Survival of detached sporangia ofPhytophthora infestans exposed to ambient, relatively dry atmospheric conditions

The effect of duration of exposure, daily weather conditions, and exposure to direct or indirect sunlight on survival of sporangia ofPhytophthora infestans under ambient, relatively dry atmospheric conditions was evaluated. Viability of sporangia was assessed by determining the proportion of potato tuber slices or leaflets that became infected after inoculation with exposed sporangia. The maximum survival time of sporangia was 24 h under moderately cool (mean of 15 C) and dry conditions (RH < 25%). Sky conditions were sunny during daylight hours during this exposure. Infection seldom occurred when sporangia were exposed directly to sunlight; only 25 of 566 (4.4%) groups of sporangia caused infection. Of these 25 groups, 23 (92%) had been exposed to mean temperatures below 33 C for 4 or fewer hours. Binary logistic regression analysis of the data showed that duration of exposure, direct sunlight, and type of day were all significant factors affecting survival of sporangia. Long exposure in direct sunlight limited survival. Survival of sporangia was more likely to occur on cool, cloudy days and cool, rainy days than on other day-types.     

无机磷形态对甜菜生长和磷吸收的效应

采用液培和砂培法,进行了不同基因型甜菜对外源无机磷吸收利用研究。结果表明:1)生长介质中有效性无机磷含量的高低,直接影响各参试甜菜品种磷的吸收效率和利用效率,且表现出明显的基因型差异;2)参试的3个品种对生长介质中不同形态无机磷的吸收表现出明显的生物多样性特点,并主要体现在Ca8-P以上形态的磷;3)在缺磷和足磷条件下,各参试甜菜品种根际周围的pH值均有不同程度的差异,但与品种的抗耐低磷胁迫能力关系不大,相差的pH值不足以显著增加土壤中Ca8-P以上形态磷的有效性。4)各甜菜品种须根系的长度与抗低磷胁迫指数呈高度一致性,是造成不同品种对难溶性无机磷胁迫抗耐能力差异的主要原因。     

大气CO2浓度对茶叶品质的影响

通过开顶式气室控制CO₂浓度,对盆栽茶树进行试验测定,研究了大气CO₂浓度升高对茶叶品质成分氨基酸、茶多酚、咖啡碱、可溶性糖和主要营养元素含量的影响。结果表明,在大气CO₂浓度为550和750βμmol/mol时,与正常大气CO₂水平相比,春茶氨基酸含量下降4.5%和12.2%,夏茶氨基酸含量降低1.7%和6.7%,秋茶降幅为2.9%和10.8%;茶叶咖啡碱含量降低3.1%~4.6%和5.1%~10.7%;但茶叶茶多酚和可溶性糖含量降CO₂浓度升高而提高,茶多酚含量提高3.8%~6.0%和6.9%~11.3%,可溶性糖含量增加8.4%~14.4%和18.1%~28.2%。同时,大气CO₂浓度的升高使茶叶营养元素氮、钾、钙、磷、钠含量有不同程度降低,而锌、镁、铁含量有所增加,其中,茶叶氮、钾元素含量降低6.1%~16.3%和12.9%~22.9%,锌、镁含量分别提高5.8%~17.8%和11.3%~16.0%。     

Characterization of sorghum genotypes for traits related to drought tolerance

Grain sorghum (Sorghum bicolor L. Moench) is a genetically diverse cereal crop grown in many semiarid regions of the world. Improving drought tolerance in sorghum is of prime importance. An association panel of about 300 sorghum genotypes from different races, representative of sorghum globally, was assembled for genetic studies. The objectives of this research were to (i) quantify the performance of the association panel under field conditions in Kansas, (ii) characterize the association panel for phenological, physiological and yield traits that might be associated with tolerance to limited moisture (drought), and (iii) identify genotypes with higher yield potential and stability under different environments that may be used in the sorghum breeding program. Results show large diversity for physiological and yield traits such as chlorophyll content, leaf temperature, grain numbers and grain weight per panicle, harvest index and yield. Significant differences were found for plant height, grain weight and numbers per panicle, harvest index, and grain yield among and within races. The US elite lines had the highest number of grains and grain weight per panicle while the guinea and bicolor races recorded the lowest. Harvest index and yield was highest for the US elite lines and the caudatum genotypes. Overall, there was a negative correlation between plant height and grain weight, grain numbers and yield. Harvest index and grain numbers were negatively affected by moisture limitation for all the races. Among the races, the caudatum genotypes were more stable in grain yield across the different environments. Overall, there was a wide variability within the association panel for physiological and yield traits that may prove to be useful for improving drought tolerance in sorghum.     

