病毒对苹果生理生化及生长结果的影响

对感染混合潜隐性病毒的富士、金冠苹果树进行了生理生化及生长结果指标检测,结果发现,与品种脱毒树相比,在生理生化方面：病毒树内含物质ＧＡ３、ＣＴＫ、ＩＡＡ、ＲＮＡ 和蛋白质含量降低,ＤＮＡ含量升高;总光合强度及净光合强度下降,呼吸强度升高。在生长结果方面：病毒树的树高、干径、冠径和一年生枝长度减弱,坐果率和产量降低;果实可溶性固形物、总糖、还原糖及Ｃａ、Ｆｅ、Ｍｎ 含量下降,果肉硬度降低     

黄霉素对异育银鲫生长和粗蛋白质消化率影响

试验一采用平均体重为6.5g的异育银鲫鱼种315尾,在基础饲料(对照组)中分别添加4、8m g/kg黄霉素,经饲养21d后,各组异育银鲫增重率分别为49.4%、53.1%、56.9%,其中添加8m g/kg黄霉素显著提高了增重率(P<0.05);试验二采用平均体重为100g的鲫鱼45尾,以三氧化二铬作指示剂进行消化试验,各组干物质消化率分别为64.4%、66.8%、66.5%,粗蛋白质消化率分别为79.5%、82.5%、83.3%,添加4、8m g/kg黄霉素均显著提高了粗蛋白质消化率(P<0.05),有提高干物质消化率的趋势(P<0.10)。     

大旱之年,海南瓜果菜喜获丰收

6月7日海南省农业厅举行新闻发布会：从去年11月15日至今年5月31日，全省共种植冬季瓜菜面积164．5万亩，比去年同期增长了7．9％；瓜果菜出岛总量为343．92万吨，总产值72．7亿元，同比分别增长17．43％、11．07％。其中，瓜菜出岛量195．11万吨，产值36．15亿元，比去年同期分别增长11．68％、9．47％。     

“冬芽定量”对“金魁”猕猴桃生产影响研究

冬芽管理是猕猴桃树体管理的重要技术环节。适宜的高质量冬芽保留,可较准确预测果实数量,提高果实大小一致性。本研究在江西省猕猴桃主栽区奉新县的赤岸镇山口果园,以10年生“金魁”猕猴桃为研究对象,研究冬芽保留数量对果实生产的影响。试验设置4个处理,每个处理以贝为单位（bay, 四根水泥柱围成的面积,18 m2）,每处理冬芽保留量处理1约为400个、处理2约为450个、处理3约为500个、处理4约为550个,每处理3次重复。结果表明：1）4个处理的冬芽保留量不影响新梢萌发量;2）处理1成花量显著大于其他处理;处理1和2,花芽/冬芽显著大于处理3和4;3）单位新梢上成花量,处理2显著大于其他3个处理;4）4个处理中,挂果量和产量没有显著差异,冬芽保留处理1的果实更大,更均匀,小果和超大果比例更小,即单位面积能生产出更多符合市场需求的优质商品果。综合分析,在试验区立地条件和现有管理水平下,冬芽保留量在约450个,有利于提高猕猴桃种植者的经济效益。     

促性腺激素释放激素类似物和左旋多巴对秀丽高原鳅体长、体重和卵巢发育的影响

秀丽高原鳅(Triplophysa venusta)为云南特有鱼类,为阐明促性腺激素释放激素类似物和左旋多巴对秀丽高原鳅体长、体重和卵巢发育的影响,本实验采用生物化学等技术,研究了促性腺激素释放激素类似物(GnRH-a,0.1 mg/kg/2周,共注射4次)和左旋多巴(L-dopa,100 mg/kg/2周,共注射4次...     

