电导法配合Logistic方程鉴定西葫芦和黄瓜果实抗寒性

为了研究冷敏果实在低温逆境下的抗寒性强弱,该试验以西葫芦和黄瓜为研究对象,通过测定在不同低温下(2、8、12、20℃)贮藏2、4、6、8、10、12 d过程中电解质外渗率的变化,分析不同贮藏温度及时间、成熟期、渗透时间、计量单位对试验结果的影响,配合Logistic方程建立回归方程,确定其低温半致死温度,以此来判定不同品种冷敏果实抗寒性强弱。结果表明,当渗透时间达到90 min时,电解质外渗率达到稳定状态。贮藏温度越低,贮藏时间越长,电解质外渗率越大。同时分别确定了西葫芦(5.37~6.56℃)、津优黄瓜(6.69~7.86℃)、申青黄瓜(8.04~8.96℃)的半致死温度,电解质外渗率的变化规律符合Logistic方程,决定系数R~2在0.9549~0.9900范围内.抗寒性顺序依次为西葫芦、津优黄瓜、申青黄瓜,且与成熟期无明显相关性。研究结果为判定不同品种西葫芦和黄瓜抗寒性强弱提供重要的依据。     

不同品种酿酒葡萄根系抗寒性鉴定

越冬冻害是制约中国北方酿酒葡萄产业发展的限制性因素之一,葡萄根系的抗寒能力很弱且随品种遗传性状差异而变化。为鉴定不同品种酿酒葡萄根系抗寒性,为葡萄越冬冻害的监测、预警和防御提供理论依据。本研究以贺兰山东麓‘赤霞珠’‘美乐’‘马瑟兰’‘威代尔’‘西拉’‘北玫’‘北红’‘龙眼’8个品种酿酒葡萄根系为试材,测定其在模拟自然降温冷冻过程中的生理响应指标(过冷却点、结冰点、可溶性糖、可溶性蛋白、电导率及半致死温度)。运用相关分析与聚类分析方法,综合评价8个品种酿酒葡萄根系的抗寒能力。研究结果表明:1)可溶性蛋白含量显著影响葡萄根系组织的抗寒性。2)供试的8个品种葡萄根系抗寒能力可分为3类:弱抗寒型(‘赤霞珠’‘美乐’‘西拉’),过冷却点–3.8～–3.2℃,结冰点-2.8～-2.3℃,半致死温度–4.34～–3.19℃;中抗寒型(‘北玫’‘马瑟兰’‘威代尔’),过冷却点为–5.4～–4.4℃,结冰点在–4.1～–3.7℃,半致死温度–5.90～–4.43℃;强抗寒型(‘北红’‘龙眼’),过冷却点在–6.4～–6.3℃,结冰点–5.2～–4.8℃,半致死温度–6.55～–6.11℃。3)根系抗寒能力在不同品种间有显著性差异,8个品种葡萄根系的抗寒能力强弱顺序为:‘北红’‘龙眼’‘北玫’‘威代尔’‘马瑟兰’‘赤霞珠’‘美乐’‘西拉’。过冷却点、结冰点温度可以作为评价葡萄抗寒性的重要指标。研究结果对于完善葡萄抗寒性评价方法及指导防寒减灾工作具有重要意义。     

不同配比基质对香合欢幼苗抗寒性的影响

采用正交试验法将天然土(A)、泥炭土(B)、珍珠岩(C)和椰糠(D)按不同的体积比例配成9种栽培基质,进行香合欢容器苗抗寒性研究试验。低温处理香合欢离体叶片后,测定相对电导率、丙二醛(MDA)含量、超氧化物歧化酶(SOD)活性、过氧化物酶(POD)活性和过氧化氢酶(CAT)活性,并拟合Logistic方程求出低温半致死温度(LT_(50)),采用隶属函数法综合评价不同配比基质对香合欢抗寒性的影响。结果表明:不同基质下,香合欢幼苗LT_(50)变化范围为-3.68～-0.88 ℃;依据隶属函数综合评价结果,筛选出最强抗寒性培养基质为N6基质,即A、B、C、D比例为1∶2∶0.5∶1。     