虎眼万年青核型分析及B染色体研究

对虎眼万年青的染色体核型进行了分析,结果表明:该物种的体细胞染色体组包括18条数目稳定的A染色体和28~36条数目不等的B染色体,各A染色体之间形态差异不明显,均为中着丝粒染色体或近中着丝粒染色体,最长与最短染色体相对长度比仅为1.35,核型类型为较对称的2A型,核型公式为2n=18=4m 14sm (28~36)Bs。B染色体在不同细胞间却表现出明显的遗传多态性,文中还讨论了B染色体的大数量出现和数目变异与虎眼万年青具有抗旱、抗逆等生理适应性之间的关系。     

Nutrient deficiency and hypoxia as constraints to Panicum coloratum growth in alkaline soils

Alkaline and saline–alkaline soils impose severe restrictions on plant growth. Panicum coloratum var. coloratum is a perennial C4 forage grass widely used in tropical and subtropical environments. Published information on its responses to alkaline soil conditions is scarce. The objectives of this study were (i) to characterize the effects of alkaline substrates on germination and initial growth in this species, (ii) to assess the influence of high pH in combination with reduced availability of either nutrients or oxygen and salinity, on plant growth and (iii) to evaluate some physiological traits potentially responsible for growth restrictions under alkaline soil conditions. Trials were conducted in a greenhouse. Germination and early plant survival were not affected by alkalinity. To isolate the effects of high pH, reduced nutrient and oxygen availability on growth, plants were grown either in neutral or alkaline soil, in hydroponics, in neutralized alkaline soil (with or without supplementary fertilization), or were flooded to induce hypoxia. Alkalinity effects on growth in hydroponics were milder than in soil. Growth in alkaline soil with nutrient supplement was still significantly lower (by 40%) than in neutral soil. Both alkalinity and hypoxia reduced growth non‐synergistically. These results show that studies of plant response to alkaline substrates carried out in aerated nutrient solutions can only partially address the complexity of this stress. Photosynthesis and PSII activity were among the physiological mechanisms negatively affected by alkalinity and may be partially responsible for the growth limitations observed in P. coloratum under alkaline conditions.     

供氮形态和水分胁迫耦合作用对磷在苗期——分蘖期水稻植株不同部位含量与分配的影响

为探讨不同形态氮素营养对干旱条件下水稻P吸收与分配的影响, 采用室内营养液培养及聚乙二醇（PEG6000）模拟水分胁迫处理的方法,在分蘖期设置3种供氮形态（NH4+ N、NO3- N以及NO3- N和NH4+ N相同浓度下等体积混合）和两种水分条件（非水分胁迫及水分胁迫）的耦合处理进行研究。结果表明： 1）在水分胁迫条件下,水稻植株及各部位含P量均是全NH4+ N营养明显高于全NO3- N营养;同时,在分蘖期,全NO3- N营养水稻植株含P量明显低于非水分胁迫条件下的相应处理,但水分胁迫对全NH4+ N以及NO3- N和NH4+ N混合营养水稻含P量影响不大;2）在两种水分条件下,全NH4+ N以及NO3- N和NH4+ N混合营养均相对降低了水稻对吸收进入体内的P向叶片和根系的运输比例;而全NO3- N营养则只相对降低了水稻体内的P向叶片的运输比例。此外,由分蘖初期到中期,在水分胁迫条件下,全NH4+ N营养水稻积累的P素增加比例最高。     

不同pH条件下TSs的形成机理及其与TFs的竞争性形成研究

采用液态发酵的方式,结合不同的pH条件,通过酶促氧化儿茶素生成相应聚酯型儿茶素（Theasinensins, TSs）或茶黄素（Theaflavins, TFs）的单体物质来深入探讨TSs的形成机理及其与TFs的竞争性形成。结果表明,酸性条件下,TSs的单体物质能够持续生成,而且一直积累;中性和碱性条件下生成的TSs单体物质达到最大值的时间很短,稳定性较差。不同pH条件下,由于自身氧化还原电位值的高低,各个儿茶素单体之间被氧化而消耗的速率有所差别,而且基于生成TSs和TFs需要共同的儿茶素底物,因此两者的形成具有竞争性。pH=6和中性条件下EGCG和EGC转化形成TSs单体的量高于形成TFs的量,而pH=5水平下则相反。     

