青稞籽粒长和宽的差异性

为了解青稞籽粒长、宽在品种(系)间的差异,以来自国内外的214份青稞品种(系)为材料,对粒长、粒宽进行鉴定分析。结果表明,青稞粒长、粒宽在品种(系)间均存在显著差异。粒长的变异范围为4.125～8.117 mm,平均值6.075 mm,总变异系数10.906%;籽粒较长的材料有北青2号(青海海北)、长芒裸大麦(云南昆明)、白青稞(西藏隆子)、山青7号(西藏山南)和喜马拉4号(西藏仁布),以喜马拉4号最长;籽粒较短的材料有湟中六棱青稞(青海湟中)、扎骨(西藏左贡)、褐青稞(青海)、米大麦(云南晋宁)和米如红(西藏南木林),以湟中六棱青稞最短。粒宽变异范围为1.670～3.553 mm,平均值2.596 mm,总变异系数13.721%;籽粒较窄材料有米如红(西藏南木林)、白青稞(西藏昌都)、丹巴黑青稞(四川丹巴)、冬207(西藏拉萨)和白青稞(西藏隆子),其中最窄品种为米如红;较宽材料为Bang-Iu(墨西哥)、紫青稞(西藏穷结)、繁29(青海)和喜马拉6号(西藏日喀则),最宽材料为喜马拉6号。从材料来源看,青稞粒长在不同地区间也差异显著,但粒宽差异不显著;甘肃材料的粒长平均值最大(6.2...     

Grain weight and grain number responsiveness to pre-anthesis temperature in wheat, barley and triticale

In temperate cereals are commonly accepted that determination of grain number (GN) and grain weight (GW) scarcely overlap during the crop cycle. However, the assumption that GW is determined exclusively after anthesis needs to be critically reviewed in the light of reports published over the few years where temperature treatments imposed before anthesis decreased GW of bread wheat. Although these evidences suggest that both GW and GN could be affected by environmental conditions before anthesis little is known about the effect of pre-anthesis temperature on these two main yield components in wheat, barley and triticale at field conditions. In addition, the effect of temperature on GW and GN at different stages prior to anthesis has been scarcely evaluated. The objectives of the current study were: (i) to evaluate the overall response, and specific differences, of GN and GW to pre-anthesis temperature, and (ii) to study the effect of different timings of high temperature at pre-anthesis on GN and GW in wheat, barley and triticale. Three fully irrigated field experiments were carried out in three successive seasons. At each season, a wheat, barley and triticale high yielding cultivar was evaluated at three temperature regimes: control, and two timings of heating before anthesis. During the first and second seasons, the timings of heating were booting-anthesis and heading-anthesis. In the thirst season, the timings were beginning of stem elongation-booting and booting-anthesis. Plots were arranged in a split-plot design with three replicates, where the main plot was assigned to thermal regime and the sub-plots to crop species. To apply heat, transparent chambers equipped with thermostatically controlled electric heaters were used. The thermal regime was controlled by sensors connected to a temperature regulator and recorded using data loggers. Temperature within the chambers was stable across developmental stages, crops, and seasons; it averaged 5.5 °C higher than air temperature. Thermal treatments consistently reduced grain yield (p < 0.05), the magnitude of the effect ranged between 5 and 52%. The highest effect was found when temperature increased during stem elongation (yield decrease: 46%), lowest when treatments were imposed during heading-anthesis (15%) and intermediate for treatments imposed during booting-anthesis (27%). Most effects of thermal treatments on yield were due to parallel effects on GN. However, thermal treatments significantly (p < 0.05) decreased GW during the three seasons. The most effecting treatment on GW was when the crops were heated during the B-A period, i.e. GW decreased up to 23%.     