切花菊苗期抗寒性评价及相关的分子标记挖掘

为明确切花菊抗寒性的遗传变异,挖掘优异基因资源,本研究利用电导率结合Logistic方程评价83个切花菊品种苗期叶片的低温半致死温度(LT₅₀),通过关联分析探究抗寒性相关的优异等位变异位点并筛选抗性品种资源。结果表明,83个切花菊品种的LT₅₀在-10.99～1.86℃之间,变异系数为79.81%,说明切花菊抗寒性差异较大;依据LT₅₀的聚类分析将83份供试品种分为抗寒、中抗寒、低抗寒和不抗寒4种类型,分别占21.67%、22.89%、32.53%和22.89%。基于混合线性模型进行关联分析,共检测到11个等位变异位点(P<0.01),表型效应值为-3.51～0.83,表型变异贡献率为11.54%～18.83%;其中8个变异位点表现为增效,特别是携带E7M12-13位点品种的耐寒性显著(P<0.01)高于未携带该位点的品种。此外,根据增效位点挖掘到南农金柠檬、Qx097、QD028、Qx049、Qx153和Qx008等6个抗寒性强的品种资源。本研究结果为今后菊花耐寒性的遗传改良和分子标记辅助育种奠定了重要基础。     

葡萄种质的耐盐性鉴定评价

采用水培法,对32份葡萄种质进行耐盐性鉴定.根据盐害指数(SI)和死亡率为指标进行聚类分析,可分为盐敏感、中抗和高抗3类.不同种质的耐盐力从0.2%～0.4%不等;香槟尼葡萄和甜冬葡萄具有较好的抗盐性;山葡萄的抗盐性较差;美洲种、山欧杂种和贝达的抗盐性中等.欧亚种和欧美杂种中大量葡萄栽培品种,各品种对盐的抗性表现出明显的差别,在欧亚种中最抗盐的品种多分布在黑海品种群中,而其它品种群的抗盐性相对要弱.通过分析表明,盐害指数(SI)和死亡率可作为判断葡萄种质耐盐力的最直观的指标.研究还表明,随着盐浓度的增加,葡萄叶片叶绿素含量逐渐降低,而膜脂过氧化产物MDA含量则逐渐增加.     

利用RAPD标记鉴定山葡萄种质

采用修改后的CTAB法获得了高质量的基因组DNA.利用随机扩增多态性即RAPD标记对山葡萄7份种质进行鉴定,用4个引物(从30个引物中筛选)对试材进行PCR扩增,共扩增出30条谱带,平均每条引物产生7.5条谱带,其中21条谱带为多态性谱带,占总谱带数的70%.不同引物扩增的谱带数不同,范围在6～9条之间.利用4个引物扩增出的多态性谱带可以将7份山葡萄种质区分.     

8个新疆野苹果优良无性系抗寒性比较

为获得新疆野苹果抗寒育种的优良资源,本试验分析比较了8个新疆野苹果优良无性系在不同时期(1月、3月)的抗寒性差异,以8个新疆野苹果优良无性系的一年生枝条为试验材料,应用电导(EL)法和电阻抗图谱(EIS)法对其抗寒性进行测定与对比分析,并在3月对低温处理枝条进行了生长恢复试验。结果表明,新疆野苹果无性系的相对电导率在-20℃低温处理下开始出现显著差异。两时期由EIS法参数中r_e、r_1计算的各无性系半致死温度与EL法所求得的半致死温度的相关系数分别达到显著水平和极显著水平(0.744*、0.751*、0.822**、0.824**),说明这2种方法适用于新疆野苹果的抗寒性测定。3月的半致死温度(-33.97~-32.33℃)均显著高于1月(-31.87~-26.33℃),部分无性系间的差异达到极显著水平,各无性系在两时期的半致死温度相关性不显著。无性系M-3、M-6、M-8枝条计算的半致死温度较低,1月分别为-32.76℃、-33.97℃、-33.52℃,3月分别为-30.47℃、-30.26℃、-31.87℃;在3月的苗木生长恢复试验萌芽率较高,-30℃处理条件下分别为76.19%、75.71%、67.38%,-50℃处理条件下分别为16.67%、17.72%、18.89%。因此,无性系M-3、M-6、M-8的抗寒表现较好,是抗寒育种的优良资源。本试验结果为深入研究不同时期新疆野苹果抗寒性差异和筛选抗寒育种的优良资源提供了科学依据。     