关中平原农户冬小麦养分资源投入的调查与分析

针对目前我国化肥用量激增的现状和农民养分资源投入中存在的问题,在关中平原冬小麦种植区域选取3个区/县进行冬小麦养分资源投入调查分析。结果表明：2009年小麦产量适中的农户占38.3 %;偏低的农户占26.7 %;很低的农户占22.5 %;偏高的农户占11.7 %;很高的农户占0.8 %。冬小麦的纯N平均用量为191.0 kg.hm-2;P2O5平均用量为129.9 kg.hm-2;K2O平均用量为43.8 kg.hm-2。氮肥投入量适中的农户占12.5%;偏低的农户占17.5 %;很低的农户占20 %;偏高的农户占11.7%;很高的农户占38.3%。磷肥投入量适中的农户占8.3%;偏低的农户占37.5 %;很低的农户占19.2 %;偏高的农户占23.3%;很高的农户占11.7%。钾肥投入量适中的农户占6.7%;偏低的占5.0 %;很低的占85.8 %;偏高的占1.7%;很高的占0.8%。养分资源投入以无机为主,有机为辅;投入形式以基施为主。     

Internodal elongation: A potential screening technique for heat tolerance in potato

Summary In pot culture experiments over 2 consecutive years, 20 potato genotypes of varying heat tolerance were grown under long day conditions and heat stressed by being exposed to high (38 °C/21 °C mean day/night) temperature. The percent increase in mean internode length of heat stressed plants over those grown at normal temperatue (25°C/16°C day/night) was correlated with the percent tuber dry matter yield of the heat stressed plants (r=0.618, P=0.01). In the same 20 genotypes, grown under short day conditions at normal temperature, the fraction of leaf bud cuttings exposed to high night temperature (23°C) that produced tuber initials correlated with the percentage increase in internode elongation in stem cuttings exposed to 25°C compared with those exposed to 15°C (r=0.680. P=0.01). Thus the relative changes in internode elongation are related to thermal tolerance, and it is suggested that this can be used as a selection criterion for heat tolerance.     

播期对青贮大麦产量和青贮品质的影响

为探究新疆北部地区播期对青贮大麦产量、青贮原料品质和青贮品质的影响,以3个大麦品种(系)(垦啤麦13、P13-3和甘啤4号)为材料,分别于3月18日、4月2日、4月17日播种,对其青贮农艺性状、干草产量、青贮原料营养成分和青贮品质进行分析。结果表明,随着播期的推迟,青贮大麦生育期大幅度缩短,4月17日播种时生育期较3月18日缩短22~23 d。晚播会显著降低大麦干草产量,晚播(4月17日)时3个品种(系)干草产量比早播(3月18日)降低15.2%~24.2%,其中垦啤麦13降幅最大。推迟播种使垦啤麦13和甘啤4号茎、穗的干物质分配比例下降,叶的干物质分配比例上升。晚播使P13-3和甘啤4号洗涤纤维含量(中性和酸性)和粗脂肪含量分别显著上升和下降,显著降低P13-3的粗蛋白含量,提高甘啤4号可溶性碳水化合物含量。播期对青贮品质影响因品种(系)而异,晚播降低了甘啤4号青贮的pH值、氨态氮含量,提高乳酸含量,对其他品种(系)无显著性影响。总体来看,新疆青贮大麦在外界条件允许的条件下,应适当早播。     

磷酸盐转运蛋白OsPT4影响水稻氮磷积累与利用的机理研究

【目的】磷酸盐(Pi)转运蛋白OsPT4是水稻Pht1家族成员之一,负责Pi吸收以及向地上部的转运。探究OsPT4超表达对不同Pi条件下水稻氮(N)和磷(P)积累与利用的影响及其机理具有重要意义。【方法】以日本晴背景的OsPT4超表达株系为研究材料,通过设置正常供Pi与缺Pi的水培与桶培实验,检测生殖生长阶段不同组织中OsPT4的相对表达量,探究不同Pi处理条件下不同组织(叶片、叶鞘、茎秆、稻壳、穗柄和糙米)中的N和P浓度,并计算Pi吸收率及N和P利用效率,同时分析株高、单株产量、千粒重和结实率等产量构成因素。【结果】OsPT4在水稻生殖生长阶段的根系中相对表达丰度较高,OsPT4超表达使水稻剑叶、叶鞘、茎秆、稻壳、穗柄和糙米中的总P浓度不同程度提高,并显著提高了不同Pi处理条件下的Pi吸收与利用效率。同时,OsPT4的超表达可显著提高正常供Pi与缺Pi土壤条件下的单株产量与千粒重,以及缺Pi土壤中生长的结实率。除此之外,OsPT4的超表达使缺Pi条件下瘪壳与糙米中总N浓度平均升高16.8%和19.8%,N利用效率平均升高6.6%。【结论】OsPT4超表达不仅显著提高Pi吸收与利用效率,同时对不同Pi条件下的生理氮素利用率起促进作用。     

