无核葡萄胚发育及早期离体培养的研究:Ⅲ.培养方式对离体胚发育的影响

对5个无核葡萄品种的试验表明,不同培养方式对离体胚发育的影响是很明显的,其中4个品种胚发育率液体培养高于固体培养,‘京早晶’在液体培养中胚发育率高达73.7%,是目前国内外胚发育率最高的报道;液体培养比固体培养胚的发育程度高,发育整齐,无畸形胚,易成苗.     

电超滤浸提土壤养分的研究 Ⅰ.石灰性土壤的电超滤特性

石灰性土壤的电超滤(EUF)特性主要是浸提时因需控制电流而必须大大降低电压。在一定范围内,降压程度与土壤 CaCO_3%有密切关系。控流限额愈低,电压需成比例地下降,但土壤EUF-值减小不多。电流控制在一定值时,离子的解吸总量亦为定值。控流主要控制了各石灰性土壤解吸/溶解份额特大的 Ca+Mg 量近于定值,对于含量小的其他养分离子则并无多大影响,仍可区辨各土壤间的差别。通过冬小麦盆栽试验和有关化学测试法等方面的相关研究,表明采用国际通用的5g 土样和控电流方法测定 EUF-K 和-P 等有效养分,对于石灰性土壤也是可行的,但其EUF-(Ca+Mg)值则毫无植物营养有效性的意义。土壤 EUF 值只是一种指数,并非真正的解吸离子量。石灰性土壤 EUF-K 值因浸提时降压控流而略低,80℃时5min 内解吸的钾不一定是非交换性钾。由于 Ca-P 和 CaCO_3在高温高电压时浸出较多,故石灰性土壤 EUF-P 和-(Ca+Mg)的80℃值/20℃值之比,与酸性土壤或非石灰性土壤相比要大得多。     

播量对水稻生长发育及干物质积累的影响

用盆栽方法进行播量对寒地水稻生长发育及干物质积累影响试验,结果表明:稀播的秧苗发根力强、分蘖多、茎基宽、充实度高。播量200g/m2的产量最高。     

“刘易斯—费景汉—拉尼斯”模型与二元结构下的乡镇企业发展

本文就“刘—费—拉”二元经济模型。提出我国乡镇企业发展模式，揭示其发展约束—金融市场缺憾，并就其发展前景作一初步探讨。     

Evaluation of Corn Gluten Feed as a Dietary Ingredient for Pond-Raised Channel Catfish Ictalurus punctatus

Abstract.— This study was conducted to evaluate corn gluten feed as an alternative feedstuff in the diet of pond-raised channel catfish Ictalurus punctatus . Three 32%-protein diets containing 0%, 25%, or 50% corn gluten feed were tested. Channel catfish fingerlings (average weight: 57 g/fish) were stocked into 15 0.04-ha ponds at a rate of 18,530 fish/ha. Five ponds were used for each dietary treatment. Fish were fed to satiation once daily for a 147-d growing period. No differences were observed in feed consumption, weight gain, feed conversion ratio, survival, or fillet protein concentration among fish fed the test diets. Fish fed diets containing 25% and 50% corn gluten feed exhibited a lower level of visceral fat and a higher carcass yield than fish fed the control diet without corn gluten feed. The diet containing 50% corn gluten feed resulted in a lower level of fillet fat and a higher level of moisture than the control diet. There were no visible differences in the coloration of skin or fillet of channel catfish fed diets with and without corn gluten feed. Results from this study indicated that channel catfish can efficiently utilize corn gluten feed at levels up to 50%n without adverse effect on feed palatability, weight gain, or feed efficiency. Corn gluten feed may be beneficial in reducing fattiness of channel catfish and improving carcass yield by reducing the digestible energy to protein ratio of the diet.     

广东山区开发的理论与实践：—广东山区开发理论与实践研讨会综述

本文述了“广东山区开发理论与实践研讨会”所达成共识的观点：广东山区开发具有重要的战略意义，广东山区开发必须走可持续肆展，农业产业化经营、工业化道路，同时必须搞好基础设施建设，组织好商品流通工作，优化资源配置。     

Investigation of Cervical Patency and Uterine Appearance in Domestic Cats by Fluoroscopy and Scintigraphy

The cervical patency of six domestic female cats was monitored under sedation by infusion of contrast medium (Omnipaque) into the cranial vagina during early oestrus, mid‐oestrus, late oestrus and interoestrus or a radiopharmaceutical (^99mTc‐HSA) during mid‐ and interoestrus in a non‐ovulatory oestrous cycle. The transport of the contrast medium or the radiopharmaceutical through the cervix and within the uterine horns was observed under fluoroscopy and with the aid of scintigraphy. In three of the queens, transcervical transport of contrast medium was demonstrated in all stages of oestrus, in one queen during mid‐oestrus, late oestrus and 1 day after oestrus, and in two queens only during late oestrus. The relations between the cervical patency to the contrast medium and the oestrous behaviour, cornification of the vaginal cells and the serum oestradiol‐17β concentration were evaluated, and a relationship was found between the cervical patency and the degree of vaginal cornification. Transcervical transport of the radiopharmaceutical was observed in three queens during mid‐oestrus. When the cervix was open, hysterography under a fluoroscope and hysteroscintigraphy were performed. The fluoroscopic and scintigraphic recordings revealed the patterns of the uterine contractions during oestrus in both ascending and descending directions, and the movement of the uterine contents back and forth between the uterine horns. The hysterograms were classified according to the shape of the uterine horns and the appearance of the endometrial lining. Spiral‐shaped uterine horns with a smooth inner contour were observed in two queens, and a corkscrew appearance with irregular filling defects in the uterine lumen was shown in two queens that had developed subclinical cystic endometrial hyperplasia. These findings demonstrated that fluids or particles deposited in the cranial vagina of the cat can be transported into the uterus during some stages of the oestrous cycle. The fluoroscopic and scintigraphic techniques developed in this study may be further modified to permit more detailed studies of uterine contractile patterns and sperm transport in the feline female reproductive tract. Hysterography proved useful to diagnose uterine disease. The information on cervical patency is of value also for the development of techniques for artificial insemination in this species, and should be studied also in the ovulatory cycle.     

污水污物潜水旋流泵性能及设计方法试验研究

对影响潜水旋流泵性能的6个主要过流件几何参数进行了试验研究，初步掌握了旋流泵叶轮及泵体主要几何尺寸对性能影响的规律。在分析16种优秀水力模型的基础上，计算出叶轮D2及b2函数回归方程式，并用设计实例进行检验，样机效率比国内外同类产品提高3％左右。     

Reproductive roles predict sexual dimorphism in internal and external morphology of lake whitefish,Coregonus clupeaformis

Abstract – The different reproductive roles of the sexes can predict the direction and magnitude of sexual dimorphism of external and internal morphology. Males should have enlarged structures that enhance the acquisition of mating opportunities, whereas females are predicted to have enlarged organs that are associated with the production of eggs. We tested these predictions in male and female lake whitefish, a species in which both sexes have similar overall body size and shape. After controlling for body size, male lake whitefish had significantly longer jaws and pectoral and pelvic fins, larger hearts, and more muscle than females. Sexual dimorphism in relative muscle mass may be one of the most fundamental morphological differences between males and females. Females had relatively heavier livers than males. Because the liver is important for the breakdown of fats and vitellogenesis, selection should favour an enlarged liver in females for the processing of energy and the production of large numbers of eggs.