警惕种子传带的南方番茄病毒Southern tomatovirus对我国番茄产业的危害

南方番茄病毒Southern tomato virus (STV)是近年来新发现的一种侵染番茄的病毒, 通常与多种病毒复合侵染, 可能与番茄的褪绿、黄化、衰退、果实变小等症状相关。该病毒最早在1984年发现, 并于2005年命名。我国首先于2015年在山东寿光发现。最近, 我们在山东和北京市多地的番茄样品中均检测到了该病毒, 并通过检测发现国内一些主要品种番茄种子的STV携带率达40%。STV基因组为一条双链RNA, 隶属Amalgaviridae科Amalgavirus属, 是严格种传病毒, 不能通过汁液摩擦接种和嫁接传播。鉴于STV的潜在危害以及与其他病毒高度复合侵染造成的严重损失, 本文介绍了STV检测方法, 并提出应开展对主栽品种的种子检测和针对性防控。     

Antinociceptive diterpene from Euphorbia decipiens

One myrsinol-type diterpene ester (1) isolated from Euphorbia decipiens was evaluated for analgesic activity in the acetic acid induced writhing test in mice. Different dose (5-20 mg/kg i.p.) of the compound showed significant antinociceptive activity, which was comparable to standard analgesic drugs, aspirin and ibuprofen (100 mg/kg i.p.).     

Using leaf tip necrosis as a phenotypic marker to predict the presence of durable rust resistance gene pair <Emphasis Type="Italic">Lr34</Emphasis>/<Emphasis Type="Italic">Yr18</Emphasis> in wheat

Fifty wheat varieties along with Jupateco-73 and Morocco were studied for the expression of leaf tip necrosis (LTN), a trait linked with the durable rust resistance gene pair Lr34/Yr18. LTN was frequent (i.e., ≥6) in nine replications of a field experiment over 3 years in 17 genotypes, and the varieties were considered positive for LTN. In molecular analyses of these varieties, having relative severity values up to 78 for yellow rust and 45 for leaf rust, the 150-bp Lr34/Yr18-linked allele was consistently amplified. Expression of LTN in six of nine replications is an appropriate threshold for predicting the presence of Lr34/Yr18 gene pair, and genotypes can be selected using this trait.     

Evaluating the role of seed priming in improving drought tolerance of pigmented and non‐pigmented rice

This study was conducted to evaluate the influence of seed priming on drought tolerance of pigmented and non‐pigmented rice. Seeds of pigmented (cv. Heug Jinju Byeo) and non‐pigmented (cv. Anjoong) rice were soaked in water (hydropriming) or solution of CaCl₂ (osmopriming). Seeds were sown in soil‐filled pots retained at 70 (well‐watered) and 35% (drought) water‐holding capacity. Drought stress caused erratic and poor stand establishment and decreased the growth of both rice types. More decrease in plant height and leaf area under drought stress was noted in pigmented rice, whereas decrease in root length and seedling dry weight, under drought, was more obvious in non‐pigmented rice. Pigmented rice maintained more tissue water and photosynthesis and had more polyphenols, flavonoids and antioxidant activity than non‐pigmented rice. Seed priming was effective in improving stand establishment, growth, polyphenols, flavonoids and antioxidant activity; however, extent of improvement was more in pigmented rice under drought. In conclusion, drought caused erratic germination and suppressed plant growth in both rice types. However, pigmented rice had better drought tolerance owing to uniform emergence, and better physiological and morphological plasticity. Seed priming was quite helpful in improving the performance of both rice types under drought and well‐watered conditions.     

Identification of cultivars of pasture legumes (Centrosema macrocarpum,C. pubescens and C. sp.n.) by acid polyacrylamide gel electrophoresis of cotyledons storage proteins

Summary An electrophoretic procedure was developed for storage proteins which can discriminate cultivars of forage legumes, Centrosema macrocarpum, C. pubescens and C. sp.n. Proteins extracted from cotyledons were separated in 10% polyacrylamide gel containing 10% sucrose. Electrophoretic patterns are presented to illustrate the results that can be obtained with the procedure described. Cultivars of all three species were distinguishable based upon the variation in their acid soluble seed proteins.Joint publiccation of the Department of Food Science, University of Manitoba (No 101) and Centro Internacional de Agricultura Tropical-CIAT.     

