4种荚蒾属植物种子内源抑制物存在特征初探

通过荚蒾种子浸提液对小白菜种子萌发的抑制作用,分析探讨荚蒾种子内源抑制物主要存在部位及其可溶性化学特征,为荚蒾属植物种子破除休眠提供科学依据。实验结果表明:4种荚蒾种子水和甲醇浸提液对小白菜种子萌发和胚根生长都有抑制作用,种皮水溶性抑制物活性:蒙古荚蒾朝鲜荚蒾暖木条荚蒾鸡树条荚蒾,胚乳水溶性抑制物活性:蒙古荚蒾鸡树条荚蒾暖木条荚蒾朝鲜荚蒾;种皮脂溶性抑制物活性:暖木条荚蒾蒙古荚蒾朝鲜荚蒾鸡树条荚蒾,胚乳脂溶性抑制物活性:鸡树条荚蒾朝鲜荚蒾蒙古荚蒾暖木条荚蒾。鸡树条荚蒾、朝鲜荚蒾、暖木条荚蒾内源抑制物主要是脂溶性物质,前两者较集中分布于胚乳,后者多存在于种皮;蒙古荚蒾以胚乳中水溶性抑制物为主。     

Marker assisted accelerated introgression of null allele of kunitz trypsin inhibitor in soybean

Development of kunitz trypsin inhibitor (KTI)-free soybean is crucial for soy-food industry as the heat inactivation employed to inactivate the anti-nutritional factor in regular soybean incurs extra cost and affects protein solubility. In the presented work, a null allele of KTI from PI542044 was introgressed into cultivar ‘JS97-52’ (recurrent parent) through marker assisted backcrossing. Foreground selection in BC₁F₂, BC₂F₂ and BC₃F₂ was carried out using the null allele-specific marker in tandem with SSR marker Satt228, tightly linked with a trypsin inhibitor Ti locus. Background selection in null allele-carrying plants through 106 polymorphic SSR markers across the genome led to the identification of 9 KTI-free lines exhibiting 98.6% average recurrent parent genome content (RPGC) after three backcrosses, which otherwise had required 5–6 backcrosses through conventional method. Introgressed lines (ILs) were free from KTI and yielded at par with recurrent parent. Reduction of 68.8–83.5% in trypsin inhibitor content (TIC) in ILs compared to the recurrent parent (‘JS97-52’) was attributed to the elimination of KTI.     

A Dominant Inhibitor Gene Inhibits the Expression of Ht2 against Exserohilum turcicum Race 2 in Corn Inbred Lines Related to B14

The purpose of this study was to elucidate the genetic cause for the lack of express ion of the gene Ht2 against Exserohilum turcicum race 2 on certain genetic backgrounds related to the inbred line B14. Two such inbreds (A635Rp and B59), susceptible to this pathogen were crossed onto the inbred Oh43—-Ht2Ht2. The following generations: F₁, F₂, F₃, F₄, backcrosses to both parents, selfings of the backcrosses, in addition to the parent lines, were evaluated for Ht2 expression in this study. Plants of each generation were inoculated with E. turcicum race 2 and evaluated for the expression of the chlorotic-lesion resistance determined by the gene Ht2. In spite of the reported dominance of Ht2 on some genetic backgrounds, the F₁ generations studied here did not show Ht2 resistant lesions. The data presented herein suggest that B₁₄ and related inbred lines carry a dominant gene(I) that inhibits the expression of the Ht2 gene. Chi-square analyses of the reactions of 108 progeny families studied supported this hypothesis.     

