, Meghalaya were diploids and triploids whereas those from the plains of south India were diploids and of north India was a triploid. The diploids had 2n=28 and triploids showed 2n=42 chromosomes. The wild taro had the most asymmetrical karyotype. The protein content varied from 4.2 to 11.4 mg/g dry wt. The maximum protein content was found in a triploid strain 8 (11.4 mg/g dry wt) and minimum in the wild taro (4.2 mg/g dry wt). The number of protein bands was 7 in the wild taro (diploid) and 12 in one of the cultivated triploid strain. Meghalaya strains showed great variation with respect to leaf size and tuber shape and size. All the strains have diverged at morphological, karyotypic and genotypic levels. It is suggested that taro might have originated in the north-eastern India.     

Predicting the relative effectiveness of direct versus indirect selection for oat yield in three types of stress environments

Summary In breeding crop varieties for stress environments, it must be decided whether to select directly, in the presence of stress, or indirectly, in a nonstress environment. The relative effectiveness of these two strategies depends upon the genetic correlation (r _g ) between yield in stress and nonstress environments and upon heritability in each. These parameters were estimated for grain yield of 116 random oat lines grown in nonstress, P-deficient, N-deficient, and late-planted environments. Estimates of r _g between yield in nonstress and yield in P-deficient, N-deficient, and late-planted environments were 0.52±0.24, 1.08±0.16, and 0.06±0.24, respectively. No consistent relationship between heritability and environment mean yield was observed. Direct selection in the presence of stress was predicted to be superior for yield in low-P and late-planted environments, but indirect selection in high-N environments was predicted to be as effective as direct selection in producing yield gain in low-N environments. These results confirm that neither high-yield environments nor environments in which the heritability of yield is maximized are necessarily optimum when the goal is to maximize yield gain in stress environments.Dep. of Agronomy, Iowa State Univ., Ames, IA 50011; USA, Journal Paper no. 13101. Project 2447.     

冬小麦体细胞无性系种子蛋白质含量的遗传

从同一单倍体的幼穗、成熟胚、继代花药愈伤组织和种子植株幼穗获得的无性系，其蛋白质含量的变幅很大，分别为１２．１４％￣２１．３３％、１３．９８％￣２０．５１％，１３．８２％￣１７．９７％和１６．６２％￣２２．１６％。无性系蛋白质含量的变异发生在早代。获得的高蛋白特性可以遗传。已从单倍体幼穗无性系获得５个蛋白质含量高（１９％以上）的冬小麦新品系。