雷州半岛红树林盐土的某些理化性质   总被引：3，自引：0，他引：3  

廖金凤 《土壤》2004,36(5):561-564

红树林盐土是红树植被下的一类特殊土壤。雷州半岛红树林盐土各土层pH值为3.08 ~ 5.98,绝大多数低于4。土壤有机质平均含量为24.1 g/㎏,在土壤剖面中有机质含量分布没有规律性。土壤阳离子代换量为3.83 ~14.53 cmol/kg,平均6.94 cmo1/kg。土壤水溶性盐分7.6 ~ 42.1g/㎏,平均18.4 g/㎏,水溶性盐分有向下淋溶的趋势。土壤中<0.01 mm粒级含量一般>200 g/kg,土壤质地大多为中壤土类至中粘土类。  相似文献   

Metabolomics Tools Assisting Classic Screening Methods in Discovering New Antibiotics from Mangrove Actinomycetia in Leizhou Peninsula     

Qin-Pei Lu  Yong-Mei Huang  Shao-Wei Liu  Gang Wu  Qin Yang  Li-Fang Liu  Hai-Tao Zhang  Yi Qi  Ting Wang  Zhong-Ke Jiang  Jun-Jie Li  Hao Cai  Xiu-Jun Liu  Hui Luo  Cheng-Hang Sun 《Marine drugs》2021,19(12)

Mangrove actinomycetia are considered one of the promising sources for discovering novel biologically active compounds. Traditional bioactivity- and/or taxonomy-based methods are inefficient and usually result in the re-discovery of known metabolites. Thus, improving selection efficiency among strain candidates is of interest especially in the early stage of the antibiotic discovery program. In this study, an integrated strategy of combining phylogenetic data and bioactivity tests with a metabolomics-based dereplication approach was applied to fast track the selection process. A total of 521 actinomycetial strains affiliated to 40 genera in 23 families were isolated from 13 different mangrove soil samples by the culture-dependent method. A total of 179 strains affiliated to 40 different genera with a unique colony morphology were selected to evaluate antibacterial activity against 12 indicator bacteria. Of the 179 tested isolates, 47 showed activities against at least one of the tested pathogens. Analysis of 23 out of 47 active isolates using UPLC-HRMS-PCA revealed six outliers. Further analysis using the OPLS-DA model identified five compounds from two outliers contributing to the bioactivity against drug-sensitive A. baumannii. Molecular networking was used to determine the relationship of significant metabolites in six outliers and to find their potentially new congeners. Finally, two Streptomyces strains (M22, H37) producing potentially new compounds were rapidly prioritized on the basis of their distinct chemistry profiles, dereplication results, and antibacterial activities, as well as taxonomical information. Two new trioxacarcins with keto-reduced trioxacarcinose B, gutingimycin B (16) and trioxacarcin G (20), together with known gutingimycin (12), were isolated from the scale-up fermentation broth of Streptomyces sp. M22. Our study demonstrated that metabolomics tools could greatly assist classic antibiotic discovery methods in strain prioritization to improve efficiency in discovering novel antibiotics from those highly productive and rich diversity ecosystems.  相似文献   

雷州半岛干旱特征、成因与治理对策   总被引：10，自引：0，他引：10  

杜尧东  刘锦銮  宋丽莉  钱光明 《干旱地区农业研究》2004,22(1):28-31

研究了雷州半岛干旱的特征,从气候因素和人为因素两方面分析了干旱的形成原因,根据生态学和系统工程学原理,提出了实施土、水、植、气四位一体的干旱综合治理对策。  相似文献   

不同性别雷州黑鸭屠宰性能及肉品质的测定     

马猛  汤绮明  苏瑛  陈琦  张辉腾 《中国畜牧兽医》2013,40(9):124-127

随机选取60只健康无病的300日龄雷州黑羽鸭,公、母各半,进行屠宰试验及肉品质分析。结果表明,公鸭全净膛率和瘦肉率显著高于母鸭(P<0.05);母鸭腹脂率和皮脂率极显著高于公鸭(P<0.01),而胸肌率却极显著低于公鸭(P<0.01);公、母鸭胸肌肉色(L、a、b值)、腿肌蒸煮损失率和胸肌嫩度均存在极显著差异(P<0.01);母鸭胸肌脂肪含量显著高于公鸭(P<0.05),胸肌和腿肌粗蛋白质含量极显著高于公鸭(P<0.01)。提示,雷州黑鸭屠宰率和全净膛率都较高,母鸭肉质和肌肉营养成分高于公鸭,胸肌优于腿肌。  相似文献   

Analysis of the Relativity Between the Nutrient Content of Pasturage and the Relative Frequency of Feeding in Leizhou Goat Grazing on Natural Grassland     

WANG Zhi-jing  WU Zheng-min  ZHUANG Gui-feng  WU Hao-hao  LI Zi-cai  CHEN Pu  WANG Ya-yun  HU Zeng-ming  YIN Fu-quan 《中国畜牧兽医》2017,44(10):2931-2936

