苜蓿对奶牛业的发展有重要作用

苜蓿(Medicigosativa)是一种优质高产,各种家畜都喜食的多年生豆科牧草,它是世界上广泛种植的优良牧草,也是我国种植面积最大,分布最广的人工牧草,以“牧草之王”而著称。苜蓿不仅产量高,而且草质优良,各种营养成分齐全,营养价值高,尤其是粗蛋白质、维生素和无机盐含量丰富,干物质中粗蛋白质含量15%～25%。优质苜蓿干草的粗蛋白含量通常在18%以上(风干基础),高于几乎所有的禾本科牧草、籽实类能量饲料和秸秆,是奶牛良好的蛋白质来源。青饲或青贮饲喂奶牛可增加产奶量,无论是青饲、青贮或调制干草,均可与精饲料媲美。而且种植苜蓿在改土肥田…     

饲料中抗营养因子--单宁的含量分析方法

针对近年来单宁在动物营养上的最新研究成果,本文重点阐述了饲料中缩合单宁、可水解单宁和总酚类化合物的分析方法。旨在为更好地利用含单宁饲料提供参考。     

品种与冬季覆盖对狗牙根耐寒性和根茎水分含量的影响

在温带，草坪管理者利用狗牙根建植草坪主要关心其越冬率。由于狗牙根对初冬低温很敏感，直到仲冬其抗寒性才能达到最大。因此利用防寒覆盖的管理可以减轻冻害，并能促进休眠后的生长。本项研究在田间进行，历时３年。每年１２月初用粘胶纤维聚脂覆盖草坪，５月末搞通上覆盖物。本文探讨了覆盖对狗牙根耐寒性和根茎水分含量的影响，并对８个选育品种的耐寒性差异进行了评定。用电解质渗漏法和２，３，５－三苯四唑氯（ＴＴＣ）还原法     

Growth and the composition and transport of carbohydrate in compatible and incompatible peach/plum grafts

The growth of scions and rootstocks of compatible (Prunus persica L. Batsch cv. Springtime/Prunus cerasifera L. Ehrh. cv. myrobolan P2032) and incompatible (Prunus persica L. Batsch cv. Springtime/Prunus cerasifera L. Ehrh. cv. myrobolan P18) peach/plum grafts were compared. The composition of soluble carbohydrates in phloem and cortical tissues of both peach/plum grafts and ungrafted plums and the translocation of these compounds across the union of grafted plants were examined. Sorbitol and sucrose were the dominant sugars in the phloem and cortical tissues of plum. A cyanogenic glycoside, prunasin, was present in peach tissues in amounts equivalent to those of sorbitol or sucrose, whereas only small amounts of prunasin were detected in plum tissues. The concentration of prunasin was significantly higher in the phloem of the P18 rootstock of the incompatible graft. Sorbitol was the only sugar significantly depleted in rootstock tissues of the incompatible graft when the first foliar symptoms of graft incompatibility became evident. Translocation studies with 1-(14)C-deoxyglucose showed that the relative distribution of radioactivity across the graft union was similar in both compatible and incompatible grafts. However, the total amount of radioactivity translocated across the incompatible graft was less than one-third of that translocated across the compatible graft. The results are consistent with the hypothesis of a progressive poisoning of the root system in the incompatible graft by a compound synthesized in peach foliage. The role of prunasin as a possible candidate is discussed.