华北地区小麦品种农艺性状比较分析

以20世纪末21世纪初华北地区先后审定的168份小麦(Triticum aestivum L.)品种为研究材料,对8个主要农艺性状进行了比较分析。结果表明,该区育成的小麦品种类型多,遗传变异丰富,8个农艺性状的变异系数(7.96%~26.51%)表现为千粒重主茎穗长株高主茎穗粒数单穗重平均穗粒数单株有效穗数单株产量。各农艺性状在4省市的差异较大,北京地区小麦品种具有株高高、主茎穗长长、千粒重高的特点;河南小麦品种具有穗粒数多、单穗重高的特点;山东小麦品种分蘖成穗率高;河北小麦品种的农艺性状比较协调。各小麦品种单株产量与单株有效穗数(0.85)、平均穗粒数(0.39)、单穗重量(0.37)、主茎穗粒数(0.27)、主茎穗长(0.20)达极显著正相关,与株高达显著正相关(0.19),与千粒重呈不显著负相关。     

保湿型洗手液的配制及其对小麦种子萌发的影响

[目的]为了降低生活污水排放对环境的影响.[方法]配制清洁保湿型洗手液,并检测其对小麦种子萌发的影响.[结果]稀释100倍洗手液的溶液会对小麦种子发芽产生较显著的影响,而稀释300倍以上的自配洗手液对小麦发芽几乎没有影响.[结论]该产品高效环保,且使用后作为生活污水排放对环境的危害小.     

四川和黄淮生态区小麦品种(系)主要产量性状比较

采用来自四川和河南两地区的主栽小麦(Triticum aestivum Linn.)品种和2012年两地部分区试小麦品系共27个材料,在河南辉县地区种植,随机区组法2次重复,生长期间和收获后调查产量结构性状,研究南方和北方生态区小麦品种产量构成的差异.比较分析结果表明:①四川品种在北方种植,其产量明显低于北方品种;②四川品种的穗粒数高于北方品种,但穗数和粒重低于北方品种;③北方的多穗型品种在北方生态区种植易获得高产,大穗型品种在产量结构合理的条件下也能获得较高产量;④单位面积穗数是北方冬麦区构成小麦产量的第一因素;⑤大穗型品种播量对单位面积穗数调节效果不明显.上述结果说明,不同类型生态区小麦最佳产量结构差异较大,北方品种高产主导因素是单位面积穗数,南方品种优势倾向于穗粒数.     

Members of soil bacterial communities sensitive to tillage and crop rotation

Pyrosequencing was used to study the effect of rotation and tillage on total bacterial communities. We designed primers to the bacterial 16s rDNA and amplified DNA from soil samples from a long-term tillage/rotation trial in Kansas for two seasons. The 2 × 2 factorial trial had two rotation treatments (wheat-wheat and wheat-soybean) and two tillage treatments (conventional and no-till). A total of 20,180 16s rDNA sequences were generated and 2337 operational taxonomic units (OTUs) were assembled using a 97% similarity cut-off. The phylum Proteobacteria represented 38% of 299 identified taxa. The second most abundant phylum was Acidobacteria, making up 20% of the sequences, the majority of which were Acidobacteria Group 1. The phyla Actinobacteria and Gemmatimonadetes comprised 12% and 3.5% of the sequences. Other groups detected included TM7, Nitrospira, Verrucomicrobia, and Bacteroidetes. Some clusters of Acidobacteria Group 1 were more frequent in continuous wheat versus wheat-soybean rotation, some Acidobacteria Group 2 were more frequent in no-till, and some Acidobacteria Group 4 were more frequent in wheat-soybean rotation. These results were validated by quantitative real-time PCR. Pyrosequencing provided taxonomic information about the overall bacterial community, and detected community shifts resulting from different cropping practices.     

Storage and Remobilization of Soluble Carbohydrates after Heading in Different Plant Parts of a Winter Wheat Cultivar

Abstract

Several types of water soluble carbohydrates (WSG) were traced into plant parts of a winter wheat (Triticum aestivum L.) cultivar from heading to physiological maturity. Field grown plants were harvested at intervals of a few days and divided into grain, chaff, leaf blades, leaf sheaths, rachis + peduncle and culm internodes. Leaf blades and sheath showed the peak of WSC contents at about anthesis. Culm internodes accumulated fructan and sucrose during the early grain-filling phase, from a week after anthesis until the milk-ripe stage, then remobilized them during late and final grain filling phases, from the milk-ripe stage until maturity. The amount of sucrose known as short-term storage WSC was higher than fructan known as long-term storage WSC in each internode throughout the grain-filling phase. Chaff showed a large amount of fructan and fructose before anthesis, although it did very little sucrose. A pattern of sucrose accumulation in chaff was very different from that of fructan, unlike the other parts. These patterns of changes in WSC contents in plant organs roughly corresponded with four grain-filling phases, the initial, early, late and final phases.     

