NaCl胁迫对藜麦幼苗生长及生理特性的影响

为探讨盐胁迫下两类不同地区藜麦品种幼苗的耐盐机制,该文利用不同浓度的NaCl溶液,对来自青海省海东市乐都区的‘LD-13’(低盐地区)和来自青海省海西州乌兰县的‘WL-192’(高盐地区)的2个藜麦品种的种子和幼苗进行盐胁迫处理,研究了种子萌发指标(发芽率、发芽势、发芽指数),生长指标(鲜重、根长、茎长)及生理指标(MDA含量及SOD、POD、CAT活性)等的变化。结果表明:低浓度盐(NaCl浓度小于250 mmol·L~(-1))胁迫下,2个藜麦品种种子的萌发、幼苗生长及生理活性表现均较适宜;但中、高浓度盐(NaCl浓度大于250 mmol·L-1)胁迫下,其种子萌发、生长及幼苗生理活性均受到不同程度的抑制。从耐盐性综合评价值D值来看,虽然同为山谷型的藜麦品种,但适应盐碱地栽培的‘WL-192’品种比低盐土壤中生长的‘LD-13’品种更耐盐。推测‘WL-192’比‘LD-13’耐盐性除了受选育地区土壤盐度的影响外,还可能与品种自身及光周期、温度、海拔、纬度等外部生长环境等因素有关。结合青海西部地区气候环境和盐碱土地资源开发利用,‘WL-192’品种更适合在青海地区推广种植。     

Insecticidal Metabolites from the Rhizomes of Veratrum album against Adults of Colorado Potato Beetle,Leptinotarsa decemlineata

The dried rhizomes of Veratrum album were individually extracted with CHCl₃, acetone, and NH₄OH/benzene to test the toxic effects against the Colorado potato beetle, Leptinotarsa decemlineata, which is an important agricultural pest. Fifteen compounds in various amounts were isolated from the extracts using column and thin‐layer chromatography. The chemical structures of 14 compounds were characterized as octacosan‐1‐ol ( 1 ), β‐sitosterol ( 2 ), stearic acid ( 3 ), diosgenin ( 4 ), resveratrol ( 5 ), wittifuran X ( 6 ), oxyresveratrol ( 7 ), β‐sitosterol 3‐O‐β‐D ‐glucopyranoside ( 8 ), diosgenin 3‐O‐α‐L ‐rhamnopyranosyl‐(1→2)‐β‐D ‐glucopyronoside ( 9 ), oxyresveratrol 3‐O‐β‐D ‐glucopyranoside ( 10 ), jervine ( 11 ), pseudojervine ( 13 ), 5,6‐dihydro‐1‐hydroxyjervine ( 14 ), and saccharose ( 15 ) using UV, IR, MS, ¹H‐ and ¹³C‐NMR, and 2D‐NMR spectroscopic methods. However, the chemical structure of 12 , an oligosaccharide, has not fully been elucidated. Compounds 4, 6, 9 , and 10 were isolated from V. album rhizomes for the first time in the current study. The toxic effects of three extracts (acetone, CHCl₃, and NH₄OH/benzene) and six metabolites, 2, 2 + 4, 5, 7, 8 , and 11 , were evaluated against the Colorado potato beetle. The assay revealed that all three extracts, and compounds 7, 8 , and 11 exhibited potent toxic effects against this pest. This is the first report on the evaluation of the toxic effects of the extracts and secondary metabolites of V. album rhizomes against L. decemlineata. Based on these results, it can be concluded that the extracts can be used as natural insecticides.     

藜麦及其资源开发利用

藜麦Chenopodium quinoa Willd.英文名:quinoa,原产于南美洲安第斯山区,是印加土著居民的主要传统食物,至今已有5 000~7 000多年的利用和种植历史。古代印加人将它称之为"粮食之母"。藜麦在20世纪80年代,被美国宇航局用于宇航员的太空食品。联合国粮农组织认为藜麦是唯一的单一植物即可满足人体基本营养需求的食物,正式推荐藜麦为最适宜人类的完美的全营养食品。本文对藜麦的植物形态、生态特性、营养价值以及在我国种植展望作了综合报道。     

Modelling field emergence patterns in arable weeds

A model was developed to simulate weed emergence patterns after soil cultivation. In the model, the consecutive processes of dormancy release, germination and pre-emergence growth were modelled in separate modules. Input variables of the model were: date of soil cultivation, soil temperature and soil penetration resistance. Output variables of the model were: seedling density and timing of seedling emergence. The model was parameterized for Polygonum persicaria , Chenopodium album and Spergula arvensis with data from previous field and laboratory experiments. The model was evaluated with data from an experiment, in which emergence of P. persicaria , C. album and S. arvensis was monitored in field plots that were cultivated once only, at one of five dates in the spring. At the same time as the field observations on seedling emergence, seasonal changes in seed dormancy of the buried weed seeds were assessed by testing the germination of seed lots that were buried in envelopes. From a comparison between field observations and simulated data, it appeared that the model overestimated the rate of dormancy release in spring, whereas germination and pre-emergence growth were simulated well. In general, therefore, both the numbers of emerging seedlings and the timing of emergence could be predicted accurately, when dormancy was not simulated but introduced from experimental data. Improvement of predictions of field emergence of weeds should mainly focus on increasing the precision of the simulation of dormancy release. Close correlations were found between seedbed temperature and both the extent and rate of seedling emergence, but analysis with the simulation model revealed that they were only partly based on causal relationships, so that they have limited predictive value.     

