Genetic polymorphism in low-molecular-weight glutenin genes from Triticum aestivum, variety Chinese Spring

Low-molecular-weight (LMW) glutenin subunits consist mainly of two domains, one at the N- terminus which contains repeats of short amino-acid motifs, and a non-repetitive one rich in cysteine, at the C- terminal region. In previous reports, polyacrylamide-gel electrophoresis has been used to show that large size variation exists among LMW and HMW glutenin subunits, and it has been suggested that deletions and insertions within the repetitive region are responsible for these variations in length. In this study, PCR-amplification of genomic DNA (Triticum aestivum variety Chinese Spring) was used to isolate three full-length LMW glutenin genes: LMWG-MB1, LMWG-MB2 and LMWG-MB3. The deduced amino-acid sequences show a high similarity between these ORFs, and with those of other LMW glutenin genes. Comparisons indicate that LMWG-MB1 has probably lost a 12-bp fragment through deletion and that LMWG-MB1 and LMWG-MB2 have an insertion of 81 bp within the repetitive domain. The current study has shown direct evidence that insertions and/or deletions provide a mechanistic explanation for the allelic variation, and the resultant evolution, of prolamin genes. Single-base substitutions at identical sites generate stop codons in both LMWG-MB2 and LMWG-MB3 indicating that these clones are pseudogenes. Received: 7 May 1999 / Accepted: 17 June 1999     

PFCA uptake and translocation in dominant wheat species (Triticum aestivum L.)

The comparative uptake of four perfluorinated carboxylic acids (PFCAs) by wheat (Triticum aestivum L.) grown in nutrient solution was investigated. Wheat is the main food crop in northern China and may become a potential pathway of human exposure to these PFCAs. The uptake of four PFCAs from water at a fixed concentration (1 μg/mL) increased over time, approaching a steady state, and except for the short-chain perfluorobutanoic acid, most of the total mass of each of the PFCAs taken up by wheat was found to be at the root. The root concentration factor (RCF) and shoot/root concentration factor (SRCF) were calculated, and with the increase in carbon chain length, the RCFs increased but SRCFs decreased, which indicated that long-chain PFCAs had stronger root uptake and weaker translocation capacities than short-chain PFCAs. In addition, pH could obviously impact the uptake of four PFCAs in the roots and shoots of wheat, and the highest concentrations were found at pH = 7 when the pH increased from 4 to 10.     

低磷和干旱胁迫对小麦生长发育影响的研究初探

研究了低磷和干旱胁迫对小麦（Triticum aestivum L.）生长发育的影响。结果表明,低磷胁迫能显著降低小麦的分蘖数、叶片相对含水量和叶绿素含量,进而抑制小麦的生长发育,降低其生物产量和经济产量,不耐低磷品种中国春受影响的程度要大于耐低磷品种烟中144。在相同条件下,干旱能够强化磷胁迫效应,表现出明显的胁迫叠加现象。     

有机酸存在下小麦体内Cd的生物毒性和植物络合素(PCs)合成的关系

采用溶液培养方式 ,研究了有机酸存在下小麦体内 Cd的生物毒性和植物络合素 (PCs)合成的相关关系 ,试图寻求一种与小麦体内 Cd的生物毒性高度相关的评价指标。结果显示 ,Cd胁迫对小麦产生明显的毒害效应并诱导小麦根系内 PCs的大量合成。EDTA、DTPA、柠檬酸、苹果酸和草酸的适量供应可不同程度减轻或消除 Cd的生物毒性 ,其强弱顺序为 EDTA >DTPA 柠檬酸 >苹果酸≈草酸。与此同时 ,小麦根系内 PCs的诱导量也有明显下降 ,与 Cd的生物毒性保持一定的线性关系 ,且在EDTA、DTPA和柠檬酸供应下尤为显著。表明 PCs可以作为一项敏感的生化指标 (biochem ical indicator)用来评价和预测环境中 Cd的污染 ,并有望成为重金属生物有效性评价系统中一种新的补充方法     

