辐照小麦花粉的诱变效应

应用５Ｇｙ、１０Ｇｙ、２０Ｇｙ和３０Ｇｙ６０ＣｏΥ射线辐照４个小麦品种（品系）的成熟花粉,研究其杂交当代籽粒的发育,Ｍ１的生理损伤及Ｍ２的诱变效应。结果表明,１０Ｇｙ辐照小麦成熟花粉的诱变效果好;在Ｍ１中,１０Ｇｙ处理的出苗率为１７．１％￣７０．２％,成株率一船达４０％左右;在Ｍ２中,突变性状有株高、穗长、熟期、颖壳颜色、芒性和育性等。用１０Ｇｙ辐照５４３６８小麦的花粉后自交,早熟突变高达５８．７     

^60Co γ射线辐照小麦干种子对M1和M2代花药离体培养的影响

对小麦干种子进行辐照处理，其Ｍ１代、Ｍ２代花药离体培养的出愈率和绿苗分化率都有明显提高。各供试品种的出愈和分化高峰值均集中于０．２５￣０．３ｋＧｙ处理之间，与小麦干种子辐射诱变处理的常用辐照剂量相同。     

水稻植株生殖细胞发育时期辐照与育性研究

用１５～７０Ｇｙ剂量辐照处理早籼稻广陆矮四号生殖细胞不同发育阶段植株,Ｍ１代表现出花粉母细胞期植株的辐射敏感性最强,其次是减数分裂、幼嫩单核期,而单核花粉阶段的敏感性较差。减数分裂期植株经２５～５０Ｇｙ辐照后,Ｍ１代异常四分体出现频率为１００％～４７６％,异常花粉率为３１４％～７７８％。在１５～５０Ｇｙ剂量范围内,Ｍ２代植株分离为正常株、半不育株、高不育株及全不育株等多种类型,其中非正常结实株率随着辐照剂量的增加而增高。Ｍ２代半不育株在Ｍ３代仍分离出约占总株数１／３左右的半不育株,Ｍ２代高不育株在Ｍ３代也能分离出少数正常株,但多为高不育株。     

唐菖蒲辐射诱变效应

唐菖浦Ｇｌａｄｉｏｌｕｓ ｈｙｂｒｉｄｕｓ Ｈｏｒｔ。辐射诱变效应研究表明，其球茎的适宜辐照剂量为４０－８０Ｇｙ。不同品种的唐菖蒲为＾６０Ｃｏγ射线的辐射敏感性不同，所引起的不同，所引起的花色、株型突变频率亦有不同，其幅度在２．０％－１４．９％。已选育出花色艳丽，观赏价值高的突变体。     

电子束注入水稻M1代生物效应初步研究

用３个水稻品种的萌动种子及干种子为诱变材料，以Ｍ１代苗高、成苗高、结实率为指标，研究电子束不同旧和剂量率的生理效应，确定萌动种子量适剂量为５０Ｇｙ；干种子量适剂量在１５０Ｇｙ左右，粳稻所受影响比籼稻略为明显。干种子照射的适宜剂量率尚需进一步试验。     

枸杞干商业化辐照杀虫研究

本文介绍了枸杞干商业化中进行γ辐照杀虫保果的研究，杀死果品表面自然污染虫卵的适宜辐照剂量为３．５ｋＧｙ左右，常温下可保藏７个月，可安全越夏，杀死小包装枸杞干虫幼虫的适宜剂量为２．０￣３．０ｋＧｙ。辐照枸杞干微生物含量可减少７４．４７％，其主要营养成分无明显变化。     

~(137)Cs叶面污染在水稻中的转移、积累与分布

６０ＣｏΥ射线辐照可显降低药用淀粉中的微生物数量。研究结果表明：杂菌的Ｄ１０值为０．７ｋＧｙ,适宜辐照剂量为３．０￣５．０ｋＧｙ,辐照剂量与杂菌存活数之间呈显的负相关（ｒ＝－０．９０５３）,辐照工艺的改变对灭菌效果有较大的影响。对５．０ｋＧｙ辐照的药用演粉进行毒性试验表明,用较低剂量辐照的药用淀粉无毒性反应、无致畸致突变等遗传性病变,因此是安全、无害的。采用以上剂量灭菌的同时,不会导致淀粉自身     

银杏果仁辐照综合保鲜技术研究

以江苏省泰兴市地方品种为材料,采用钴－６０辐照新技术,对不同辐照时期、辐照剂量,包装,前处理和贮藏条件等因素进行试验。结果表明,新收获银杏果仁,经一定包装后,保鲜剂量０．２ｋＧｙ较好,种胚已充分后熟的银杏,则需采用灭菌贮藏剂量３ｋＧｙ辐照后常温贮藏,３个月保鲜效果在９５％以上,辐照前处理有一一保鲜效果。     

137Csγ射线对陆地棉花粉及其M1的辐射效应

本以浙棉９号和浙１０２花粉为材料,研究了＾１３７Ｃｓγ射线对陆地棉花粉及其Ｍ１,Ｆ１Ｍ１的辐射诱变效应。研究结果表明：１．辐射剂量与芬分活力呈高度负相关,浙棉９号和浙１０２花粉的半致死剂量分别为５．１７和４．６９Ｇｙ;２．７．５１Ｇｙ以上剂量辐射花粉后,对其ＡＭ１,Ｆ１Ｍ１的出苗,幼苗生长均有明显的抑制作用,辐射的致畸作用因品种而不同;     

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。     

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.     

“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.     

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.     

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.     

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     

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.     

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.