利用桑树叶资源发展畜牧业生产的可行性分析

桑树适应性广 ,我国各地均有分布 ,有些地区大面积栽培 ,主要用于养蚕生产。桑树是目前木本叶用植物中产量最高的树种之一 ,比经人工改造的南方山原草地的单位载畜量提高 5倍左右。桑叶的营养成分高于一般牧草 ,是木本植物中含量较高的树种。其粗蛋白和氨基酸总量不及大豆粉高 ,但各种氨基酸比例趋向一致 ,桑叶作为畜禽饲料养分很全面。养禽畜试验表明 ,桑叶作饲料适口性好 ,无采食障碍 ,食用后具有很高的消化率 ,品质提高……。因此 ,利用桑叶作为畜牧业的饲料非常有潜力 ,开发前景广阔。     

植物多糖的研究与开发应用进展

植物多糖不仅具有免疫调节、降血糖、降血脂、抗氧化等生物活性,而且大多具有毒性较小的特点,在疾病预防及保健产品开发等方面具有广阔的应用前景。综述了近年来植物多糖的提取与分离纯化方法,多糖的结构鉴别技术以及在免疫调节、抗肿瘤、降血糖、降血脂、抗氧化、抗病毒等药理活性方面的研究与应用进展,并对桑叶多糖的研究与开发应用概况作了简要评述。     

Ralstonia solanacearum virulence in tomato seedlings inoculated by leaf clipping

Ralstonia solanacearum is a phytopathogenic bacterium that colonizes the xylem vessels of host plants leading to a lethal wilt disease. Although several studies have investigated the virulence of R. solanacearum on adult host plants, infection studies of this pathogen on the seedling stages of hosts are less common. In a preliminary observation, inoculation of R. solanacearum F1C1 on 6‐ to 7‐day‐old tomato seedlings by a simple leaf‐clip strategy resulted in a lethal pathogenic condition in seedlings that eventually killed these seedlings within a week post‐inoculation. This prompted testing of the effect of this inoculation technique in seedlings from different cultivars of tomato and similar results were obtained. Colonization and spread of the bacteria throughout the infected seedlings was demonstrated using gus‐tagged R. solanacearum F1C1. The same method of inoculating tomato seedlings was used with R. solanacearum GMI1000 and independent mutants of R. solanacearum GMI1000, deficient in the virulence genes hrpB, hrpG, phcA and gspD. Wildtype R. solanacearum GMI1000 was found to be virulent on tomato seedlings, whereas the mutants were found to be non‐virulent. This leaf‐clip technique, for inoculation of tomato seedlings, has the potential to be a valuable approach, saving time, space, labour and costs.     

天女木兰叶斑病病菌生物学特性研究

以天女木兰叶斑病病菌为试材,研究不同碳、氮源对天女木兰叶斑病病菌生长的影响;试验结果表明：适合菌丝生长碳源是乳糖与葡萄糖;适合菌丝生长的氮源是硝酸铵;最适合孢子萌发的碳源是葡萄糖;适合孢子萌发的氮源是硝酸铵;25益适宜菌丝的生长,适宜孢子萌发的温度是20~25益;全光适宜菌丝的生长和孢子萌发。适合菌丝的生长和孢子萌发PH8与PH7。     

Genetic variability within Phaeoisariopsis griseola from Central America and its implications for resistance breeding of common bean

The genetic and virulence variability of 112 isolates of Phaeoisariopsis griseola , collected from various locations in Central America, were studied using seven random amplified polymorphic DNA (RAPD) primers and 12 common-bean differential genotypes. Broad molecular diversity ( H  = 0·92) among isolates was found using RAPD markers. Fifty pathotypes were identified on 12 differential bean genotypes, 29 of which were represented by only one isolate. Only 18 pathotypes were found in two or more countries. Pathotype 63-63 was the most virulent and caused leaf spots on all 12 common-bean differential genotypes. Comparison of virulence phenotypes and RAPD profiles to known Andean P. griseola isolates confirmed that all isolates belonged to the Mesoamerican group. Pairwise comparison between individual RAPD loci showed that the majority were in gametic phase linkage disequilibrium, revealing that P. griseola maintains a genetic structure that is consistent with asexual reproduction. The molecular and virulence diversities of P. griseola isolates from Central America imply that using single resistance genes to manage angular leaf spot is inadequate and stacking resistance genes may be necessary to manage the disease effectively.     