Root exudation of diclofop-methyl and triasulfuron from foliar-treated durum wheat and ryegrass

In this study, we evaluated the release of diclofop-methyl and triasulfuron from the roots of foliar-treated ryegrass and wheat. The study with ¹⁴C-diclofop-methyl indicated a basipetal translocation of foliar-applied herbicide in wheat and ryegrass. No root exudation from ¹⁴C-diclofop-methyl-treated wheat plants was observed, while 20 days after treatment (DAT) 0.2–0.9% of radioactivity absorbed by ryegrass was found exuded in the growing medium. Root exudation was stimulated three to six times by the presence of untreated wheat or ryegrass sharing the growing medium with diclofop-methyl-treated ryegrass. No subsequent uptake of exuded radiolabel by untreated plants (ryegrass or wheat) in the same pot with ¹⁴C-diclofop-methyl-treated ryegrass was observed. The study with ¹⁴C-triasulfuron indicated a basipetal translocation of foliar-applied herbicide in wheat and ryegrass and also into the growing medium. By 20 DAT, 0.5–4.2% of radioactivity absorbed by wheat or ryegrass was found exuded in the growing medium. The presence of untreated plants (wheat or ryegrass) in the same pot as triasulfuron-treated ryegrass or wheat induced exudation seven to 32 times more. The study also revealed a subsequent uptake of exuded compounds by untreated wheat or ryegrass sharing the medium of ¹⁴C-triasulfuron-treated plants. This study has demonstrated for the first time that the root exudation of exogenous compounds can be related to plant arrangement in pots. The implication is that herbicide root exudation and transfer, a form of allelopathy, could be significant in the field. A precise estimation of environmental fate, unexpected ecological side effects and residual activity of herbicides may require quantification of such exudation.     

Potassium deficiency impedes elevated carbon dioxide‐induced biomass enhancement in well watered or drought‐stressed bread wheat

Potassium (K) deficiency reduces photosynthesis and biomass production of crop plants and also renders them vulnerable to drought stress, whereas elevated carbon dioxide (CO₂) has a positive effect on photosynthesis and yield and ameliorates the adverse effects of drought stress. This study aimed to characterize the physiological responses of wheat (Triticum aestivum L.) stressed with K deficiency under elevated CO₂ and drought conditions. Increased biomass production caused by elevated CO₂ as a consequence of increased photosynthesis and water use efficiency was absent in young K‐deficient wheat plants. Shoot K concentration was negatively affected by elevated CO₂ particularly under K‐deficient conditions, whereas K content per plant was greatest in plants supplied with adequate K and adequate water. Specific leaf weight was increased as a consequence of carbohydrate accumulation in the source leaves of K‐deficient plants particularly under elevated CO₂ and drought stress. Potassium deficiency clearly impeded the impact of elevated CO₂ in both well watered as well as drought‐stressed plants. Adequate K fertilization is a prerequisite for efficient harvesting of atmospheric CO₂ through increased photosynthesis, decreased transpiration, and increased biomass production under changing atmospheric CO₂ and soil moisture conditions.     

Shift of grain protein composition in bread wheat under summer drought events

Climate change bears the risk of more frequent drought stress in the northern hemisphere with more frequent early summer drought events affecting main grain crops. Winter wheat (Triticum aestivum L.) is susceptible for such drought events at the flowering and grain filling stages. After drought, the grain yield decrease of three hybrids was about 20% lower compared to three wheat lines analyzed. Wheat grain proteins are classified into four main components such as albumin and globulin, gliadin, and glutenin. The latter two are closely related to the baking quality of flour and might be affected by drought. However, detailed knowledge about the influence of drought on the synthesis of specific storage protein fractions is scarce. By analyzing the grain protein fractions by means of SDS‐PAGE technique, we detected an increase in grain protein content as well as in HMW and some LMW glutenin sub‐fractions. The glutenin fraction seems to be most variable in gene expression under different environmental scenarios such as drought. However, the protein yield as well as the grain yield may be strongly decreased, which might be not acceptable in practice.