基于差热分析技术的4个酿酒葡萄品种不同部位抗寒性综合评价

越冬冻害是中国北方地区的主要气象灾害之一,严重影响着西北内陆埋土防寒区酿酒葡萄产业的可持续发展。葡萄不同部位抗寒能力具有差异,主要受品种遗传性状差异及各部位特性影响。本文基于差热分析技术对不同品种酿酒葡萄不同部位抗寒性进行测定,为葡萄越冬冻害的防御工作提供理论依据。本研究以贺兰山东麓主栽的4种酿酒葡萄‘赤霞珠’‘美乐’‘西拉’和‘北玫’的主根、副根和枝条为试材,在模拟自然降温冷冻过程中测定其过冷却点、结冰点、相对电导率和枝条含水率,并应用模糊隶属函数法综合评价4个品种酿酒葡萄根系的抗寒能力。研究结果表明:1)不同品种间的抗寒能力有显著差异,且不同品种根系、枝条抗寒能力趋势表现较为一致, 4个品种抗寒能力大小顺序为:‘北玫’‘赤霞珠’‘美乐’‘西拉’。2)半致死温度与根系过冷却点呈显著性相关,结合半致死温度确定供试品种根系的过冷却点温度范围为-5.2～-2.7℃,可作为4个酿酒葡萄品种根系越冬冻害的温度参考指标。供试品种各部位中枝条抗寒能力最强,主根次之,副根最弱,且主根抗寒能力显著大于副根。研究结果对于酿酒葡萄越冬冻害监测、预警和防御能力具有重要意义,也为酿酒葡萄抗寒性育种、优良品种的推广应用提供理论参考。     

基于主成分分析法的红枣1年生枝条抗寒性研究

以6个红枣品种临泽小枣、俊优2号、脆枣、骏枣、爆米花和子弹头的1年生枝条为试材,测定相对电导率、可溶性糖、可溶性蛋白、丙二醛、游离脯氨酸含量等指标,研究其在低温处理下的生理变化特征,并用主成分分析法对其抗寒性进行综合评价.结果表明,6个品种枣树的半致死温度值(LT50)为-23.73～-16.06℃,俊优2号的最低、子...     

红小豆萌发期耐旱种质筛选

本研究采用聚乙二醇(PEG-6000)模拟干旱胁迫的方法,首先研究了不同PEG-6000浓度对3份红小豆品种发芽期的根长、上胚轴长、真叶数、发芽指数和活力指数的影响,明确了红小豆萌发期模拟干旱胁迫的最适PEG-6000浓度为10%;进而以10%的PEG-6000对40份红小豆种质资源进行萌发期抗旱性鉴定,利用隶属函数法进行耐旱性的综合评价筛选耐旱红小豆种质2份,较耐旱型种质2份,耐旱中间型种质5份,干旱较敏感型种质6份,其余25份为干旱敏感型种质。     

Soil-profile distribution of primary and secondary plant-available nutrients under conventional and no tillage

Nutrient distributions under no tillage (NT) compared with conventional disk-and-bed tillage (CT) management in the warm, humid region of the southeastern USA need to be assessed so that future placement, quantity, and type of fertilizers can be altered, if necessary, to efficiently match crop demands. We determined soil-profile distributions of pH, N, P, S, K, Ca, Mg, Na, Zn, Fe, Mn, and Cu to a depth of 0.9 m at the end of 8.5 years of continuous CT and NT management on a Weswood silty clay loam (fine, mixed, thermic Fluventic Ustochrept) in southcentral Texas. Most dramatic changes occurred within the 0–0.05 m depth, where soil under NT had lower pH, Fe, and Cu than under CT, but greater P, K, Zn, and Mn. Greater P and K under NT than under CT also occurred below the till-zone (0.15–0.3 m). At a depth of 0–0.3 m, soil under NT contained greater amounts of extractable P, K, Zn, Fe, Mn, and Cu than under CT. Nitrogen fertilization had little effect on nutrient distributions, except resulting in greater extractable K at 0–0.05 m and greater nitrate at 0–0.15 m. Few changes in soil-profile distributions were observed for extractable S, Ca, Mg, and Na. Long-term continuous use of NT on this fine-textured, high-fertility (except for N) soil had no apparent adverse effects on nutrient distributions relative to CT, but enhanced conservation and availability of P, K, Zn, Fe, Mn, and Cu near the soil surface where crop roots proliferate.     