川藏高原地区青稞育成品种醇溶蛋白遗传多样性的比较分析

利用A-PAGE(Acid-polyacrylamide gel electrophoresis)技术研究了43份来自四川、西藏的青稞(裸大麦)育成品种醇溶蛋白的遗传多样性。结果表明:43份材料共分离出22种相对迁移率不同的醇溶蛋白谱带,41种不同的电泳图谱,说明供试材料醇溶蛋白的遗传多态性丰富。就遗传多样性差异来说,在醇溶蛋白位点I,四川>西藏(P<0.01);在位点Ⅱ,四川<西藏(P<0.01);在位点Ⅲ,四川<西藏(P>0.05)。四川材料的遗传多样性平均值略高于西藏材料,差异不显著。四川、西藏材料间的遗传分化较低。聚类分析结果表明,43份材料可分成A、B、C3大类,材料聚类与其生长的地区有明显的相关性。四川材料间、西藏材料间的平均遗传距离较低。在超级青稞育种中,应发掘和利用新的优异青稞资源,扩大青稞的遗传基础。     

大麦籽粒和苗粉蛋白质含量的检测

为了解大麦籽粒及苗粉中蛋白质含量的差异,以242份大麦为材料,研究了不同基因型大麦籽粒及苗粉蛋白质含量的差异。结果表明,大麦籽粒蛋白质含量高于20%的有7份,含量低于10%的有7份,含量中等的有228份;大麦苗粉蛋白质含量高于33%的品种有8份,含量低于20%的有24份,含量中等的有210份。青稞的蛋白质含量较高;分蘖期大麦苗粉可作为高蛋白饲料。大麦籽粒和苗粉蛋白质含量相关系数为0.461,达极显著水平(P0.01)。     

The effects of extrusion on the content and properties of dietary fibre components in various barley cultivars

Wholemeal flour from five Czech spring barley materials was processed in a single-screw extruder at 130 °C, addition of 20% water and a screw speed of 220 rpm. Two barleys (AF Cesar, AF Lucius) were hulless cultivars with a standard starch composition, while three barleys (KM 2624, KM 2460-1, KM 2460-2) were hulled waxy lines. The effect of extrusion on content of different dietary fibre fractions was determined. Also the changes of the molar mass of β-glucan were studied. Regardless of the barley genotype (standard starch or waxy), the extrusion had no significant effect on arabinoxylan content. A significantly higher beta-glucan and soluble dietary fibre content in barley cultivars with standard starch composition was observed after extrusion. The content of insoluble dietary fibre decreased significantly in all extruded flours. The molar mass of water-extractable beta-glucan increased independently of the barley variety after extrusion. But the increase in beta-glucan extractability due to extrusion was not observed.     

播期、播种密度及肥料运筹对青稞产量及产量性状的影响

以13个来自西藏不同生态区的青稞(Hordeum vulgare L.var.nudum HK.f.)品种为材料,研究播期、播种密度、肥料运筹及其互作对青稞籽粒产量和产量性状的影响。结果表明:参试青稞品种的籽粒产量与产量性状在品种间、播期间均存在显著(P<0.05)或极显著(P<0.01)差异;春播青稞籽粒产量显著低于秋播(P<0.05)。播种密度和肥料运筹对参试品种籽粒产量影响不显著。每穗粒数在播种密度和肥料运筹间差异显著(P<0.05),千粒质量在肥料运筹间差异显著(P<0.05)。     

氮肥对耐盐啤酒大麦产量、品质及光合功能的影响

为了提高沿海地区啤酒大麦的产量和品质,研究了施氮量、氮肥运筹对耐盐啤酒大麦泰兴9425籽粒产量、品质与光合功能的影响.结果表明,随着施氮量的增加,啤酒大麦籽粒产量、干物质积累量、叶面积、SPAD值、光合速率、籽粒蛋白质含量均呈上升趋势,籽粒淀粉含量呈下降趋势;同一施氮量水平下不同氮肥运筹(基肥∶分蘖肥∶拔节肥)间的产量、干物质积累量、叶面积均表现为B2(7∶1∶2)＞B3(5∶3∶2)＞B1(9∶1∶0),SPAD值、光合速率、蛋白质含量表现为B3＞B2＞B1,淀粉含量高低表现为B1＞B2＞B3.在本试验条件下,耐盐啤酒大麦泰兴9425每盆施纯氮3.92g(折合180 kg·hm-2),基肥∶分蘖肥∶拔节肥施氮比例为B2(7∶1∶2),可实现高产与优质协调发展.     