豇豆胰蛋白酶抑制剂和硫氧还蛋白的融合表达和活性测定

采用融合蛋白表达技术，通过1个人工设计合成的柔性接头，将豇豆胰蛋白酶抑制剂(cowpea trypsin inhibitor,CpTI)基因与表达载体上的硫氧还蛋白(thioredoxin )基因连接，构建了融合表达载体。将表达载体转入大肠杆菌(Escherichia coli )GI724，通过色氨酸诱导获得高效表达，产物以可溶状态存在。活性测定显示，融合蛋白具有抑制胰蛋白酶的生物学活性。以大豆胰蛋白酶抑制剂为参照，将融合蛋白热处理后进行活性测定，发现它具有较好的热稳定性。将肠激酶(enterokinase)与融合蛋白在37 ℃作用16 h，可获得切掉thioredoxin的CpTI蛋白。活性测定显示，切除thioredoxin后CpTI的胰蛋白酶抑制活性比同样处理条件下的thioredoxin-CpTI明显下降，比活力仅为原来的80%，说明融合蛋白具有更高的稳定性。研究结果为thioredoxin-CpTI作为一种生物农药的应用奠定了基础。     

碳水化合物降解产物对酿酒酵母乙醇发酵的影响

研究了木质纤维原料预处理产生的主要碳水化合物降解产物对酿酒酵母乙醇发酵的影响,以及酿酒酵母对玉米秸秆酶水解液的乙醇发酵.碳水化合物降解产物对酿酒酵母NLH13乙醇发酵毒性依次为:甲酸>乙酸>糠醛>羟甲基糠醛,酿酒酵母NLH13乙醇发酵可耐受的甲酸和乙酸质量浓度分别为1和4 g/L,酿酒酵母NLHl3在2～10 g/L范...     

Alteration of glutathione S-transferase properties during the development of <Emphasis Type="Italic">Micromelalopha troglodyta</Emphasis> larvae (Lepidoptera: Notodontidae)

Micromelalopha troglodyta (Graeser) is an important pest of poplar in China. Glutathione S-transferases (GSTs) are known to be responsible for adaptation mechanisms of M. troglodyta. The activities and kinetic constants of glutathione S-transferases in M. troglodyta were studied. Significant differences in glutathione S-transferase activity and kinetic characteristics were observed among five instars of M. troglodyta larvae. Furthermore, the inhibition of glutathione S-transferase activity in five instars by 24 inhibitors was conducted. The results show the inhibition of GST activity of different instars by 24 inhibitors was different. For GST activity in the 1st instar, chlorpyrifos, lambda-cyhalothrin, endosulfan, abamectin, fipronil and pyridaben were the best inhibitors tested, and for GST activity in the 2nd instar, tannic acid and quercetin were the most potent inhibitors tested, and for GST activity in the 3rd instar, the inhibitory effects of quercetin, chlorpyrifos and lambda-cyhalothrin were the highest, and for GST activity in the 4th instar, quercetin and lambda-cyhalothrin were the best inhibitors, and the inhibitory effect of phoxim was the highest for GST activity in the 5th instar. Our results show that glutathione S-transferases in different instars are qualitatively different in isozyme composition and thus different in sensitivity to inhibitors.     

Ammonium‐driven nitrification plays a key role in increasing Mn availability in calcareous soils

Background : Manganese deficiency often becomes a yield limiting factor, particularly on calcareous soils, even though the total soil manganese content is usually sufficient. Although it is known that acidifying N fertilizers can improve Mn availability, the reason of this effect is still unknown. Aim : Our aim was to investigate the effect of stabilized ammonium fertilizers as a tool to distinguish between physiological‐ and nitrification‐induced acidification. Method : Two pot experiments with Triticum aestivum L. and one soil incubation experiment using different nitrogen forms (CN = calcium nitrate, AN = ammonium nitrate, AS = ammonium sulfate, ATS = ammonium thiosulfate) with and without addition of nitrification inhibitors (DCD, Nitrapyrin, Piadin, DMPP) were conducted to examine the effect on Mn availability in the soil and Mn uptake by the plants at different development stages (EC 31 und 39). Results : With increasing fertilizer ${\mathrm{NH}}_4^{+}$ content a higher Mn concentration was detected: CN: 32 µg Mn g^?1 DM, AN: 39 µg Mn g^?1 DW, AS: 55 µg Mn g^?1 DM, ATS: 109 µg Mn g^?1 DM. The addition of a nitrification inhibitor resulted in a significantly lower rhizosphere pH compared to the non‐stabilized fertilizer. Surprisingly, the use of different nitrification inhibitors led to unchanged (CN, AN) or lower Mn concentrations of wheat. Especially in the ${\mathrm{NH}}_4^{+}$ treatments (AS and ATS), this negative effect was very evident (AS+DCD: 42 µg Mn g^?1 DM; ATS+DCD: 55 µg Mn g^?1 DM). Conclusions : Mn availability was enhanced by ongoing nitrification process rather than physiological acidification. Compared to other N forms, ammonium thiosulfate led to the highest Mn availability in bulk soil.     

