胡椒主要病害及其防治方法

胡椒是1种重要的调味品和香料作物,病害是其生产的主要障碍,每年造成大量的损失。对胡椒病害的研究具有重要意义。综述了几种常见胡椒病害,分析了各种病害的病原菌,并提出了相应的防治方法。     

胡椒丽绿刺蛾的发生及防治

丽绿刺蛾在海南胡椒种植区每年发生2～3代,以老熟幼虫在主蔓上结茧越冬。该虫1年有2次发生高峰期,分别在5月下旬至6月中下旬和7月下旬至9月中旬。第1代幼虫发生量大,危害严重,是防治的关键时期。根据其发生规律提出相应的防治策略。     

Effect of calcium silicate on growth and dry matter yield of Chloris gayana and Sorghum sudanense under two soil water regimes

The effects of five rates [0 (control), 1, 2, 4 and 6 Mg ha^?1] of calcium silicate on the growth and water consumption by rhodes grass (Chloris gayana Kunth) and sudan grass (Sorghum sudanense Piper) under wet and dry soil water regimes (60 g and 30 g H₂O kg^?1 soil respectively) were evaluated in a pot experiment. The effect of the application of silicate on plant biomass was similar to that of the control. However, the shoot and root dry mass varied significantly (P < 0.001) according to the soil water regime and plant species. During the first cut, the shoot dry mass was 5.7 g per pot under the wet soil moisture regime, significantly exceeding that under the dry soil water regime proportionately by 0.68. For sudan grass, the shoot dry mass varied from 3.6 g per pot in the control to 4.3 g per pot in the treatment that received 6 Mg ha^?1 of calcium silicate. Plant water demand decreased as the rate of calcium silicate application increased, suggesting that an application of calcium silicate could reduce drought stress and enhance water economy. For the soil under study, the reduction in plant water demand represents a water saving ranging from 0.076 to nearly 0.20.     

Autumn Irrigation Alerted the Geochemistry of Groundwater in Hetao Irrigation District：Take Yichang Irrigation District as an Example北大核心CSCD

【Objective】Surface infiltration could change biogeochemical reactions in groundwater thereby alerting its chemical compositions. The aim of this paper is to investigate the responsive change in chemical composition of groundwater to infiltration following the autumn irrigation in irrigation districts.【Method】The experiment was conducted in Hetao Irrigation District, during which we measured the change in concentration of Na+, K+, Ca2+, Mg2+, SO42-, Cl-, HCO3- and CO32- and then statistically analyzed them.【Result】The irrigation increased the concentration of Cl-, SO42-, KNa, Mg2 and HCO3-, but slightly reduced the concentration of Ca2+. The TDS was higher in south and lower in north of the irrigation district. The Piper diagram showed that the Cl-Na was the dominant groundwater type, accounted for 75% and 61% of the studied area before and after the irrigation respectively. Irrigation turned groundwater in 16.7% of the studied area to Mg-SO4-Cl type. The Gibbs model and ion proportional coefficient diagram revealed that the chemistry of groundwater in the studied region was mediated by evaporation, weathering and leaching of silicate and evaporite, and is independent of precipitation. 【Conclusion】The mean TDS in the groundwater increased by 32.9% after the autumn irrigation, indicating the impact of soil leaching. Improving drainage after the autumn irrigation is hence essential. © 2019 Journal of Irrigation and Drainage. All rights reserved.     

Screening of endophytic bacteria and evaluation of selected isolates for suppression of burrowing nematode (Radopholus similis Thorne) using three varieties of black pepper (Piper nigrum L.)

Radopholus similis is a serious threat to black pepper (Piper nigrum L.) cultivation being the main causal organism of slow decline disease. Because of its migratory nature most fungal and bacterial antagonists are ineffective in suppressing R. similis. The presence of a number of endophytic bacteria in black pepper tissues has been proved in earlier studies. This study was undertaken to evaluate the bacteria isolated from black pepper for suppressing R. similis. In vitro and in vivo screenings were used initially to identify the efficient strains of endophytic bacteria that suppress R. similis. Seventy four isolates of endophytic bacteria obtained from black pepper were screened against R. similis by various bioassays. Results of the in vitro experiments were inconclusive and did not match the rest of the studies. However, six isolates were short-listed based on the preliminary in vivo screening and further tested in an evaluation trial using three varieties of black pepper. Irrespective of the varieties, significantly higher nematode suppression was observed with one isolate (TC 10) followed by another (BP 17). These isolates were identified to the species level by sequence analysis of the 16S rRNA gene. The results showed that these isolates shared 99% identity with Bacillus megaterium and Curtobacterium luteum, respectively. More studies are required to understand their mode of action as well as the dose–response relationship with nematodes.     

