发根农杆菌介导的白花草木樨毛状根转化体系的建立

白花草木樨（Melilotus albus Medic.ex Desr.）是草木樨最常见的栽培用种之一，具有较强的抗逆性和固氮能力。为了开发一套高效的草木樨转化体系，本研究以白花草木樨为材料，以结瘤基因MaROP6为目的基因，建立了发根农杆菌（Agrobacterium rhizogenes）介导的高效白花草木樨毛状根转化体系。结果表明：利用该方法可以在两周左右获得毛状根，其发生率可达78%，MaROP6基因的毛状根转化率可达70.8%。qRT-PCR鉴定结果表明，MaROP6转基因毛状根的平均相对表达量为对照的36.87倍。毛状根转化体系的建立为白花草木樨基因功能的验证奠定了基础。     

Effects of dietary vitamin C on growth,antioxidant activity,and immunity in ricefield eel (Monopterus albus)

A 10-week feeding trial aimed to investigate the effects of dietary vitamin C (l -ascorbic acid) on growth, antioxidant activity, and immunity in ricefield eel, Monopterus albus. Six diets were formulated with different levels of vitamin C supplementation (0.1, 17.5, 34.8, 68.6, 139.7, and 278.5 mg/kg). The results indicated that the weight gain (WG) of the M. albus fed the diets with vitamin C was remarkably higher than that of the M. albus fed the control diet (p < .05), and the quadratic analysis showed an optimal vitamin C level of 80.66 mg/kg. Compared with the control group, serum lysozyme activities, the complement pathway, red blood cell counts, white blood cell counts, immunoglobulin M, and phagocytosis percentage were significantly increased (p < .05) in the treatment groups, and superoxide dismutase activity, serum glucose, and malondialdehyde content were significantly decreased (p < .05) in the treatment groups. The challenge trial with Aeromonas hydrophila showed that the M. albus fed the diets with vitamin C had remarkably reduced cumulative mortality compared with those fed the control diet (p < .05), and mortality in the 68.60 mg/kg diet group was the lowest. Based on WG, the optimal vitamin C supplementation level for M. albus was estimated to be 80.66 mg/kg.     

不同饲养密度对鳝苗的生长性能研究

本试验以水蚯蚓作为饵料,研究了60日龄鳝苗不同密度下的增重、存活率及饵料转化率。试验分3个密度组,其对应的密度分别为2000尾/m2、3000尾/m2、4000尾/m2,每个密度组设4个平行;试验时间为30d。结果表明:在本试验条件下,3个密度组鳝苗的增重率、存活率随着密度的增大呈下降趋势,而其饵料系数随着密度增大而增大;其中在4000尾/m2的密度下,鳝苗的增重率最低,仅为1.12±0.13;饵料系数最高,为5.71±1.37。     

投喂频率对黄鳝幼鱼摄食、生长及饵料利用效率的影响

研究了不同投喂频率对黄鳝(Monopterus albus)摄食率、特定生长率、饵料效率、体重分化、鱼体组成的影响。试验共设5组不同投喂频率(2、3、4、12次/d和24次/d),每组3个重复,试验持续30 d。结果显示:投喂频率4次/d组的摄食率显著高于其它各组(P<0.05);特定生长率有不同程度增高,4次/d组达到最高(P<0.05);饲料利用效率4次/d组显著高于2次/d组(P<0.05),与其它组无显著性差异(P>0.05);随着投喂频率增加,各试验组组内个体体重无显著差异(P>0.05),黄鳝的规格趋于整齐。试验各组黄鳝的鱼体成分无显著性差异(P>0.05);饵料蛋白质和能量的表观消化率,在4次/d时达到最高(P<0.05)。试验表明:黄鳝的生长受投喂频率的影响,每天投喂4次是黄鳝养殖的最佳投喂频率。     

黄鳝人工感染温和气单胞菌的组织病理学研究

对黄鳝(Monopterus albus)人工感染温和气单胞菌(Aeromonas sobria)的临床症状和病理变化进行了观察。结果显示,感染后12~36h为死亡高峰期,其感染症状与自然发病的黄鳝相似。染病黄鳝的肝脏、肠道和肾脏的病理变化明显,肝细胞变性,肠绒毛脱落,肾小球结构消失并充满大量红细胞;感染后9~27h,肝细胞索排列紊乱,肝细胞肿大并空泡化;感染后3~30h,小肠绒毛脱落,固有层淋巴小结增生,粘膜下层、肌层、浆膜层红细胞增多;感染后3~21h,肾小管上皮细胞肿胀,严重颗粒变性,肾小球上皮细胞坏死;感染后21~30h,肌纤维细胞坏死,大量炎性细胞浸润。     