Assessing the effectiveness of conservation measures: Resolving the “wicked” problem of the Steller sea lion

“Wicked” problems are those that are complex and that change when solutions are applied. Many conflicts in conservation fall into this category. The study approached the problem of how to constrain the apparent wickedness of a problem in the conservation management of a species by using simple empirical indicators to carry out iterative assessment of the risk to a population and to document how this risk evolves in relation to the addition of new data and the implementation of management actions. Effects of high levels of uncertainty within data and also concerning population structure were examined through stochastic simulation and by exploration of scenarios. Historical trends in the example used, the Steller sea lion, showed rapid declines in abundance in some regions during the 1980s. The current total population is 130,000-150,000 Steller sea lions through Alaska and British Columbia and this number has been stable since about 1990 in spite of regional differences in population dynamics. Regional differences in the sequence of changes in the number of pups and non-pups, suggested that an internal re-distribution of juveniles could have happened between 1980 and 1990. Current productivity also appears close to the long-term mean. Stochastic population projection using various scenarios showed that, based upon this history, the risk of extinction for the population has declined and is below reasonable thresholds for considering the population to be endangered. The trends in risk suggest that management actions taken since 1990 have probably been effective. Consequently, the conservation management objectives for the Steller sea lion are probably being met. The approach provides a mechanism, based upon experience and scenario analysis, for exploring future policy options and may help to constrain the debate amongst stakeholders about the cost-benefit trade-offs associated with different options.     

Enhanced establishment and growth of giant cardon cactus in an eroded field in the Sonoran Desert using native legume trees as nurse plants aided by plant growth-promoting microorganisms and compost

To evaluate the feasibility of long-term desert reforestation technology of mixed vegetation, cardon cactus (Pachycereus pringlei) seedlings from indoor and outdoor nurseries were planted in the field adjacent to one seedling of potential legume nurse trees: mesquite amargo (Prosopis articulata), yellow palo verde (Parkinsonia microphylla), and blue palo verde (Parkinsonia florida). Some of the planting holes were also supplemented with common dairy compost. Additionally, the combinations of legume tree–cactus were inoculated with either a consortium of desert arbuscular mycorrhizal (AM) fungi, plant growth promoting bacteria (PGPB; the diazotroph Azospirillum brasilense Cd, and the phosphate solubilizer Paenibacillus sp.), or a mixture of all. The field experiments were evaluated periodically during 30 months for survival and growth. Cardons reared in an outdoor screen house survived better in the field than those reared in a controlled growth chamber and hardened later outdoors. Association with any legume nurse tree increased survival and enhanced growth of untreated cardons. For cardons growing alone, application of either compost, AM fungi, and all the treatments combined increased survival. For these plants, no treatment affected plant growth during the first 3 months after transplanting. Later, all treatments, except for AM fungi, enhanced plant growth. However, only 2 years after transplanting the enhanced growth effect of AM fungi was also significant. In the presence of the legume nurse trees, transient positive effects on cardon growth were recorded. General evaluation after 30 months of cultivation showed that the treatments positively affected cardon growth when growing alone or in combination only with mesquite amargo but not with the other two legume trees. This study proposes that young legume trees have the capacity to enhance survival and growth of cardon cactus, depending on the legume cactus combination. Additional treatments such as compost or PGPB can either amplify the effect or else attenuate it.     