干旱胁迫下小麦叶片脯氨酸和蛋白质含量变化与染色体的关系

以中国春-Synthetic 6x小麦染色体代换系及其亲本为材料,研究干旱胁迫条件下染色体对不同生育时期叶片脯氨酸和蛋白质含量的调控效应。结果表明,在干旱胁迫条件下,1D和5D代换系叶片的脯氨酸含量变化在孕穗期、开花期、灌浆期始终显著或极显著高于中国春;而4A、4B、2D和6D代换系的可溶性蛋白质含量变化始终显著或极显著低于中国春。表明,Synthetic 6x的5D和1D染色体上可能有干旱胁迫下促进脯氨酸积累的基因存在,Synthetic 6x的4A、4B、2D和6D染色体上可能有干旱胁迫下抑制蛋白质含量下降的基因存在,小麦叶片游离脯氨酸的积累与可溶性蛋白质含量的下降无显著相关性。     

小麦蛋白质和淀粉含量与籽粒发育过程中内源激素含量的关系

研究粒重差异较小、蛋白质和淀粉含量差异大的小麦品种‘川麦107’和‘川麦36’籽粒发育过程中激素含量变化与籽粒蛋白质和淀粉积累之间关系的结果表明,‘川麦36’蛋白质含量一直高于‘川麦107’的,而其淀粉含量一直低于‘川麦107’;‘川麦36’籽粒中ZR初始含量和IAA峰值高些,开花后5~20d籽粒中ZR含量与蛋白质含量呈显著正相关,IAA峰值与此期的蛋白质积累速率跃变相对应。两品种籽粒中GA峰值与蛋白质含量的低谷相对应,开花后5~30d的籽粒中GA含量与淀粉含量呈极显著正相关,而‘川麦107’籽粒中GA含量较高。     

Isolation,Selection and Characterization of Root-Associated Rock Phosphate Solubilizing Bacteria in Moroccan Wheat (Triticum aestivum L.)

Abstract

Phosphorus (P) is the most important macronutrient next to nitrogen for the growth and development of plants. But often unavailable for plants because of its high reactivity with many soil constituents. Thus, the use of phosphate solubilizing bacteria (PSBs) as biofertilizers seems to be an effective way to resolve the soluble phosphorus availability in soil. The present study was conducted to isolate and characterize rock PSB associated with the rhizosphere of wheat (Triticum aestivum L.) from fourteen different wheat-growing sites of Meknes region in Morocco. A total of one hundred ninety-eight (198) rock PSBs were isolated employing NBRIP medium amended with rock phosphate (RP), out of which five strains (A17, A81, B26, B106, and B107) were selected for their strong ability to dissolve RP and were tested in vitro for plant growth-promoting (PGP) traits including production of indole acetic acid (IAA), siderophores, hydrogen cyanide (HCN), and antifungal activity, as well as their response to the effect of extrinsic and intrinsic stress. The 16S rRNA gene sequencing and phylogenetic analysis identified these isolates belong to four genera, Pantoea, Pseudomonas, Serratia, and Enterobacter. The phosphate solubilization index (SI) of selected isolates ranged between 2.3 and 2.7, and the amount of solubilized phosphorus in the liquid medium varied from 59.1 to 90.2 µg mL^?1. HPLC analysis revealed that all the selected isolates produced multiple organic acids (oxalic, citric, gluconic succinic, and fumaric acids) from glucose under aerobic conditions. Except for the A81 strain, all selected isolates were able to produce IAA ranging between 2.9 and 21.2 µg mL^?1. The isolates A17, B26, and B107 showed the ability to produce siderophores ranging from 79.3 to 20.8% siderophore units. Only two strains (A17 and B26) were able to produce HCN. All selected isolates showed good resistance against different environmental stresses like 10–50?°C temperature, 0.5–2?g L^?1 salt concentration and 4.5–9?pH range, and against different antibiotics. The antagonistic effect showed that among the five selected strains, only two strains (B26 and A17) were able to suppress the growth of tested fungi. This study clearly indicates that our selected rock PSBs can be used as biofertilizers for grain crops after studying their interaction with the host crop and field evaluation.     