青海BYDV-GAV青稞分离物基因组克隆及结构特征分析

大麦黄矮病毒(Barley yellow dwarf viruses,BYDVs)病是一种在世界范围内发生危害的禾谷类作物病毒病害。2014年笔者在对青海重要作物病毒病调查时发现田间青稞作物上有疑似BYDVs危害的症状,利用BYDVs引物对田间采集的9份典型症状病样进行了RT-PCR检测,结果均扩增到目的条带(约300bp),随机抽选样品进行序列测定,BLAST分析结果显示其与BYDV-GAV同源性最为接近(99.2%)。为进一步明确该分离物的分类地位及基因组结构特征,根据已测定的BYDV-GAV序列设计全长扩增引物,利用分段法克隆了其全基因组序列,发现其全长为5 683bp,具有典型的黄症病毒属的特征,编码6个ORF,有4个非编码区(UTR)。基因组序列聚类进化分析结果显示,其与BYDV-GAV聚类于同一分支,与中国陕西渭南小麦分离物亲缘关系较近。以上结果说明,该分离物是BYDV-GAV的一个分离物,这是青海BYDV-GAV青稞分离物全基因组的首次报道。     

播种期和氮肥用量对春大麦灌浆期籽粒蛋白质和游离氨基酸含量的影响

为提供更合理的氮肥运筹和适宜播期以促进大麦的优质高产,以蒙啤1号、蒙啤3号、甘啤4号、垦啤7号4个春大麦品种为试材,研究了不同施氮水平和播期处理下内蒙古东部灌区春大麦灌浆期间籽粒蛋白质含量和游离氨基酸含量及其与成熟期籽粒蛋白质含量的相关性。结果表明,随着播期的推迟,相同灌浆期4个品种的籽粒游离氨基酸含量和蛋白质含量均呈升高的趋势;随着施氮量的增加,相同灌浆期4个品种的籽粒游离氨基酸含量和蛋白质含量均呈先升高后降低的趋势。成熟期籽粒蛋白质含量与花后7d、28d和35d籽粒蛋白质含量呈显著或极显著正相关。逐步回归分析结果表明,影响成熟期籽粒蛋白质含量最大的是花后28d籽粒蛋白质含量,而通径分析结果显示,对成熟期籽粒蛋白质含量影响最大的是花后14d的籽粒蛋白质含量。成熟期籽粒蛋白质含量与灌浆期籽粒游离氨基酸含量的相关性均达到极显著水平,对成熟期籽粒蛋白质含量影响最大的是花后7d的游离氨基酸含量,其次是花后21d的游离氨基酸含量。     

Use of advanced recombinant lines to study the impact and potential of mutations affecting starch synthesis in barley

The effects on barley starch and grain properties of four starch synthesis mutations were studied during the introgression of the mutations from diverse backgrounds into an elite variety. The lys5f (ADPglucose transporter), wax (granule-bound starch synthase), isa1 (debranching enzyme isoamylase 1) and sex6 (starch synthase IIa) mutations were introgressed into NFC Tipple to give mutant and wild-type BC₂F₄ families with different genomic contributions of the donor parent. Comparison of starch and grain properties between the donor parents, the BC₂F₄ families and NFC Tipple allowed the effects of the mutations to be distinguished from genetic background effects. The wax and sex6 mutations had marked effects on starch properties regardless of genetic background. The sex6 mutation conditioned low grain weight and starch content, but the wax mutation did not. The lys5 mutation conditioned low grain weight and starch content, but exceptionally high β-glucan contents. The isa1 mutation promotes synthesis of soluble α-glucan (phytoglycogen). Its introgression into NFC Tipple increased grain weight and total α-glucan content relative to the donor parent, but reduced the ratio of phytoglycogen to starch. This study shows that introgression of mutations into a common, commercial background provides new insights that could not be gained from the donor parent.     