贻贝雌性生殖系统的组织学研究

从组织学方面研究了贻贝雌性生殖系统的构造。卵巢壁薄、由外膜和内生殖上皮构成。外膜主要由结缔组绢,意志支上皮和薄层肌肉构成。由其产生的许多延伸物伸入卵巢中把卵巢分成一个个不规则小区。内生死上皮不断增殖平生生殖带,其中含卵原细胞阁阶段雌性生殖细胞和滤泡细胞。卵原细胞较小,核圆形,核仁不明显。初级卵母细胞体积增加,核呈生发泡状,核仁１个,明显。次级卵母细胞卵圆形、细胞体积更大,核仁１个,十分明显。当卵母     

Release of critically endangered crocodiles: Development and application of a food web approach to determine suitability of release habitat

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The replacement of fish meal with fermented soya bean meal or soya bean meal in the diet of Pacific white shrimp (Litopenaeus vannamei)

The present study evaluated the effects of replacing fish meal (FM) with soya bean meal (SM) or fermented soya bean meal (FSM) on growth, nutrient utilization, digestive enzyme activity and intestinal histology of Pacific white shrimp. The basal diet (control) contained 18% FM, and then, FM in basal diet was replaced by 1/6 (17%), 1/3 (33%) and 1/2 (50%) by the inclusion of SM and FSM, referring to SM17, SM33, SM50, FSM17, FSM33 and FSM50 respectively. The shrimp (3.0 g) were fed one of the seven diets for 8 weeks. The results showed that the control group had the highest weight gain (WG) (653.8%) and the lowest feed conversion ratio (FCR) (1.61). SM33, SM50 and FSM50 groups showed significantly lower WG, crude protein (CP) digestibility, hepatopancreatic protease, amylase activity and higher FCR than the control (p < .05). The villi height of SM33, SM50 and FSM50 groups and the intestinal wall thickness of SM groups and FSM50 group were significantly lower than those of the control (p < .05). In conclusion, fish meal (18%) in white shrimp diet could be replaced by 1/6 (17%) and 1/3 (33%) with SM and FSM respectively. Fermented soya bean meal could replace more fish meal than soya bean meal did.     

Cork and guar gum supplementation enhanced the buoyancy of faeces,and protease supplementation alleviated the negative effects of dietary cork on growth and intestinal health of tilapia,Oreochromis niloticus × O. aureus

To evaluate the effects of dietary cork, protease and guar gum on growth, intestinal health and faecal floatability of tilapia, fine or coarse particle cork (0.45–0.60 mm, 0.60–0.83 mm) was included in diets at 0 (control), 20 g/kg, 30 g/kg and 40 g/kg, and then, 0.175 g/kg protease (P) and 3 g/kg guar gum (G) were supplemented to the 40 g/kg coarse particle diet individually or in combination (P + G). Tilapia with an initial body weight of 15.0 ± 0.5 g were fed one of the 10 diets for 60 days. The results showed that weight gain (WG), apparent digestibility coefficient (ADC) of dry matter (DM) and crude protein (CP), intestinal evacuation ratio, intestinal digestive enzyme activity (IDE) and villus height decreased, and floating faeces ratio increased with the increasing cork level in diets. At the same supplementation level, coarse particle groups showed significantly higher floating faecal ratio than fine particle groups (p < .05). Dietary protease increased the WG, ADC of DM, IDE and villus height (p < .05), and guar gum increased floating faecal ratio when compared to 40 g/kg coarse particle group (p < .05). However, the ADC of DM, IDE and villus height of protease group were still inferior to those of control group (p < .05). In conclusion, dietary cork increased the floating faeces ratio, and the coarse particles produced more floating faeces than fine particles. Moreover, the supplementation of guar gum in cork‐supplemented diet further increased the floating faeces ratio. However, dietary cork negatively affected the growth performance of tilapia, which could be partially alleviated by the supplementation of protease.     

中国杉木林的生态系统服务价值评估

采用森林生态系统定位研究网络台站多年连续观测数据和森林资源清查数据及公共数据对中国杉木林生态服务价值物质量和价值量进行详细评估.结果表明:1994-1998年和1999-2003年期间,中国杉木林生态服务总价值分别为15 643.82亿元·a-1和17 043.86亿元·a-1,单位面积价值分别为12.62万元.hm-2 a-1和12.34万元·hm-2a-1,其中在所评估的六大服务项中各服务项的价值所占比例次序为涵养水源>积累营养物质>固碳释氧>生物多样性保护>净化大气环境>固土保肥.