不同施氮量对皇竹草生长的影响

[目的]研究不同施氮量对皇竹草生物学性状及单株产量的影响。[方法]刈割后,测定不同氮施量的皇竹草生物学指标及单株鲜重。[结果]皇竹草的分蘖数、有效茎直径、叶片数、株高、节数及单株鲜重都随着施肥量的增加而明显提高。但是,当单穴施肥量超过40 g或45 g时,这些生物学性状会明显减少。[结论]45 g单穴施氮量为皇竹草最适生长肥料量,此时单株鲜重达到最大值,为640.73 g。     

皇竹草工业原料林丰产栽培技术研究

皇竹草不同密度、不同施肥量、肥料N、P、K不同配比正交试验结果表明:在土壤瘠薄的山地种植皇竹草,对密度因素而言,以每亩种植密度3000株的最佳,对施肥量而言,以每亩180 kg的为佳,对肥料N、P、K配比因素而言,以2∶1∶2的为最好,试验组合以Ⅲ-3-B为最优。从不同土壤栽培对比试验可以看出,皇竹草适应性很强,在农田、瘠薄的山地红、黄壤种植均能正常生长,但要获得高产,必须做到科学施肥。     

EM处理皇草饲喂肉牛效果初探

为提高皇草利用率，评价EM处理皇草饲喂肉牛效果，先后进行了60天饲养试验。饲养试验用改良公牛27头，按随机区组设计分为3组，各组牛口喂精料2kg，皇草自由采食，维生素A每天每头10000IU。试验结果表明，皇草经EM处理后，其营养物质提高，适口性改善，每100kg体重采食干物质量显著增加，EM、微贮、氨化分别为2．64、2．52、2．35kg，各组日增重分别为0．798、0．719、0．661kg，皇草利用率显著提高，EM处理效果在各项测定指标中最好。     

3种观赏草的持水性能

本研究以福建地区比较常见的3种观赏草旱伞草（Cyperus alternifolius）、狼尾草（Pennisetum alopecuroides）和麦冬（Ophiopogon japonicus）为研究对象，应用浸泡法分别测定3种观赏草根、茎、叶的持水量并进行分析。研究表明，3种观赏草的持水性能存在差异，其中狼尾草的持水性能最强。观赏草的各部位持水性同样存在差异，浸泡时间与持水率呈极显著正相关关系，与吸水速率呈极显著负相关关系（P<0.001）。3种观赏草均有良好的持水性能，对园林造景和生态保护具有积极的作用。     

Growth of Roots Emerged from Excised Phytomers of Three Gramineous Species under a Low Osmotic Potential

Abstract

The growth of crown and lateral roots emerged from the excised phytomers of pearl millet (Pennisetum typhoideum Rich.), barnyard millet (Echinochloa frumentacea Link.) and maize (Zea mays L.) was studied under normal and low osmotic potential conditions. The plants were grown in two solutions with osmotic potentials of –0.02 and –0.54 MPa for 6 days. The relative growth rate of the roots in total length (RGR_L) , was not affected by osmotic stress in pearl and barnyard millets, but that in stressed maize was reduced to 64% of the control. Similarly, the relative growth rate of the roots in dry weight (RGR_W), was not affected by osmotic stress in pearl and barnyard millets, but significantly reduced in maize. Osmotic stress increased the specific root length of the lateral roots in pearl and barnyard millets, but did not affect that of maize. The photosynthetic rate (Pr) in the two millets was decreased to ca. 60% of the control by the stress, and that in maize was reduced to 21%. Under the stress, Pr in the three species was limited mainly by low stomatal conductance, but no clear relationship was found between Pr and osmotic adjustment of the leaf. The relative water content of the leaf was lower in maize than in the two millets. The resistance to water flow through the phytomer (R) was significantly increased by osmotic stress in maize, but not significantly in the two millets. The mean root length (RL) was decreased by the stress in maize, but not in the two millets. The maintenance of RGR_L in the two millets was associated with sustained R, RL and also with the maintenance of Pr and allocation of assimilates to roots.     