云南澜沧县景迈古茶园土壤养分和土壤酶活性研究

云南省分布着大量的古茶园,被认为是普洱茶的起源。澜沧县景迈古茶园是典型的栽培型古茶园,在古茶园区内大平掌处选择相邻的古茶园、台地茶园和天然林三种利用类型的土壤,进行了土壤养分和土壤酶活性的调查。结果表明:三种类型的土壤都呈明显的酸性,土壤pH在3.80~3.91,茶园土壤的酸度相对更低;三种类型的土壤主要养分含量和酶活性在表层0~20cm都比下层20~40cm高,但Mg、Al和K无明显的垂直分布;三者有机质含量都很高,有机质和氮的含量分布为台地茶园<古茶园<天然林,而磷含量为古茶园最高;土壤酶活性的差异与养分的差异不一致,不同的酶活性在三种土壤中的大小规律不一样;土壤pH与金属元素相关性显著,氮元素与其它养分相关性最强,养分与土壤酶活性有显著相关性,尤其是C、N、P和K等主要营养元素。     

ZnO-mediated photocatalytic degradation of Benzopurpurine BP4B in aqueous solution

The photocatalytic degradation of a commercial azo dye Benzopurpurine 4B (BP4B) in aqueous solution was investigated under UV-A light at different operating conditions, including irradiation time, pH solution, initial dye concentration, amount of catalyst, light intensity as well as band gap of other semiconductor groups by UV-spectrophotometric monitoring. The highest decomposition efficiency was obtained at pH 8 as a result of 97.24 % degradation of BP4B for 80 min of irradiation time. Photodecomposition reaction of BP4B dye was correlated with pseudo-first-order kinetic model. The degradation data of BP4B dye were satisfactory described by Langmuir-Hinshelwood (L-H) mechanism.     

Changes in the survival rate and fecundity of the rice leaffolder, Cnaphalocrocis medinalis Guenée (Lepidoptera: Pyralidae), at different magnesium concentrations in hydroponic culture

The rice leaffolder, Cnaphalocrocis medinalis Guenée (Lepidoptera: Pyralidae), is a leaf-feeding pest and the physical and chemical nature of the rice leaf affects its feeding, survival and fecundity. We examined changes in the survival rates of larvae and pupae, pupal weight and the number of eggs laid by adult females developed from a resistant variety (Huaidao 9) and a susceptible variety (Yangjing 9538) in hydroponic solutions containing different concentrations of magnesium (Mg). The concentration of Mg in the hydroponic solution significantly affected the survival rates of the larvae and pupae, the pupal weights and the numbers of eggs laid. Larval survival rates on the resistant variety were significantly higher for fourth instars exposed to 60 and 80 ppm Mg and pupae exposed to 20, 40, 60 and 80 ppm Mg than those for the control treatment (without Mg). For the susceptible variety, survival rates of first, second and third instars were significantly higher at high concentrations of Mg than those under control conditions. In addition, the number of eggs laid by adult females increased with increasing Mg concentrations, though there was a slight decrease at 80 ppm compared to 60 ppm. These results indicate that Mg is beneficial to the development, survival and fecundity of C. medinalis. They further suggest that high levels of nitrogen fertilizer in rice fields favour outbreaks of this pest because application of nitrogen elevates the chlorophyll content and Mg levels in the rice leaf.     

Design and preparation of a nanoprobe for imaging inflammation sites

To image inflammation sites, we developed a novel nanoparticle, hydroxylamine-containing nanoparticle (HANP), which emits an intense electron spin resonance (ESR)-signal triggered by enzymatic oxidation reaction and pH-sensitive self-disintegration. The nanoparticle was prepared from an amphiphilic block copolymer, poly(ethylene glycol)-b-poly[4-(2,2,6,6-tetramethylpiperidine-1-hydroxyl)aminomethylstyrene] (PEG-b-PMNT-H), which spontaneously forms a core-shell type polymeric micelle (particle diameter = ca. 50 nm) in aqueous media. Because the PMNT-H segment in the block copolymer possesses amino groups in each repeating unit, the particle can be disintegrated by protonation of the amino groups in an acidic pH environment such as inflammation sites, which is confined to the hydrophobic core of HANP. Mixing HANP with horseradish peroxidase (HRP)/H(2)O(2) mixture resulted in enzymatic oxidization of the hydroxylamines in the PEG-b-PMNT-H and converted the hydroxylamine to the stable nitroxide radical form in PEG-b-poly[4-(2,2,6,6-tetramethylpiperidine-1-oxyl)aminomethylstyrene] (PEG-b-PMNT), which shows an intense ESR signal. It is interesting to note that the ESR signal increased at a greater rate under acidic conditions (pH 5.6) than that under neutral conditions (pH 7.4), although the enzymatic activity of HRP under neutral conditions is known to be much higher than that under acidic conditions. This indicates that enzymatic oxidation reaction was accelerated by synchronizing the disintegration of HANP under acidic conditions. On the basis of these results, HANP can be used as a high-performance ESR probe for imaging of inflammation sites.     

