Wheat biomass and yield increased when populations of the root-lesion nematode (Pratylenchus thornei) were reduced through sequential rotation of partially resistant winter and summer crops

The root-lesion nematode, Pratylenchus thornei, can reduce wheat yields by >50%. Although this nematode has a broad host range, crop rotation can be an effective tool for its management if the host status of crops and cultivars is known. The summer crops grown in the northern grain region of Australia are poorly characterised for their resistance to P. thornei and their role in crop sequencing to improve wheat yields. In a 4-year field experiment, we prepared plots with high or low populations of P. thornei by growing susceptible wheat or partially resistant canaryseed (Phalaris canariensis); after an 11-month, weed-free fallow, several cultivars of eight summer crops were grown. Following another 15-month, weed-free fallow, P. thornei-intolerant wheat cv. Strzelecki was grown. Populations of P. thornei were determined to 150 cm soil depth throughout the experiment. When two partially resistant crops were grown in succession, e.g. canaryseed followed by panicum (Setaria italica), P. thornei populations were <739/kg soil and subsequent wheat yields were 3245 kg/ha. In contrast, after two susceptible crops, e.g. wheat followed by soybean, P. thornei populations were 10 850/kg soil and subsequent wheat yields were just 1383 kg/ha. Regression analysis showed a linear, negative response of wheat biomass and grain yield with increasing P. thornei populations and a predicted loss of 77% for biomass and 62% for grain yield. The best predictor of wheat yield loss was P. thornei populations at 0-90 cm soil depth. Crop rotation can be used to reduce P. thornei populations and increase wheat yield, with greatest gains being made following two partially resistant crops grown sequentially.

Total peroxidase activity and peroxidase isoforms as modified by salt stress in two cultivars of fox-tail millet with differential salt tolerance

The effect of NaCl on total peroxidase activity, induction of isoperoxidases and lipid peroxidation in 5-day-old seedlings of two contrasting genotypes of Setaria italica L. (Prasad, a salt tolerant cultivar and Lepakshi, a salt susceptible cultivar), was studied. Total peroxidase activity increased under NaCl salinity and the degree of elevation in the activity was salt concentration dependent. Nevertheless, a greater activity was recorded in the tolerant cultivar (cv Prasad) compared to the susceptible (cv Lepakshi) one in all days of sampling. Further, the pattern of isoperoxidases was modified during stress conditions as evident from the electrophoregrams. Although, five acidic isoforms were detected in both cultivars, differences were found between the cultivars. Furthermore, it was observed that acidic isoperoxidases were strongly expressed and an acidic isoperoxidase, A(3p) (27 kDa) is specifically found in the tolerant cultivar (cv Prasad) under NaCl stress. This isoform was partially purified and found to be thermostable with pr 5.5 and the optimum pH 7.4. A close correlation exists between the rate of lipid peroxidation in terms of malonaldehyde (MDA) content and total peroxidase activity per gram fresh weight with salt tolerance of the two cultivars. The tolerant cultivar (cv Prasad) had low MDA content and high total peroxidase activity than the susceptible variety (cv Lepakshi) during salinity stress. (C) 1999 Published by Elsevier Science Ireland Ltd. All rights reserved.