In order to understand the correlation between the grazing behavior of Leizhou goat and natural meadow nutrient content, the pasture behavior of Leizhou goats were tracked and recorded for 7 consecutive days, then the grass samples were collected according to the feeding conditions. The results showed that the relative feeding frequency of Pharbitis nil, Eleusine indica, Isachne globosa and Imperata cylindrica for Leizhou goats were 55.51%,28.70%, 8.13% and 1.18%,respectively.Among the determinated pastures, the contents of dry matter (DM)(P < 0.05),neutral detergent fiber (NDF)(P < 0.05) and acid detergent fiber (ADF) in Imperata cylindrica were the highest; Bidens pilosa had the highest contents of crude protein (CP)(P < 0.05),calcium (Ca)(P < 0.05),phosphorus (P)(P < 0.05), crude ash (ASH) and crude fat (EE);The crude fiber (CF) content in Isachne globosa was the highest. The correlation coefficient between the content of grass CP,CF,ADF,NDF,Ca as well as P and relative feeding frequency was 0.793(P < 0.05),-0.813(P < 0.05), -0.328(P > 0.05), -0.945(P < 0.01),0.804(P < 0.05),0.735(P < 0.05),respectively. In conclusion, there were significant positive correlation between the relative feeding frequency of Leizhou goats and the cotent of CP, Ca and P in native grass, and had a significant or extremely significant negtive correlation with CF and NDF content.  相似文献   

雷州半岛雷电活动特征及其对农业生产的影响和防御对策     

叶明  李杏  吴芳华  柳志江 《安徽农业科学》2010,38(22):11806-11807,11820

分析雷州半岛雷电活动规律,结合当地农业生产的特点,提出科学、有针对性的雷电防御对策,为农业安全生产提供有效的帮助。  相似文献   

雷州黄牛GAD1和GHR基因的多态性分析     

魏伍川  邓家琪  王文怡 《广东农业科学》2010,37(3):10-12

利用PCR-RFLP技术分析了61头雷州黄牛的谷氨酸脱羧酶1(GAD1)基因3′端片段和生长激素受体(GHR)基因第10外显子片段的多态性。结果表明,雷州黄牛群体在该2个基因位点均存在核苷酸变异多态性。在GAD1基因3′-UTR区,雷州黄牛的等位基因以B型占绝对优势,基因频率为0.9344,等位基因A的频率为0.0656;基因型频率以BB型占优势,占到牛个体数的87%。等位基因和基因型频率分布态势与国外品种海福特牛和西门塔尔牛相同,基因和基因型频率大小也与海福特牛和西门塔尔牛相近。在GHR基因第10外显子位点,雷州黄牛的等位基因频率与南阳黄牛和利木赞接近,而基因型频率差异较大,雷州黄牛以杂合AB基因型占绝对优势,达到0.95。这可能是取样或基因型影响出栏牛的收购等级,AB基因型牛可能具有较高等级的原因所致。  相似文献   

雷州半岛玄武岩母质土壤剖面稀土元素分布及其与常量元素、粒度的关系   总被引：1，自引：0，他引：1  

张立娟  李徐生  李德成 《土壤学报》2011,48(1):1-9

对雷州半岛玄武岩母质土壤剖面稀土元素地球化学特征进行了研究,结果表明:土壤剖面中稀土元素的分布既受母岩的控制,又叠加了风化成壤作用的影响,∑REE和δEu对母岩有明显的继承性,风化成壤作用则导致REE在剖面上部富集以及土壤中Ce的显著正异常,并造成轻、重稀土之间发生一定的分馏(以轻稀土富集为主要特征),但轻稀土或重稀土内部未出现明显的分异;∑REE与Fe2O3含量呈极显著负相关,可能与风化成土过程中铁氧化物结晶程度提高,富含REE的无定形铁含量降低有关;∑REE与P2O5、MnO则呈极显著正相关,应当是由于剖面中含有较多的赋存REE的磷酸盐矿物和锰氧化物矿物所致;∑REE与黏粒组分(尤其是<1μm的组分)呈极显著正相关,表明风化成壤过程中黏土矿物含量增加所导致的对REE的吸附效应是造成该区REE富集的重要原因,其中黏粒对轻稀土元素的吸附更为明显。  相似文献   

雷州半岛甘蔗植期的分析   总被引：1，自引：0，他引：1  

蔡仁林 《中国糖料》2006,(4):44-45,54

分析了雷州半岛甘蔗不同植期的优缺点,提出了该蔗区不同植期所占配比的建议:以冬植蔗为主,占30%～40%,稳定宿根蔗面积40%,合理搭配春植蔗10%～15%,秋植蔗占5%;抓好夏植蔗的试验、示范、推广工作。  相似文献   

雷州半岛提高糖业综合竞争力的研究   总被引：3，自引：0，他引：3  

戚荣  江永  杨俊贤  吴文龙  张允远 《中国糖料》2007,(3):35-39,47

对雷州半岛糖业进行深入、全面的调查,分析其发展的优势与劣势,提出解决问题的措施和方法,为企业提高综合竞争力提出建设性意见,旨在促进雷州半岛糖业的可持续发展。  相似文献