行距配置对高产冬小麦籽粒灌浆特性及淀粉和蛋白质积累的影响

为研究不同行距配置对小麦籽粒发育及淀粉和蛋白质积累的影响,以4个高产冬小麦品种为材料,在河南浚县农业科学研究所超高产攻关田研究了不同行距配置下小麦籽粒灌浆特性及淀粉、蛋白质的积累动态.结果表明,高产小麦籽粒中可溶性糖含量下降与淀粉含量的增加趋势基本吻合,宽窄行种植模式(S1)籽粒中可溶性糖含量较高,且转化利用较快,促进了籽粒淀粉积累.从行距配置看.周麦22籽粒蛋白质含量以等行距种植模式(S2)较高,偃展4110和矮抗58均以S1较高,而豫麦49-198在两种种植模式下无明显差异.籽粒灌浆速率、千粒重和产量则表现为豫麦49-198、周麦22和矮抗58均以S较高,而偃展4110以S2较高.灌浆模型分析表明,灌浆持续天数和最大灌浆速率出现时间是行距配置影响粒重的主要因素.     

Effects of variety and fertiliser nitrogen on alcohol yield, grain yield, starch and protein content, and protein composition of winter wheat

The effects of nitrogen (N) fertiliser on grain size and shape, starch and protein concentration, vitreosity, storage protein composition, and alcohol yield of two winter wheat varieties contrasting in endosperm texture were studied in a field trial in Herefordshire, UK in 2004. Averaged across varieties, the alcohol yield was 439 L/tonne for grain with a protein concentration of 11.5 g/100 g. The soft endosperm wheat variety Riband produced on average 7.7 L more alcohol per tonne of grain at a given protein concentration than the hard endosperm variety, Option. At the same time, N fertiliser was shown to have significant effects on alcohol production through its major influence on grain protein concentration. Averaged over both varieties, there was a reduction in alcohol yield of 5.7 L for each 10 kg increase in protein content per tonne of grain. The starch concentration of Riband was 2.9 g/100 g higher than Option at a given grain protein concentration, supporting its higher observed alcohol yields. A low conversion of starch to alcohol in this study (6.30 L/10 kg starch) compared to the theoretical value (6.61 L/10 kg starch) indicated that there is potential for improvement of this character. The traits relating to grain size and shape were principally influenced by genotype, and were not influenced by N fertiliser. Conversely, there were only minor genotypic effects on grain protein concentration and vitreosity. An important finding was that there were no interactions between variety and N treatment for any of the variables considered, indicating that the response of the two varieties to changes in applied N was the same, resulting in consistent differences in starch concentration and alcohol yield between genotypes at different levels of grain protein. An analysis of the composition of the wheat storage proteins by size-exclusion chromatography showed that the gliadins increased on average by 0.56 g per g increase in total grain protein and were quantitatively the major protein fraction, suggesting that selection for low gliadin content may be a desirable means by which to reduce grain protein, and thereby increase alcohol yield in wheat. The relationship between alcohol yield per unit area and applied N rate was described by a quadratic function and the maximum alcohol yield per unit area was ca. 3630 L/ha. Statistical analysis suggested that the economic optimum rate of N applied for grain yield was close to the optimum N rate for maximum alcohol productivity.     