大豆种子抗老化鉴定的方法研究

选用遗传差异相对较大的皖豆24、皖豆25(杂交品种)及合豆3号的种子,在温度为40℃、湿度为85%的条件下老化处理4、8和12 d,研究加速老化过程中不同基因型大豆种子成苗率、发芽率、电导率及单株幼苗干重的变化规律。结果表明:随着加速老化时间的延长种子活力下降;加速老化处理8 d,3个品种的各项鉴定指标均发生改变:品种的成苗率、发芽率及单株幼苗干重显著降低,电导率明显升高,且品种间有显著差异;发芽率和成苗率的变化在品种间具有一致性,电导率、单株幼苗干重的变化和成苗率品种间一致性较差;成苗率和发芽率的相关性最高(r=0.972**)。利用国家大豆微核心种质中的91份资源对老化鉴定方法进行验证,结果在温度为40℃,湿度为85%条件下老化8 d的种子发芽率及老化指数与在自然条件下老化15个月的发芽率及老化指数极显著相关(r=0.943**,0.716**)。综合分析认为,温度为40℃,湿度为85%条件下老化处理8 d,以种子发芽率为活力鉴定指标可作为大豆种子抗老化性的鉴定方法。     

禾生指葡孢霉生物学特性及室内药剂筛选

为了给青稞和燕麦鞘腐病的科学防治提供技术支持,对其病原菌-禾生指葡孢霉的生长温度、适宜培养基种类、适宜pH值、存活时间等生物学特性进行了研究,并选取麦类作物上常用的8种杀菌剂进行了室内药剂筛选。结果表明,禾生指葡孢霉在5~30℃下可生长,适宜生长温度为20~25℃;在PSA、PDA、CA、CMA和OMA培养基平板上均可生长、产孢,适宜病菌生长、产孢的培养基为PDA和PSA;在pH值为4~10的PDA平板上均可生长、产孢,适宜生长的pH值为6~10;在5~10℃冷藏条件下,禾生指葡孢霉存活时间超过5a。在试验浓度(推荐剂量)下,8种杀菌剂对禾生指葡孢霉菌丝生长均具有不同程度的抑制效果,其中50%多菌灵可湿性粉剂(500×)、70%代森锰锌可湿性粉剂(500×)、430g·L-1戊唑醇悬浮剂(5 000×,8 000×)和400g·L-1氟硅唑乳油(5 000×,10 000×)的抑菌效果达100%。     

Comparison of attrition in citric acid modified soybean hulls and commercial cation exchange resins

The integrity of ion exchange media used under conditions of different times of use, temperatures and pH values is important in its selection. This study was conducted to quantify the lack of integrity (attrition) in base-extracted (BE), citric acid (CA)-modified soybean hulls, a lignocellulosic cation exchange material and compare its attrition to two synthetic, commercial cation exchange resins. Attrition was determined in both batch and column operations. Batch studies included measuring attrition over a 24 h period under conditions of constant pH, variable pH and at different temperatures. Under conditions of a constant pH of 4.8, 25°C and using a stir bar, modified hulls had mostly lower attrition than the two commercial products. Under acidic conditions, modified hulls demonstrated very low (<5%) attrition. At alkaline pH values, modified hulls had higher attrition than the resins after 24 h of stirring at 25°C. Although attrition increased at alkaline pH, the modified hulls ability to bind copper ion (Cu²⁺) was unaffected by pH. After 24 h shaking at 65 and 85°C, modified hulls also had greater attrition than the synthetic polymers. At these temperatures, a decreased ability of the modified hulls to bind copper ion was observed compared to the lower temperatures of 25 and 45°C. When the products were compared in column experiments at 25°C, all materials had low (<10%) attrition. Our studies indicate that in terms of product integrity, modified soybean hulls could be useful in several applications requiring a metal ion adsorbent, but not necessarily at high temperatures.