The Role of Leaf Petiole in Photoperiodic Induction of Flowering

Explants of Chenopodium rubrum, a short-day plant, were decapitated and exposed to floral inductive treatment, and the extent of flowering of axillary buds was afterwards assessed. Isolated buds never responded to induction, whereas the presence of the petiole of the subtending leaf already assured a high degree of flowering. We may assume either that the petiole is the receptor organ of the photoperiodic signal or that its transporting role is indispensable.     

Purification and some properties of strawberry mottle virus

Strawberry mottle virus (SMoV) (three isolates: HJ, 3E and N) were transmitted to Chenopodium quinoa plants by sap inoculation. All three isolates induced very similar symptoms consisting of chlorotic spots and ringspots in inoculated leaves, and vein chlorosis, mottling, and dwarfing of the upper leaves. SMoV isolate HJ was purified from infected C. quinoa by homogenisation with 10 mM phosphate buffer, pH 7.2 containing 5% Triton X-100, followed by differential, sucrose density-gradient and CsCl equilibrium density-gradient centrifugations. A fraction with a buoyant density of 1.42g^- cm^-3 after CsCl density-gradient centrifugation was highly infectious to C. quinoa and contained many isometric virus-like particles c. 37 nm in diameter. These virus-like particles were never found in fractions from uninfected preparations. Electrophoretic analysis of a fraction containing virus-like particles revealed that these particles might have a single coat protein subunit with the apparent molecular mass of 26 K daltons and one nucleic acid of 6.6 kilobases. Double-stranded RNA analysis of isolate HJ-infected or uninfected C. quinoa and Fragaria vesca var. semperflorens seedling line ‘Alpine’ plants showed that both infected plants had two infection-specific dsRNA bands of mol. wts 4.5 and 3.9 × 10⁶.     

橄榄(Canarium album)种子形态结构与数量性状分析

以福建主栽的橄榄（Canarium album（Lour.）Rauesch.）品种‘长营’种子为材料,观察其成熟种子及不同发育时期种子的形态结构,对数量性状进行测量与统计分析,并运用概率分级建立形态指标的正态分布分级标准。结果显示,橄榄种子表型性状和形态结构变异较大,各数量性状变异系数为6.77%~19.04%,具有丰富的遗传多样性;橄榄种子心室类型有12种,其中三心室占比最高（97.80%）;胚数量0~4个不等;经K-S检验,各数量性状符合正态分布,依据各性状可划分为5级分级标准。本研究为橄榄种质的系统学研究提供了种子形态方面的新内容,可为橄榄资源描述的标准化及遗传育种研究提供一定的参考。     

Net fluxes and pools of nitrogenous compounds during suspension culture of photoautotrophic Chenopodium rubrum cells

Abstract. Suspension cultured cells of Chenopodium rubrum were grown photoautotrophically under a diurnal light-dark cycle of 16-8h. The following phases of the batch culture were differentiated: a short lag, a cell division phase terminated by a pronounced transition to stationary maintenance which finally gradually passed into senescence. Nitrogen fluxes typical of these stages were followed by measuring uptake of NO₃ and NH₄⁺ from the medium and their incorporation into the cellular fractions of nitrogenous compounds. Activities of seven N-metabolizing enzymes were determined. Compartmentation of enzymes and nitrogenous compounds was analysed after isolation of intact chloroplasts and vacuoles from protoplasts. Eighty-two per cent of the N originally present in the medium was taken up and incorporated to an extent of 80% into protein until the end of the division phase. Net protein synthesis ceased upon transition to the stationary phase. During the division phase a vacuolar pool of NO₃ was established and then maintained throughout the resting phase. Free cellular NH₄⁺ was not localized within the vacuole and responded to the ammonium content of the medium. Amino acids accumulated in the cells especially during the stationary phase, during which they were present in the vacuole. Typical nitrogen relations are portrayed as flux diagrams for one day of each of the essential developmental phases. The enzyme activities were easily sufficient to account for the observed flow rates of the corresponding nitrogenous compounds. Hence, uptake of NO₃ and NH₄⁺ must be considered as steps limiting N metabolism in Chenopodium rubrum cell suspensions.