Effect of Ultraviolet Disinfection of Hydroponic Solutions on Pythium Root Rot and Non-target Bacteria     

W. Zhang  J.C. Tu 《European journal of plant pathology / European Foundation for Plant Pathology》2000,106(5):415-421

Dispersal of root pathogens is a major concern in closed hydroponic cultures. To limit dispersal, ultraviolet (UV) disinfection technology has been used to remove pathogens but its effect on non-target bacterial populations is largely unknown. In this study, the circulating solution was disinfected with various UV doses (i.e., 19, 38, 59, 88mJcm^–2) before recirculation. At the beginning of the experiment, the hydroponic solution was inoculated with Pythium aphanidermatum at 6.7±1.5CFUmL^–1. Four months later the population density of P. aphanidermatum reached 1030CFUmL^–1 in the control and 1028, 970, 610, and 521CFUmL^–1 in the solutions treated by the above UV doses. In all UV-treated solutions, significant (P<0.05) reduction of both Pythium and bacterial populations was noted. For the former, its reduction did not result in decrease of Pythium root rot nor increase of tomato fruit yield. For the latter, its reduction showed a concomitant decrease of the populations in the rhizosphere. The bacterial populations in the rhizosphere were 6.77×10⁹CFUmg^–1 fresh roots at the beginning of the experiment and were 7.89×10⁸, 9.93×10⁷, 7.33×10⁷, and 3.51×10⁷CFUmg^–1 fresh roots at the end of the experiment in the control, UV38, UV59, and UV88 treatments, respectively. The bacterial density also decreased with time in the control (UV0) although at a low rate. The results suggest that the attempt to control Pythium root rot by UV irradiation of recirculating solutions to remove P. aphanidermatum also affects the non-target bacterial populations in the rhizosphere. The interaction between the target pathogen and non-target bacterial flora in UV-treated hydroponics needs further investigation.  相似文献   

扁穗牛鞭草组织浸出液对潜在混生种萌发及幼苗的影响     

杨春华  李向林  张新全  左艳春 《草业学报》2006,15(5):38-44

采用生物检测的方法研究了扁穗牛鞭草根、茎、叶水浸液对潜在混生种的化感作用。结果表明,扁穗牛鞭草根、茎、叶水浸液对牧草种子萌发的化感作用大体包括延迟和抑制萌发2种方式;不同浓度的化感物质对幼根和幼苗伸长的影响表现为促进、抑制或多种作用并存,0.100%和0.200%浓度的茎、叶水浸液使白三叶幼根扭曲畸变,0.200%浓度根水浸液使紫花苜蓿叶片变小皱缩。经初步试验表明,扁穗牛鞭草较理想的混生种是红三叶。  相似文献   

中药穴位注射对奶牛胎衣不下的疗效观察   总被引：1，自引：0，他引：1  

郭玉金  郭希萍  刘长松 《中国畜牧兽医》2006,33(11):104-105

奶牛产后胎衣不下对奶牛业造成极大的经济损失。本试验旨在研究一种简便易行、成本低、高效的非手术治疗方法。本试验应用当归及复方丹参注射液经百会穴及交巢穴注射,使胎衣排出率达100%,用药后的当年受孕牛占96.2%。可见,此方法可以有效治疗奶牛产后胎衣不下并能提高奶牛的当年受孕率。  相似文献   

2种保鲜方法对脐橙果实风味和色泽变化的影响   总被引：2，自引：0，他引：2  

郭琳琳  刘庆  伊华林 《果树学报》2007,24(6):792-795

以赣南纽荷尔脐橙冷藏和留树保鲜果实为材料,进行品质分析,并运用HPLC技术分析果皮与果肉的类胡萝卜素组成和色泽变化。结果表明,冷藏果实固酸比(17.08)比对照(21.36)降低了4.28;而留树保鲜果实固酸比增加到33.33,约为冷藏果实的2倍;冷藏果实在缺乏光照条件下仍可合成类胡萝卜素,尤其是β-隐黄质和玉米黄质,但是果皮偏黄色,可能是由类胡萝卜素的组成、比例及空间分布的改变引起的;留树保鲜类胡萝卜素的合成积累约为冷藏的1.5倍,果皮呈现鲜艳的橙色,是紫黄质和(9Z)-紫黄质大量积累的结果。  相似文献   

Cryopreservation of carnation (Dianthus caryophyllus L.) shoot tips by encapsulation-vitrification     