DNA超甲基化在小麦耐盐胁迫中的作用

运用高效液相色谱技术测定小麦(Triticum aestivumL.)耐盐品种‘德抗961’和盐敏感品种‘豫麦34’盐胁迫后叶片和根DNA中5-甲基胞嘧啶百分含量的变化,结果表明,经150 mmol/L NaCl处理6 d后,‘德抗961’叶片和根DNA中的5-甲基胞嘧啶的百分含量显著下降,但经150 mmol/L NaCl处理10 d后,耐盐品种‘德抗961’叶片和根DNA中的5-甲基胞嘧啶的百分含量都比盐敏感品种‘豫麦34’的高。由此推测DNA超甲基化可能是植物耐盐机制的一部分。     

Aluminum stress and protein synthesis in near isogenic lines of Triticum aestivum differing in aluminum tolerance

Aluminum (Al) stress was examined in three lines of wheat ( Triticum aestivum L.) by measuring root lengths, protein synthesis and protein accumulation in seedling root tips grown in a hydroponic system. An Al-sensitive, recurrent wheat parent (cv. Katepwa) showed very little root growth in low Al concentrations. In contrast, an Al-tolerant near isogenic line (Alikat) and Al-tolerant donor (cv. Maringa) had much greater root growth. Segregation data from an F₂ population (Katepwa × Alikat) showed that one major gene controlled Al tolerance based on root growth ( X ²= 0.651). All three lines showed an approximately 2-fold increase in [³⁵S]-Met incorporation in root tips after 3 days in Al and a comparable increase in root-tip dry weight. Maringa and Alikat root tips showed an increased total protein content while Katepwa root tips showed no increase in total protein content during the Al stress. Based on higher specific activities, insoluble proteins were preferentially translated in all three lines during Al stress. Proteinase activity in Katepwa root tips was 1.7-fold higher during Al stress, with Maringa and Alikat showing no change in proteinase activity. The Al-induced, increased proteinase activity in Katepwa appeared to inhibit soluble protein accumulation.     

不同类型土壤上种植的小麦籽粒中与淀粉合成相关的酶活性变化

测定池栽条件下灰潮土、水稻土、砂姜黑土上种植的强筋小麦‘郑麦9023’籽粒灌浆过程中腺苷二磷酸葡萄糖焦磷酸化酶（AGPP）、尿苷二磷酸葡萄糖焦磷酸化酶（UGPP）、可溶性淀粉合成酶（SSS）、淀粉粒结合淀粉合成酶（GBSS）、淀粉分支酶（SBE）5个与淀粉合成有关的酶活性变化的结果表明,不同类型土壤上种植的小麦籽粒中AGPP、UGPP、SSS、GBSS、SBE活性均呈单峰曲线变化,花后18d,AGPP、UGPP、SSS和SBE活性达到峰值,而GBSS则在花后24d达到峰值。AGPP、SSS、SBE活性峰值表现为灰潮土〉水稻土〉砂姜黑土,UGPP峰值表现为灰潮土〉砂姜黑土〉水稻土,GBSS峰值则表现为水稻土〉灰潮土〉砂姜黑土。     

外源水杨酸对光抑制条件下小麦叶片光合作用的影响

以浓度为50、100、200 mg·kg-1的水杨酸(SA)预先处理灌浆期的小麦叶片,可有效防护强光所致的氧化损伤,维持较高的超氧化物歧化酶(SOD)和抗坏血酸过氧化物酶(APX)活性,减轻丙二醛(MDA)积累.叶片在光抑制条件下,可维持较高的通过PSⅡ电子传递速率(Fm/Fo)、PSⅡ原初光化学效率(Fv/Fm)、PSⅡ量子效率(ΦPSⅡ)、光化学猝灭系数(qP)、净光合速率(Pn)和较低的非光化学猝灭系数(qNP).其中,以较低浓度SA(50 mg·kg-1)的效果较好.     