“绿色革命”以来大气CO2浓度升高对C3作物营养品质的影响

自20世纪60年代"绿色革命"以来,育种技术和农耕技术的发展促进了农作物产量的大幅提升,然而作物的营养品质出现下降趋势。在相似的遗传背景下,大气CO_2浓度升高会使单位体积农作物产品的营养元素含量下降,因此"绿色革命"至今,农作物产品的营养元素下降可能受大气CO_2浓度升高影响。通过植物生长箱模拟"绿色革命"初期和目前的大气CO_2浓度水平(310μmol/mol和400μmol/mol),针对主要C_3作物水稻、小麦和大豆,研究"绿色革命"以来大气CO_2浓度升高对其籽粒的C、N、Fe、Zn元素含量的影响,结果表明:CO_2浓度升高对3种作物籽粒的C元素含量几乎没有影响,变化幅度在±1.5%之间;籽粒的N、Fe、Zn元素含量普遍呈现下降趋势,但均未达到显著水平。     

Potential of wild species for genetic enhancement of some semi-arid food crops

Discovery and incorporation of genes from wild species provide means to sustain crop improvement, particularly when levels of resistance in the cultigens are low and virulent strains of pests and pathogens overcome the host plant resistance. The extent of utilization and the potential of the wild genepool for genetic enhancement were reviewed in five important food crops viz. sorghum, pearl millet, chickpea, pigeonpea and groundnut grown in the semi-arid tropics. Introgression from compatible wild germplasm in the primary gene pool resulted in transfer of new cytoplasmic male sterility systems in pearl millet and pigeonpea, development of high protein, cleistogamous flower and dwarf pigeonpea lines and foliar disease resistant groundnut cultivars. Utilization of wild species in secondary and tertiary gene pools has been generally limited due to sterility, restricted recombination or cross incompatibility. Nevertheless, these species are extremely important as they contain high levels of resistance to several important biotic and abiotic stresses. Several of them, like those belonging to the Parasorghum section and the rhizomatous Arachis species are sources of multiple resistances and hold great promise to sustain crop productivity.     

Karyotypic and genome size variation in Cajanus cajan (L.) Millsp. (pigeonpea) and some wild relatives

Detailed karyotypes and 4C DNA amounts have been studied in five cultivars of Cajanus cajan and 20 species belonging to Cajanus, Rhynchosia, Dunbaria, Flemingia and Paracalyx. C. cajan shows intraspecific variability and its karyotype is most similar to that of C. cajanifolius (sect. Cajanus) in the morphology and number of satellite chromosomes and the lack of any correlation between chromosome size within the complement and asymmetry. Karyotypes of C. lineatus and C. sericeus belonging to sect. Atylia are similar with respect to maximum r-index and the ratio of longest and shortest chromosomes in their respective complements. C. acutifolius (sect. Frutocosa) is distinct in having a very low ratio (1.44) between the longest and the shortest chromosomes, while in C. albicans, C. goensis, C. scarabaeoides (sect. Cantharospermum) there is no chromosome pair with r-index >2.0. C. mollis and C. volubilis (sect. Volubilis) show similarity with regard to ratio between the longest and the shortest chromosomes and a distinct chromosome pair with an arm ratio of 2.7 and C. platycarpus is distinct (sect. Rhynchosoides) in having the smallest ratio (1.36) between the longest and the shortest chromosomes. 4C DNA amounts in Cajanus and Rhynchosia vary between 3.28 pg to 11.69 pg and 4.92 pg to 11.13 pg respectively, while in Dunbaria, Flemingia and Paracalyx these vary between 4.70 and 7:06 pg. In the genus Cajanus karyotypic features and 4C DNA amounts agree with the sectional classification and bring out a close relationship between C. cajan and C. cajanifolius. This is supported by studies based on seed protein patterns, isozyme analysis, trypsin and chymotrypsin inhibitor patterns, RFLP and RAPD data and crossability relationships. A clear relation between DNA amount and abnormalities effecting the extent of pairing and recombination in interspecific hybrids shows the importance of this study in developing future breeding programme involving C. cajan and its wild relatives that are of potential value.     

Effect of some fungicide seed treatments on the survival of Bradyrhizobium japonicum and on the nodulation and yield of soybean [Glycine max. (L) Merr.]

