小麦耐热及热敏感基因型在高温胁迫下膜透性及膜脂组分的差异

高温逆境下,植物膜透性的增加导致细胞代谢紊乱并诱导热激基因表达.脂肪酸是构成生物膜的主要物质,饱和脂肪酸的含量及饱和程度高,有利于保持膜在高温时的流动性和稳定性.本研究利用小麦(Triticum aestivum)耐热基因型TAM107和热敏感基因型中国春(CS)为对象,研究了高温胁迫对膜透性、叶绿素荧光参数Fv/Fm、膜脂组分及其相关脂肪酸去饱和酶基因(FAD7)表达的影响,结果表明,高温胁迫下,两基因型膜透性均增加,膜脂中的三烯脂肪酸含量下降,但TAM107变化幅度明显高于中国春,在脂肪酸水平上说明耐热小麦品种的膜系统较热敏感品种对高温逆境有较强的耐受性;中国春比TAM107中FAD7的表达对高温更加敏感,这直接影响了热胁迫前后膜脂中三烯脂肪酸含量的变化,在转录水平上说明了耐热小麦基因型较热敏感基因型对高温逆境有较强的耐受性.三烯脂肪酸含量在热胁迫前后的变化可作为一种新的耐热鉴定指标.     

小麦细胞膜热稳定性的配合力与杂种优势分析

细胞膜热稳定性是较好地反映小麦品种耐热性大小的重要生理指标.本文利用冬、春小麦各6个亲本分别组配的6×6完全双列杂交(包括反交),对该性状(以相对热损伤率RI%表示)进行了配合力和杂种优势分析.结果表明:(1)该性状的一般配合力效应(GCA)、特殊配合力效应(SCA)和反交效应(R)均达极显著水平.上述三因素相对作用大小冬、春小麦分别为3.9:1:1.6和2.1:1:0.5,说明该性状的遗传虽以加性基因效应占一定优势,非加性基因效应和反交效应也起重要的作用.(2)该性状受质核互作和(或)细胞质的明显影响.(3)一些杂种F_1的细胞膜热稳定性具有明显的杂种优势,并存在超亲遗传现象.这将对小麦的耐热性遗传改良和杂种优势利用提供理论指导和依据.     

日本鲟肌动球蛋白热变性和冷冻变性

研究了日本鲟肌动球蛋白经变性和冷冻后ＡＴＰａｓｅ活性、总巯基数和不饱和巯基数及蛋白质浓度的变化。结果表明,热变性后肌动球蛋白Ｃａ＾２＋－ＡＴＰａｓｅ和Ｍｇ＾２＋－ＡＴＰａｓｅ活性下降,且Ｃａ＾２＋－－ＡＴＰａｅｓ活性有明显转折。低温热变性对总巯基数影响较小,温度增高时,巯基数逐渐下降,而不饱和巯基数在３０℃之前,呈动态变化,之后又逐渐减少。热变性后,肌动球蛋白浓度也降低。冷冻变性后,肌动球蛋白ＡＴ     

Determination of Moisture Deficit and Heat Stress Tolerance in Corn Using Physiological Measurements and a Low‐Cost Microcontroller‐Based Monitoring System

In the southern United States, corn production encounters moisture deficit coupled with high‐temperature stress, particularly during the reproductive stage of the plant. In evaluating plants for environmental stress tolerance, it is important to monitor changes in their physical environment under natural conditions, especially when there are multiple stress factors, and integrate this information with their physiological responses. A low‐cost microcontroller‐based monitoring system was developed to automate measurement of canopy, soil and air temperatures, and soil moisture status in field plots. The purpose of this study was to examine how this system, in combination with physiological measurements, could assist in detecting differences among corn genotypes in response to moisture deficit and heat stress. Three commercial hybrids and two inbred germplasm lines were grown in the field under irrigated and non‐irrigated conditions. Leaf water potential, photosynthetic pigments, cell membrane thermostability (CMT) and maximum quantum efficiency of photosystem II (Fv/Fm) were determined on these genotypes under field and greenhouse conditions. Variations observed in air and soil temperatures, and soil moisture in plots of the individual corn genotypes helped explain their differences in canopy temperature (CT), and these variations were reflected in the physiological responses. One of the commercial hybrids, having the lowest CT and the highest CMT, was the most tolerant among the genotypes under moisture deficit and heat stress conditions. These results demonstrated that the low‐cost microcontroller‐based monitoring system, in combination with physiological measurements, was effective in evaluating corn genotypes for drought and heat stress tolerance.     

热激处理对甘蓝幼苗叶片细胞膜系统热稳定性的影响

采用二因素(热激温度、热激时间)二次回归正交旋转组合设计,对耐热性不同的2个甘蓝品种的种子进行了热激处理,然后在苗期测定了甘蓝幼叶中细胞膜的电解质渗漏量。结果表明:热激处理后不耐热品种叶片中细胞膜透性的增幅大于耐热品种,热激温度、热激时间二因素与细胞膜热稳定性之间有显著的回归关系,并且回归分析出最优热激处理组合为42℃2.3 h。     

Evaluation of cultivated barley (Hordeum vulgare) germplasm for the presence of thermostable alleles of β-amylase