Metabolic characteristics in ruminants of the proteins in newly developed hull-less barley varieties with altered starch traits

Recently, new varieties of hull-less barley have been developed with altered carbohydrate traits. To our knowledge, there is no study on metabolic characteristics in ruminants of the proteins in the newly developed hull-less barley varieties. The objectives of this study were to: compare metabolic characteristics of the proteins of zero-amylose waxy (CDC Fibar), low-amylose waxy (CDC Rattan), high-amylose (HB08302), and normal starch (CDC McGwire) hull-less barley. In situ animal trials were carried out to generate the original rumen fermentation data for modeling nutrient supply to dairy cattle by using two dairy nutrition models – Dutch DVE/OEB system and NRC 2001. The major comparisons were made in terms of i) truly absorbed protein in the small intestine (DVE or MP, and ii) degraded protein balance (DPB). The study revealed that zero-amylose waxy hull-less barley was superior (P < 0.05) in both DVE (123 vs. 117, 114, 103 g kg⁻¹ DM) and MP (112 vs. 93, 96, and 87 g kg⁻¹ DM) when hull-less barley was evaluated as a single feed for dairy cattle. All of four hull-less barley varieties had negative DPB (DPB^OEB; −37.4, −17.1, −30.2, and −28.2 g kg⁻¹ DM for normal starch, zero-amylose waxy, waxy, and high-amylose cultivar, respectively), indicating the potential N shortage. In conclusion, the alteration of starch structure in granule provided a relatively balanced energy and protein for microbial synthesis in the rumen. The DVE and DPB predicted by using the DVE/OEB system can be explained (r² > 0.76) by the equivalent parameters, predicted by using the NRC 2001 model. The alteration of starch structure in granule affects metabolic characteristics of the proteins of hull-less barley in ruminants.     

刈割留茬高度对青稞饲草与籽粒产量及饲用品质的影响

为探究适宜于高寒区青稞多元化利用最佳刈割留茬高度,以昆仑14号、昆仑18号和柴青1号为试验材料,以未刈割为对照(CK),于分蘖盛期开展不同留茬高度的刈割处理,探究留茬高度对青稞农艺性状、籽粒产量、饲草产量及营养品质的影响。结果表明,随着刈割留茬高度的降低,各青稞品种青苗饲草产量均呈逐渐增加的趋势;青苗中粗蛋白含量呈逐渐降低趋势,而纤维类物质含量呈逐渐升高的趋势,使青苗相对饲喂价值显著降低。各青稞品种秸秆饲草产量随刈割留茬高度的降低而降低,且降幅随留茬高度的降低而增大。刈割使青稞秸秆中粗蛋白含量增多,纤维类物质含量减少,相对饲喂价值升高。留茬8 cm有助于促进青稞穗部、茎部和根系的生长发育,使籽粒产量升高;留茬5 cm会抑制青稞各器官的生长发育,使籽粒产量锐减。各品种在留茬8 cm时综合经济产值最高,其中昆仑14号综合经济产值最高,为2.86×10⁴元·hm^-2。参试材料中,昆仑14号为高寒区最适用于粮饲兼用的青稞品种,8 cm为适宜于青稞饲草与籽粒兼收的最佳刈割留茬高度。     

Grain number and its relationship with dry matter, N and P in the spikes at heading in response to N×P fertilization in barley

The aim of this work was to study the effects of nitrogen (N) and phosphorus (P) deficiencies and their interaction on spike N, P and biomass around flowering in barley (Hordeum vulgare spp. distichum L.) and its relationship with grain number and grain yield. Two experiments were carried out with microcrops grown in 200 l containers using malting barley (cv. Quilmes Palomar). Treatments were a factorial combination of two levels of N and two or three levels of P fertilization. Dry matter partitioning to spikes was not or only slightly affected by nutrient deficiencies. Then, the effects on spike biomass were similar to those on total aboveground dry matter. Although partitioning of N to the spike in N fertilized treatments was lower than in N stressed ones, spike N content was higher in the N fertilized.

Number of grains was positively associated with spike N and P content as well as spike dry matter at heading in both experiments. Number of grains per unit of spike dry matter at heading in N fertilized microcrops tended to be higher than in N stressed ones, though this effect was not associated with N fertilization effects on N concentration in spikes.