CO2倍增对禾本科植物幼苗形态结构的影响

本论文为国家自然科学基金重大项目“中国陆地生态系统对全球变化的反应模式研究”的部分研究内容。 本文对C02正常浓度(350ppm)和C02倍增(700ppm)条件下，小麦（Triticum, aestivum）、半野生小麦(Triticum aestivum spp．tibeticumShao)、大麦（Hordeum vulgare）、野大麦（Hordeum brevisubulalum）、水稻（Oryza sativa,）、野生稻（Or7za sativa ssp．）、谷子（Setaria italica）、狗尾草（Setaria viridis）、高粱（Sorghum vulgare）、玉米（Zea mays）、旱雀麦（Bromus tectorum）、旱麦草（Eremopyrum triticeum）等12种禾本科植物幼苗的叶片厚度、叶肉细胞密度、维管束鞘细胞中的叶绿体数、叶肉细胞中的叶绿体数、表皮细胞密度、气孔密度、气孔指数、气孔长度、气孔阻抗及平均株高、鲜重、茎秆直径、根的直径、种子的萌发率及叶绿体超微结构等进行了比较研究。 结果表明，C02倍增使不同种类、不同测试项目反应不一。总体上看，CO2浓度倍增，使10种禾本科植物（野大麦、玉米外）的吐片厚度普遍增加。除个别种类外，C4种类的平均株高、鲜重、根直径倍增组比对照组减小;气孔平均密度增加，而C3种类则呈相反趋势o C4种类比C3种类的叶片气孔开度对C02倍增反应更为敏感。在高浓度C02条件下，C4种类的叶绿体超微结构变化较明显，淀粉粒显著增加。野生种类的表皮细胞密度，叶肉细胞密度，维管束鞘细胞中的叶绿体数及茎秆直径，C02倍增组比对照组减少，栽培种类则显著增加。气孔密度与气孔指数基本呈正相关;而气孔长度与气孔密度则大体上呈负相关。 文中对高浓度C02条件下，供试植物形态结构的变化和规律，及全球大气变化对未来农业可能产生的影响进行了讨论。

谷子体细胞无性系变异和抗除草剂基因转化研究

谷子是我国北方具有区域重要性的禾谷类粮食作物。谷子的体细胞无性系变异和外源基因转化相对其它作物研究较少。本研究利用谷子生产的育种中应用的多个优良品种为材料，分析了谷子体细无性系变异发生的影响因素、变异性和频率、DNA分子水平变异和育种应用等问题;采用基因枪法和花粉管通道法，进行了谷子抗除草剂基因转化研究。 主要结果包括： 1. 通过几种外植体的愈伤组织诱导分析,找到了小花分化期前后的谷子幼穗是愈伤组织诱导的最好外植体.提出谷子愈伤组织可按生长状态和结构划分为质密型、松软型和松散型三种基本类型的观点。前两种为胚性愈伤组织并可相互转换，松软型愈伤组织生长状态稳定，可塑性好，是继代培养和因基化的首选类型。供试品种中豫谷1号、高39、郑407和矮宁黄为易培养品种，矮88、豫谷2号、系238、冀14号、C445和青丰谷为相对难培养品种。这些结果为谷子组织培养和生物技术操作提供了基础资料。 2. 首次对多个谷子品种较大群体的无性系变异进行了分析。结果表明，以R_2株系为单位的谷子体细胞无性系表现型变异频率平均为13.0%，不同基因型的变幅为4.3～32.9%;变异涉及株高、抽穗期、穗粒重、出谷率、叶鞘色、育性、抗病性、米色、穗型等多个性状，多数变异为株高和抽穗期等数量性状，少数为矮秆等质量性状：变异的性状多数能在R_3稳定并遗传给后代。从谷子体细胞无性系变异中选出了一批农艺性状得到改良的新品系，其中系103已进入省区域试验，并提供给多家育种单位作为亲本应用。 3. 将RAPD分析技术引入谷子体细胞无性系变异研究。豫谷2号无性系的RAPD多态性变化既有亲本带的缺失，也有新带的产生。用RAPD多态性变化的SMC值度量无性系同亲本相比DNA水平变异的大小，表现型发生变异的无性系,其SMC值分别为0.905～1.0;表现型未发生变异的无性系，RAPD多态性也可能发生变化，其SMC值分布为0.953～1.0。 4. 通过Gus基因瞬时表达单位数的比较，优化了JQ－700基因枪转化谷子松型愈伤组织的操作参数：质粒DNA用量3μg/mg钨粉，CaCl_2农度1.5M，亚精胺浓度40mM，样品室高度7cm，粗弹头为微弹载体，每皿愈伤组织用量1～2g，每次轰击钨粉用量50μg，轰击前4小时和轰击后16～20小时，用含蔗糖150g/l的高渗培养基处理。利用该技术体系，以bar基因为目的基因转化豫谷2号愈伤组织。经选择培养和植株再生，首次获得了抗0.1% bialaphos的正常可育植株，经PCR和Southern blot分析，bar基因已整合到转化体的基因组中，为创造抗除草剂的谷子新种质提供了材料和技术基础。 5. 研究了花粉管通道法转化和花粉介导的基因枪转化谷子的可行性。花粉管通道法转化后代中，获得了抗0.1% bialaphos的抗性植株，经X-gluc组织化学检测，抗性植株叶片的Gus反应为阳性。初步说明该植株可能为转化体，在谷子上为花粉管通道法转化的可行性提供了佐证。花粉介导的基因枪转化未获得转化体。 本文对体细胞无性系变异形成的原因和应用、无性系变异的分子生物学分析、以及谷子的外源基因转化方法等问题进行了讨论。