A cleaved amplified polymorphic sequence marker was used to detect the alleles Bmy‐Sd2H and Bmy‐Sd3 identifying highly thermostable isoforms of the enzyme b‐amylase, which improves fermentability during brewing. Among the 889 accessions of barley (Hordeum vulgare) investigated, and two accessions of H. spontaneum a total of 166 accessions were identified carrying the superior b‐amylase alleles. These thermostable alleles of b‐amylase were most frequently observed in six‐rowed varieties originating from Asia, especially Japan, with 61.9% of the accessions from Asia carrying the alleles of interest. Additional six‐rowed barleys carrying the relevant alleles were identified among accessions from America, Africa and the Near East. In the European varieties, the percentage of accessions with the alleles of interest was 5.1% with a strong predominance in two‐rowed spring barleys. A pedigree analysis identified the cross ‘Binder’ x ‘Gull’ as the main source of the thermostable b‐amylase alleles in European varieties. The data suggest that an improvement of malting quality in barley could be achieved by introduction of the Bmy1‐Sd2H and Bmy1‐Sd3 alleles into the European breeding programmes.     

北方冬麦区与黄淮北片优良小麦品种(系)耐热性评价

为筛选小麦耐热种质资源,在开花后15d开始覆盖塑料大棚,模拟高温胁迫,对来自我国北方冬麦区和黄淮北片主推的53个小麦品种(系)的千粒重热感指数、容重热感指数、几何平均产量进行分析,并以耐热品种TAM107为对照,结合苗期细胞膜热稳定性对参试材料的耐热性进行评价。结果表明,在三年(2008-2011)试验中,千粒重热感指数均小于1的品种(系)有9个(05CA306、京冬8号、邯6228、衡6632、农大3492、农大3432、济麦19、农大212和衡4399),容重热感指数均小于1的品种(系)有8个(衡观216、农大3492、农大413、京冬8号、山农2149、农大212、衡6632和济麦19)。依据参试品种(系)在3年的几何平均产量及热感指数的结果,农大212、农大3492、京冬8号、济麦19、衡6632、农大413、山农2149和衡观216可作为耐热高产品种(系)在生产上推广应用。利用细胞膜热稳定性筛选出44个苗期耐热性好的品种(系)。综合细胞膜热稳定性法及田间评价结果,农大212、衡6632、农大3492、济麦19、农大413、山农2149和衡观216为耐热性较好的品种(系)。     

Genetic variability of heat tolerance, and its effect on yield and fibre quality traits in upland cotton (Gossypium hirsutum L.)

Global temperature is rising because of increasing concentrations of CO₂ and other greenhouse gases (e.g. methane, nitrous oxide, etc.) in the atmosphere because of the excessive use of fossil fuels. High temperature causes heat stress which reduces crop productivity. The development of heat-tolerant varieties is feasible and will help mitigate the effects of climate change. Fifty-one cotton accessions were screened in heat-stressed and non-stressed conditions in the glasshouse and field. Relative cell injury percentage (RCI %), a measure of cell membrane thermostability (CMT), was used to assess heat tolerance. Heat-tolerant accessions had more stable yield and yielded more seed cotton with better quality fibre than the heat-intolerant accessions across four environments. The responses of the 51 accessions to all four environments for the measured traits were strongly associated. RCI % of the accessions and hybrids was strongly and negatively associated with yield and fibre traits. CMT was concluded to be a useful technique for identification of heat-tolerant cotton.     

低剂量杀虫剂与高温结合对西花蓟马种群的防控

为了探究低剂量杀虫剂与高温结合防控西花蓟马Frankliniella occidentalis种群的最佳组合,选用啶虫脒、多杀菌素、高效氯氰菊酯和灭多威4种杀虫剂的LC_(50)剂量处理西花蓟马成虫和2龄若虫18~76 h后,分别在41、43、45℃进行2 h热激处理,观察并记录每种组合下西花蓟马的存活情况。结果表明,药剂处理成虫或若虫18 h和28 h后再进行热激处理,西花蓟马的存活率显著低于其它处理。经4种杀虫剂的LC_(50)剂量处理后,不同高温热激均能不同程度降低成虫或若虫种群存活率,热激后存活率显著低于对照组;经灭多威LC_(50)剂量处理的成虫或若虫,再经高温热激处理后的存活率最低,其中45℃热激处理对成虫和若虫的存活率影响最明显,经45℃热激处理18 h和28 h后的成虫存活率为10.1%和5.9%,若虫存活率为6.1%和3.3%。研究表明,杀虫剂LC_(50)剂量与高温热激联合增强了对西花蓟马种群的抑制作用,药剂处理后选择最佳热激时间可最大限度降低西花蓟马的耐热性,进一步增强高温热激的防治效果。     

兽用吲哚美辛注射液的含量测定及热稳定性考察

目的:为控制其质量,建立了测定兽用吲哚美辛注射液含量的HPLC方法,并初步考察了该注射液的热稳定性.方法:采用高效液相色谱法测定含量,其含量测定的色谱条件是:色谱柱Ultimate XB-C18,流动相为0.1mol/L冰醋酸溶液-甲醇(20∶80),流速为1.00mL/min,柱温为室温,检测波长为228nm;热稳定性试验采用初均速法.结果:在该条件下测得兽用吲哚美辛注射液的含量为18.648±0.295mg/mL,在25℃下的有效期为2.21年.结论:该方法准确,可用于测定兽用吲哚美辛注射液的含量.