Combining these results with others from the literature from wheat crops, we found a strong relationship between number of grains and spike N content at flowering, but this relationship does not seem to be better than that with spike biomass, judged by the regression coefficients. This indicates that the early application of N may induce a higher number of grains than that predicted by increased spike dry weight at flowering, but this additional effect is not universally related to differences in spike N concentration.     

Barley for food: Characteristics,improvement, and renewed interest

Barley (Hordeum vulgare vulgare L.) is an ancient cereal grain, which upon domestication has evolved from largely a food grain to a feed and malting grain. However, barley food use today remains important in some cultures around the world, particularly in Asia and northern Africa, and there is renewed interest throughout the world in barley food because of its nutritional value. This review covers basic and general information on barley food use and barley grain processing for food use, as well as an in-depth look at several major aspects/traits of interest for barley food use including kernel hardness and colour, grain starch, and β-glucan contents. These traits are described in terms of their effects on processing and nutrition, as well as their inheritance and the prospects for barley improvement through breeding. Whereas, the aspects listed above have been studied relatively extensively in barley in terms of content, form, genetics, physiology, and in some cases nutritional quality, little is know about functional properties for processing and food product development. Renewed interest in barley for food uses largely centres around the effects of β-glucans on lowering blood cholesterol levels and glycemic index. Wholegrain barley foods also appear to be associated with increased satiety and weight loss. There is great potential to utilise barley in a large number of cereal-based food products as a substitute partially or wholly for currently used cereal grains such as wheat (Triticum aestivum), oat (Avena sativa), rice (Oryza sativa), and maize (Zea mays).     

磷肥对西藏青稞叶水势、光合生理及产量因素的影响

为探讨施磷量对西藏青稞叶水势、光合、产量等因素的影响,以西藏主栽春青稞品种喜马拉雅22号为试材,通过田间微区试验,设不施磷(CK)、低磷(P2O575kg·hm~(-2))、中磷(P2O5150kg·hm~(-2))和高磷(P2O5225kg·hm~(-2))处理,测定青稞开花后4d的旗叶水势(LWP)、光合和叶绿素荧光参数,以及成熟后千粒重和产量,并利用数字图像分析法精准提取籽粒表型性状。结果表明,与CK相比,施磷可明显降低青稞旗叶水势,显著提高旗叶和倒2叶叶绿素含量,但磷肥处理间叶绿素含量差异不显著;施磷条件下青稞旗叶净光合速率(Pn)、气孔导度(Gs)和蒸腾速率(Tr)均高于CK(除高磷处理的Tr外),其中低磷条件下最大,而高磷条件下最低;胞间CO_2浓度(Ci)随施磷量增加呈下降-平稳-下降趋势。PSII的最大量子效率(Fv/Fm)、实际光量子产量(ΦPSⅡ)、光合电子传递的相对速率(ETR)、光化学淬灭(qP)值随施磷量的增加均呈先增后降趋势,并以中磷处理最大;非光化学淬灭(qN)在CK、低磷、中磷处理间差异较小,而高磷处理时显著下降。随着施磷量的增加,籽粒二维面积、直径、周长、长度、宽度均呈增大趋势,而粒圆度呈减小趋势。随施磷量的增加,小粒和较小粒占比逐渐下降,而中粒和大粒占比逐渐提高。低磷处理下青稞千粒重和籽粒产量分别较CK提高6.66%和17.53%,中磷处理分别提高17.20%和21.10%,高磷处理分别提高8.72%和16.16%,但磷肥利用效率(PUE)随施磷量增加呈逐渐降低趋势。综合来看,在本试验条件下,青稞适宜施磷量应控制在75～150kg·hm~(-2)以内。     

