An acute case of Pimelea elongata toxicity in cattle in western New South Wales

In May 2019, 96 cattle died from Pimelea toxicity in a period of 19 days after potential exposure, with the first deaths occurring within 5 days. After examining the circumstances, we suspect that several factors contributed to the deaths. These included that recently purchased stock and transported had access to flooded land containing Pimelea elongata. This weed species contains simplexin and 18 other compounds. Roots, flowers and seeds are significantly more toxic than the stem, branches and leaves. We suspect that thirsty and hungry stock consumed seed and roots from flooded pastures and consumed lethal doses of simplexin. Blood tests were not good indicators of the conditions. Management strategies are suggested.     

褐飞虱迁飞轨迹研究

借鉴现代统计－天气理论中的大气传输与扩散模型，对褐飞虱秋季回迁的轨迹进行模拟，计算了回迁昆虫在高空１０００ｍ和１５００ｍ的迁飞轨迹，通过对比分析，发现两高度的轨迹在迁飞方向、迁飞速度和迁飞距离上存在着较大的差异；通过对迁飞风场和迁温度场的分析，进一步证实了１０００ｍ高度的迁飞轨迹模拟能够更直接、更准确地反映出昆虫迁飞的实际情况，同时对导致１０００ｍ和１５００ｍ两高度轨迹差异的环流进行了归类，定性地     

吡蚜酮防治褐飞虱的使用技术及对天敌的安全性研究

通过室内生物测定、盆栽和田间试验,研究了新型杀虫剂吡蚜酮对水稻褐飞虱的作用方式、不同龄期毒力、田间使用技术及防治效果,并初步探讨了吡蚜酮对天敌黑肩绿盲蝽和蜘蛛(机敏漏斗蛛)的毒力及其田间数量的影响。结果表明:吡蚜酮对褐飞虱不仅具有触杀作用,还具有较强的内吸作用。吡蚜酮对褐飞虱1龄、3龄若虫的168hLC50值分别为14.99mg·L-1、13.08mg·L-1,显著低于5龄若虫和成虫。盆栽试验发现当盆钵中保持水层时,吡蚜酮的防治效果更高。在褐飞虱低龄期、田间保持水层条件下,应用25%吡蚜酮WP制剂300g·hm-2、450g·hm-2和600g·hm-2,药后15d的防治效果可达95%以上。进一步的研究发现,吡蚜酮对黑肩绿盲蝽成虫的安全性级别为较不安全(Ⅲ级),田间使用吡蚜酮后黑肩绿盲蝽数量减少;吡蚜酮对蜘蛛安全性级别为安全(Ⅰ级),田间使用吡蚜酮后蜘蛛数量无明显变化。研究结果为吡蚜酮的合理使用提供了科学依据。     

温度胁迫对褐飞虱不同抗性水平水稻 营养生长和生理指标的影响

[目的]研究温度胁迫对褐飞虱不同抗性水平水稻营养生长和生理指标的影响,为抗虫稻种的选育及合理布局提供参考.[方法]分别将处于四叶一心期和拔节期的抗虫稻ASD7、高感稻TN1和感虫稻桂育9号(GY9)置于人工气候箱中,设高温恒温、高温变温、异常低温和对照(CK)4个处理,连续处理5 d后测定水稻叶宽、株高、生物量、株水含率及叶片可溶性糖和可溶性蛋白含量.[结果]四叶一心期和拔节期,不同褐飞虱抗性水平水稻品种的叶宽均以异常低温处理最宽,高温恒温处理最窄;株高、株鲜重及水含率在高、低温胁迫下均较CK有不同程度的降低;水稻株干重、叶片可溶性糖及可溶性蛋白含量在异常低温处理下较CK升高,在高温变温处理下较CK降低.同一温度处理下,GY9的叶宽、株高和生物量最高,且其拔节期的水稻叶片可溶性糖和可溶性蛋白含量也相对较高.[结论]感虫稻GY9在不同温度胁迫下的生长发育较快、生理代谢物质含量较高,对温度胁迫的耐受力相对较强,能够适应广西初夏多变的气候.     

Induction of hypericins and hyperforin in Hypericum perforatum L. in response to biotic and chemical elicitors

Hypericum perforatum L. produces hyperforins, a family of antimicrobial acylphloroglucinols; and hypericins, a family of phototoxic anthraquinones exhibiting anti-microbial, anti-viral, and anti-herbivore properties in vitro. To determine whether these secondary metabolites are part of the specific plant defense systems that are mediated by methyl jasmonate or salicylic acid, we used meristem cultures to assess the effects of exposure to exogenous application of these chemical elicitors. Levels of hypericins in plant tissue increased in response to both elicitor treatments; total hypericin levels increased as much as 3.3 times control levels when treated with 200 μ methyl jasmonate for 14 days. Increased hyperforin concentrations were detected when plantlets were treated with 1 m salicylic acid or 50 μ methyl jasmonate. For assessing responses to a biotic elicitor, greenhouse-grown plant materials were inoculated with the plant pathogen, Colletotrichum gloeosporioides. Levels of hypericins increased twice as much as the control when inoculated with 1 × 10⁴ spores per ml; higher doses of spores overwhelmed the plant defenses. The elevation of hypericins and hyperforin in response to chemical and biotic elicitors suggests that these secondary metabolites are components in the inducible plant defense responses of H. perforatum.     

