黄瓜根腐病致病病原的鉴定

在天津市及周边地区采集病株进行组织分离，同时分离到两类病原菌，经初步的生物学特性鉴定表明，引起黄瓜根腐病的主要病原菌为甜瓜疫霉、尖孢镰刀菌和茄病镰刀菌。经接种试验，认为甜瓜疫霉为主要致病菌。     

鹿源细小病毒的分离与鉴定

选用PK-15传代细胞系从吉林农业大学鹿场采集的梅花鹿粪样病料中分离出一株病毒,经血凝试验、血凝抑制试验及电镜观察对该病毒进行鉴定。结果表明:该病毒为鹿源细小病毒。     

中越水稻迁飞性害虫稻飞虱、稻纵卷叶螟发生关系分析

中越两国同属东亚季风区,水稻病虫害在发生危害上为一个整体。每年水稻稻飞虱、稻纵卷叶螟(以下简称"两迁"害虫)随着季节和气温变化,在两国间往返迁飞,发生为害,相互影响。研究两国水稻迁飞性害虫发生的关系和影响规律,对于提高监测预警的早期预见性和防控工作的主动性,有效控制其危害具有重要意义。2010年以来,中越两国实施了中越水稻迁飞性害虫监测与防治合作项目,通过连续多年开展交流合作,初步明确了越南"两迁"害虫发生规律。本文简要分析了影响越南"两迁"害虫发生的主要因素,探讨了中越两国水稻"两迁"害虫发生规律的相关性,对提高中国"两迁"害虫中、长期预报能力和综合治理水平发挥了积极作用。     

褐藻糖胶脱蛋白及脱色方法研究

采用Sevag法、三氯乙酸(TCA)法和Sevag法与三氯乙酸法相结合的方法对褐藻糖胶进行脱蛋白研究,并研究脱蛋白与未脱蛋白对褐藻糖胶脱色的影响.结果表明,Sevag法与三氯乙酸法相结合脱蛋白效果最佳,当Sevag法操作2次,TCA溶液添加量为1.3 mL/10mL多糖溶液时,蛋白脱除率为78.68%,多糖损失率为28...     

甘蔗与抗旱性相关差异蛋白质组分析

采用桶栽方式,对抗旱性强的F172和抗旱性弱的YL6甘蔗品种在苗期进行重度干旱胁迫处理后,应用蛋白质双向电泳技术进行差异蛋白质分析,分别找出差异显著的28和20个差异蛋白点,其中部分呈现上调表达,部分呈现下调表达,还有部分新增的蛋白点,因品种抗性不同而表现各异,F172叶片中的差异蛋白主要表现为上调表达,而YL6中大多表现为下调表达。在重度干旱胁迫下,抗旱性不同的甘蔗品种蛋白质丰度变化有显著差异。采用MALDI-TOF-TOF/MS鉴定所获得的差异蛋白,从YL6、F172中分别鉴定出18、14个蛋白的氨基酸序列,对所鉴定的蛋白质根据功能分为8类。YL6中参与自由基清除的2个,参与光合作用的6个,参与细胞生长和分裂的1个,参与基础代谢的6个,参与防卫反应的2个,未知功能蛋白1个。F172中参与自由基清除的1个,参与光合作用的2个,参与细胞生长和分裂的2个,参与基础代谢的4个,参与信号转导的2个,参与蛋白加工的1个,未知功能蛋白2个,其中22 k D干旱诱导蛋白的丰度明显提高,而在YL6中则检测不到此蛋白。这说明在干旱胁迫下抗旱性不同的甘蔗品种在蛋白质组成上有很大差异,推测这是不同甘蔗品种间抗旱性差异的重要分子基础。     

In vitro and in silico studies of salicylic acid on systemic induced resistance against bacterial leaf blight disease and enhancement of crop yield

Salicylic acid (SA) is an effective elicitor to promote plant defenses and growth.  This study aimed to investigate rice (Oryza sativa L.) cv. Khao Dawk Mali 105 treated with salicylic acid (SA)-Ricemate as an enhanced plant protection mechanism against bacterial leaf blight (BLB) disease caused by Xanthomonas oryzae pv. oryzae (Xoo).  Results indicated that the use of SA-Ricemate as a foliar spray at concentrations of more than 100 mg L^–1 can reduce the severity of BLB  by 71%.  SA-Ricemate treatment also increased the hydrogen peroxide (H₂O₂) content of rice leaf tissues over untreated samples by 39–61%.  Malondialdehyde (MDA) in rice leaves treated with SA-Ricemate also showed an increase of 50–65% when comparing to non-treated samples.  The differential development of these defense compounds was faster and distinct when the SA-Ricemate-treated rice was infected with Xoo, indicating plant-induced resistance.  Besides, SA-Ricemate elicitor at a concentration of 50–250 mg L^–1 was correlated with a substantial increase in the accumulation of total chlorophyll content at 2.53–2.73 mg g^–1 of fresh weight which suggests that plant growth is activated by SA-Ricemate.  The catalase- and aldehyde dehydrogenase-binding sites were searched for using the CASTp server, and the findings were compared to the template.  Chemsketch was used to design and optimize SA, which was then docked to the catalase and aldehyde dehydrogenase-binding domains of the enzymes using the GOLD 3.0.1 Software.  SA is shown in several docked conformations with the enzymes catalase and aldehyde dehydrogenase.  All three catalase amino acids (GLN7, VAL27, and GLU38) were discovered to be involved in the creation of a strong hydrogen bond with SA when SA was present.  In this mechanism, the aldehyde dehydrogenase amino acids LYS5, HIS6, and ASP2 were all implicated, and these amino acids created strong hydrogen bonds with SA.  In field conditions, SA-Ricemate significantly reduced disease severity by 78% and the total grain yield was significantly increased which was an increase of plant height, tiller per hill, and panicle in three field trials during Aug–Nov 2017 and 2018.  Therefore, SA-Ricemate can be used as an alternative elicitor on replacing harmful pesticides to control BLB disease with a high potential of increasing rice defenses, growth, and yield components.     

Husbandry Factors and the Resumption of Luteal Activity in Open and Zero‐Grazed Dairy Cows in Urban and Peri‐Urban Kampala,Uganda

The study investigated the influence of selected husbandry factors on interval to resumption of post‐partum cyclicity among dairy cows in urban and peri‐urban Kampala. A prospective study of 85 day post‐partum period of 59 dairy cows in open (n = 38) and zero grazing (n = 21) systems was conducted on 24 farms. Cows of parity 1–6 were recruited starting 15–30 days post‐partum. Progesterone (P4) content in milk taken at 10–12 day intervals was analysed using ELISA. The cow P4 profiles were classified into ‘normal’ (< 56 days), ‘delayed’ (> 56 days), ‘ceased’ or ‘prolonged’ (if started < 56 days but with abnormal P4 displays) resumption of luteal activity and tested for association with husbandry and cow factors. Of the 59 cows, luteal activity in 81.4% resumed normally and in 18.6%, delayed. Only 23.7% maintained regular luteal activity, while the others had ceased (10.2%), prolonged (37.3%) or unclear luteal activity (20.3%). There were no differences between open and zero‐grazed cows. Milk production was higher (p < 0.05) in zero than open grazing, in urban than peri‐urban and in cows fed on brew waste (p < 0.001) compared with mill products and banana peels. Results suggest that luteal activity resumes normally in a majority of cows, although only a minority experienced continued normal cyclicity once ovulation had occurred, in the two farming systems irrespective of feed supplements or water, and that supplementing with brew waste is beneficial for milk production.