苏铁叶绿体的超微结构和功能及对CO2浓度倍增的响应

本研究首次揭示了七种苏铁类植物叶绿体的超微结构。即苏铁科(Cycadaceae)的攀枝花苏铁(C. panzhihuaensis).苏铁(C. revoluta)、叉叶苏铁(C.micholitzii)、 刺叶苏铁(C.rumphii和多歧苏铁(C.multipinnata)，蕨铁科(Stangeriaceae)的蕨铁(Stangeria eriopus)和泽米科(Zamiaceae)的米德尔堡大苏铁(Encephalortos middelburgensis).根据它们叶绿体内膜结构的不同将其大体分为两种类型：1、阴生型叶绿体：多歧苏铁和刺叶苏铁为此类型，它们的叶绿体类囊体垛叠程度高，基粒垛较宽，单个基粒中类囊体的数量很多，有的甚至上百;2、阳生型叶绿体：攀枝花苏铁、米德尔堡大苏铁、苏铁、蕨铁和刺叶苏铁以及外类群的凤尾蕨(Pteris vittata)的叶绿体均有阳生型叶绿体的特征：类囊体膜垛叠程度低，基粒较小。根据它们叶绿体的结构特征，又将其分为两组： ( 1)攀枝花苏铁，米德尔堡大苏铁和叉叶苏铁叶绿体中均有类囊体膜膨大的现象： (2)苏铁和蕨铁在苏铁类中是比较原始的种类，它们的叶绿体与在系统进化上较苏铁类低等的凤尾蕨的叶绿体中都有几个基粒聚集成簇的现象，说明苏铁类在进化的同时一些较原始的性状仍保留了下来。这些苏铁都在温室相同的条件下生长了两年多，但它们的叶绿体结构仍然能够反应原产地生境特点，说明在长期进化中，叶绿体对环境的适应方式已在基因水平上稳定下来，苏铁类植物不同叶绿体结构的形成有其遗传基础。 多歧苏铁，攀枝花苏铁，叉叶苏铁的叶绿体膜垛叠程度依次降低，与此相应，它们的chla/b和F730/F684依次升高，反应了结构与功能的一致性。 选用具有阳生型叶绿体的攀枝花苏铁和有阴生型叶绿体的多歧苏铁用不同的C02浓度（350 umol mol-l和700umol mol-l）处理后观察其叶绿体结构的变化，结果发现C02浓度倍增对它们的叶绿体影响甚微，而作为对照的无论是C3植物小麦(Triticum italica)还是C4植物谷子(Setaria italica)在C02倍增的条件下叶绿体内均有大量淀粉粒积累，并有膜结构改变。这说明苏铁的叶绿体结构有保守性，这有可能是苏铁类能历经亿万年的沧桑而生存下来的结构基础之一。

Respuesta del cultivo de Moha al sistema de implantación

p.59-67

Distribución de fertilizantes marcados con 15 N en la rotación ajo - moha

p.105-110

Quantitative response of the longevity of seed of twelve crops to temperature and moisture in hermetic storage

