分子标记技术在油菜育种中的应用探讨

本文从控制油菜重要性状的基因定位、遗传图谱构建、亲缘关系、起源及分类、辅助育种、杂种优势预测等方面综述了分子标记技术在油菜育种中的应用。     

化肥减量对麦田土壤微生物量及微生物区系的影响

为了解化肥减量和有机培肥配施对冬小麦田土壤微生物的影响,以单施常量化肥(表示为NPK,分别施尿素、磷酸二铵和硫酸钾251.8、255.7和375.2kg.km-2)为对照,设置不同化肥(不减量、减量30%、减量50%和减量70%)和有机肥(18 000、25 500和34 500kg.km-2,分别用LM、MM和HM表示)配施处理,采用系列稀释平板法和氯仿熏蒸培养法分别测定了不同处理下土壤微生物量碳、氮以及微生物区系分布的差异。结果表明,有机无机肥配施显著增加了麦田土壤微生物量碳、氮以及细菌、固氮菌、放线菌等微生物数量,但不影响土壤真菌数量。施肥效果在化肥不减量时随有机肥施用量增加呈上升趋势,在化肥减量时以50%NPK+MM处理最佳。说明化肥适度减量和配施有机肥能够改善土壤微生物量,有利于提高土壤肥力。     

冬小麦低温处理叶片细胞膜透性的QTL定位

为探索冬小麦抗寒性的分子机制,以168个花培3号×豫麦57的双单倍体株系为作图群体,利用已构建含有324个SSR标记的遗传图谱,对电导法测定低温(−18℃)处理后的叶片膜透性进行QTL定位。利用完全区间作图法,在3种环境下共检测到21个与叶片膜透性相关的加性QTLs,分布于1B、2A、3A、3B、5B、6A、6B、6D、7B和7D染色体上,其中4个位点(qCMP-1B-1、qCMP-3B-2、qCMP-5B-1和qCMP-5B-4)遗传贡献率大于10%,属主效基因,其余QTL的遗传贡献率较小,属微效基因。3种环境条件下在5B染色体的Xgwm213–Xswes861.2区间检测到共同位点,与Xswes861.2的遗传距离为0 cM,其中qCMP-5B-1 (环境1)和qCMP-5B-4 (环境3)的贡献率高达17.5%和14.0%。研究结果对于小麦抗寒标记选择和抗寒育种具有应用价值。     

有机培肥化肥减量对夏玉米含碳率及固碳量影响

为探讨不同施肥措施对玉米固碳能力的影响,以传统施肥为对照,设置化肥减量增施有机肥和秸秆6个处理,在玉米抽穗期、吐丝期和成熟期取样,分析不同器官含碳率和固碳量的差异。结果表明,不同生育期玉米植株器官含碳率有差异,地上器官(叶、茎、籽粒等)含碳率显著高于地下器官(根)。化肥减量30%增施有机肥和化肥减量30%增施秸秆2个处理相对化肥减量50%和化肥减量70%处理能有效提高玉米全株含碳率。化肥减量增施有机肥不仅提高植株收获物籽粒的含碳率,还增加还田产物茎和叶器官的含碳率。对不同处理玉米区域固碳量分析表明,玉米地上部分固碳量显著高于地下部分,化肥减量增施有机肥各处理平均区域固碳量高于化肥减量增施秸秆处理。     

3个构树无性系幼龄材纤维形态和化学成分分析

以人工培育的3个构树无性系幼龄材为试验材料,对其纤维形态和化学成分进行测定和分析,并揭示不同构树无性系幼龄材纤维形态和化学成分的变化规律.结果表明:构树1号木材的纤维长度和长宽比最大,分别为684.95 μm和57.51,构树3号木材的纤维长度和长宽比最小,分别为482.65 μm和34.73;3个构树无性系木材的纤维...     

Are all three components of conservation agriculture necessary for soil conservation in the Sudan Savanna?

