葡萄离体培养中胚状体发生的研究Ⅰ.胚状体发生的组织细胞学观察

以葡萄（ＶｉｔｉｓｖｉｎｉｆｅｒａＬ．）的花药和花丝为实验材料，观察了葡萄离体培养中胚状体的发生发育过程．结果表明：（１）葡萄的花药和花丝经诱导都可形成胚性和非胚性两类不同的愈伤组织，与外植体来源无关，胚状体经胚性愈伤组织产生．（２）胚状体多起源于胚性愈伤组织表层或表层以下的单个细胞，这些细胞核大，细胞质浓，染色深，在表层者易于脱落而处于单个离散状态，它们的第一次分裂有均等分裂，也有不等分裂，经２细胞、３细胞、多细胞原胚等阶段发育为成熟的胚状体．（３）葡萄胚状体具有与双子叶植物合子胚相似的发育过程

THE EFFECT OF THROXINE ON THE HEPATIC LDL RECEPTOR IN GOLDEN HAMSTERS

The purpose was to study the effect of throxine on serum lipids and LDL receptor,30 male Golden hamsters were divided into 2 groups,the control and treatment group.The hamsters in the control group were fed with ordinary diets plus cholesterol(0.12%),the hamsters in treatment group were fed with ordinary diets,cholesterol(0.12%)plus throxine (0.10%).All animals were fed for 5 weeks.The results indicated as follows:the serum TC,TG,LDL C,VLDL C,were decreased very significantly in treatment group ( p <0.01),while HDL C was increased lightly ( p >0.05),kd of 125 I LDL binding to hepatic LDL receptor in two groups has no obvious difference,while the number of hepatic LDL receptor was increased significantly in the treatment group ( p <0.01).The results of the present study suggest that lipid lowering effect of throxine is intimately associated with the elevation of hepatic LDL receptors.