不同冠温特征冬小麦籽粒灌浆过程中内源激素含量的变化

"豫麦50"在灌浆后期冠层温度明显降低,表现为冷尾型;而"豫麦34"和"豫麦70"则在灌浆后期冠层温度有上升趋势,表现为暖尾型,在灌浆末期冷尾型与暖尾型小麦冠层温度相差超过2.5℃.冷尾型"豫麦50"强势粒中ZR、IAA、GA3含量峰值均高于其它两个品种,其ZR/ABA、GA3/ABA、IAA/ABA峰值亦高于暖尾型"豫麦70"和"豫麦34",ABA含量在灌浆中期上升快,高峰值大于"豫麦70"和"豫麦34",达到高峰后下降较快;"豫麦50"弱势粒中的各种激素含量仍较高.     

条锈病对小麦(Triticum aestivum L.)叶片光合功能及光合功能蛋白D1表达的影响

测定了小麦(Triticum aestivum L.)感染小麦条锈病后的光合常数,以及叶绿素含量、类囊体膜光合电子传递速率和光合反应中心D1蛋白的变化.实验显示,条锈病侵染导致感病小麦叶片净光合速率与叶绿素含量降低;抗病小麦经侵染后净光合速率却有恢复过程,叶绿素含量先降后升.此外,感病小麦叶片被侵染后全链电子传递速率受到抑制,PSII电子传递速率的变化与全链电子传递速率的变化趋势相似,但PSI电子传递速率受到的影响较小;抗病小麦小麦叶片被侵染后电子传递速率所受影响较小.同时发现,病程中,感病和抗病小麦PSII的光合反应中心D1蛋白含量变化总是与PSII电子传递速率的变化类似,推测D1蛋白的表达量变化是引起PSII电子传递活性与全链电子传递速率变化的主要因素之一.     

水肥不同层次组合对冬小麦（Triticum aestivum L.）氮磷养分有效性和产量效应的影响

以肥熟土垫旱耕人为土为供试土样,用分层土柱试验法研究了不同层次水分、氮、磷组合对冬小麦(Triticum aestivum L.)氮磷养分有效性和产量效应的影响.结果表明,不同土层水肥处理的氮磷养分有效性和产量效应差异显著.氮素养分有效性在4.73%～41.19%之间,磷素养分有效性在4.11%～13.58%之间.对氮素养分有效性,单施氮整体湿润时(0～90cm土层湿润)较上干下湿(0～30cm土层干旱胁迫,30～90cm土层湿润)低4.87%,而氮磷配施在整体湿润时较上干下湿高6.38%,差异均达显著水平;对磷素养分有效性,氮磷配施时,在整体湿润时较上干下湿增加5.01T(p<0.05).从不同施肥土层看,氮素养分有效性均以0～90cm土层施肥处理最高;对氮磷配施处理,在上干下湿时分别比0～30cm、30～60cm和60～90cm土层施肥处理高9.5%、10.1%和20.2个%;对磷素养分有效性,整体湿润处理,以0～30cm土层施肥显著高于其它土层施肥处理.单施氮或磷,上干下湿时氮磷养分的产量效应均高于整体湿润处理,但氮磷配施时均以整体湿润处理较高;从不同土层施肥看,氮素养分的产量效应以0～90cm土层施肥最高;磷素养分的产量效应则表现为0～90cm与0～30cm土层施肥处理显著高于30～60cm和60～90cm土层施肥处理.分析0～90cm土层残留硝态氮和有效磷累积量可以看出,不同处理土壤残留硝态氮含量存在显著差异,上干下湿时CK、单施氮、单施磷和氮磷配施土壤残留硝态氮分别比整体湿润相应施肥处理增加125.8%、20.1%、21.9%和2.1%;不同处理有效磷差异性不及硝态氮明显.整体看,在两种水分状况下,均以0～90cm和0～30cm土层施肥有利于提高氮磷养分对冬小麦的有效性和产量效应,减少硝态氮和有效磷在土壤中的残留累积.考虑到生产上的可操作性,仍以施入0～30cm土层最适,说明即使在上干下湿情况下,保证上层有效养分供应仍具重要作用.     