Studies on antidepressant and antinociceptive effects of ethyl acetate extract from Piper laetispicum and structure-activity relationship of its amide alkaloids

Piper laetispicum C.DC. (Piperaceae), is an endemic climbing, glabrous plant distributed in the southern part of China. A novel alkaloid amide, Laetispicine, from it has been proven to possess antidepressant activity. In this present study, antidepressant and antinociceptive effects of the ethyl acetate extract (EAE) of P. laetispicum have been studied in forced swimming, open field, acetic acid writhing and formalin tests in KM mice. A significantly antidepressant-like effect was showing at doses of higher than 60 mg/kg, which was not due to an increase in locomotive activity. The EAE also presented an analgesic effect, in our studies. At lower doses (30 mg/kg) the antinociceptive effect was likely mediated via peripheral inflammation and changes in central processing, and at higher doses (120 mg/kg) that was due to both central and peripheral pathways. We also quantitatively analyzed the major components of EAE by HPLC and approached the structure–activity relationship between structure of amide alkaloids and its antidepressant activities. The antidepressant effective components of EAE might be Leatispiamide A and Laetispicine. In their molecular structures, the isolated double bond from benzene ring and conjugated double bond located at 2–3 and 4–5 were necessary for its antidepressant activity.     

Protective effect of Piper longum fruit ethanolic extract on radiation induced damages in mice: a preliminary study

The radioprotective property of an ethanolic extract of Piper longum fruits (EEPLF) was investigated in Swiss mice. The white blood cell (WBC) count in irradiated control mice was drastically reduced to 1900 cells/mm3 on third day but in treated animals the count was 2783.3 cells/mm3. The number of bone marrow cells and alpha-esterase positive cells was also enhanced by the EEPLF administration (16.7 x 10(6) cells/femur and 946.5/4000 cells, respectively) when compared to the radiation exposed control animals (12.2 x 10(6) cells/femur and 693.5/4000 cells, respectively). EEPLF reduced the elevated levels of glutathione pyruvate transaminase (GPT), alkaline phosphatase (ALP), and lipid peroxidation (LPO) in liver and serum of radiation treated animals. The extract administration also increased the reduced glutathione (GSH) production to offer the radioprotection.     

基于SCI-E收录论文的胡椒学科发展研究

以Web of Science平台的SCI-EXPANDED数据库为统计源,采用文献计量学方法,从国家、研究机构、期刊、研究方向等方面统计分析2004~2013年有关胡椒科技论文被SCI-E的收录情况,其中反映了世界各国胡椒论文数量变化和所涉及的研究方向,旨在把握国际上胡椒研究热点的现状、科研动态及发展趋势。     

苏丹草种子活力TTC测定试验

采用四唑法和标准法分别测定苏丹草种子的生活力和发芽率,结果表明苏丹草种子生活力和发芽率之间具有极显著的正相关(r=0.775**)。经过试验和统计分析还显示,苏丹草种子的生活力和发芽率的结果相一致,即四唑法测定苏丹草种子生活力的结果可代表其发芽率的结果。     

Isobutyl amides--potent compounds for controlling Diatraea saccharalis

BACKGROUND: A dichloromethane‐methanol extract of the seeds of Piper tuberculatum Jacq. (Piperaceae) and two isobutyl amides, 4,5‐dihydropiperlonguminine (1) and pellitorine (2), which were isolated by chromatographic methods, were assayed for their lethality against the sugarcane borer Diatraea saccharalis F. (Lepidoptera: Pyralidae). RESULTS: Bioassays were carried out with fourth‐instar caterpillars through topical application of test solutions to the dorsal surface of the prothorax, and dose–response correlations were determined. Significant insect mortalities were observed 24, 48 and 72 h after treatment at concentrations of ≥ 100 µg insect^?1. The LD₅₀ and LD₉₀ values for compound 1 were 92.83 and 176.50 µg insect^?1, and for compound 2 they were 91.19 and 184.56 µg insect^?1. CONCLUSION: According to the LD₅₀ and LD₉₀ for compounds 1 and 2, it can be inferred that the values reflect an acute lethal response to both compounds, based on interaction(s) of the toxicants with a primary target or series of targets. Thus, the amides were demonstrated to have potential value in the control of the sugarcane borer. Copyright © 2008 Society of Chemical Industry