Adela Halmagyi  Constantin Deliu 《Scientia Horticulturae》2007

Shoot tips excised from in vitro cultured plants of Dianthus caryophyllus L. (cv. Pallas, cv. Pink Candy and cv. Wanessa) were successfully cryopreserved using an encapsulation-vitrification method. Shoot tips (2–3 mm in length) were encapsulated in sodium alginate, precultured on liquid Murashige and Skoog (1962) medium supplemented with various sucrose concentrations (0.25, 0.5, 0.75, 1.0 M) for 24 h or 48 h and dehydrated with the vitrification solution PVS2 (up to 4 h) at 24 °C or 0 °C prior to direct immersion in liquid nitrogen (−196 °C). A maximum of shoot regeneration from cryopreserved shoot tips was obtained with the following combinations: preculture in 0.5 M sucrose and 180 min dehydration treatment at 0 °C for cv. Pallas (60% shoot formation), or preculture in 0.75 M and 200 min dehydration at the same temperature for cv. Pink Candy (66.6% shoot formation) and cv. Wanessa (73% shoot formation).  相似文献   

Pretreatment of hypertonic saline attenuates the hepatic ischemia reperfusion injury induced by neutrophils     

KE Qing-hong  ZHENG Shu-sen  LIANG Ting-bo  XIE Hai-yang  XIA Wei-liang 《园艺学报》2007,23(7):1326-1330

AIM: To explore the effect of the pretreatment of hypertonic saline (HTS) in hepatic ischemia reperfusion (I/R) injury.METHODS: The rats were divided into sham group (sham group), ischemia reperfusion group (IR group) and pretreatment of hypertonic saline group (HTS group). Partial hepatic ischemia reperfusion model was used. The rats were sacrificed at the time of 1 h, 3 h, 6 h, 12 h and 24 h after reperfusion in each group, respectively. Blood samples were obtained to examine ALT. The expression of the CD11b/CD18 (Mac-1) on the neutrophils was analyzed by flow cytometry. RT-PCR and Western blotting were used to examine the expression of intercellular adhesion molecule-1 (ICAM-1) in livers and chromatometry was performed to detect the activity of myeloperoxidase (MPO) in livers. The morphology of hepatocytes and the structure of sinusoid were observed by histological examinations. RESULTS: ① HTS pretreatment decreased the level of ALT at the time points of 3 h, 6 h and 12 h after reperfusion (P<0.05). ② Mac-1 expression in HTS group was lower at 6 h and 12 h after reperfusion compared with IR group (P<0.05). ③ MPO activity in HTS group was lower at 6 h, 12 h and 24 h compared with IR group (P<0.05). ④ RT-PCR and Western blotting analysis indicated that the pretreatment of HTS inhibited the expression of ICAM-1 in livers after reperfusion. ⑤ Moderate hepatocyte swelling and few neutrophil infiltration were observed in HTS group.CONCLUSION: Pretreatment with HTS has the effect on hepatic ischemia reperfusion injury by inhibiting the expression of Mac-1 on circulating neutrophils and the expression of ICAM-1 in the liver.  相似文献   

蘑菇培养料加入864菌液发酵与二次发酵的效果比较   总被引：1，自引：0，他引：1  

江枝和 《中国食用菌》1998,17(3):38-38

通过加入８６４菌液发酵和二次发酵栽培蘑菇的试验,比较培养料中微生物群落、培养料成份及产菇量,说明加入８６４菌液发酵是代替二次发酵栽培蘑菇的较好方法。  相似文献   

二阶泛函微分方程周期解存在性的重合度方法     

马世旺  庾建设 《湖南农业大学学报(自然科学版)》1999,26(4)

利用 Ｍａｗ ｈｉｎ 的重合度理论，研究了二阶泛函微分方程周期解的存在性，并举例说明了其应用⒚  相似文献   

菊花无土栽培技术研究   总被引：11，自引：0，他引：11  

刘云  何书萱 《山西农业科学》1999,27(3):62-65

采用无土栽培技术，对９０余个品种的２６０余盆菊花进行了营养液配方及基质、栽培方式的试验研究，认为在太原市水质及气候条件下，菊花的无土栽培方式以虹吸式、半液式为宜，营养液配方采用３号配方、１号配方或朱士吾提出的通用配方略加调整。  相似文献   

输油管道仿真技术及其应用   总被引：2，自引：0，他引：2  

欧阳忠滨  吴长春  艾慕阳 《油气储运》2004,23(8):1-5

系统阐述了输油管道仿真软件的基本理论,即数学模型与数值解法.介绍了现代管道仿真技术及其发展趋势,列举了一些目前国际上比较通用的商业软件,给出了开发国内输油管道软件的建议.  相似文献