小麦秸秆复合基质的理化指标及其对黄瓜幼苗生长和光合参数的影响

以小麦(Triticum aestivum L.)秸秆基质(发酵)为主,按不同比例分别添加蛭石、珍珠岩和草炭,配制10种复合基质;以不含小麦秸秆基质的复合基质为对照,对各基质的基本理化性状进行了分析和比较,并研究了不同基质对黄瓜(Cucumis sativus L.)幼苗生长、叶片叶绿素含量和光合参数的影响。结果显示:不同基质的理化指标有明显差异,小麦秸秆基质与蛭石、珍珠岩和草炭混配均降低或显著降低了基质的容重、总孔隙度、持水孔隙度、水气比、小颗粒含量、pH值和电导率,提高了通气孔隙度以及大、中颗粒的含量。按V(小麦秸秆基质)∶V(蛭石)∶V(草炭)=50∶25∶25的比例配制的复合基质T9的容重、总孔隙度、通气孔隙度、持水孔隙度、水气比和电导率分别为0.33g.cm-3、68.1%、15.3%、52.8%、3.45和3.91 mS.cm-1,理化性状最佳,具有良好的吸水和保水性能。总体上看,随复合基质中小麦秸秆基质比例的降低,黄瓜幼苗的株高、茎粗、根总长、根总体积、平均单根直径和根尖总数、生物量和壮苗指数以及叶片的叶绿素含量均呈上升趋势;复合基质中小麦秸秆基质比例较高,黄瓜叶片的净光合速率、气孔导度和蒸腾速率均较低,但与对照相比,不同基质对叶片胞间CO2浓度及水分利用效率无显著影响。在复合基质T9中黄瓜幼苗的这些生长指标、壮苗指数以及叶片叶绿素含量和光合参数总体上高于或显著高于对照和其他复合基质,生长良好。结果表明:复合基质T9较适合黄瓜幼苗的生长发育,可作为黄瓜育苗基质。     

普通小麦与冰草间杂种的细胞遗传学及其自交可育性

为了进一步研究冰草属（Ａｇｒｏｐｙｒｏｎ Ｇａｅｒｔｎ．）的Ｐ染色体组与小麦染色体组间的遗传关系和评价Ｐ染色体组在属间杂种自交可育性上的遗传效应,获得了普通小麦品种Ｆｕｋｕｈｏ（Ｔｒｉｔｉｃｕｍ ａｅｓｔｉｖｕｍ ｃｖ．Ｆｕｋｕｈｏ,２ｎ＝４２;ＡＡＢＢＤＤ）与３个不同来源的四倍体冰草（Ａ．ｃｒｉｓｔａｔｕｍ＜Ｌ．＞Ｇａｅｒｔｎ．,２ｎ＝２８;ＰＰＰＰ）间的杂种（２ｎ＝３５;ＡＢＤＰＰ）。结果表明     

小麦体细胞无性系SSR位点的遗传变异特性分析

研究结果表明:(1)小麦体细胞无性系SSR位点变异类型有:扩增片段迁移率的变大或变小、扩增片段缺失以及新的扩增片段;(2)变异特点为:变异频率与基因型有关,不同染色体组上的SSR位点变异频率不同,而不同无性系后代的SSR位点变异频率也不同;(3)同一SSR位点的变异类型在同一基因型的无性系后代中变异表现一致,在不同基因型无性系后代中的变异表现不同,有的SSR位点在无性系后代中表现出一致的变异,而有的则不一致。