Strong heritability across years and sites for pod wall proportion and specific weight in Lupinus albus and genotypic correlation with other pod and seed attributes

Thinner pod walls might contribute to increased yield potential and adaptation of lupins. Fourteen autumn‐sown genotypes of Lupinus albus L. were evaluated over 2 years at four sites in southern Chile. Pod wall proportion (PWP), pod wall specific weight (WSW) and five other pod‐related characters were measured to estimate their genetic variation, heritability across years and sites, and genotypic and phenotypic correlations among the characters. Ranges for PWP and pod WSW were 22.9−43.1% and 16.4−37.4 mg/cm², respectively. PWP in cultivated L. albus was similar to that reported in L. angustifolius; however, specific weight was substantially lower. Highly significant genotypic effects were found for both characters. Broad sense heritabilities were high for PWP (0.63) and moderate for pod WSW (0.46). These characters were significantly correlated, more so genotypically (r_g = 0.67) than phenotypically (r_ph = 0.36). Selection for low PWP should lead to lower pod wall thickness or density, both of which contribute to pod WSW. Nevertheless, selection for pod WSW could achieve further reductions, particularly if practised among low PWP materials.     

花魔芋和白魔芋褐变机理及褐变抑制研究

该文通过研究花魔芋和白魔芋球茎中酚类物质含量、多酚氧化酶(Polyphenol Oxidase, PPO)活性、褐变底物和干燥脱水过程中褐变的机理，探讨了无公害酶促褐变抑制剂植酸、抗坏血酸、柠檬酸、L-半胱氨酸对魔芋褐变的抑制效果。结果表明：从11月至次年1月，白魔芋球茎的总酚含量始终高于花魔芋，花魔芋的PPO活力始终强于白魔芋，白魔芋的褐变强度始终弱于花魔芋的褐变强度，褐变强度跟魔芋球茎PPO活力呈正相关。引起魔芋褐变的主要底物可能是多巴胺。引起白魔芋和花魔芋褐变的酶均为多酚氧化酶。对白魔芋采用0.01% L-半胱氨酸单因子抑制剂浸泡5 min，并在60℃下烘烤，所得白魔芋干片颜色白，效果最好。对花魔芋采用0.15% L-半胱氨酸+1%柠檬酸+1%植酸+0.01%抗坏血酸组合抑制剂浸泡5 min，并在60℃下烘烤，所得魔芋干片颜色白，效果最好。     

黄鳝的营养需求研究及其配合饲料质量评价

文章概述了黄鳝(Monopteras albus)的营养需求研究及其配合饲料质量评价的进展,主要包括黄鳝的蛋白质、脂肪、碳水化合物、维生素等营养需求研究及其配合饲料质量评价体系,并对今后开展黄鳝营养需求研究及构建完善的黄鳝配合饲料质量评价体系提出了若干建议。     

黄鳝线粒体DNA的提取及其酶切分析

用碱裂解法从黄鳝肝脏组织中提取线粒体DNA,并对提取的线粒体DNA纯度、完整性进行了检测.结果表明,其紫外吸收比值为OD26/280在1.72～1.96之间,纯度较高,琼脂糖凝胶电泳表明提取线粒体的完整性好;用EcoR Ⅰ和HindⅢ对黄鳝线粒体DNA进行酶切,用琼脂糖凝胶电泳检测,均能检测出两套不同的酶切片段,证明黄鳝线粒体DNA存在多态性.     

白浆土上草木樨的磷肥效应初报

在白浆土上对草木樨进行了三年(1984—1986)磷肥试验。以亩施N素1kg作底肥,设每亩施磷肥(以P_2O_5计)0、1、3、6、9kg各处理组。施磷各处理组三年平均增产分别为13.7、33.7、41.0和45.0％,均达到极显著(α=0.01)水准。草木樨的品质也随施磷(P_2O_5)量的变化而变化。草木樨各处理组的粗蛋白含量分别增加11.3％、19.3％、8.7％和8.0％。经回归和相关分析,草木樨产量(鲜重与干重)和品质的磷肥效应函数方程分别为 y鲜=1125.7+133.74x-9.11x~2; y干=270.06+32.12x-2.19x~2; y蛋白=15.078+1.733x-0.255x~2。相关皆极显著,|r|>r_(0.01)。根据草木樨干草和磷肥的价格比值,核算出最佳经济施磷(P_2O_5)量为每亩3.36kg;粗蛋白含量最高的施磷(P_2O_5)量为每亩3.4kg。在当前价格条件下,两者巧合。按P_2O_5每亩3kg将磷肥分层施用(1/3作种肥,2/3施于15～20cm深处),可促使草木樨根系密集层下移,根瘤增加,有利于改良土壤,绿色体产量也有所增加。