不同种源毛竹叶表叶绿素浓度动态

通过对 9个毛竹种源叶表叶绿素 a、b及总量浓度的分析 ,结果表明各种源叶表叶绿素 a浓度和总浓度都以北带 >南带 >中带 ,而叶绿素 b的浓度为南带 >北带 >中带 ,不同种源叶表叶绿素浓度达到高峰值的时间不同 ;各月份叶表叶绿素 a/b的比值变化与叶绿素各组分浓度的变化相反 ,总体上呈现出“高 -低 -高”的变化趋势 .叶表叶绿素浓度与叶绿素含量、叶片含水率、枝条含水率、胸径等因子相关显著 ,叶表叶绿素 a/b与种源的经度显著相关 ,叶表叶绿素各组分之间达极显著相关     

枣疯病的发生及综合防治技术

枣疯病又名丛枝病,是枣树的一种毁灭性病害.主要寄主为枣和酸枣.症状表现为丛枝、黄化、花器返祖、花梗明显伸长,萼片和花瓣反常生长变为小叶,小枝叶丛生,冬后不落;病枝丛生、纤细、节间缩短叶小而黄萎.根部发病后,萌生的根蘖也呈稠密的丛枝状,后期根皮腐烂死亡.树干上原是休眠期的隐芽大量萌发,抽生黄绿细小的枝丛.病枝上的果实着色浅,组织松散萎缩变小,果面凹凸不平,呈花脸状.枣疯病发生一般是部分枝条和根蘖上表现症状,后逐渐扩展至全树.幼树从染病到死亡约1～3 a,大树染病约4～6 a逐渐死亡.     

一圃三级小麦种子生产技术及其应用

根据我国育种者种子及良种繁育工作的现状,借鉴农业发达国家禾谷类作物种子生产方法和我国良种繁育的先进技术,结合我场多年来小麦种子的生产实践,将循环选择技术路线与重复繁殖技术路线有机地结合在一起,研究总结出一圃三级小麦种子生产技术。该技术可使小麦种子的生产周期缩短两年,解决了我国现阶段育种者种子在小麦育种繁育中存在的问题,具有省工、省时、提高繁殖系数,易于操作的优点,并可保持优良品种的典型性和纯度,有     

有效利用土壤磷的小麦种质筛选方法研究

利用由不同地点采集的土壤样品布置了9次土培试验, 对437份不同小麦品种 在不同有效磷含量土壤中的磷营养特性表现进行了较全面的鉴定。 发现, 施磷处理和减 磷处理土壤有效磷含量的差距即选择压力是土培试验鉴定成败的关键因素。 施磷处理的土 壤有效磷含量为24 mg/kg左右, 减磷处理的土壤有效磷含量为8 mg/kg左右是利用     

带遗传标记的玉米基因雄性不育的发现及遗传和利用研究

1992年在玉米族远缘杂交组合3402F3(丹340×403-2)中首次发现带标记性状的基因雄性不育(GMS)材料。 遗传分析结果表明, 不育性受一对隐性基因控制。 当不育株(A)与可育株(B)进行兄妹交, 育性分离比例接近1∶1; 而可育株(B)自交的后代, 可育株与不育株的分离比例为3∶1。 连锁遗传分析结果证明, 不育基因(ms°)与标记性状     

GIS技术在水土保持初设中的应用--以四川省遂宁市玉丰小流域为例

介绍了在四川省遂宁市市中区玉丰小流域的水土保持初设中 ,运用地理信息系统 (GIS)软件Ar cView进行了流域空间分析、获取水保初计数据、绘制和打印所需图版以及系统演示的应用方法 ,并探讨了地理信息系统与水土保持体系的相互关系     

黄土丘陵沟壑区多尺度地貌单元输沙能力及水沙关系

以黄土丘陵沟壑区裴家峁沟为原型观测流域,利用流域内相互嵌套的全坡面径流场、水文站网等观测设施,定量研究黄土丘陵沟壑区不同空间尺度地貌单元水沙关系和输沙能力特征。结果表明:1)坡面尺度地貌单元的径流深和输沙模数在多年平均时间尺度上均大于流域尺度地貌单元。当地貌单元空间尺度达到流域尺度时,多年平均径流深随着流域尺度增加而增加,输沙模数与流域面积之间存在着负相关关系。但在次降雨条件下,不同空间尺度地貌单元径流深和输沙模数峰值可能出现在全坡面、桥沟一支沟、桥沟或裴家峁沟。2)不同空间尺度地貌单元水流输沙能力随着空间尺度的增大而减少,相对于裴家峁沟,全坡面径流场、桥沟一支沟和桥沟的单位水流功率含沙量分别是裴家峁沟的186、77和58倍。3)不同空间尺度地貌单元径流量与输沙模数的水沙关系表现出较好的线性关系,且径流量与输沙模数关系随着空间尺度增加更为密切,但随着空间尺度增加,径流量和输沙模数的水沙关系曲线斜率急剧减小。研究成果可为水土流失空间尺度效应及尺度转换的研究提供科学依据。     

Improved Information Value Model and Its Application in the Spatial Prediction of Landslides

Information Value Model is used frequently in domestic landslide hazard zonation prediction, which plays a very important role for land-use planning especially in mountain area. Through theoretical analysis, the prerequisite of Information Value Model which should be used with influence-factors independent from each other is studied. Factor Analysis is adopted to evaluate and eliminate the influence of correlation between influence-factors in spatial prediction of landslides which are showed through case study. Relationships between landslides and influence-factors are studied based on a certain watershed in which the Information Value Model and Factor Analysis are applied. The probability of landslides changes regularly with the influence-factors, and based on which a method for the discretization of influence-factors is advised. The distribution of landslide susceptibility of above watershed is calculated and validated based on the area-ratio index with landslides occurring in nearly 5 years, which proves the credibility of Information Value Model.     

Chemical compositions and insecticidal effects of essential oils isolated from Achillea gypsicola, Satureja hortensis, Origanum acutidens and Hypericum scabrum against broadbean weevil (Bruchus dentipes)

The essential oils of aerial parts of Achillea gypsicola Hub.-Mor., Hypericum scabrum L., Satureja hortensis L., and Origanum acutidens (Hand.-Mazz.) Letswaart were analyzed in this study by GC and GC–MS and their oils were tested for toxicity against broadbean weevil (Bruchus dentipes). A. gypsicola oil contained camphor (40.17%), 1,8-cineole (22.01%), piperitone (11.29%), borneol (9.50%) and α-terpineol (1.56%) as major components. A total of 74 components were identified by GC–MS in H. scabrum oil, including α-pinene (9.26%), terpinen-4-ol (5.12%), camphor (5.94%), δ-cadinene (4.52%), pulegone (4.45%), γ-muurolene (4.12%), pinocarvone (3.97%) and β-caryophyllene (3.42%) as predominant components. The essential oils of O. acutidens and S. hortensis were characterized by high contents of carvacrol (86.99% and 55.74%), γ-terpinene (0.71% and 20.94%), p-cymene (1.95% and 12.30%), α-terpinene (0.13% and 2.04%) and β-caryophyllene (1.30% and 1.08%). All of the essential oils were toxic to adults of B. dentipes and insect mortality increased with increasing concentration of each oil. The oils (20 μl dose) brought about 100% mortality in 36 h. Although desirable insecticidal activities against the pest were achieved with the oils from all four plant species, S. hortensis and O. acutidens oils were more effective, particularly after 6 h of treatment. The current results concluded that the essential oils, in particular O. acutidens and S. hortensis oils, may be used as potential botanical insecticides against B. dentipes.