Several commercial fungicide seed treatments were evaluated for their possible effect on the survival of Bradyrhizobium japonicum on seeds and on the nodulation and yield of soybeans in a greenhouse and a field experiment. quinolate Pro (carbendazim and oxine copper), Vitavax 200FF (carboxin and thiram), and Monceren (pencycuron) had a small effect or no effect on the survival of B. japonicum and on the nodulation and yield of soybeans. They can thus be considered compatible with soybean seed inoculation. Germipro UFB (carbendazim and iprodione), Apron 35J (metalaxyl), and Tachigaren (hymexazol) decreased B. japonicum survival and the nodulation and yield of soybeans and thus cannot be considered compatible with soybean seed inoculation.     

Faculty positions:Center for Agricultural Resources Research,Chinese Academy of Sciences

正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications     

Einfluss der düngungsmethoden auf die entwicklung von zuckerrübenkrankheiten

Während neunjähriger (1994-2002) Untersuchungen in der Versuchsanstalt Ba?cyny (Fahlerde, Fall-Gleyboden, ausgebildet aus leichtem Lehmboden) wurde der Befall mit Krankheiten an der Zuckerrübe in Abhängigkeit von der Düngungsmethode bewertet. Folgende Methoden wurden angewendet: A - Mineraldünger, B - Stalldung und Mineraldünger, C - Stroh-, Gründung und Mineraldünger, D - Kompostdünger und Biopräparate (ökologische Düngung). Auf den Objekten A, B, C wurden bei konstanter Phosphor-Kalium-Düngung die Stickstoffgaben von 0 bis 180 kg.ha^?1 differenziert. Auf dem ökologischen Objekt D ohne Mineraldünger wurden statt Stickstoff die Biopräparate P₅₀₀ und P₅₀₁ verabreicht. Der geringste Befall von Krankheiten wurde an der Zuckerrübe auf jenem Objekt festgestellt, das mit Kompost und den Biopräparaten gedüngt worden war. Im Rahmen der konventionellen Düngungsmethoden wurde allgemein die höchste Intensität der Krankheiten an der mit Stroh, Gründung und Mineraldünger gedüngten Zuckerrübe beobachtet. Ausnahmen von dieser Regel bildete das Vorkommen von echtem Mehltau und Keimlingsfäule. Auf den Objekten A, B, C nahm die Intensität der Krankheiten mit der Steigerung der Stickstoffgabe zu. Auch die auf Objekt D verabreichten Biopräparate stimulierten die Entwicklung der Krankheiten. The effect of various fertilization methods on the diseases of sugar beet was estimated on the basis of nine-year studies (1994-2002) conducted in the Experimental Production Farm in Ba?cyny on loess-based, sedimentary-gley, light-clay soil. The following fertilization methods were applied: A - mineral fertilization, B - mineral and manure fertilization, C - straw, green manure and mineral fertilization, D - ecological compost and biodynamic preparations fertilization. In the objects A, B and C fertilized with phosphorus and potassium, various doses of nitrogen ranging from 0 to 180 kg/ha^?1 were used. In the ecological object D, where mineral fertilization was not used, biodynamic preparations P₅₀₀ and P₅₀₁ were applied instead of nitrogen. The lowest ratio of the diseases of sugar beet was observed in the object fertilized with the compost and biodynamic preparations. In view of the conventional fertilization methods, generally the highest incidence of diseases was noted in the sugar beet fertilized with straw, green manure and mineral fertilizers. The exception was the occurrence of powdery mildew and the black leg. In objects A, B and C the incidence of the diseases increased with the increase in nitrogen doses. The applied biodynamical preparations in the object D stimulated the development of diseases too.     

Prospects for control of Pythium damping-off of lettuce with Trichoderma,Gliocladium and Enterobacter spp.

Summary Damping-off of lettuce (Lactuca sativa) caused by Pythium ultimum was studied in pots containing a non-sterile potting mix in the glasshouse. Fifty P. ultimum sporangia g^-1 compost reduced the plant stand to 15% and shoot dry weight to 18%, but this reduction was totally prevented by applying Trichoderma harzianum at 2×10⁵ viable propagules g^-1 potting mix. Gliocladium virens and Enterobacter cloacae also alleviated the damping-off. E. cloacae did not adversely affect the action of the fungal antagonists. The co-existence of the bacterial and fungal antagonists was revealed on the root surface and inner surface of the testa by scanning electron microscopy, indicating the compatibility of the biocontrol agents.