ABSTRACT

Conservation agriculture (CA) as recommended by the Food and Agriculture Organization of the United Nations consists of three components: minimum soil disturbance, soil cover, and crop rotation/association. CA was expected to become an effective countermeasure against water erosion in the Sudan Savanna, but it has not been adopted by local smallholder farmers. As markets for grain legumes (including cowpea) have not been developed in the Sudan Savanna, crop rotation/association should be considered impractical for these farmers. Therefore, we examined whether legume intercropping as a crop rotation/association component is necessary for preventing soil erosion in the Sudan Savanna. Three-year field experiments were conducted in runoff plots at Institute of Environment and Agricultural Research Saria station. The four treatments were conventional practice (full tillage, no sorghum residue mulching, and no intercropping), two-component CA (minimum tillage (MT) and sorghum residue mulching without intercropping), and three-component CA with velvet bean (VB) or pigeon pea (PP) intercropping. It was revealed that: (1) MT and sorghum residue mulching (without intercropping) effectively reduced the annual soil loss by 54% mainly due to the improvement of soil permeability by the boring of termites and wolf spiders found under the sorghum stover mulch; (2) intercropping in combination with MT and crop residue mulching had no effect on soil erosion control mainly because: (a) PP did not survive the long dry season; (b) VB did not serve effectively as a cover crop since soil loss was concentrated at the beginning of the rainy season when VB was still too small; (c) unexpectedly, in combination with MT and crop residue mulching, intercropping with VB did not increase mulch biomass, especially sorghum biomass which prompts the boring of termites and wolf spiders. These results demonstrate that the third component of CA, namely legume intercropping, is not always necessary; rather, the two remaining components – minimum soil disturbance and soil cover – are sufficient for soil conservation in the Sudan Savanna. This finding lightens the burden of adopting CA and thus facilitates its future promotion to the smallholder farmers in the Sudan Savanna.     

不同基因型油菜成熟期根系特征及其与根际土壤养分关系

为缓解西北风沙区冬季地面裸露、风蚀严重的问题,以3种油菜类型共20个油菜品种为试材,在相同的栽培条件下于油菜成熟期分析油菜总根长、根表面积、根体积、根干质量、主根长、主根直径、直径小于2mm的总根长、根尖数等根系指标及油菜根际土的全氮、速效磷、速效钾、有机质质量分数的差异,并进行了相关性分析,旨在探索不同类型不同品种油菜根系差异以及根系对根际土壤养分的影响,进而为选择出根系发达的油菜类型和油菜品种增加相应的实践经验。结果表明,不同类型油菜、同一类型不同品种油菜间的根系指标及根际土养分质量分数存在显著差异,表现为:(1)甘蓝型和白菜型油菜的总根长、根表面积、根尖数、直径小于2mm的总根长普遍大于芥菜型,其中甘蓝型油菜的根表面积相对芥菜型提高15.10%~94.00%;芥菜型油菜的根体积和根干质量最大,其中芥菜型油菜平均根体积分别比白菜型、甘蓝型油菜平均根体积提高11.26%、12.39%,平均根干质量分别减少49.77%和43.14%;芥菜型和甘蓝型油菜的主根长和主根直径普遍大于白菜型油菜。(2)3种油菜类型根际土壤全氮、速效钾、有机质质量分数大体上符合芥菜型白菜型甘蓝型的趋势,速效磷质量分数表现为白菜型芥菜型甘蓝型。(3)油菜总根长、根表面积、根尖数、直径小于2mm的总根长与各养分指标呈负相关;油菜根表面积、根长、根尖数越大,养分吸收越多;芥菜型油菜主根发达,生物量大,可在土壤贫瘠、易风蚀的区域种植用于防风固土,培肥地力;甘蓝型油菜根系表面积大,可在水肥条件较好的地方种植用于收获经济产量。     

Genetic diversity within two Tunisian wild jirds: Meriones shawi and Meriones libycus (Rodentia,Gerbillinae)