Isoenzyme and cotyledon protein variation for identification of black beans (Phaseolus vulgaris L.) with similar seed morphology

Summary Methods developed to identify genetically diverse varieties of beans (Phaseolus vulgaris L.) were applied to closely related lines that were difficult to distinguish on the basis of seed morphology. Seedling tissues and seeds of black beans, were examined electrophoretically for isoenzyme and cotyledon proteinn protein patterns. Seven enzymes, extracted from seeds or from seedling stem, root or leaf tissues, were compared for polymorphism. Peptidase, polyphenol oxidase, phosphoglucoisomerase and glutamate oxaloacetate transaminase patterns were the same for all lines. Some differences were observed for acid phosphatase, peroxidase and esterase patterns, but complete discrimination of the six selected lines was not possible on the basis of isoenzyme patterns alone. Using polyacrylamide gel electrophoresis (PAGE) of dissociated 0.1 M acetic acid soluble proteins at pH 3.1 (acid-PAGE), or sodium dodecyl sulphate PAGE (SDS-PAGE) of residual protein extracts, all but one pair of samples in each case could be distinguished from the other samples. Using both techniques all of the lines could be identified unequivocally.     

Rhizobium specificity of Trifolium ambiguum M. Bieb × T. repens L. hybrid clovers

Growth of full-sib families of an F₁ interspecific hybrid between Trifolium ambiguum M.Bieb and T. repens L, and two generations of backcross hybrids (BC₁F₂ and BC₂F₁) with T. repens as the recurrent parent, were compared to their parental species. Plants were grown in a N-free medium and inoculated with Rhizobium leguminosarum biovar trifolii rhizobia effective on T. ambiguum or T. repens. Hybridisation produced progeny that nodulated with rhizobia from either T. ambiguum or T. repens, but plant growth varied. Mean weights of T. repens and hybrids, particularly F₁ and BC₁F₂, were higher when inoculated with a mixture of strains isolated from field grown T. repens than with the New Zealand inoculant strain for T. repens. When inoculated with the mix of rhizobia from T. repens, mean weights were 242, 189, 132, 125, and 100 mg/plant for T. repens, BC₂F₁, BC₁F₂, F₁ and T. ambiguum, respectively. However, although the mean weight of BC₂F₁ lines was significantly less than T. repens, there was considerable variation in individual full-sib families indicating the potential to select within BC₂F₁ hybrids for high plant growth/symbiotic nitrogen fixation. The weight of T. ambiguumplants inoculated with the New Zealand inoculant strain for hexaploid T. ambiguum was similar to T. repens inoculated with the mix of rhizobia from T. repens (253 and 242 mg/plant, respectively). Mean fresh weights of F₁ hybrid plants were similar when inoculated with rhizobia for T. ambiguum or T. repens (125 and 130 mg/plant, respectively). However, weight of T. repens, BC₁F₂ and BC₂F₁ hybrids inoculated with rhizobia for T. ambiguum were all less than 90 mg/plant. There was a significant relationship between plant fresh weight and ethylene production. The results indicate that measuring weights of inoculated plants growing in N-free media is a rapid initial method of screening a range of plant germplasm for plant growth/symbiotic nitrogen fixation rates. This revised version was published online in August 2006 with corrections to the Cover Date.     

Effect of Changing Temperature on the Deterioration of Soya Beans

Deterioration rates as indicated by carbon dioxide evolution for soya bean (Glycine max L. Merr.) stored under changing temperature conditions were quantified and compared with those predicted using equations. Experiments included soya bean moisture contents of 18, 22, and 26% (wet basis), constant storage temperatures of 15, 20, 25, and 30°C, and cyclical storage temperatures that changed between 15 and 25°C and between 20 and 30°C on a 24 h basis. Also, the growth of micro-organisms was identified after 10 days from the treatments by using the pour plate method.The results indicated an increase in deterioration by increasing storage temperature and moisture content of soya bean. Equations of carbon dioxide weight versus time for each moisture content and storage temperature were fitted. The longest allowable storage time to reach 0·5% dry matter loss (1132 h) occurred at lower moisture content and lower constant storage temperature, while the shortest allowable storage time (170 h) occurred at higher moisture content and higher constant storage temperature. The allowable storage times for soya bean stored under cyclical temperatures were close to the allowable storage time for soya bean stored at a constant temperature equal to the average cyclical temperature. Microbial infection levels increased with increasing storage temperature and moisture content. The increasing rate of micro-organism growth decreased by increasing the storage temperature over 25°C. However, this increasing rate of micro-organism growth for soya bean exposed to a cyclical storage temperature was usually lower than that for soya bean held at constant storage temperatures of about 20°C (the average of 15 and 25°C) and 25°C (the average of 20 and 30°C).