小麦光合器官对不同穗位和粒位粒重及蛋白质含量的影响

为探明小麦叶片与非叶光合器官对不同穗位和粒位籽粒发育的影响,以济麦22为试验材料,开花期设置剪叶、包穗、包茎等7种处理,分析了不同处理下不同穗位和粒位粒数、粒重和蛋白质含量的差异。结果表明,小麦穗对穗上部和下部弱势粒数影响显著,与叶片共同作用对穗上部强势粒数及穗中部和下部粒数,以及与茎和叶片共同作用对穗上部粒数、穗中部和下部弱势粒数均影响显著;穗对不同穗位强势粒重和穗上部弱势粒重影响显著,旗叶对穗中部和下部强势粒重、穗上部和中部强势粒重及穗下部粒重影响显著;包穗、剪旗叶和剪倒二叶处理显著提高穗上部强势粒及穗中部和下部籽粒蛋白质含量;剪倒三叶和剪倒四叶+剪倒五叶处理显著提高穗下部强势粒蛋白质含量;同一穗位的强势粒蛋白质含量大于弱势粒,不同穗位籽粒的平均蛋白质含量表现为穗下部穗中部穗上部;同一穗位的弱势粒蛋白质含量变异系数大于强势粒,穗上部的籽粒蛋白质含量变异系数大于穗中部和下部。因此,建议小麦育种中应注重穗光合选择,适当增加小穗排数,减少高穗位粒数,可能是提高小麦产量潜力和改善品质的重要途径。     

夏玉米不同粒位蛋白质组分氮素效应及与子粒脱水的关系研究

从蛋白质粒位差异的角度,以不同自然脱水类型玉米品种为材料,分析不同氮肥运筹处理下不同部位子粒蛋白质组分含量、子粒脱水速率,研究子粒脱水与蛋白质组分和氮素施用的关系。结果表明,脱水速率差异较大的品种总蛋白质存在较大差异,蠡玉16和先玉335总蛋白质含量分别为11.25%、12.16%。增施氮肥蛋白质含量明显增加;增施氮肥主要增加了醇溶蛋白和谷蛋白含量,清蛋白和球蛋白含量影响较小。增施氮肥生理成熟后不同处理间脱水速率存在显著差异;蛋白质组分和脱水速率之间存在密切关系,先玉335生理成熟后不同部位间醇溶蛋白和谷蛋白与脱水速率呈显著或极显著负相关,醇谷比与子粒脱水呈正相关。     

花后高温和干旱对冬小麦光合、抗氧化特性及粒重的影响

为了解花后高温和干旱双重胁迫对小麦的效应,以石麦15为材料,于花后15 d到21 d进行高温（34~36 ℃）和干旱（土壤含水量为田间持水量的40%~45%）处理,研究了高温和干旱胁迫对小麦旗叶光合性能、旗叶丙二醛（MDA）含量和抗氧化酶活性、籽粒淀粉含量和千粒重的影响。结果表明,胁迫第7 d（花后21 d）时,干旱和高温-干旱双重胁迫显著降低了小麦旗叶净光合速率（P_n）和叶绿素相对含量(SPAD值),胁迫解除后P_n降幅缩小,高温胁迫下P_n和SPAD值与对照的差异不显著。高温-干旱双重胁迫显著降低了旗叶F_v/F_m值,且胁迫解除后恢复程度较小。胁迫期间,旗叶MDA含量和过氧化物酶（POD）活性持续升高,超氧化物歧化酶（SOD）和过氧化氢酶（CAT）活性均呈先升后降趋势,SOD和CAT活性对干旱、高温-干旱双重胁迫更敏感,胁迫第7天时高温-干旱双重胁迫下降幅度最大。旗叶P_n和SPAD的变化趋势与籽粒淀粉积累量和千粒重变化趋势基本一致,说明灌浆期高温、干旱胁迫下小麦籽粒淀粉积累量和粒重的降低与质膜过氧化、叶绿素的降解和旗叶早衰导致的光合性能下降密切相关,在双重胁迫下光合性能受抑加剧。