高海拔山地引种栽培中华圣桃技术

通过对湖南省桑植县引种栽培的中华圣桃,进行环境适应能力和产量及品质的调查,总结出中华圣桃的引种栽培技术。中华圣桃在高海拔山地生长发育情况正常,产量稳定,经济价值高,完全适宜推广栽培。     

江苏省褐飞虱迁入量的中长期预测模型

根据1983-2010年江苏省褐飞虱灯诱资料及1982-2010年全球海温场资料和美国国家环境预测中心（NCEP）气象再分析资料,对江苏稻区代表站高邮、通州和宜兴的褐飞虱迁入量与前一年1月-当年6月太平洋海温场、前一年12月-当年6月中南半岛近地表气温场和前一年7月-当年6月北半球大气环流特征量的相关关系进行分析,并运用逐步回归方法建立一系列褐飞虱年总迁入量的预测预报方程。结果表明：（1）高邮、通州和宜兴3站的褐飞虱迁入量在不同时空阈限内与太平洋海温场、中南半岛气温场和北半球大气环流特征量之间存在不同程度的相关性。3站褐飞虱迁入量的对数值与前一年海温场呈负相关,其中与通州和宜兴站褐飞虱迁入量对数值相关显著的海温区主要分布在北、中太平洋,高邮站则在南太平洋;高邮站褐飞虱迁入量的对数值与前一年12月和当年4月中南半岛西南部的近地表气温场呈正相关,通州站与前一年12月和当年2、3月中南半岛北部的近地表气温场呈负相关,宜兴站与当年1、3月中南半岛西南部的近地表气温场呈正相关、与当年4月中南半岛大部的近地表气温场呈负相关;3站褐飞虱迁入量的对数值主要与前一年7月-当年6月的各副高指数、各极涡指数、大西洋欧洲环流型、亚洲纬向环流指数、东亚槽强度、冷空气强度、西太平洋编号台风强度、南方涛动指数等相关显著。（2）从上述海温场、气温场和环流特征量中筛选出显著相关（P<0.05）的因子作为预测因子,建立褐飞虱年迁入量的预测模型,并筛选出回检正确率70%以上、预检正确率66.7%以上模型17个,适用性评估表明,各模型的预报结果与实测值基本吻合,表明模型可应用于单站褐飞虱年迁入量的预测。     

Development of colchicine‐induced tetraploid St. Augustinegrass (Stenotaphrum secundatum) lines

St. Augustinegrass is well suited for lawns and commercial landscapes. While many genotypes are cross‐fertile, all cultivars are propagated vegetatively in sod production. To ensure varietal purity, development of sterile triploid hybrids by crossing tetraploid and diploid genotypes has been successfully used in other warm‐season turfgrasses. Applying this model in St. Augustinegrass would be beneficial to sod producers and turf managers who require purity for certification and uniformity for performance, respectively. This study was conducted to develop colchicine‐induced tetraploid lines of St. Augustinegrass. Seeds of cultivar ‘Raleigh’ were treated with four colchicine concentrations at four exposure times. A non‐treated control was included among the treatments. Seedlings that germinated were screened for genome size changes using flow cytometry. Line DSA 13005 and two progeny lines derived through selfing, DSA 16001 and DSA 16016, were corroborated as tetraploids (2n = 4x = 36) through chromosome counts. These lines will be used in future breeding efforts to attempt development of sterile triploid cultivars of St. Augustinegrass.     

An analysis of structure of tree seedling populations on a Lahar

The structure of a tree seedling population is dependent on the interaction of several processes including seed dispersal, germination, survival, and competition on a physical landscape. Structural components (composition, size distributions, spatial distributions, age distributions, density, and history) of a tree seedling population on the Muddy River Lahar on the east side of Mount St. Helens were examined over a range of extents (1/10 m to 1000 m). Many of these component have rarely been examined at the larger extents listed here. Composition reflected distances to seed source and seed morphology. Seedling sizes are inversely proportional to depth to a buried soil if one existed. Spatial patterns indicated that seedling are clustered for tree seedlings less than 200 m apart, random for tree seedling from 200 m to 400 m and uniform for seedling greater than 400 m apart. This was confirmed by two measures of multidimensional spatial point pattern. Age distributions did not reflect the size distributions; old seedlings could be almost any size, young seedlings were constrained to be small in size. Densities appear to be typical for forests in the area. History of disturbance events (the lahar establishment, and successive ash, pumice, and erosion) has strongly influenced this tree seedling community.