Three Meriones species inhabit Tunisia, namely M. shawi, M. libycus and M. crassus, but little genetic data exist on these gerbils. We collected Meriones from eight localities in Tunisia, and obtained mitochondrial (cytochrome b) and nuclear (IRBP) gene sequence data for 37 and 13 specimens, respectively, belonging to two species: M. shawi and M. libycus. We also optimised three microsatellite markers previously described in M. unguiculatus to obtain a finer analysis of their genetic diversity and geographic structure, given their wide distribution. Phylogenetic inferences of cyt b and IRBP data for these species, in the context of other gerbillin data, corroborate their taxonomic affinities reported by previous studies. High cyt b haplotype diversity was observed in both species (25 haplotypes in 29 and 27 sequences for M. shawi and M. libycus, respectively) with little geographical structure for M. shawi but three divergent groups in M. libycus. The average microsatellite diversity within each population was high (H_O ≥ 0.6, H_E ≥ 0.8) with M. libycus populations attaining the highest values. Population differentiation was moderate for several population pairs (F_st ≥ 0.1), the highest being between M. shawi populations. However, genetic distance among populations was not significantly correlated with geographic distance in either M. shawi or M. libycus. Our results contribute to a better characterisation of Tunisian Meriones species, suggesting high geographic structure in mtDNA of M. libycus populations within North Africa.     

Reproductive investment of <Emphasis Type="Italic">Pinus pseudostrobus</Emphasis> along an altitudinal gradient in Western Mexico: implications of climate change

Climate varies along altitudinal gradients and species performance may be affected in response to these variations. Climate change can modify these gradients and, at the lower limit of species distributions, individuals may become stressed and their general health and reproductive performance may decrease. Study and prediction of the effects of climate change on the distribution of species along these gradients is therefore necessary. Our model study species, Pinus pseudostrobus, is a widely distributed pine in Mexico, ranging from 1600 to 3200 masl in altitude. In order to explore changes in health condition and reproductive investment along an altitudinal gradient, ten reproductive trees were selected in each of four populations (at 2300, 2400, 2700 and 2900 masl). As a proxy of individual health, we conducted a rapid visual assessment for each tree, based on crown defoliation, dead branches and foliage discoloration. This stress condition index (SCI) ranges from zero to fifteen, and lower values indicate low stress and therefore better health conditions. We also evaluated reproductive (cone weight, number/weight of seeds) and progeny (germination/seedling growth) traits. In addition, the relationships between SCI and the reproductive/progeny traits were assessed. The lowest altitude population presented poor health, with higher values of SCI (mean ± SE = 6.3 ± 0.9) that reduced up to 4.8-fold in higher-altitude populations. Cone weight also differed among altitudes, with lighter cones in the lower population (mean ± SE = 38.2 ± 4.3 g), and 1.5-fold heavier cones found in the higher populations. In general, all of the reproductive/progeny traits differed among altitudes. The population of intermediate altitude (2700 masl) presented the highest values for all traits evaluated, indicating higher performance at this altitude. Finally, a negative relationship was found between stress condition and cone weight. Based on our results and climate change models and their predictions, an increase in physiological stress can be expected in individuals of low altitude populations. Furthermore, possible increases in pests and pathogens are likely to contribute to the decline of this population. It is therefore necessary to maintain efforts of stress condition assessment and population dynamics, as well as to permanently monitor the climate along altitudinal gradients.     

黄芪解毒汤诱导乳腺癌细胞凋亡及对β-catenin、C-myc基因表达影响的研究

目的 探讨黄芪解毒汤体外干预人乳腺癌细胞MCF-7凋亡及对β-catenin、C-myc基因表达的影响,及该方抑制乳腺癌复发转移的可能机制。方法 培养MCF-7细胞并将其分为黄芪解毒汤组、阿霉素组及空白对照组。以黄芪解毒汤浓缩液、阿霉素液及细胞培养液分别干预各组MCF-7细胞24h后,以流式细胞仪检测其对MCF-7乳腺癌细胞凋亡的影响,实时荧光定量PCR检测其对β-catenin, C-myc基因表达的影响。结果 与空白对照组比较,黄芪解毒汤组、阿霉素组可明显诱导MCF-7细胞的凋亡（P<0.01）;黄芪解毒汤组及阿霉素组β-catenin、C-myc表达量明显低于空白对照组（P<0.01）。结论 黄芪解毒可诱导乳腺癌细胞MCF-7凋亡,显著降低β-catenin、 C-myc基因表达,该结果为黄芪解毒汤在乳腺癌术后治疗中的应用提供实验依据。