Comparative performance of four multi-purpose trees associated with four grass species in the humid regions of Southern India

The results of a field trial conducted at the Livestock Research Station, Thiruvazhamkunnu, Kerala to study the compatibility of different components in a silvo-pastoral system revealed that growth and yield of fodder species were significantly influenced by the tree components only after tree canopy formation. The fodder species such as Pennisetum purpureum Schum., Panicum maximum Jacq., Brachiaria ruziziensis Griseb. and Euchlaena mexicana Schrad. grown in association with Casuarina equisetifolia J. R. & G. Forst. and Ailanthus malabarica DC recorded comparatively higher forage yield even after canopy formation. However, forage crops grown in combination with Acacia auriculiformis A. Cunn. ex Benth. and Leucaena leucocephala (Lam.) de Wit. registered relatively lower values for growth and yield. Increased light infiltration into the understorey due to the cladophyllous canopy can be attributed as reason for the higher fodder productivity under Casuarina. Due to the combination of crown size and shape, tree height and spacing the amount of light intercepted by Ailanthus also was very low. Among the four multi-purpose trees used, Acacia recorded the maximum growth rate followed by Casuarina, Ailanthus and Leucaena. Forage productivity of the four species was in the order: Pennisetum purpureum > Panicum maximum > Brachiaria ruziziensis > Euchlaena mexicana. Casuarina with Pennisetum/ Panicm were found to be optimal tree — forage combinations for silvo-pastoral systems.     

添加纤维素酶和乳酸菌对“桂牧1号”杂交狼尾草青贮品质的影响

为研究纤维素酶和乳酸菌单独添加、混合添加对“桂牧1号”杂交狼尾草青贮品质和营养价值的改善效果,将杂交狼尾草经全株收割、粉碎后,分别添加纤维素酶（CEL）、乳酸菌（LD1、LD2）、乳酸菌+纤维素酶（CEL+LD1 ～ LD2）,密封袋密封60 d后,测定饲料品质和营养成分。结果表明：纤维素酶组、LD2组青贮料pH含量和对照组差异不显著（P > 0.05）,纤维素酶+乳酸菌（CEL+LD1 ～ LD2）组青贮料pH分别为4.54、4.50,比对照组高。纤维素酶组及纤维素酶+乳酸菌组氨态氮含量比对照组含量分别低18.44%、26.95%、16.31%。LD2组青贮料中无丙酸、丁酸产生。杂交狼尾草青贮时单独添加纤维素酶,青贮饲料粗蛋白质（CP）含量较对照组高6.08%（P < 0.05）,酸性洗涤纤维（ADF）、中性洗涤纤维（NDF）分别低于对照组2.93%、4.81%（P < 0.05）,表明单独添加纤维素酶能够提高青贮品质。青贮料中添加乳酸菌益4-J1,可有效抑制丙酸、丁酸产生,对青贮品质有改善作用。 [关键词] 纤维素酶|乳酸菌|“桂牧1号”杂交狼尾草|青贮品质     

象草4CL基因片段的克隆及RNAi 表达载体构建

 象草是热带和亚热带地区广泛栽培的多年生资源植物。为探讨华南象草４-香豆酸：ＣｏＡ 连接酶（4CL）基因下调表达对木质素合成的影响,本研究设计１对特异引物,ＰＣＲ 扩增获得一段长为３７４ｂｐ的干扰片段。通过ＴＯＰＯ 克隆,将该片段克隆到载体ｐＣＲ ／ＧＷ／ＴＯＰＯ  ,构建了入门克隆载体ｐＥＮＴＲ-４CL;再经过ＬＲ 反应使ｐＥＮＴＲ-４CL上的干扰片段进入目的载体ｐＣＢ２００４Ｂ 上,形成表达载体ｐＣＢ２００４Ｂ-４CL,最后通过冻融法将其转入到根癌农杆菌ＥＨＡ１０５中。菌液ＰＣＲ 结果表明ＲＮＡｉ质粒已成功转入农杆菌,为进一步利用ＲＮＡｉ技术研究４CL基因的功能奠定了基础。