Macronutrient accumulation in wheat crop (Triticum aestivum L.) with Azospirillum brasilense associated with nitrogen doses and sources

Abstract

New studies are needed to optimize the nitrogen (N) amount that can be applied to utilize the Azospirillum brasilense benefits. In addition, information regarding the interaction between the urease inhibitor and biological nitrogen fixation (BNF) and how they affect the macronutrients accumulation are also needed. We evaluate the effect of N sources and doses associated with A. brasilense regarding the macronutrients accumulation in straw and grains and wheat grain yield in tropical conditions. A randomized block experimental design was used with four replications in a 2?×?5?×?2 factorial arrangement as follows: two N sources (urea and urea with urease enzyme inhibitor NBPT; five N doses (0, 50, 100, 150, and 200?kg ha^?1) applied in topdressing; with and without A. brasilense inoculation. We found that an increase in N doses positively influenced the accumulation of macronutrients in straw and grains and the wheat grain yield. N sources have similar effects. Inoculation with A. brasilense increased accumulation of Mg and S in straw and P, Ca, and Mg in grains, regardless of the N dose. The inoculation with A. brasilense associated with 140?kg ha^?1 of N increased wheat grain yield. The inoculation can contribute in a more sustainable way to wheat nutrition and optimizing N fertilization.     

Effects of concentration,incubation temperature,and repeated applications on degradation kinetics of dicyandiamide (DCD) in model experiments with a silt loam soil

Summary The kinetics of dicyandiamide (DCD) decomposition were studied (at 80% water-holding capacity) in pretreated and non-pretreated soils, using model experiments. DCD was added in different concentrations (6.7, 16.7, and 33.3 g DCD-N g^–1 dry soil) and incubated at various temperatures (10°, 20°, and 30°C). Additionally, DCD decomposition was examined in sterile soil (with or without Fe₂O₃) after inoculation with a DCD-enrichment culture. In the sterile variant, (30°C)the applied dicyandiamide concentration remained constant, even after 36 days. In the sterilized and reinoculated variant, DCD disappeared within 7 days. Addition of Fe₂O₃ powder to the sterilized soil had no effect on DCD degradation. In the pretreated soils, DCD mineralization started immediately at all temperatures and concentrations without a lag phase. A temperature increase of 10°C doubled the mineralization rate. The mineralization rates were independent of the initial concentrations. In the non-pretreated soils (except at 30°C with 16.7 and 33.3 g DCD-N g^–1 dry soil) DCD decreased only after a short (30°C) or a long (10°C) lag phase. These results suggest that an inducible metabolic degradation occurred, following zeroorder kinetics.     

抗盐小麦突变体的诱变筛选及其抗盐性的比较

Ｘ射线辐照前用修复抑制剂咖啡因预处理或辐照后热处理诱变冬小麦萌发种子，Ｘ射线剂量８．６Ｇｙ，剂量率２．１５Ｇｙ／ｍｉｎ。在不同浓度的ＮａＣｌ溶液中进行抗盐突变体的筛选。３个原始品种的诱变处理对比实验表明，相对于单纯的Ｘ射线２，Ｘ射线分别与咖啡因以及热复合处理，能够显提高小麦萌发１．９％ＮａＣｌ溶液中生长１５天的苗存活率。将在１．９％ＮａＣｌ溶液中生长１５天存活的小植株移植到人工气候室中加代繁殖。