Seeds of 39 seed lots of a total of twelve different crops were stored hermetically in a wide range of air-dry environments (2-25% moisture content at 0-50 degrees C), viability assessed periodically, and the seed viability equation constants estimated. Within a species, estimates of the constants which quantify absolute longevity (K-E) and the relative effects on longevity of moisture content (C-W) and temperature (C-H and C-Q) did not differ (P >0.05 to P >0.25) among lots. Comparison among the 12 crops provided variant estimates of K-E and C-W (P< 0.01), but common values of C-H and C-Q (0.0322 and 0.000454, respectively, P >0.25). Maize (Zea mays) provided the greatest estimate of K-E (9.993, s.e.= 0.456), followed by sorghum (Sorghum bicolor) (9.381, s.e. 0.428), pearl millet (Pennisetum typhoides) (9.336, s.e.= 0.408), sugar beet (Beta vulgaris) (8.988, s.e.= 0.387), African rice (Oryza glaberrima) (8.786, s.e.= 0.484), wheat (Triticum aestivum) (8.498, s.e.= 0.431), foxtail millet (Setaria italica) (8.478, s.e.= 0.396), sugarcane (Saccharum sp.) (8.454, s.e.= 0.545), finger millet (Eleusine coracana) (8.288, s.e.= 0.392), kodo millet (Paspalum scrobiculatum) (8.138, s.e.= 0.418), rice (Oryza sativa) (8.096, s.e.= 0.416) and potato (Solanum tuberosum) (8.037, s.e.= 0.397). Similarly, estimates of C-W were ranked maize (5.993, s.e.= 0.392), pearl millet (5.540, s.e.= 0.348), sorghum (5.379, s.e.=0.365), potato (5.152, s.e.= 0.347), sugar beet (4.969, s.e.= 0.328), sugar cane (4.964, s.e.= 0.518), foxtail millet (4.829, s.e.= 0.339), wheat (4.836, s.e.= 0.366), African rice (4.727, s.e.= 0.416), kodo millet (4.435, s.e.= 0.360), finger millet (4.345, s.e.= 0.336) and rice (4.246, s.e.= 0.355). The application of these constants to long-term seed storage is discussed.

Produção e composição bromatológica de forrageiras em sistema de integração lavoura-pecuária em diferentes épocas de semeadura

O objetivo deste trabalho foi avaliar a produção de matéria seca e a composição bromatológica de forrageiras em sistema de integração lavoura-pecuária, em diferentes datas de semeadura. Foi usado delineamento experimental de blocos ao acaso, em esquema fatorial 4x3, com quatro forrageiras - braquiária, Urochloa brizantha; capim-moa, Setaria italica; milheto, Pennisetum glaucum; e sorgo forrageiro, Sorghum bicolor - semeadas em três datas nas estações inverno/primavera e verão/outono, em sucessão à soja. O milheto e o sorgo forrageiro produziram maior quantidade de matéria seca em todas as datas de semeadura, nas duas estações de cultivo e, ao contrário da braquiária e do capim-moa, não diminuíram o teor de nutrientes digestíveis totais no inverno/primavera. Os teores de proteína bruta reduziram com o avanço das datas de semeadura no inverno/primavera e aumentaram no verão/outono, exceto para braquiária e milheto. O sorgo apresentou os menores teores de fibras em detergente neutro nas segunda e terceira datas de semeadura no inverno/primavera, e na primeira data de semeadura no verão/outono. Nas segunda e terceiras datas do inverno/primavera, o sorgo apresentou menor teor de fibras em detergente ácido. Quanto aos constituintes da parede celular, apenas os teores de hemicelulose não se alteram nas forrageiras em virtude das datas de semeadura, em ambas as estações.

Drought Adaptation in Millets

Millets are major food and feed sources in the developing world especially in the semi-arid tropical regions of Africa and Asia. The most widely cultivated millets are pearl millet [Pennisetum glaucum (L.) R. Br.], finger millet [Eleusine coracana (L.) Gaertn], foxtail millet [Setaria italica (L.) P. Beauvois], Japanese barnyard millet [Echinochloa esculneta (A. Braun) H. Scholz], Indian Barnyard millet [Echinochloa frumetacea Link], kodo millet [Paspalum scrobiculatum L.], little millet [Panicum sumatrense Roth.ex.Roem. & Schult.], proso millet [Panicum miliaceum L.], tef [Eragrostis tef (Zucc.) Trotter] and fonio or acha [Digitaria exilis (Kippist) Stapf and D. iburua Stapf]. Millets are resilient to extreme environmental conditions especially to inadequate moisture and are rich in nutrients. Millets are also considered to be a healthy food, mainly due to the lack of gluten (a substance that causes coeliac disease) in their grain. Despite these agronomic, nutritional and health-related benefits, millets produce very low yield compared to major cereals such as wheat and rice. This extremely low productivity is related to the challenging environment in which they are extensively cultivated and to the little research investment in these crops. Recently, several national and international initiatives have begun to support the improvement of diverse millet types.