竹叶提取物对奶牛瘤胃体外发酵参数及产气量的影响

本试验旨在研究竹叶提取物对奶牛瘤胃体外发酵参数及产气量的影响。试验选用健康、体况相近的荷斯坦奶牛用于瘤胃液的采集,以精粗比为4∶6的全混合日粮作为发酵底物。试验组分为6组,各组分别添加0(对照)、0.75、1.50、3.00、4.50、6.00 mg/g的竹叶提取物,每组6个重复,每个重复3个批次。体外发酵24 h后,记录产气量,测定瘤胃发酵参数。结果表明:1)各组的发酵液pH均无显著差异(P>0.05)。试验组的发酵液中氨态氮(NH_3-N)浓度均显著低于对照组(P<0.05),其中3.00和4.50 mg/g竹叶提取物组的发酵液中NH_3-N浓度显著低于其他各组(P<0.05)。试验组的发酵液中干物质消失率均显著高于对照组(P<0.05)。2) 4.50、6.00 mg/g竹叶提取物组的发酵液中总挥发性脂肪酸浓度显著高于其他各组(P <0. 05); 3. 00、4.50、6. 00 mg/g竹叶提取物组的发酵液中乙酸浓度显著高于其他各组(P <0. 05); 4. 50、6.00 mg/g竹叶提取物组的发酵液中丙酸浓度显著高于对照组(P <0. 05); 3. 00、4. 50、6. 00 mg/g竹叶提取物组的发酵液中丁酸浓度显著低于其他各组(P<0.05); 6.00 mg/g竹叶提取物组的发酵液中异戊酸浓度显著低于对照组(P<0.05)。各组的发酵液中异丁酸、戊酸浓度以及乙酸/丙酸均无显著差异(P>0.05)。3)试验组的体外发酵甲烷体积和甲烷含量均显著低于对照组(P<0.05)。各组的体外发酵产气量无显著差异(P> 0.05)。综上所述,体外条件下添加竹叶提取物在不影响瘤胃发酵模式的同时可以显著降低甲烷排放,其中添加4.50 mg/g竹叶提取物效果最佳。     

Response of Ugandan common bean varieties to Pseudocercospora griseola and Angular leaf spot disease development in varietal mixtures

Angular leaf spot (ALS) is one of the most economically important bean diseases in Africa. One promising control option for the disease is the use of mixtures of resistant and susceptible varieties. This research evaluated (1) the reaction of farmer preferred bean varieties to ALS in the screenhouse and on-station and (2) the effect of different spatial arrangements of resistant and susceptible bean varieties on ALS disease development. For the latter, five mixture combinations and two controls were laid out in a Randomized Complete Block Design having three replicates. Analysis of variance and least significant differences (LSDs) were used to compare disease levels in both studies above. Varietal screening showed significant differences in varietal reaction to ALS. Screenhouse disease scores ranged between 0 and 5, compared to 0.7–3.9 in the field. For the varietal mixture trial, the lowest disease levels and the highest mixture efficiencies were observed for the combination of equal proportions of the susceptible and resistant varieties randomly mixed (even mixture) prior to planting. We conclude that even mixtures reduce the amount of ALS disease that develops in the season.     

裂叶红麻的光合器官数量性状与麻皮产量相关性分析

对６个裂叶红麻品种（系）不同光合器官的数量性状与干皮产量作了相关分析。结果表明总叶数、７裂叶数及麻皮长和麻皮宽的光合器官之间及与干皮产量之间的相关都是显著的，而圆叶数、３裂叶数及５裂叶数与干皮产量相关不显著。总对数、７裂叶数及麻皮长的数量性状其广义和狭义遗传力都很低．表明主要光合器官的表现易受环境影响，注意选择圆叶数性状可能有助于培育高产品种。     

高温胁迫下AM真菌对牡丹叶片解剖结构和蒸腾特性的影响

作者研究了高温胁迫下丛枝菌根(arbuscular mycorrhizal,AM)真菌对盆栽牡丹幼苗叶片解剖结构和蒸腾特性的影响。结果表明,供试AM真菌摩西球囊霉(Glomus mosseae)和地表球囊霉(Glomus versiforme)均能侵染牡丹根系,其侵染率分别为47%和44%。接种AM真菌的比未接种对照(CK)植株的叶片细胞排列紧密,叶片厚度、栅栏组织和海棉组织厚度均表现为接种G.mosseae植株>接种G.versiforme植株>CK。在相同高温下接种AM真菌处理的牡丹叶片蒸腾速率、气孔导度和气孔开度均显著低于CK。AM真菌提高了牡丹植株的抗热性,这对于高温胁迫下保持和提高光合效率是十分重要的。其中接种G.mosseae处理的效果优于G.versiforme     

枸橼种质对柑橘溃疡病的抗性鉴定

柑橘溃疡病(Xanthomonas citri subsp. citri,Xcc)是严重阻碍柑橘产业发展的世界性检疫病害,防控困难,选育抗病品种为防治溃疡病的唯一有效办法。枸橼C-05是柑橘属独特的抗溃疡病种质,为抗性机理和抗病育种提供了种质基础。为了进一步评价枸橼C-05的抗性,另外收集了13份枸橼种质,对其进行溃疡病的离体和活体抗性评价。叶片形态学观察表明,14份枸橼种质存在较大的形态学差异。采用离体与活体注射接种不同浓度的柑橘溃疡病菌,根据叶片的感病症状、病斑周围黄色晕圈大小等典型溃疡病症状,综合评价枸橼类种质的抗病性。结果表明:枸橼种质之间对溃疡病的抗性存在极大差异,溃疡病的抗性评价综合病情指数显示枸橼C-05、园香橼、矮果香橼、美国枸橼、普通枸橼和印度大果综合病情指数较小,表现为极抗病或抗病,其他枸橼种质表现不同程度的感病性;枸橼种质的抗病或感病性与其叶片形态特征无关。枸橼C-05和5个抗病枸橼种质对柑橘溃疡病具有针对性的抗性,这对进一步研究抗病机理和抗病育种具有重要意义。