谷子（Setaria italical L.）叶绿体psbD基因的分子克隆

本文用改良的高盐pH方法提取了龙谷25、龙谷28的叶绿体DNA，用pTB20质粒上含有烟草叶绿体psbD基因的pstI/SacⅡ片段进行了鉴定。并初步发现龙谷25和龙谷28在其叶绿体基因psbD结构序列或附近3'下游区存在者多态性。以pUC19质粒为载体，E.coli HB101为宿主菌，克隆了谷子叶绿体DNA 4.8kb的SacⅠ片段，得到了重组质粒，命名为pSIBD，并对sPIBD重组片段进行了限制图谱解析。

Oxidative activities in mitochondria-like particles from Setaria digitata, a filarial parasite

The oxidative metabolic potential of Setaria digitata, a filarial parasite found in the intraperitoneal cavity of cattle, was investigated. These worms showed active wriggling movements which were not affected by respiratory poisons such as cyanide, rotenone and malonate. They also possessed cyanide-insensitive and glucose-independent oxygen consumption pathways. By differential centrifugation of sucrose homogenates, a fraction containing mitochondria-like particles was obtained in which the activity of the marker enzyme, succinate dehydrogenase, was recovered. This fraction catalysed succinate- and NADH-dependent reduction of both cytochrome c and dyes. Oxygen uptake found with succinate, NADH and ascorbate as substrates was not sensitive to cyanide. Cytochromes could not be detected in either this fraction or homogenates of the worms. H2O2 generation with a number of substrates and lipid peroxidation by measuring malondialdehyde formed as well as by accompanying oxygen uptake were demonstrated in the mitochondria-like particles. A lipid quinone, possibly with a short side chain and related to ubiquinone, was detected in the worms. The results suggested the existence of two cyanide-insensitive oxygen-consuming reactions in Setaria: one respiratory substrate-independent lipid peroxidation, and a second substrate-dependent reaction that requires an auto-oxidizable quinone but not a cytochrome system.

Validación de dos variedades y un híbrido de brócoli (Brassica oleracea vr. italica) en época de riego en la comunidad Almaciguera - Estelí

La agricultura en nuestro país presenta un bajo desarrollo, influenciado por diversas razones como: adaptabilidad de variedades, deficiente manejo agronómico, uso del monocultivo, utilización de misma fecha de siembra, conllevando a obtener bajos precios debido a que el mercado se encuentra saturado de un mismo producto. El presente estudio se realizó en la finca Las Nubes que tiene una altura de 1250-1450 m.s.n.m, ubicada en la comunidad La Almaciguera-Estelí, durante la época seca (Enero-Abril, 2003), con el propósito de validar dos variedades y un híbrido de brócoli (Brassica oleracea vr Italica) para utilizarlo como fuente alternativa de materiales para siembra, que presenten buena adaptación y rendimiento, con resistencia o tolerancia a plagas. El área experimental fue de 345m2 arreglado en un diseño BCA (Bloques completos al azar) con tres repeticiones, evaluándose tres tratamientos: Pirata (híbrido), Wattham 29, Green sprouting Calabrese, utilizando como testigo al híbrido. Se diseñaron hojas de recolección de datos para las variables evaluadas en cada etapa del cultivo, los datos obtenidos fueron sometidos a Andeva en el programa EXCEL (Microsoft Windows 98) realizando las separaciones de medias de forma manual, utilizando la tabla de Duncan (Pr < 0.05). De acuerdo a los resultados obtenidos, en etapa de semillero no hubo diferencias entre los tratamientos, mientras que en desarrollo vegetativo el tratamiento que sobresalió en las variables número, largo y ancho de hoja, además de grosor del tallo fue Pirata, presentando mejor apariencia en vigor y desarrollo del follaje, dicho híbrido fue el único del que se obtuvieron rendimientos ya que produjo cabezas compactas, en cambio las dos variedades presentaron cabezas en forma de racimos, las cuales no son utilizadas para la comercialización.

Características reproductivas de Setaria lachnea (Nees) Kunth (Poaceae, Paniceae)

p.59-66